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Properties and uses of Glycols CONTENTS PROPERTIES AND USES OF GLYCOLS COMBINED PROPERTY TABLE SOME COMMERCIAL USES Ethylene Glycol . Diethylene Glycol . . Triethylene Glycol. Tetraethylene Glycol. Propylene Glycol Dipropylene Glycol Tripropylene Glycol . .. CHEMISTRY OF THE GLYCOLS PHYSICAL PROPERTIES Solubility........................................ Hygroscopicity............................. Vapor Pressure And Boiling Point Viscosity Freezing Point Specific Heat Density Surface Tension Flammability Flefractive Index TOXICOLOGICAL CONSIDERATIONS............................... STORAGE ANALYTICAL METHODS APPENDIX 'CP*'Gt-T '956 1961 DOW >MiCAl ;:vphny 1 2 3 3 3 4 4 4 5 5 6 9 9 12 17 26 32 33 35 43 43 44 45 47 51 55 PROPERTIES AND USES OF Glycols are aliphatic organic compounds having two hydroxyl groups per molecule. The glycols resemble water in that they are essentially clear, colorless liquids with prac tically no odor. However, they are heavier and more viscous than water at any given temperature and their boiling points are much higher. Many of the uses for the glycols depend on the fact that they are excellent solvents for many organic compounds and are com pletely water soluble. Since they can under go chemical reactions on one or both hy droxyl groups, they are important as chem ical intermediates. The wide range of practical applications for the glycols accounts for their great indus trial importance. They are found in such widely diverse products as dynamite, sham poos, cigarettes, printing ink, antifreeze formulations, and glue. It is hoped that the data contained in this booklet will assist you in developing further products and im proving present ones. Seven glycols are discussed in this book let, but The Dow Chemical Company's inter est in this type of compound does not end here. Dow also produces a series of poly ethylene and polypropylene glycols, and welcomes inquiries on these or any other glycol derivatives which may be of interest to you. I \/ V1 L I f \ I Cj SEVEN GLYCOLS ARE DISCUSSED IN THIS BOOK *1Z.C0/. d a is i Physical UJ S-. properties m O So -3 a >o of FUJ(3 ui O 5 UJ 2* 8 25 ui (j 2 UJ Z g., |8 pUJ UJ 25 30 >0 0>--I ca.co UJ 1 0 o5 gu o 5 UzJ 3-1 >0 Q.O 05 0 2 GLYCOLS H ST0278375 FORMULA CjHiOj C<H 10O3 CaH uOa CaHieOs C 3 H8O2 C4H14O3 CHio04 MOLECULAR WEIGHT 62.1 106.1 150.2 1 *4.2 76.1 134.2 192.3 BOILING POINT* AT 760 mm Hg F 387.1 472.6 545.9 597.2 369.0 447.8 514.4 BOILING POINT* AT 760 mm Hg C 197.3 244.8 288 327 187.2 231.0 268.0 VAPOR PRESSURE* AT 77 F (25 C ) mm Hg 0.12 <0.01 <0.01 <0.01 0.22 0.03 <0.01 DENSITY AT 77 F (25 C ) 1.110 1.113 1.119 1.120 1.033 1.023 1.016 AT 140F (60C ) 1.085 1 088 1.092 1.092 1.007 0.996 0.992 POUNDS PER GALLON AT 77F (25C ) 9.26 929 9.34 9.34 8.62 8.54 8.51 FREEZING POINT. "F 8 17 19 22 Supercools Supercools Supercools POUR POINT. F - -65 -73 -42 -71 -38 -42 VISCOSITY IN CENTIPOISES AT 77 F (25C ) 16.5 28.2 37.3 44.6 44.0 74.1 56.2 AT 140F (60C ) 4.68 6.99 8.77 10.2 8.50 11.1 9.80 SURFACE TENSION AT 77F (25C ) DYNES/CM 47 44 45 45 36 33 34 REFRACTIVE INDEX AT 77 F (25C ) 1.430 1.446 1.454 1.457 1.431 1.439 1 442 SPECIFIC HEAT AT 77= F (25C ) B.T.U./LB./0F 0.58 0.55 0.53 0.52 0.60 0.58 0.51 FLASH POINT. F (C.O.C.)t 240 280 320 365 215 260 285 FIRE POINT. F (C.O.C.)t 245 290 330 375 220 260 310 I Note These properties are laboratory resuits on pure compounds or typical of the product, but should not oe confused with, or regarded as specifications Pure Compound r Available in Industrial and USP Grades SOME COMMERCIAL USES OF DOW GLYCOLS ETHYLENE GLYCOL Many of the present uses for ethylene glycol are based on its properties as a freezing point depressant, but this compound is also valuable in numerous applications which depend upon one or more additional proper ties. The ease with which it reacts with other chemical intermediates plus its solvent, lubricant, plasticizing, and hygroscopic properties--all are likewise responsible for its popularity as an industrial raw material. One of the major applications for ethylene glycol is as the prime ingredient of perma nent-type automotive antifreeze formula tions. It is also employed as an antifreeze agent in de-icing formulations for aircraft and automatic fire-sprinkler systems. In corporated in latex paint, glass cleaners, dyes, waxes and other products damaged by freezing, ethylene glycol gives depend able cold weather protection. Ethylene glycol is also used as a solvent for stains, dyes and resins and is a mutual solvent or coupling agent in inks, soluble oils, hydraulic fluids and textile-processing chemicals. The chemical reactivity of ethylene glycol is used in the production of an extensive series of esters. One of the more important esters is ethylene glycol dinitrate, an essen tial component of low-freezing gelatin dyna mites. Another group of important glycolderived products is the alkyd resins, which are used in paints, enamels and varnishes. A synthetic rubber with high resistance to chemicals, petroleum products and abrasion plus high tensile strength is ob tained by reacting ethylene glycol and other glycols with adipic acid followed by crosslinking with diisocyanates. Ethylene glycol is permitted in various indirect additive food uses under paragraphs 121.2514; 121.2526; 121.2559; 121.2519; 121.2520; 121.2522; 121.2548; 121.2576. 121.2569 of the Food Additive Regulations under the Federal Food. Drug and Cos metic Act. Polyester resins, prepared by reacting ethylene glycol with polybasic acids, rep resent still another failly of highly impor tant glycol-derived products. The uses for polyester resins are extremely varied. They are employed in molding boat hulls, for pre paring sheet and board used by the build ing industry for roofing, fencing, flashing, copings, cornices, gutters and down spouts. in the manufacture of automobile and airplane bodies and components; and for molding luggage, motor housings, pipes, tanks, ducts, dies, and a variety of house hold furniture and appliances. The polyester produced from ethylene glycol and terephthalic acid is used to produce packaging films as well as a very useful and popular textile fiber. Further information concerning the manufacture and uses of these products may be found in the Dow booklet, "Polyester Resins ", which is available upon request Because of its hygroscopic properties and compatibility, ethylene glycol functions ef fectively as a plasticizer for cellophane. It has also proven to be an excellent and eco nomical mold lubricant in manufacturing heavy asphalt objects, such as burial vaults Ethylene glycol finds additional use as an intermediate to the electrolyte in dry capa citors and as a solvent and coupling agent in numerous other applications. Because they have properties similar to those of ethylene glycol, many of the higher glycols also find use in these same applica tions. In each instance the exact range of properties which the particular application demands will determine which glycol can be used most advantageously. DIETHYLENE GLYCOL Diethylene glycol is similartoethyleneglycol in many respects but has a higher boiling point, viscosity and specific gravity --as might be predicted from its higher molecular weight. Its properties are sufficiently different from those of ethylene glycol to make it a more desirable material in many applications. S I U^ / b J / b 3 The affinity of diethylene glycol for water makes it an excellent material for dehydrat ing natural gas Drying this gas eliminates freezing of moisture in transmission lines and the formation of hydrocarbon hydrates which foul instruments and reduce the ca pacity of the lines Diethylene glycol is also employed as a humectant in the foundry sand used for magnesium molding. Less water is necessary to make the treated sand workable and as a result there is less mag nesium-water reaction to cause imperfect castings. Diethylene glycol is completely miscible with water yet dissolves many organic chemicals. This property makes it suitable as a solvent and coupling agent in textile lubricants, cutting oils, drycleaning soaps and hand soaps. It is also a good solvent for many dyes and for the resins in the steamset inks used in modern high-speed print ing presses. Diethylene glycol has been widely ac cepted as a plasticizer and softener for paper, cellophane, glue. cork, and numerous other materials. Its high boiling point, low volatility, hygroscopicity and wide range of compatibility all play a part in its selection for this purpose. Diethylene glycol is also valuable as an intermediate in the produc tion of plasticizers for these and other applications. Diethylene glycol is permitted in indirect food use under paragraphs 121.2514; 121.2519: 121.2520; 121.2526; 121.2534; 121.2548; 121.2550; 121.2554; 121.2559; 121.2569 and 121.2576 of the Food Additive Regulations under the Federal Food. Drug and Cosmetic Act TRIETHYLENE GLYCOL Being less volatile than either ethylene glycol or diethylene glycol, triethylene glycol is suitable for many applications in which these other materials will not perform sat isfactorily Its high boiling point and excel lent solubility properties, coupled with low volatility and low toxicity have led to its use as a high-boiling solvent and plasti cizer. Triethylene glycol is especially effective as a plasticizer in products made from ground cork held together by a binder. Un less the binder is plasticized, the product will be brittle and. therefore, weak. Trieth ylene glycol not only imparts the required resiliency, but also permits longer retention of the desired properties than do the lowerboiling glycols. Triethylene glycol likewise shows utility as a plasticizer in many glues and resins and, in addition, is a valuable intermediate in the production of other plasticizers. Triethylene glycol is receiving increasing attention as a dehumidifymg agent for air and natural gas. Its superiority over other products in these applications stems from its hygroscopicity and higher boiling point. Triethylene g,FwJl is also incorporated as a resin solvent into steam-set printing inks. Many of the resins used in these inks are soluble in Triethylene Glycol but unaffected by mixtures of glycol with water Triethylene glycol is permitted in indirect food uses under paragraphs 121.2507; 121.2511; 121.2514, 121.2520; 121 2526; 121.2531; 121.2543; 121.2548; 121 2550; 121.2559; 121.2567 of the Food Additive Regulations under the Federal Food, Drug and Cosmetic Act. and other petitions are pending. TETRAETHYLENE GLYCOL Tetraethylene glycol is of special interest as a plasticizer and solvent where a high boiling point and low volatility are important. It is completely miscible with water and a wide range of organic solvents, but has only a very slight affinity for certain aliphatic hydrocarbons --a fact which may be used to advantage in some applications The producers of textile lubricants and formulations, in which water soluble and insoluble compounds must be mixed, have found tetraethylene glycol an effective coupling agent. It may also be reacted with fatty acids to produce emulsifiers useful in the textile and agricultural chemical fields. Tetraethylene glycol is also a suitable plasticizer for cork products, glues, and similar products in which a long shelf life is highly desirable. It may also be reacted with dibasic acids to produce a series of plasti cizers having a wide range of usefulness. PROPYLENE GLYCOL Propylene glycol is unique among the glycols in that its very low toxicity permits it to be taken internally. Because of this fact, Dow offers propylene glycol in two grades -- Propylene Glycol, U.S.P. for foods, pharma ceuticals, cosmetics and other applications involving possible ingestion or absorption through the skin, and Propylene glycol. Industrial for other uses. In common with the other glycols, propylene glycol is odor less and colorless, and has a wide range of solvency for organic materials, plus being completely water soluble. It is permissible to use propylene glycol as a direct or indirect food additive under 4 O' cc o. paragraphs 121 101, 121 102, 121 1122; 1212514, 1212519: 1212520, 1212522, 1212526, 1212534; 121 2548, 1212550, 1212551, 1212559; 121,2562; 121.2576 of the Food Additive Regulations under the Federal Food. Drug and Cosmetic Act and by the Meat Inspection Division of the U.S. Department of Agriculture for several uses. Propylene glycol, U.S.P is an important solvent for aromatics in the flavor con centrate industry, enabling manufacturers to produce low-cost flavor concentrates of high quality. It is also an excellent wetting agent for natural gums, greatly simplifying the compounding of citrus and other emul sified flavors. Propylene glycol. U.S.P. finds additional use as a solvent in elixirs and pharmaceutical preparations containing some water-soluble ingredients, and as a solvent and coupling agent in the formula tion of sun screen lotion, shampoos, shav ing creams and other similar products. Cer tain esters of propylene glycol such as propylene glycol monostearate, are also popular as emulsifiers in cosmetic and phar maceutical creams. Propylene Glycol. Industrial, is an im portant intermediate in the production of alkyd resins used in paints and varnishes. When reacted with dibasic acids, styrene or vinyltoluene, and other glycols, pro pylene glycol. Industrial forms a series of polyester resins which are increasing in im portance as laminating, coating and potting resins (see p. 3). Propylene Glycol. U.S.P. is also valuable as a low temperature heat-transfer medium in brewing and dairy cooling systems and in other refrigeration equipment having cooling coils which are in direct contact with beverages and liquid foods. In aqueous solution it displays excellent antifreeze properties. Used in hydraulic fluids. Propylene Glycol. Industrial functions as a solvent and coupl ing agent and inhibits the rubber swelling caused by other components of the fluid. Propylene glycol is also valuable as a humectant and preservative in tobacco, a foam stabilizer in shaving creams, a solvent for printing inks, and a solvent and coupling agent in many other applications. Further information concerning the use of this product in foods, pharmaceuticals, and cosmetics may be found in the bulletin, "Dow Propylene Glycol, U.S.P.."' available upon request. of use are comparable. However, its greater solvency for certain materials, coupled with a higher surface tension ana viscosity, makes it of interest in certain applications for which the other glycols are not so well suited The great solvency of dipropylene glycol for castor oil indicates its usefulness as a component of hydraulic brake-fluid formu lations. while its affinity for certain other oils has likewise led to its use in cutting oils, textile lubricants and industrial soaps. Dipropylene glycol is permitted as an in direct additive under paragraphs 121.2520. 121 2526. 121 2531. 121.2557, 121.2571. 121.2576. 121.2569 of the Food Additive Regulations under the Federal Food, Drug and Cosmetic Act. TRIPROPYLENE GLYCOL Tripropylene glycol is an excellent solvent in many applications where other glycols fail to give satisfactory results. Its ability to solubilize printing-ink resins is especially marked; so much so that it finds its way into creams designed to remove ink stains from the hands. A combination of water solubility and good solvent power for many organic compounds plus low volatility and high boil ing point also has led to its use by formulators of textile soaps and lubricants, cutting-oil concentrates and many similar products. DIPROPYLENE GLYCOL Dipropylene glycol is similar to the other glycols in general properties and its fields 5 0 /- 0 1. 6 U ..1 CD CHEMISTRY OF THE GLYCOLS The formulas of the GLYCOLS discussed in this booklet are: ETHYLENE GLYCOL CHz--OH 1 CHi--OH DIETHYLENE GLYCOL CHj-CHj-OH ''''CHj-CHj-OH TRIETHYLENE GLYCOL CHj--0--CHj--CHi--OH 1 CHj--0--CHj--CH2--OH 6/.G0/.2UJ.S TETRAETHYLENE GLYCOL CHi--CHj--0--CHj--CH2--OH / 0 OH 2--CHj- 0--CHj-CHj-OH PROPYLENE GLYCOL OH OH 11 CHj-CH-- CHj DIPROPYLENE GLYCOL OH OH 11 CHj--CH--CHr--O--CHj-CH-- CHj* TRIPROPYLENE GLYCOL O| H C| Hs OI H CHj-CH-CHj-O-CHj-CH-O-CHj- CH-CHj* And Other Isomers 6 The chemistry of the glycols centers on the two hydroxyl (OH) groups which char acterize them as glycols. Glycols are there fore intermediate in their properties between the alcohols with their single hydroxyl group and glycerine with its three hydroxyl groups Likewise, the solubility characteristics of the glycols tend to be intermediate between those of the alcohols and glycerine. Like glycerine, glycols are normally quite stable in air under the usual conditions of storage At high temperatures they tend to oxidize in air, giving rise to a wide variety of oxidation products such as aldehydes and acids. This oxidation can be practically elimi nated by the use of stabilizers so that the glycols may be used as heat transfer media at relatively high temperatures Under suitable dehydrating conditions, glycols can be made to split out water in these three ways: 1 One molecule of water from one molecule of glycol to form aldehydes CHj-OH I ---------- - CHj-CHO + H20 CH2-OH ETHYLENE GLYCOL---------- > ACETALDEHYDE + WATER 2 One molecule of water from two molecules of glycol to form a polyglycol OH 2iH OH CH2-CH OH / o + H2O CH CH2-OH ETHYLENE GLYCOL---------- * DIETHYLENE GLYCOL + WATER 3 Two molecules of water from two molecules of glycol to form cyclic ethers. CH2-OH 2I CH2-OH 0 /\ CH 2 CH2 + 2H20 CH2 CH2 V ETHYLENE GLYCOL DIOXANE + WATER This reaction can be carried out stepwise, diethylene glycol being the intermediate product. 7 Glycols, like alcohols, react with hydrogen halides (HC1. etc ) or with phosphorous halides (PCb. etc.) to replace one or both of the hydroxyls with halogen CH2--OH CH2--OH + HCI---------- > I + HrO CHr-OH CHr--Cl ETHYLENE GLYCOL + HYDROGEN CHLORIDE ETHYLENE CHLOROHYDRIN + WATER CHr--OH CHr-Cl 1 + 2HCI----- -----* 1 CHr--Cl 01 1 XO ETHYLENE GLYCOL + HYDROGEN CHLORIDE ETHYLENE + WATER DICHLORIDE 4 The hydrogens In either or both of the hydroxyl groups can be replaced by an alkali metal 5either by direct reaction or by splitting out water from the corresponding alkali metal hy droxide CH2-0H 21 + 2Na CHr-OH ETHYLENE GLYCOL + SODIUM CHr-ONa 2 1 + Hr CHr--OH ETHYLENE GLYCOL MONOSODIUM DERIVATIVE + HYDROGEN CH2-OH I + NaOH CHr-OH CHr--ONa I + HrO CHr-OH ETHYLENE GLYCOL SODIUM HYDROXIDE ETHYLENE GLYCOL + WATER MONOSODIUM DERIVATIVE Glycols readily form mono- and diesters by reaction with acids, acid halides or acid anhydrides. CHr-OH CHr-- OOCCHr I + CHrCOOH----------- -I + HrO CHr-OH CHr-OH ETHYLENE GLYCOL + ACETIC ACID-----------> GLYCOL MONOACETATE + WATER CHr--OH CHr--OOCCHr I + 2CH3COOH----------- I + 2HrO CHr--OH CHr--OOCCHr ETHYLENE GLYCOL + ACETIC ACID----------- GLYCOL DIACETATE + WATER 6 1 NO CO CO CO 8 PHYSICAL PROPERTIES OF GLYCOLS STn ? 7G3 0 2 SOLUBILITY The glycols discussed here possess the property common to all low-molecularweight alcohols of being soluble in all pro portions in water In addition, many waterimmiscible materials can be carried into clear water solutions by means of the coupling action of the mutually-soluble glycols. As a general rule, propylene glycol is a better solvent for oils and organic chemicals than ethylene glycol. The polyethylene and polypropylene glycols show increased sol vency over the monoglycols. Tripropylene glycol, for example, has the most extensive solvent properties of the entire group. This relationship is well demonstrated by Figure 1. which illustrates the relative sol vent properties of glycols for a number of oils and other organic substances. Saturated hydrocarbon oils are virtually insoluble in these glycols. The ester or acid type oils and gums are soluble to some ex tent in all the glycols but are most soluble in tripropylene glycol. Aromatic compounds in general have ap preciable solubility in the glycols, while alcohols and aromatic hydroxy compounds, such as phenols and resorcinol, are readily soluble and most are miscible in all pro portions. The effect of glycols on rubber and syn thetic rubber is shown in Figure 2. A value of more than 0.2% shows definite action of the glycol on the rubber Any value of 0.2% or less indicates that solvent action is ques tionable. Although the glycols became dis colored through contact with GN-427T1, there appeared to be no effect on the flex ibility or strength of any of the rubber samples. Ethyl cellulose and cellulose acetate are completely insoluble in all glycols, as shown by Figure 3. Cellulose nitrate swells in ethylene glycol and propylene glycol and shows distinct solubility in the polyglycols. Small amounts of ethylene, polyethylene or propylene glycol can be tolerated in clear ethyl cellulose and cellulose nitrate films. Slightly larger amounts produce hazy or opaque films. Large amounts of dipropylene glycol are compatible in all three cellulose films. Cellulose acetate shows compatibility for substantial quantities of all glycols. 9 SOLUBILITIES OF MATERIALS IIM GLYCOLS (Per Cent By Weight) FIGURE 1 S Completely Soluble 1 Insoluble < = Less Than > = Greater Than ETHYLENE GLYCOL OIETHYL ENE GLYCOL TRIETHYLENE GLYCOL TETRAETHYLENE GLYCOL PROPYLENE GLYCOL 01PROPYL- ENE GLYCOL TRIPROPYL- ENE GLYCOL Benzene Carbon Tetrachloride * Oibutyf Phtbalate Dichloroethy! Ether Diethanolamine * 00WAN0L 1 PM 'Glycol Ether DOWANOL* DPM 'Glycol Ether Ethyl Alcohol Ethyl Ether Methyl Alcohol Methyl Isobutyl Carbinol Methyl Isobutyl Ketone Monochlorobenzene* Monoethanolamme* ortho-Oichlorobenzene * Perchloroethylene* Phenol * Styrene* Toluene Urea Castor Oil Coconut Oil Cottonseed Oil Hydrous Wool Fat Lard Oil Linseed Oil Oitiaca Oil Olive Oil Pine Oil Soya Bean Oil Sperm Oil Tall Oil Tung Oil Turkey Red Oil Paraffin Oil SAE No 10 Oil VMP Naphtha Animal Glue (Oryl Dextnn Gum Damar Kaun Gum Sudan III Shellac 5.7 6.2 0.5 10.6 S S S S 8.2 S S 12 5.7 S 4.5 0.7 S 3.4 2.9 48 1 1 1 <0.5 1 1 <1 1 S 1 1 <1 1 <1 1 1 <1 <0.5 <1 <0.5 <05 <05 <0.5 31 3 26.2 10.6 S S S S S 16.3 S S s s s 48.4 10.7 S 36 17.2 30 <0.5 1 1 <0.5 1 1 <1 1 S 1 1 <1 1 <1 * 1 1 <t <05 <1 <05 <05 <05 <0.5 Product of The Dow Chemical Company '"Forms stable emulsion from this concentration to 100% "Becomes too viscous to stir beyond 16% 10 S 33.6 16.5 S S S s s 16.9 S S S S S S 15.0 S s 248 37 <0.5 1 1 <0.5 1 1 <1 1 S 1 1 <1 1 1** 1 1 <1 <05 <1 <0.5 <05 <0.5 <0.5 S 62 S S S S S S 20 S S S S s s 19.0 S S 89 28 <1 <1 <1 <1 <1 <1 <1 <1 S <1 <1 <1 <1 1** <1 <1 1 <1 <1 <1 >16*** <1 <1 19.2 23.4 8.1 37.1 S S s s s s s s 22.5 S 19.4 14.5 s 15 12.3 29 0.8 1 1 <0.5 1 1 <1 1 S 1 1 <1 1 <1** 1 1 1 <05 <1 <05 <5 <05 <0.5 S s s s s s s s s s s s s s s s s s s 12 s 1 1 <0.5 1 14 <1 0.7 S 1 1 S 1 3** 1 1 10 <0.5 <1 <0.5 < .5 <05 <0.5 S S s s s s s s s s s s s s s s s s s 10 s 3 <1 <1 <1 25 <1 1.5 s <1 <1 S <1 4** <1 <1 14 <1 <1 <1 >16*** <1 <1 F M P .m / n i 1 fe FIGURE 2 EFFECT OF VARIOUS GLYCOLS ON SYNTHETIC RUBBER SAMPLES RESULTS REPORTED> AS ?/0 VOLUME ANDJ& WEIGHT INCREASE GLYCOL ETHYLENE OlETHYLENE TRIETHYLENE PROPYLENE OIPROPYLENE ETHYLENE OlETHYLENE TRIETHYLENE PROPYLENE OIPROPYLENE GN-427T1 GRS-53115T FA-THIOKOl % VOL % WT. % VOL WT. % VOL % WT. 3 DAYS IMMERSION -.2 -2 -.1 -.5 -.12 -2 - 1 - 5 - 1 - 1 - 1 -5 -2 - 2 1 -3 - 1 -2 0 -5 .5 3 .5 3 3 2 0 I 0 -1 [ 10 DAYS IMMERSION -2 - 2 -3 - 7 - 3 -3 - 2 -8 0 - 1 - 1 -6 -.1 - 1 -3 - 7 .1 -2 -.1 -6 32 30 .6 3 0 -.1 1 -2 GUM RUBBER 1 VO%L % WT. 2 .2 10 3J 20 11 35 -2 0 .0 .1 -.1 0 .0 .1 `lo e a ttiiis FIGURE 3 A. SOLUBILITY OF CELLULOSE DERIVATIVES IN GLYCOLS GLYCOL ETHYLENE DIETHYLENE TRIETHYLENE PROPYLENE OIPROPYLENE 50 CPS. ST. E/C Insoluble Insoluble Insoluble Insoluble Insoluble V5 SECOND CELLULOSE NITRATE Swelled >20% Soluble >20% Soluble Swelled >20% Soluble CELLULOSE ACETATE FM 3 Insoluble Insoluble Insoluble Insoluble Insoluble GLYCOL ETHYLENE OlETHYLENE TRIETHYLENE PROPYLENE OIPROPYLENE B COMPATIBILITY OF FILM CAST FROM 80/20 = TOLUENE/ALCOHOL. TABLE SHOWS % GLYCOL IN FILM WITH THE PROPERTIES SHOWN. i 50 CPS. ST. E/C CLEAR HAZE OPAQUE 15 SECOND CELLULOSE NITRATE i CELLULOSE ACETATE FM 3 CLEAR HAZE OPAQUE CLEAR HAZE OPAQUE 1% 3% 10% 1% 3% 10% 1% 3% 1% 3% 10% 20% 25% 30% 3% 1% 1% 1% >50% 5% 5% 3% 3% 10% 10% 15% 10% >10 20 >20 30 >20 30 >10 20 >40 50 11 HYGROSCOPICITY The glycols are hygroscopic. If placed in an atmosphere containing water vapor, they will pick up and retain mois ture. This property is responsible for the many applica tions of glycols as humectants and dehydrating agents. In many of these applications, glycol-water solutions are used. Since the addition of water modifies the properties of the glycols, data on such solutions are needed. The properties of both anhydrous glycols and glycol-water solutions are presented in this booklet. i he relative humectant value of the glycols is influenced by humidity and temperature variations. These variations for a range of temperatures and humidities frequently encountered in humectant problems are shown in Figure 4, which may be used to determine the amount of glycol needed to condition a given quantity of a product requiring b humectant. S88/.r:0!S FIGURE 4 RELATIVE HUMECTANT VALUES* TEMPERATURE OF AIR F GLYCOL RELATIVE HUMIDITIES 10% 20% 30% 40% 50% 60% ETHYLENE 97.5 93.4 89.3 85.7 82 78 DIETHYLENE 978 95.1 92.0 89.0 86 83 20 TRIETHYLENE 98.5 96.8 94.0 91.1 89 83 PROPYLENE 96.8 91.4 90.0 84 6 77 73 DIPROPYLENE 98.5 97 0 95.1 92.6 89 85 ETHYLENE 97 3 93.2 89.1 85.4 82 76 DIETHYLENE 97.7 95.0 92 0 89.0 86 82 40 TRIETHYLENE 98.4 96.5 93.8 91 0 68 83 PROPYLENE 97.0 92.3 90.2 85.2 78 74 DIPROPYLENE 98.4 96.9 95.0 92.5 89 85 ETHYLENE 97.1 93.0 88.9 85.0 81 75 OIETHYLENE 97.7 95.0 92.0 89.0 86 82 60 TRIETHYLENE 98.2 96.2 93.6 90.8 86 62 PROPYLENE 97.1 92.9 90.4 85.8 80 74 DIPRQPYLENE 98.4 96.8 94.8 92.4 89 85 ETHYLENE 96.8 92 a 88.6 84.7 80 73 DIETHYLENE 97.6 949 92.0 89.0 85 81 80 TRIETHYLENE 98.1 96.0 93.4 90.7 85 82 PROPYLENE 97.1 93.5 90.5 86.3 81 75 DIPROPYLENE 98.3 96.7 94.7 92.3 89 85 ETHYLENE 96.6 92.7 88.4 84.3 79 72 DIETHYLENE 97.6 94.8 92.0 89.0 85 81 100 TRIETHYLENE 98.0 95.7 93.2 90.6 84 82 PROPYLENE 97.2 93.9 90.6 86.6 82 75 DIPROPYLENE 98.3 96.6 94.6 92.1 89 85 . ETHYLENE 96.4 92.5 88.2 84.0 DIETHYLENE 97.6 94.8 92.0 89.0 120 TRIETHYLENE 97.8 95.4 93.0 90.5 PROPYLENE 97.2 94.3 90.7 86.7 DIPROPYLENE 98.2 96.5 94.5 92.0 78 85 83 83 89 71 80 82 76 85 70% 80% 72 63 78 68 78 66 68 55 79 67 69 60 77 67 77 65 68 55 79 67 66 v V 57 76 66 77 65 68 55 79 67 64 55 75 65 76 64 68 55 79 67 63 53 74 64 76 64 68 55 79 67 62 51 73 63 75 63 68 55 79 67 90% 48 52 51 40 51 42 50 51 40 51 37 48 50 40 51 36 47 50 40 51 35 46 49 40 51 34 45 49 40 51 * Note. Values are given as the percent oy weight of glycol in water solutions, required to maintain equilibrium in contact with air of various temperatures and humidifies 12 For Example . . . If six pounds of water is required to condi tion 100 pounds of product, and propylene glycol is chosen as the humectant. the fol lowing calculation can be made from Fig ure 4. With a 60% relative humidity and at 80 F, a 75% propylene glycol solution in water is indicated in the table. Since six pounds of water is required. 6 divided by 0.25 equals 24 pounds of solution needed. Subtracting the 6 pounds of water, the total amount of propylene glycol required is 18 pounds. It should be borne in mind that a product will normally contain a certain amount of moisture, the exact amount depending on prevailing conditions of temperature and hurndity. Therefore, in calculating the quan tity of conditioner required, only moisture other than that normally present need be considered. It should also be assumed that the presence of a moisture is at least par tially desirable because of its plasticizing effect. Propylene glycol will also have a plasticizing effect, therefore much smaller amounts of total conditioner are usually required. A natural gas producer wishes to depress the dew point of the gas before turning it into the transmission lines in order to pre vent the formation of hydrates that may plug the lines. The natural gas is introduced into the contactor in which the glycol solution is contained. The solution temperature is 80 F. It is desirable to depress the dew point of the gas to 50F. Assume that diethylene glycol is being used as the dehydrating medium. Turn to Figure 6 and locate 80 F on the horizontal scale entitled "Solution Temperature. Degrees Fahrenheit" Follow this line vertically up the scale until it inter sects the 50 F line of the vertical scale entitled "Water Vapor Dew Point. Degrees Fahrenheit ". The point thus found falls be tween the 90% by weight solution line and the 92% by weight solution line, but is nearer the 90% line. By estimation, approxi mately 91% diethylene glycol solution would be required. Substituting the other glycols in the same example. Figure 5 shows that 86% ethylene glycol solution would be needed. Figure 7 shows that 92% triethylene glycol solution would be necessary. Figure 8 indicates that 88% propylene glycol solu tion would be called for, and Figure 9 shows that 93.5% dipropylene glycol solution would be required. When glycols are used for dehydration of gases, the dew point or temperature at which the water will condense from the gas is used as a measure of the amount of water vapor present in the gas. Thus the dew point is depressed as water vapor is removed from the gas Gases may be dried by bringing them in contact with glycol-water solutions. The glycol solutions will draw out the mois ture until a state of equilibrium is reached. Water vapor dew points for gases in equi librium with glycol-water solutions are given in Figure 5 for ethylene glycol. Figure 6 for diethylene glycol. Figure 7 for trieth ylene glycol. Figure 8 for propylene glycol and Figure 9 for dipropylene glycol. The graphs extend over the range of tempera tures most commonly encountered, from 20 to 320 F and may be used to calculate dew point depressions of gases at equili brium with the glycol solution at atmos pheric pressure. 13 CZ OCX CT WATER VAPOR DEW POINTS OVER AQUEOUS ETHYLENE GLYCOL SOLUTIONS FIGURE 5 /.eeo/.^ms SOLUTION TEMPERATURE, DEGREES FAHRENHEIT WATER VAPOR DEW POINTS OVER AQUEOUS DIETHYLENE GLYCOL SOLUTIONS FIGURE 6 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 SOLUTION TEMPERATURE, DEGREES FAHRENHEIT 14 WATER VAPOR DEW POINTS OVER AQUEOUS TRIETHYLENE GLYCOL SOLUTIONS FIGURE 7 SOLUTION TEMPERATURE, DEGREES FAHRENHEIT WATER VAPOR DEW POINTS OVER AQUEOUS PROPYLENE GLYCOL SOLUTIONS FIGURE 8 R R C . f i / I f, 15 WATER VAPOR DEW POINTS OVER AQUEOUS DIPROPYLENE fitVCOl S'OlDTflONS FIGURE 9 60GG/.2UJ.S VAPOR PRESSURE AND BOILING POINT All liquids form vapors which exert pres sures characteristic of the materials. The pressure exerted by these vapors in the presence of the liquid is called the vapor pressure. The vapor pressure increases with temperature, as shown by Figures 10. 11. 12, 13. and 14 on pages 18. 19 and 20. The boiling point of a liquid is the temperature at which its vapor pressure is equal to the external pressure on the surface of the liq uid. When the liquid is heated in an open vessel, it will boil when its vapor pressure is equal to the atmospheric pressure, which for purposes of physical measurement has been defined as 760 mm Hg. In Figures 10, 11. 12, 13. and 14, heavy lines have been drawn across the curves at 760 mm. The normal boiling points of each of the glycols are the points at which the glycol vaporpressure curves cross these heavy lines. The glycols have lower vapor pressures than water and their boiling points are above the boiling point of water. If the external pres sure is reduced, the glycols will boil at lower temperatures, as shown in Figures 10. 11, 12, 13, and 14, where the vapor pressures of the glycols are equal to the reduced ex ternal pressure. The following table lists the boiling points of water and the glycols when the external pressure is reduced to 50 mm Hg. The glycols are considered high boiling point liquids because of their low vapor pressure compared to that of water at any given temperature. It is interesting to note that at 68 F the vapor pressure of water is more than 100 times as great as that of propylene glycol, the most volatile of the glycols listed. This low volatility of the glycols lessens their tendency to evaporate and has led to their use as plasticizers, "permanent" type antifreeze agents, solvent vehicles, hygroscopic agents, and ingredi ents of brake fluids. BOILING POINTS AT 50 mm Hg WATER EThYLENE GLYCOL DIETHYLENE GLYCOL TRIETHYLENE GLYCOL TETRAETHYLENE GLYCOL PROPYLENE GLYCOL DIPROPYLENE GLYCOL TRIPROPYLENE GLYCOL 100F 258F 338F 387F 453F 240F 307F 356F c c u 17 TOTAL PRESSURE OVER AQUEOUS ETHYLENE GLYCOL SOLUTIONS VERSUS TEMPERATURE FIGURE 10 TEMPERATURE,DEGREES FAHRENHEIT TOTAL PRESSURE OVER AQUEOUS DIETHYLENE GLYCOL SOLUTIONS VERSUS TEMPERATURE FIGURE 11 ;'0 --! CO CO V-O 18 TOTAL PRESSURE OVER AQUEOUS TRIETHYLENE GLYCOL SOLUTIONS VERSUS TEMPERATURE FIGURE 12 co cz o: cc rv TOTAL PRESSURE OVER AQUEOUS PROPYLENE GLYCOL SOLUTIONS VERSUS TEMPERATURE FIGURE 13 32 40 1000 800 600 400 300 200 100 80 60 40 CO CO 30 cac. 20 o 10 8 6 4 3 2 1.5 60 80 100 120 140 160 180 200 240 280 320 360 400 TEMPERATURE, OEGREES FAHRENHEIT 19 TOTAL PRESSURE <CWEB AQUEOUS GLYCOL SOLUTIONS VEBStfS TEWF^7438fc' .i i FIGURE 14 IO O JO Glycol-water mixtures generally have phys ical properties between those of water and anhydrous glycols; consequently, the addi tion of water to a glycol results in a mixture having a boiling point lower than that of the anhydrous glycol. The smaller the concen tration of glycol, the lower the boiling point will be. Ethylene glycol-water solution boil ing points at pressures of 100. 300 and 600 mm Hg are shown in Figure 15. page 21. The boiling points of aqueous solutions of diethylene, triethylene, propylene and dipro pylene glycols are shown in Figures 16 to 19, pages 22-25. To determine the boiling point of an 0.8 molar ethylene glycol-water solution at 600 mm Hg for example, turn to Figure 15 and. on the horizontal scale titled "Mole Fraction Ethylene Glycol ', lo cate the 0.8 molar line. Follow the 0.8 molar line vertically to the point where it intersects the liquid curve for solutions at 600 mm Hg. The boiling point of this solution can then be read off the vertical scale. In this example it is 288 F. it is often desirable to determine the com position of the vapors in equilibrium with any given solution. This information may also be obtained from Figures 15 to 19 In the example quoted above for an 0 8 molar ethylene glycol solution, the vapor composition is found by reading across the chart on the 288 F line to its point of inter section with the vapor curve--a point which turns out to be directly above 0.156 on the horizontal scale. It is sometimes desirable to enrich the glycol-water solution periodically by remov ing part of the water, rather than by adding glycol. These vapor-liquid composition curves are useful in engineering such an operation. The vapor-liquid equilibrium diagrams pre sented in this publication are plotted as mole fraction vs. temperature. It is often desirable or necessary to express these values in weight percent or volume percent Figure A1-A7 in the Appendix can be used for making conversions between mole frac tion. weight percent, and volume percent 20 VAPOR-LIQUID COMPOSITION CURVES FOR AQUEOUS ETHYLENE GLYCOL SOLUTIONS FIGURE 15 STD?78394 21 VAPOR-LIQUID COMPOSITION CURVES FOR AQUEOUS DIETHYLENE GLYCOL SOLUTIONS FIGURE 16 22 VAPOR-LIQUID COMPOSITION CURVES FOR AQUEOUS TRIETHYLENE GLYCOL SOLUTIONS FIGURE 17 23 VAPOR-LIQUID COMPOSITION CURVES FOR AQUEOUS PROPYLENE GLYCOL SOLUTIONS FIGURE 18 TEMPERATURE, DEGREES FAHRENHEIT / fipft/ ?.ni s 24 VAPOR-LIQUID COMPOSITION CURVES FOR AQUEOUS DIPROPYLENE GLYCOL SOLUTIONS FIGURE 19 TEMPERATURE, DEGREES FAHRENHEIT ft fi E ft / / I I ! c 25 VISCOSITY Viscosity is a measure of the internal fric tion of a liquid. As viscosity increases, the tendency to flow decreases. Viscosities of the glycols vary inversely with temperature Hot glycols flow freely but their viscosities increase as they cool, until they eventually set and fail to flow The lowest temperature at which a liquid will flow is called the pour point The pour points of the glycols are listed below. Ethylene, diethylene, triethylene, and tetraethylene glycols will freeze above their pour points if agitated or seeded The viscosities of anhydrous glycols are shown by Figure 20. page 27. and those of aqueous glycol solutions by Figures 21-27. pages 28-31. 66 E0 /. f, u ..1S GLYCOL ETHYLENE GLYCOL DIETHYLENE GLYCOL TRIETHYLENE GLYCOL TETRAETHYLENE GLYCOL PROPYLENE GLYCOL DIPROPYLENE GLYCOL TRIPROPYLENE GLYCOL POUR POINT <-75F --65F --73F --42F --71F --38F --42F These curves are of value where viscosity information is required for pumping, filter ing, and piping calculations. Although the viscosities of the glycols are shown in centipoises. the values can easily be converted to centistokes if de sired. To do so. divide centipoises by the density in grams per milliliter at the indi cated temperature The densities of glycols 26 and aqueous glycol solutions are shown m Figures 31 -37. pages 36-42. The glycols are more fluid than many of the high boiling solvents and plasticizers For this reason they are often employed either alone or in combination with other fluids, to reduce the viscosities of composi tions with too much body > *! ..Cr... VISCOSITIES OF ANHYDROUS GLYCOLS FIGURE 20 27 VISCOSITIES OF AQUEOUS J ETHYLENE GLYCOL SOLUTIONS FIGURE 21 VISCOSITY, CENTIPOISES m o rm TEMPERATURE, DEGREES FAHRENHEIT 28 VISCOSITIES OF AQUEOUS DIETHYLENE GLYCOL SOLUTIONS FIGURE 22 VISCOSITY, CENTIPOISES TEMPERATURE, 0E6REES FAHRENHEIT 29 VISCOSITIES OF AQUEOUS TRIETHYLENE GLYCOL SOLUTIONS FIGURE 23 VISCOSITY, CENTIPOISES CO'lfl/ /.II IS TEMPERATURE, OEGREES FAHRENHEIT 30 VISCOSITIES OF AQUEOUS FIGURE 24 TETRAETHYLENE GLYCOL SOLUTIONS VISCOSITIES OF AQUEOUS FIGURE 26 DIPROPYLENE GLYCOL SOLUTIONS VISCOSITIES OF AQUEOUS FIGURE 25 PROPYLENE GLYCOL SOLUTIONS rCMFCfUTUftC, DEGREES FAHRENHEIT VISCOSITIES OF AQUEOUS FIGURE 27 TRIPROPYLENE GLYCOL SOLUTIONS 31 FREEZING POINT When liquids are cooled they eventually solution with a freezing point below that of either crystallize like ice or become increas water. This has led to the extensive use of ingly viscous until they fail to flow and set glycol-water solutions as cooling media at up like glass. The first type of behavior rep temperatures appreciably below the freez resents true freezing, the second is known ing point of water. Instead of having sharp as supercooling. The glycols do not have sharp freezing points. Under normal conditions, ethylene glycol and the other members of the ethyl freezing points, glycol-water solutions be come slushy during freezing As the temper ature is lowered, the slush becomes more and more viscous and finally fails to flow ! ene series supercool rather than freeze; Freezing points of glycol-water solutions however, freezing points can be obtained if are shown in Figure 28. below. It should be I seeding and agitation are properly employed. Propylene glycol and its homologs like remembered that the freezing points are the temperatures at which the first crystals wise set to glass-like solids, rather than form, and that even below these tempera freezing. tures, a slushy solution exists which will The addition of water to a glycol yields a still flow FREEZING POINTS OF AQUEOUS GLYCOL SOLUTIONS FIGURE 28 0 10 20 30 40 50 60 70 80 90 100 GLYCOL, WEIGHT PERCENT 32 SPECIFIC HEAT Specific heat is the amount of heat required to raise a unit weight of substance one de gree in temperature It can be expressed either as calories per gram per degree Centi grade. or as British Thermal Units per pound per degree Fahrenheit, and the expressions are numerically equal The specific heat of water is approximately 1 at ordinary temper atures Specific heat varies with tempera ture, and the specific heats of the glycols are shown in Figure 29. below for tempera tures from 0 F to 240" F. Specific heats of glycol-water solutions are shown in Figure 30 As would be ex pected, the addition of water to a glycoi increases the specific heat This is important whenever glycol solutions are considered for use as heat transfer media. A liquid with a high specific heat will do more work per unit weight than one with a low specific heat if all other factors are equal. SPECIFIC HEAT OF ANHYDROUS GLYCOLS FIGURE 29 90*i O/.2U1S 33 SPECIFIC HEATS OF AQUEOUS GLYCOL SOLUTIONS (Btu/lb/F) FIGURE 30 S I 1!'/ / U4U / GLYCOL, % BY WEIGHT Temp. F 100________ 80 60________ 40_______ 20 ETHYLENE GLYCOL_________ 60 563 80 .576 100 .590 120 604 140 .618 160 632 180 646 200 .660 220 .674 240 .688 660 673 685 697 .710 722 735 748 761 .774 757 .769 780 792 .803 .814 825 .837 849 861 .855 .864 .872 880 888 896 905 914 922 930 CIETHYLENE GLYCOL .940 .942 .944 .946 .948 .950 952 .954 956 958 60 543 80 .555 100 565 120 575 140 583 160 593 180 603 200 613 220 623 240 634 .631 .645 .659 .672 .686 .700 714 728 742 756 736 749 .762 .774 787 800 813 826 839 852 849 922 .855 .927 861 932 868 .937 .874 .943 880 948 886 .954 893 960 900 965 907 .971 TRIETHYLENE GLYCOL 60 525 80 .534 100 540 120 550 140 .562 160 .569 180 .577 200 586 220 .595 240 .605 .637 .648 659 .669 680 .690 .701 .711 .722 782 .749 .758 .768 .777 .787 .796 .806 815 825 834 866 872 878 .884 890 895 901 .907 .913 919 PROPYLENE GLYCOL 935 938 .941 .944 .946 .949 .952 .955 .957 960 60 .587 80 603 100 .619 120 635 140 .651 160 .667 180 .683 200 .699 220 .715 240 .731 687 .702 717 733 .748 .763 .778 .794 .809 824 .795 .808 .821 833 .846 .857 .871 .882 .895 .907 900 907 913 919 .925 .930 .936 .944 949 954 DIPROPYLENE GLYCOL 970 .972 .975 .977 .980 983 984 987 .990 .993 60 .570 .687 .801 .900 967 80 582 .698 .810 .905 970 100 .594 .708 .819 .910 .972 120 606 .718 .828 .915 .974 140 618 728 .836 .920 976 160 .631 .739 845 924 978 180 644 749 854 929 .980 200 .656 .760 .863 934 983 220 668 770 .872 939 .985 240 680 .781 881 944 .988 34 10 Temp. *C 976 977 978 .979 .980 .981 .982 .982 983 984 15.6 26 7 37.8 48.9 60.0 71 1 82.2 93.3 104 4 115.5 949 954 960 965 970 .975 .980 .985 .990 .995 15.6 26.7 37.8 48.9 60.0 71 1 82.2 93.3 104.4 115.5 .979 980 .981 981 982 983 984 985 .985 .986 .985 .986 .988 .990 991 992 .994 .995 996 998 15.6 26.7 37 8 48 9 60.0 71.1 82.2 93.3 104.4 115.5 15.6 26.7 37 8 48.9 60 0 71 1 82.2 93.3 104 4 115 5 985 .986 .988 .990 991 .993 .995 .997 998 999 15.6 26 7 37 8 48.9 60.0 71.1 82.2 93.3 104 4 115.5 DENSITY Density is the weight per unit volume of a mass. Density varies with temperature and the graphs on Pages 36-42 show the den sities of Dow glycols and glycol-water solu tions over a range of temperatures. Figures 35 and 36 show that the densities of propyl ene glycol-water solutions and dipropylene glycol-water solutions may be the same for two concentrations. Therefore, density alone is not a reliable method of testing for solutions concentration. Although the graphs in this booklet show the densities of the glycols and glycol-water solutions, it may sometimes be desirable to know the specific gravities at certain temperatures. The specific gravity can be obtained by dividing the density of the glycol or glycol-water solution by the den sity of water. Densities, and therefore spe cific gravities, vary with temperature hence it is necessary to indicate the temperatures of both the glycol and water. A specific gravity of ethylene glycol, the density of which is 1.1097 at 77F. when compared to water, which has a density of 0.9970 at 77 F. could be calculated as follows: Specific Gravity of Ethylene Glycol at 77F/77F 1.1097 0.9970 1 1130 Specific gravities may be expressed at vari ous temperatures, as follows: Specific Gravity of Ethylene Glycol at "x"0F/"y"0F* = Density of Ethylene Glycol at "x"F Density of Water at "y"F * and V may be the same or different numbers The weight per gallon of a glycol or aqueous glycol solution is determined as follows: Density at tC x 8.345 = lb./gal. at tsC Weight per Gallon at 77F Ethylene Glycol................................ 9.26 lb Diethylene Glycol............................. 9.29 lb Triethylene Glycol........................... 9.34 lb Tetraethylene Glycol........................ 9.34 lb Propylene Glycol.............................. 8 62 lb Dipropylene Glycol.......................... 8.54 lb. Tripropylene Glycol......................... 8.51 lb. Volume changes resulting from heating or cooling glycols or glycol-water solutions may be readily calculated from the data pre sented in Figures 31-37. For example, in heating 10.000 lb. of ethylene glycol from 77 F to 140 F, the increase in volume will be: (140*F) <77* f) 10,000 9 05 10.000 9.26 1105- 1080= 25 gal OD CO CO CO DENSITIES OF AQUEOUS ETHYLENE GLYCOL SOLUTIONS (PERCENT BY WEIGHT) FIGURE 31 DENSITY GRAMS PER ml POUNDS PER GALLON cn vx 36 DENSITIES OF AQUEOUS DIETHYLENE GLYCOL SOLUTIONS (PERCENT BY WEIGHT) FIGURE 32 DENSITY,GRAMS PER ml POUNDS PER GALLON 37 DENSITIES OF AQUEOUS TRIETHYLENE GLYCOL SOLUTIONS (PERCENT BY WEIGHT) FIGURE 33 DENSITY, GRAMS PER ml POUNDS PER GALLON 1.1600 1.1500 1.1400 1.1300 1.1200 I 1100 1.1000 1.0900 1.0800 1.0700 1.0600 1.0500 1.0400 1.0300 1.0200 1.0100 1.0000 0 9900 0.9800 -40 - 20 0 20 40 60 80 100 120 TEMPERATURE, DEGREES FAHRENHEIT 38 140 160 180 DENSITIES OF AQUEOUS TETRAETHYLENE GLYCOL SOLUTIONS (PERCENT BY WEIGHT) FIGURE 34 DENSITY, GRAMS PER ml POUNDS PER GALLON TEMPERATURE, DEGREES FAHRENHEIT 39 oo cx: rv DENSITIES OF AQUEOUS PROPYLENE GLYCOL SOLUTIONS (PERCENT BY WEIGHT) FIGURE 35 DENSITY, GRAMS PER ml DENSITY, GRAMS PER ml TEMPERATURE, DEGREES FAHRENHEIT 40 DENSITIES OF AQUEOUS DIPROPYLENE GLYCOL SOLUTIONS (PERCENT BY WEIGHT) FIGURE 36 DENSITY,GRAMS PER ml DENSITY GRAMS PER ml oo --i CO -~ 41 DENSITIES OF AQUEOUS TRIPROPYLENE GLYCOL SOLUTIONS (PERCENT BY WEIGHT) FIGURE 37 SURFACE TENSIONS OF AQUEOUS SOLUTIONS OF GLYCOLS AT 77F TEMPERATURE, DEGREES FAHRENHEIT FIGURE 38 RI *i R/. 20 si 42 SURFACE TENSION Surface tension is that force on the surface of a liquid which tends to diminish the sur face area to the minimum. It is an important property when t1''' wetting or penetrating ability of a liquid is considered. Surface tensions of the glycols are lower than that of water Solutions of glycol and water have varying surface tensions, de pending on the concentration of glycol in the solution. This is illustrated by Figure 38, page 42. When heat is applied to liquids their sur face tension is reduced. In the case of glycols, however, heat does not affect the surface tension materially except near the boiling points. FLAMMABILITY The flash and fire points of the seven glycols are above the boiling point of water. For this reason the glycols present practically no fire hazard in storage or handling. Flash and fire points determined by the ASTM Cleve land Open Cup method are as follows. GLYCOL ETHYLENE GLYCOL DIETHYLENE GLYCOL TRIETHYLENE GLYCOL TETRAETHYLENE GLYCOL PROPYLENE GLYCOL DIPROPYLENE GLYCOL TRIPROPYLENE GLYCOL FLASH POINT F C 240 116 280 138 320 160 365 185 215 102 260 127 285 141 Note These properties are laOoratorv results on pure compounds or typical of the product but should not be confused with or regarded as. specifications FIRE POINT F C 245 119 290 142 330 166 375 191 220 104 260 127 310 154 c c 43 REFRACTIVE INDICES OF AQUEOUS GLYCOL SOLUTIONS AT 77F FIGURE 39 1.460r 1450 1.440 1.430 eo 1.420 LXU 1.410 1.400 U>i F-- 1390 < 8E (.380 ac 1.370 1.360 1.350 1.340 1.330 DIET HYLENE GLYCOL1 TRIETHYLENE GLYCOL uirnvrr lc JE 6LYC0L -- ----- pf 0PYLENE GLYCOL - ETHYLI :ne glyoOL 10 20 30 40 50 60 70 80 90 100 6 LYC0L, WEIGHT PERCENT REFRACTIVE INDEX The refractive index of a materiaf is an optical measurement of its ability to bend a beam of light entering it. The refractive index may be used to determine the purity of the material. Figure 39. above, shows the refractive indices of the glycols and their aqueous solutions at 77F L I 'lO UUiS 44 TOXICOLOGICAL CONSIDERATIONS c c ACUTE ORAL TOXICITY All of the glycols considered in this booklet display a lowacute oral toxicity. The accompanying table lists the LDso values obtained when the various glycols are fed in single oral doses to rats Glycol Ethylene........................................................................................ Diethylene..................................................................................... Triethylene.................................................................................... Tetraethylene................................................................................. Propylene...................................................................................... Dipropylene................................................................................... Tripropylene ........................................................................... Largest dose survived by ail rats tested 10 0 gm/kg caused the death of all the rats tested. LDso. gm/kg 5.5 148 22.0 32.8 32.5 148 30* Human experience indicates that man seems to be more susceptible to injury caused by ethylene glycol and diethylene glycol than laboratory animals. The lethal dose for humans for ethylene glycol appears to be about 14 ml./kg. and for diethylene glycol about 1.0 ml./kg. CHRONIC ORAL TOXICITY The glycols vary considerably in chronic oral toxicity. Propylene glycol is especially low in this respect; studies in which rats were fed drinking water containing as much as 10 percent propylene glycol over a period of 140 days showed no apparent ill effects, while other investigations have revealed that rats can tolerate up to 4.9 percent propylene glycol in the diet for 24-month periods without significant effect on growth rate However, minor liver damage was ob served Because of its low chronic oral toxicity, propylene glycol is considered safe for use in foods and pharmaceuticals. Since 1942. it has been included \n New and NonOfficial Remedies as a proper ingredient for pharmaceutical products and is listed in the United States Pharmacopoeia. It is widely used and accepted as an ingredient of dental preparations and is considered generally recognized as safe for use in foods if used in accordance with good manufacturing practices. Triethylene glycol and tetraethylene gly col are likewise low in chronic oral toxicity The first of these has been fed in the drink ing water of rats at 4 percent concentration and over a two-year period with no apparent ill effect. Similarly, no adverse effects have been evidenced in rats fed diets containing 2.5 percent of the second material for 90 days. Because of their low chronic oral toxicity, triethylene glycol and tetraethyl- 45 ene glycol have been adjudged safe for many applications where intake is limited In contrast, ethylene glycol and diethyl ene glycol are regarded as too toxic for applications where there is a possibility of ingestion. The feeding of rats for two years on diets containing 0.5 and 1 0 gm./ kg. of ethylene glycol caused a toxic action centered chiefly in the kidneys. The ethylene glycol shortened the life span of the rats, produced calcium oxalate bladder stones, severe renal tubular atrophy, and fatty de generation in the liver. With diethylene glycol, two-year feeding studies revealed that one-percent concentrations retarded growth slightly and produced a low inci dence of calcium oxalate bladder calculi accompanied by slight kidney and infre quent liver damage. Sufficient studies have not been carried out on dipropylene glycol and tripropylene glycol to permit conclusions to be drawn re garding their suitability for uses involving ingestion, although they are permitted in various indirect additive food uses under the Food Additive Regulations under the Federal Food, Drug and Cosmetic Act. SKIN IRRITATION AND ABSORPTION The glycols produce a negligible degree of irritation when applied to the skin and there is no evidence to indicate that they are ab sorbed through the skin in quantities suffi cient to produce systemic injury A slight macerating action comparable to that caused by glycerine may result from very severe prolongs:- -a-:,,-cv;, -ttbv/lene glycol and diethylene gvcc,. t'-uctsr severe conditions of exposure su.rn as actually bathing the body wire i.friyrc'.ne giycol or diethylene glycol for prolonged periods of time, it is possible that enough -.of the material might be absorbed to cause sys temic injury. Because of these cnnsiderations, the use of glycols--othet 'than pro pylene glycol and possibly triethylene glycol and tetraethylene glycol --in preparations intended to be applied over extensive areas of the body is considered unwise. VAPOR INHALATION Inhalation of the vapors of the glycols ap pears to present no significant hazard in ordinary applications Atmospheric concen trations of ethylene glycol vapors in the order of 0.35 to 040 mg/liter (140-160 ppm.) for 80 pe. .ods of 8 hours each during 16 weeks caused no injury in mice or rats. However, it would seem wise to avoid in haling vapors rising from heated material, particularly if exposure is prolonged and repeated. Limited human experience indi cates that breathing of mists of these gly cols may be harmful, therefore, it would seem wise to avoid breathing spray mists of these materials. Prolonged inhalations of saturated vapors of triethylene glycol and propylene glycol have produced no ill effects. Very little work has been done on the vapor toxicity of the other glycols; how ever, because of their very low vapor pres sures and low systemic toxicities, it is very unlikely that injury would occur due to vapor inhalation. GENERAL CONCLUSION: The glycols discussed in this book have a relatively low degree of toxicity and present no serious hazard insofar as their normal industrial handling and use are concerned. The toxicological information on these glycols has t>een reviewed and summarized m Patty s Industrial Hygiene ana Toxicology, second revised edition. Volume H 1962 Chapter 35 which is published by interscience Publishers a division of John Wiley and Sons. New York fi i o/. 'i nj s 46 STORAGE OF GLYCOLS INTRODUCTION The storage of glycols presents no unusual problems. A tank truckload can be emptied into available drums or tanks and kept with little difficulty since glycols do not readily solidify, can easily be handled without haz ard of toxicity, and are noncorrosive. How ever. if more elaborate storage facilities are required for ease of handling or to maintain purity, special precautions should be taken. The following information is presented as a guide to trouble-free storage of glycols. STORAGE TANKS Ordinary steel tanks are normally satisfac tory for glycol storage. However, during extended storage in such tanks, a slight coloration may develop due to iron contami nation. This problem can be avoided by using stainless steel or aluminum tanks, or by coating an ordinary steel tank with a vinyl or phenolic resin. Satisfactory vinyl resins include Durakon'. lankote2. and Amercoat 233 resins. Among phenolic materials. Heresite* resin has met with approval. ' Product of United Paint & Chemical Company. Highland Park, Mich. 2 Product of J. Landau Company. Newark, New Jersey. 3 Product of Amercoat Corporation. Evanston. Illinois. * Product of Heresite Chemical Company. Manitowoc, Wisconsin. 47 Before a storage tank is coated, all rough spots caused by welding and machining must be completely removed until the sur face is perfectly smooth. If this is not done, pinholes may form in the coating. Then the tank must be carefully cleaned. Usually five or six coats of resin are necessary to insure good protection and each coat should be thoroughly dried before the next is applied Warm air can be used to hasten drying Both vertical and horizontal tanks are available for storage Vertical tanks are more economical to install and occupy less space, while horizontal tanks are easier to maintain and repair. If future compartmentation of the tank is likely, a horizontal tank should be chosen since it is easier to modify Usually, however, the decreased mainte nance generally required with horizontal tanks does not offset their higher cost and greater space requirements; hence vertical tanks are generally recommended. Vertical tanks should be diked and all vegetation in the vicinity should be removed to reduce the possibility of fire. Storage tanks located on the ground are recommended in preference to underground tanks because above-ground installation and maintenance are cheaper and less troublesome. With underground storage, gauging and pumping are also more difficult In addition, leakage is more difficult to de tect and usually more expensive to correct For continuous storage of glycols at low temperatures, to prevent pumping pir,piers.' due to high viscosity and freezing, irrsulatio?<and heat are required. Ethylene, diethylene and triethylene glycols should not be per mitted to drop below 253F. while tetraethyl- ene. propylene, dipropylene and tripropylene glycols should be maintained at tempera tures above 35F. If storage temperatures only occasionally drop slightly below these prescribed limits, steam heating coils alone will prevent freezing or excessive viscosity of the glycols. However, if the low tempera tures are sustained, both heating coils and insulation are necessary for satisfactory storage. A 1 -inch to 1 '/z-inch layer of mag nesia asbestos has served satisfactorily as an insulating material. Heating coils should be of stainless steel if even slight coloration of the glycol is undesirable, otherwise or dinary steel coils are satisfactory Either a pencil-type coil or a return-bend coil can be used if it provides the required heating sur face. This coil should be removable for cleaning and maintenance. Normally, 10 to 30 pound steam is satisfactory for heating. Storage tanks should be provided with a manhole or some other means of entry to facilitate cleaning. The tanks should be vented to prevent excess pressure buildup and to facilitate the discharge of the glycol. Use of a pressurevacuum relief valve is recommended for this purpose. Glycols will not deteriorate in an atmosphere of air at normal storage tem peratures, therefore, air--which, because of the hygroscopic nature of the glycols, must be dry--is satisfactory for padding the tank. The opening in the vent should be downward so that rain and dust cannot get into the tank and contaminate the glycol. Flake calcium chloride is an efficient and inexpensive desiccant for drying the air used for padding. The trap containing the desic cant should be inspected periodically, cleaned and recharged with fresh, dry mate rial to keep it from becoming plugged with dissolved calcium chloride. If the trap does become plugged, the pad system will be inoperative and the tank will be able to breathe only through the relief valve. FITTINGS -AND W'tffcS Centrifugal -purupi- ,vs-. -u:r.-y im.-d in glycn1 service evh r<et, p.>::c a:-r.y lumps are utwdtwhen-'gl.ycol*mvjjbtiumjH^nrt high heads. Pumps car. .wide- u; orrinanv steel if slight coloration vt guc.ni n. rot ob jectionable, otherwise stam.h.s.'.-ijrfcvei'pumps should be employed. Piping valves and fitting;; can also be of ordinary steel unless coloration of the glycol is objectionable, in which case stainless steel should be used. Regardless of the metal used, schedule-ten piping, which will withstand normal pumping pressures, is recommended. PUMP PACKING AND GASKETS Glycols are difficult materials to contain and are prone to leak past any defective fittings or packing. Consequently, the installation of all fittings, packings and gaskets should be done with the utmost care Pipe dopes that have been used success fully include a mixture of graphite and cutting oil, formulated into a thick paste and applied directly. Asbestos-base materials are recom mended for gaskets and packing in glycol service. With centrifugal pumps, JohnsManville C-7' shaft packing and Crane2 asbestos shaft packing are recommended. Garlock 9002 and Johns-Manville 60 gasket material are recommended for flange gaskets. Whenever reciprocating pumps are used. Johns-Manville No. 60 gaskets are recom mended. Among packing materials Palmento No. 12004 Packing has served satisfactorily. 1 Product of Johns-Manville Company. Manville, New Jersey. 2 Product of Crane Packing Company. Morton Grove, Illinois. 3 Product of Garlock Packing Company. Palmyra, New York. 4 Product of Green Tween & Company, North Wales. Pennsylvania. /b I 11 / 0 H L I 48 DIAGRAM OF HORIZONTAL STORAGE TANK FOR ETHYLENE GLYCOL 18" Manhole Gauging Mole 1 "-1 'A" Thick Insulation Anhydrous Calcium Chloride Air Dryer To Point Of U$e Centrifugal Pump Flexible Metal Hose 7 7<iH/ ?:i l I S 49 DIAGRAM OF VERTICAL STORAGE TANK FOR ETHYLENE GLYCOL 50 ez*io/.ms ANALYTICAL METHODS FOR DOW GLYCOLS SCOPE This general method is applicable to the analysis of ethylene, diethylene, triethylene, tetraethylene. propylene, dipropylene, and tripropylene glycols. Procedures are given for the determination of distillation range, specific gravity, acidity, inorganic chlorides, water, and color. Specific methods are avail able for each glycol separately covering its specification items. SAMPLING 1. APPLICATION This procedure is applic able to the sampling of glycol in tanks, tank cars, and tank trucks. 2. APPARATUS Use a suitable weighted bottle with a %-inch diameter opening fitted with a cork stopper. See Figure 2 of ASTM D270. 3. PROCEDURE (a) Lower the weighted, stoppered bottle as near as possible to the draw-off level. Pull out the stopper with a sharp jerk of the cord, and raise the bottle at such a rate that it is nearly (but not com pletely) full as it emerges from the liquid. (b) Stopper the bottle and wash off all traces of the glycol. Label the bottle and de liver to the laboratory for analysis. DISTILLATION RANGE 4. PRINCIPLE The distillation range is de termined essentially by ASTM Designation D 1078. The procedure is empirical and will give reproducible results only if the speci fied conditions are employed. 5. APPARATUS The apparatus as spec ified under ASTM Designation D 1078 is used with the following modifications: (a) Distillation flask. Use a standard 100ml Engler distillation flask for ethylene, propylene and dipropylene glycols and a standard 125-ml Engler distillation flask for diethylene, triethylene, tetraethylene and tripropylene glycols. (b) Thermometer. For all glycols except triethylene and tetraethylene glycols, this should be one such as ASTM 2C, 76-mm immersion, temperature range to include -5 to 300C., graduated m 13C An MCA R4 should be used in case of question or where greater accuracy is desired. Optionally, a platinum resistance thermometer may be used. For triethylene and tetraethylene glycols a thermometer such as ASTM 3C, 76 mm immersion, temperature range to 4003 C graduated in 1C should be used. 6. PROCEDURE Follow ASTM Designation D 1078 with two modifications: (a) Source of heat. When a gas burner is used, the flame shall never be so large that it spreads over a circle greater than 3Vi inches on the under surface of the asbestos board. (b) Dry point. Adjust the heat input if necessary so that the time required to reach the dry point after the liquid residue in the flask is approximately five ml does not ex ceed five minutes. 7. NOTE For correction of the boiling point for barometric pressure, the value of K is as follows: Ethylene glycol........... .... 0.042C per mm Diethylene glycol........ .... 0.049C per mm Triethylene glycol........ .... 0.054C per mm Tetraethylene glycol. .. .. 0.043'C per mm Propylene glycol......... . . 0 042C per mm Dipropylene glycol .... .... 0.050C per mm Tripropylene glycol...... .... 0055C per mm 51 SPECIFIC GRAVITY 8. PRINCIPLE The specific gravity in air at 20 or 25C is determined by weighing a known value of sample in a Lipkin bicapillary pycnometer. For a compk description of apparatus and procedure, see ASTM Desig nation D 941. 9. APPARATUS (a) Pycnometer, Lipkin bicapillary (b) Constant temperature bath, controlled to 20.00 or 25 00 0.05'C. Sargent S84805. or equivalent. (c) Analytical balance, sensitivity of 0.05 to 0.10 milligrams, either one or two pan type. (d) Analytical weights. Class S. These are calibrated and checked periodically against National Bureau of Standards weights. If a one pan balance is used, no weights are necessary. 10. PROCEDURE (a) Pour approximately 15 ml. of sample into a clean, dry, shallow dish (approximately 15 ml capacity), placed near the edge of the working desk to facili tate filling the pycnometer. Submerge the curved end of the pycnometer in the liquid. Carefully and slowly apply suction to the other opening and fill to the necessary vol ume. about "3 to 5 stem reading" To accom plish this, release suction just before the bulb of the pycnometer is filled, then re move the filling tip of the pycnometer from the sample just as the liquid begins to enter the second column. (b) Hold the pycnometer in a vertical posi tion and be sure there are no entrapped air bubbles in either the bulb or the calibrated stems. Place the pycnometer in a constant temperature bath for at least 20 minutes Hold the bath temperature to 20 00 or 25.00 0.05C during the determination (see 12a). (c) While the pycnometer is still in the bath, take readings and record. Dip the pycnometer in an acetone bath, then allow it to dry for five minutes and weigh. Run all determinations in duplicate. The results should not differ more than 0.0002 units 11 CALCULATION grams of sample (a) Sp. gr. at 20/20C = ml of sample x 0.99823 grams of sample (b) Sp. gr. at 25/25C = ml of sample x 0.99707 12. NOTES (a) A calibrated mercury ther mometer should be used for reading the temperature of the constant temperature bath. The thermometer should have 0.1 C graduations. (b) Optionally, a standard pycnometer may be used. See Method C of ASTM Desig nation D 891. 52 ACIDITY 13 PRINCIPLE The free acidity is titrated with a standard solution of sodium hydrox ide and calculated as acetic acid. 14 REAGENTS (a) Sodium hydroxide, standard 0.01 N solution This solution is standardized against hydrochloric acid. (b) Phenol red indicator. 0 05% solution Dissolve 11 gm. of the sodium salt of phenolsulfonephthalein (Eastman No. 6131) and dilute to two liters with water 15. PROCEDURE Dilute 50 ml of sample with 50 ml of distilled water in an Erlen- meyer flask. Then add four to six drops of phenol red and titrate the solution with 0 01 N NaOH to a permanent pink color which persists for 15 seconds. 16. CALCULATION (ml of 0.01 N NaOH) x 0.00060 x 100 (ml of sample) x sp. gr. = % acetic acid INORGANIC CHLORIDES 17. PRINCIPLE The inorganic chlorides are titrated with a standard solution of silver nitrate by the Volhard procedure 18. REAGENTS (a) Nitric acid. 1 10 solu tion in distilled water. (b) Silver nitrate, standard 0.01 N solu tion. Dissolve 1.7 grams of reagent grade silver nitrate in water and dilute to one liter Standardize against a standard solution of hydrochloric acid by the Volhard method (c) Ammonium thiocyanate, standard 0.01 N solution. Dissolve 0.761gram of recrystal lized ammonium thiocyanate in water and dilute to one liter. Standardize this solution against the 0.01 N silver nitrate solution (d) Volhard indicator Dissolve 100 grams of ferric ammonium sulfate. Fe?(NH.ih(SO,i)., 24H2O, with 15 ml of concentrated nitric acid and dilute with water to one liter. 19. PROCEDURE Pipet 50 ml of sample into a clean 250-ml Erlenmeyer flask and dilute with 50 ml of distilled water Add about one to two ml of dilute nitric acid from a dropping bottle. Add approximately one ml of Volhard indicator and one ml of 0.01 N ammonium thiocyanate from a buret. Titrate to a white end-point with silver nitrate. Add about two ml in excess and back titrate with 0.01 N ammonium thio cyanate until the first appearance of a pink color which remains for one minute. The total ml of 0.01 N silver nitrate, minus the total ml of 0.01 N ammonium thiocyanate, is equivalent to the chlorides present in the sample. This is the net ml of 0 01 N silver nitrate. 20. CALCULATION (net ml N/100 AgNQi) x 355~4 x 100 = % chlorides ml of sample x sp. gr. O c r c WATER 21. PRINCIPLE In an alcohol-pyridine solu tion. iodine is not reduced by sulfer dioxide unless water is present. Karl Fischer reagent, which contains all of these components ex cept water, can be used for titrating the latter. The brown iodine color of the reagent changes to yellow as long as water is avail able to permit the reaction to proceed. The determination is based on the following re action in solution and appears to take place in two distinct steps: CsHsN I2 + CsHsN SO2 + CsHsN + H2O-- H SO2 2CsH5N + CsHsN^ \\ SO2 H CsHsN + ROH------- CsHsN^ \ SO4 R 22. REAGENTS (a) Methanol (anhydrous). (b) Solution W, water-in-methanol stand ard. Pipet 2 5 ml of water into a liter volu metric flask. Dilute to the mark with anhydrous methanol and mix well. (c) Karl Fischer reagent can be obtained from laboratory supply houses. It is pre pared as follows: (1) Dissolve 127 grams of finely granu lated iodine in 1200 ml of anhydrous meth anol (less than 0.05 la water) contained in a two-liter, brown, glass-stoppered bottle. Add 395 grams of anhydrous pyridine and mix thoroughly. (2) Connect a sulfur dioxide cylinder to the reagent bottle through a one-gallon bottle arranged as a trap. Use glass delivery tubing with rubber connectors. (3) Place the reagent bottle on a large solution balance, and add 95 grams of sulfur dioxide in small increments. Cool the solu tion. Dilute to volume with methanol and mix thoroughly. This reagent loses strength gradually It must be standardized daily. 23. APPARATUS Any suitable Karl Fischer apparatus for water determinations in cluding automatic 25-ml burets of a type which minimizes errors due to reaction of the reagents with atmospheric moisture. See ASTM D 1123. Optionally, an instru ment for detection of the "dead-stop" end point such as the Beckman Aquameter may be used 24. STANDARDIZATION OF REAGENTS (a) Add an excess of Fischer reagent to 25 ml of methanol. Back-titrate to the end point with solution W. This procedure will remove the last traces of water from the methanol and leave it neutral with respect to Fischer reagent. (b) Add an excess of three to five ml of Fischer reagent to the dry methanol, and record the exact amount. (c) Titrate the excess Fischer reagent with solution W. Repeat several times and com pute the average equivalence ratio between the Fischer reagent and solution W: F _ ml of Fischer reagent a ~~ ml of solution W (d) Add an excess of Fischer reagent to 25 ml of methanol and back-titrate to the end-point with solution W. (e) Add approximately 0.05 gram of water to the dried methanol. Record the exact weight to the nearest 0.1 mg. Use a Lunge pipet or a one-ml syringe and needle. (f) Add an excess of two ml of Fischer reagent. Record the exact amount. (g) Back-titrate with solution W. Com pute the water equivalent (Ff) in grams of water per ml of Fischer reagent: ^gm of water added (ml of Fischer) - Fa(ml of solution W) 25. PROCEDURE (a) Add an excess of two to five ml of Fischer reagent to about 25 ml of methanol. (b) Back-titrate to the end-point with solu tion W. (c) Add a 50-ml sample to the neutralized methanol. (d) Add an excess of two ml of Fischer reagent. Record the exact amount. (e) Back titrate the excess Fischer rea gent with solution W. Record the titration. 26. CALCULATION Where. net ml of Fischer = (ml of Fischer) - Fa(ml of solution W). then ((mnel, tomf.--ls-a-o-mf--Fp- li--esc)-h-x-e--rs)--p-x.--g-F-r-.fx 100 = %0/water. APHA COLOR 27. PRINCIPLE A sample is compared with APHA standards. The APHA color number of a standard which most nearly matches the sample is reported as the color of the sample 28. APPARATUS (a) Nessler tube. 100-ml. matched. (b) Hellige comparator, with color disc 0-50, color disc 0-100. two comparator tubes and plungers. 29. REAGENT Platinum-cobalt color stand ard. This standard is useful where a Hellige comparator is unavailable. Dissolve 1.245 grams of potassium chloroplatinate (K2PtCU). containing 0.500 gram of plati num, and one gram of crystallized cobaltous chloride (C0CI2 6H2O), containing about 0 25 gram of cobalt, in water with 100 ml of concentrated hydrochloric acid. Dilute to one liter with distilled water. This solution has an APHA color of 500. 53 30 PROCEDURE (Using the Hellige Com parator) Fill the tube on the left side of the comparator with distilled water and insert the plunger Put the sample in the tube on the right and close the instrument. Compare the colors by rotating the color wheel on the instrument. Read the closest matching color from the circular opening beneath the prism housing within the light shield. Re cord this as the APHA color. 31. PROCEDURE (Using Solution Color Standards) (a) Prepare standards having APHA colors of 5. 10. 15....... 30. etc., by diluting 1.0. 2.0. 3.0___6.0 ml., etc., of the above solution in Nessler tubes to 100 ml with water. Stopper the tubes when not in use to prevent evaporation and dust contamination. (b) Pour the sample into a clean, dry Nessler tube to the 100-ml mark and com pare with the standard by looking down through the Nessler tubes against a white background. Report as the APHA color the number of the standard which most nearly matches the sample. REFERENCES 32. LITERATURE REFERENCES (a) Lipkm. M. R.. Davison. J. A . Harvey, W. T., and Kurtz. S. S.. "Pycnometer for Volatile Li quids." Ind. Engr. Chem., Anal. Ed., 16. 55 (1944). (b) Almy. E. G.. Griffin, W. C., and Wilcox. C. S., "Fischer Volumetric Determination of Water," Ind. Eng. Chem.. Anal. Ed., 12. 392- 396 (1940). (c) Mitchell, J . and Smith. D. M.. "Aquam- etry," Chapter 2. Interscience Publishers. New York. N. Y. (d) American Society for Testing and Ma terials, 1916 Race Street. Philadelphia 3. Pa.: "Distillation Range of Lacquer Solvents and Diluents." D 1078. "Density and Spe cific Gravity of Hydrocarbon Liquids by the Lipkin Bicapillary Pycnometer," D 941: "Spe cific Gravity of Industrial Aromatic Hydro carbons." D 891: "Color of Clear Liquids (Platinum-C-bait Scale)." D 1209: "Sam pling Petroleum and Petroleum Products," D 270. ST0278427 54 >.... . -- APPENDIX CONVERSION CHART FOR AQUEOUS ETHYLENE GLYCOL SOLUTIONS FIGURE A-1 mole FRACTI0N glycol 0 Z *l0 L Z 0 IS 55 CONVERSION CHART FOR AQUEOUS DIETHYLENE GLYCOL SOLUTIONS FIGURE A-2 MOLE FRACTION GLYCOL CONVERSION CHART FOR AQUEOUS TRIETHYLENE GLYCOL SOLUTIONS FIGURE A MOLE FRACTION GLYCOL 10 56 CONVERSION CHART FOR AQUEOUS TETRAETHYLENE GLYCOL SOLUTIONS FIGURE A-4 CONVERSION CHART FOR AQUEOUS PROPYLENE GLYCOL SOLUTIONS FIGURE A-5 ui --i o no i CO CO o 57 CONVERSION CHART FOR AQUEOUS DIPROPYLENE GLYCOL SOLUTIONS FIGURE A-6 MOLE FRACTION GLYCOL MOLE FRACTION GLYCOL ie<l01L201S CONVERSION CHART FOR AQUEOUS TRIPROPYLENE GLYCOL SOLUTIONS FIGURE A- WEIGHT PERCENT GLYCOL 58 Properties and uses of Glycols ; >sfe<^^**.k5.*r*r-*4"5V'i Ife' >_.. AREA HEAOQUARTStS .;-te$pa* CHEMICAL U.S.A.,-!...... ....... ...... MIDLAND. Michigan 0$ga* CHEMICAL LATIN'AMERICA. f^fpQW CHEMlCALEUROPE S.A ...... LM-$nuf CHEMICAL PACIBC.. '.-jr.',' . CORAL GABLES. Florida ..... ZURICH, Switzerland ..... HONG KONG, B C.C. CHEMICAL OF CANADA LIMITED DOW CHEMICAL U.SJL SALES OFFICES r^.<* .......SARNIA. Ontario `4M.ri-^TLANTA..... ,r^v^TON ROUGED.... .. 1515 Lenox Towers, 3400 Peachtree Rd.. N. E.. Atlanta. Ga. 30326 2526 Sherwood Forest Blvd., Baton Rouge. La. 70816 ' :>>bOSTON.... ................................................. 1330 Boylston St.. Chestnut Hill. Mass. 02167 ' ;tBUFFALO.',,'........ ............. ..................... 560 Delaware Ave.. Buffalo. N. Y 14202 `CHARLOTTE...... Suite 120.2 Woodlawn Green. Woodlawn Road. Charlotte. N.C. 28210 .CHICAGO .................................... 1400 East Touhy Ave.. Des Plaines. Ill 60018 CINCINNATI :I. ..'jg*-......... .-Colonial Center Bldg.. 5725 Dragon Way. Cincinnati. 0 45227 -f- ^CLEVELAND__ ....................... ................ .................... 55 Public Square. Cleveland. O. 44113 ^BALIAS . ...... .................. ..................... 1401 Elm Street. Dallas. Texas 75202 ^^bEreOrr Northland Towers West. 15565 Northland Dr.. Southfield. Mich, 48075 if^i^GRAND RAPIDS.......CSiroelot East Bldg.. 3446 Lake Eastbrook Blvd.. Grand Rapids. Mich. 49508 P. O. Box 3387. Attn: Sales Office. Houston. Texas 77001 fr........ P. O. Box 88350. Indianapolis. Ind. 46208 P. O. Box 13646. Kansas City. Mo. 64199 P. O. Bin 48, Pasadena. California 91109 ..,,1220 Clark Tower. 5100 Poplar Avenue. Memphis. Term. 38137 ... .........^fcr.4901 West 77th St.. Minneapolis. Minn. 55435 Rockefeller Plaza. New York. N. Y. 10020 .rMr^SJ.'.^^gj^Parfc 80 Plaza East. Saddle Brook. N. J. 07662 P. O. Box 350. Moorestown. N. J. 08057 \ Four Gateway Center, Suite 1313. Pittsburgh. Pa. 15222 800 Pierre Laclede Center. 7733 Forsyth Blvd.. St. Louis. Mo. 63105 .... ."...i.'.i.'i.-.. 350 Sansome St.. San Francisco. Cal. 94106 777-106th St.. N. E. Bellevue. Wash. 98004 Washington Plaza. 1351 Washington Blvd.. Stamford. Conn. 06902 booklet Is presented In good faith, but no warranty, express or impSsd. a owned by The Dow Chemical Company or by others to be inferred. <**-*. ' -Ls... * & ,;SU - . DOW CHEMICAL U.S.A. AN OPMATING UNIT OF TH 00W CHCMtCAL COMPANV AG-ORGANICS DEPARTMENT MIDLAND. MICHIGAN 48640 ST0278432 TEMPERATURE CONVERSION DATA FIGURE A-8 F -940 -76.0 -58.0 -40.0 -22.0 - 4.0 - 2.2 - 0.4 + 1.4 + 3.2 + 5.0 + 6.8 + 8.6 + 10.4 + 12.2 + 14.0 + 15.8 + 17.6 + 194 + 21.2 + 23.0 + 24 8 + 26 6 + 28.4 + 30.2 + 32.0 + 33.8 + 35.6 + 37.4 + 39.2 + 41.0 + 42.8 + 44.6 + 46.4 +48.2 + 50.0 + 51.8 + 53.6 + 55.4 + 57.2 + 59.0 + 60.8 + 62.6 + 64 4 + 66.2 +68.0 + 69 8 + 71.6 + 73.4 + 75.2 + 77.0 + 78.8 + 80.6 + 82.4 + 84.2 + 86.0 + 87.8 + 89.6 + 91.4 + 93.2 + 95.0 + 96.8 + 98.6 + 100.4 + 102.2 TEMP. -70 -60 -50 -40 -30 -20 -19 -18 -17 -16 -15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5 +6 +7 +8 +9 + 10 + 11 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19 -20 + 21 + 22 + 23 + 24 + 25 + 26 + 27 + 28 + 29 + 30 + 31 + 32 + 33 + 34 + 35 + 36 + 37 + 38 -39 1 'C F -56.67 + 104.0 -51.11 ! +105.8 -45.56 1 +107.6 -40.00 I +109.4 -34.44 | + 111.2 -28.89 | + 113.0 -28.34 + 114.8 -27.78 + 116.6 -27.23 | + 118.4 -26.67 | + 120.2 -26.12 + 122.0 -25.56 | + 123.8 -25.00 + 125.6 -24.44 + 127.4 -23.89 | + 129.2 -23.33 | + 131.0 -22.78 | + 132.8 -22.22 + 134.6 -21.67 + 136.4 -21.11 | -r 138.2 -20.56 | + 140.0 -20.00 + 141.8 -19.44 1 + 143.6 -18.89 | --145 4 -18.33 + 147.2 -17.78 + 149.0 -17.22 + 150.8 -16.67 | +152.6 -16.11 + 154.4 -15.56 | +156.2 -15.00 | + 158.0 -14.44 +159.8 -13.89 + 161.6 -13.33 + 163.4 -12.78 + 165.2 -12.22 + 167.0 -11.67 + 168.8 -- 11.11 +170.6 -10.56 | +1 72.4 -10.00 +174.2 - 9.44 + 176.0 - 8.89 | + 177.8 - 8.33 + 179.6 - 7.78 + 181.4 - 7.22 + 183.2 - 6.67 + 185.0 - 6.11 | + 186.8 - 5.56 1 + 188.6 - 5.00 + 190.4 - 4.44 + 192.2 - 3.89 1 + 194.0 - 3.33 | + 195.8 - 2.78 + 197.6 - 2.22 1 + 199.4 - 1.67 , +201.2 - Ill + 203.0 - 0.56 + 204.8 + 0.00 + 206.6 + 0.56 + 208.4 + 1.11 + 210.2 -r 1.67 + 212.0 + 2.22 + 230.0 + 2.78 + 248.0 + 3.33 + 266.0 - 3.89 + 284.0 TEMP. + 40 + 41 -42 + 43 + 44 + 45 + 46 + 47 +48 +49 + 50 + 51 + 52 + 53 + 54 + 55 + 56 -- 57 + 58 + 59 + 60 -61 +62 + 63 +64 +65 +66 + 67 + 68 + 69 + 70 + 71 + 72 + 73 + 74 + 75 + 76 + 77 + 78 + 79 + 80 + 81 +82 + 83 + 84 +85 + 86 + 87 + 88 + 89 + 90 + 91 + 92 + 93 + 94 + 95 + 96 + 97 + 98 + 99 + 100 + 110 + 120 + 130 + 140 C + 4.44 + 5.00 + 5.56 + 6.11 + 6.67 + 7.22 + 7.78 + 8.33 + 8.89 + 9.44 + 10.00 + 10.56 + 11.11 + 11.67 + 12.22 + 12.78 + 13.33 + 13.89 -14 44 -15.00 + 15.56 + 16.11 + 16.67 -17.22 + 17.78 + 18.33 +18.89 +19.44 + 20.00 + 20.56 + 21.11 + 21.67 + 22.22 + 22.78 + 23.33 +23.89 + 24.44 + 25.00 + 25.56 + 26.11 + 26.67 + 27.22 + 27.78 + 28.33 + 28.89 +29.44 + 30.00 + 30.56 + 31.11 + 31 67 + 32.22 + 32.78 + 33.33 + 33.89 + 34.44 + 35.00 + 35.56 + 36.11 + 36 67 + 37.22 + 37.78 + 43.33 + 48.89 + 54.44 + 60.00 F TEMP. 3C +302.0 + 320.0 + 338.0 + 356.0. + 374.0; +392.0 +410.0 +428.0+446.0 + 464.0 + 482.0 + 500.0 + 518.0 + 536.0 + 554.0 + 572.0 + 590.0 + 608.0 +626.0 + 644.0 +662.0 + 680.0 + 698.0 -r 71 6.0 + 734.0 + 752.0 + 770.0 + 788.0 +806.0 +824.0 +842.0 +860.0 +878.0 + 896.0 + 914.0 + 932.0 + 950.0 + 968.0 + 986.0 + 1004.0 + 1022.0 + 1040.0 + 1058.0 + 1076.0 1 +1094.0 + 1112.0 + 150 + 160 + 170 + 180 + 190 +200 + 210 +220 +230 + 240 +250 +260 +270 + 280 +290 + 300 + 310 + 320 + 330 + 340 + 350 + 360 + 370 + 380 + 390 + 400 +410 +420 + 430 + 440 + 450 + 460 + 470 +48Q + 490 + 500 + 510 + 520 + 530 + 540 + 550 + 560 + 570 + 580 + 590 + 600 + 65.56 + 71.11 + 76.67 + 82.22 + 87.78 + 93.33 +98.89 + 104.44 + 110.00 + 115.56 + 121.11 + 126.67 + 132.22 + 137.78 + 143.33 + 148.89 + 154.44 + 160.00 -165.56 -171.11 -176.67 -182.22 + 187.78 + 193.33 + 198.89 + 204.44 + 210.00 + 215.56 -221.11 + 226.67 + 232.22 + 237.78 + 243.33 + 248.89 +254.44 + 260.00 +26556 + 271.11 + 276.67 -282.22 -287.78 + 293.33 + 298.89 + 304.44 -310.00 + 315.56 INTERPOLATION FACTORS F 1.8 1 3.6 i 5.4 7.2 9.0 10.8 12.6 14.4 16.2 18.0 TEMP. 1 2 3 4 5 6 7 8 9 10 C 0.56 1.11 1.67 2.22 2.78 3.33 3.89 4.44 5.00 5 56 CONVERSION FORMULAE F = (1.8 x C )+ 32 C = (F - 32) 1.8 59