Document o9arJEXMmN7akQKz5o7ED238g

/ --JS Chemical Research Report No. 633 --*-- /-n ,'ONFIDENTIAL INTERIM REPORT DEGRADATION OF ARCCLOKG MONSANTO CHEMICAL COMPANY RESEARCH AND ENGINEERING DIVISION Chemical Research Department Dayton, Ohio ot i:. iiiliN'SANTO CHEMICAL COMi Job No . : A-40L2 'Written: July 09, 193^ Typed: November p, 195^ A. 3. Kenyon W. A. 'White Prepared by: A. S. Kenyon W. A. White 0690365 HARTOLDMON0005071 Chemical Research Report No 833 Copy No DISTRIBUTION SHEET J. J. Healy - St. Louis H. G. Johnson - " -3r~9^Central Report Files-" H. K. Nason - " H. L. Hubbard - " A. M. Ellenburg - " E. W. Gluesenkamp R. L. Jenkins R. A. Ruehrwein A. S. Kenyon Extra Extra Extra Copy No. 1 2 3 4 5 6 7 8 9 10 11 12 1? i 0690366 I HARTOLDMON0005072 TABLE OP CONTENT, Tage No INTRODUCTION II. SUMMARY III. CONCLUSIONS IV. USES AND APPLICATIONS V. REFERENCES A. Literature References B. Patent References C. Reference to Previous Work at Monsanto VI. EXPERIMENTAL WORK A. Raw Materials B. Apparatus 1. Aroclor degradation 2. Continuous primary degradation of chlorobenzene 3. Resistivity measurements C. Experiments 1. Thermal degradation 2. Ultraviolet absorption spectra 3. Photodegradation 4. Effect of added impurities 5- Reduction of resistivity by hydrogen chloride 6. Chlorobenzene reactions 7- Stabilizers 8. Syntheses of compounds I 1 2 3 3 3 4 4 5 5 5 5 6 6 6 6 7 7 9 10 11 13 13 0690367 HARTOLDMON0005073 TABLE OF CONTENTS (Contd.) VII. DISCUSSION A. Thermal Degradation of Aroclors B. Ultraviolet Spectra of Aroclors C. Photodegradation of Aroclors D. Effect of Addition of Impurities E. Prototype Studies 1 P. Aroclor Stabilization VIII . RECOMMENDATIONS IX. DESCRIPTION OF RECOMMENDED PROCESS X . FATENT STATUS XI . COST ESTIMATES XII. ANALYTICAL PROCEDURE XIII. TOXICITY AND HAZARDS XIV. XV. ACKNOWLEDGMENT APPENDIX Page No. 15 15 16 16 18 20 23 2 it 25 25 25 25 26 26 26 0690368 HARTOLDMON0005074 TABLES Table 1 II III IV V VI Title Thermal Degradation of Aroclors at 25>0C. Thermal Degradation of Fractionated Aroclor 1242 Specific Extinction Coefficients for Various Lots of Aroclor 1242 Effect of Various Additives as Im purities in Aroclor 1242 Effect of Dissolved HC1 on the Re sistivity of Aroclor 1242 Stabilization of Resistivity of Aroclor 1242 0690369 'l HARTOLDMON0005075 FIGURES Figure 1 ? 3 U 3 6,7, $ 9,10 11 1? 13 14 Title Thermal Degradation Apparatus Photochemical Degradation Apparatus Continuous Photochemical Degradation Apparatus for Chlorobenzene U.V. Absorption Spectra of Aroclors 1221, 1232, 12112 and 1246 U.V. Absorption Spectra of Aroclors 1231+, 1260, 1262 and 1268 U.V. Absorption Spectra of Fraction ated Aroclor 1242 U.V. Absorption Spectra of Fraction ated Aroclor 1254 Photodegradation of Aroclor 1242 Resistivity vs. Time Resistivity of Aroclor 1242 with Added Trlphe.iyInethyl Cl.' 'ride U.V. Absorption Spectra of Chloro- ' benzene Degradation Products Infrared Absorption Spectra of Chloro benzene to Degradation Products 0690370 HARTOLDMON0005076 n ONnr>{--N riAL I, INTRODUCTION Monsanto manufactures large quantities of chlorinated bi phenyls (Aroclor series 12) which are sold as dielectric fluids. Research to Improve the Aroclors is part of a con tinuing program within Monsanto for better products. Degrad ation c' Aroclors, which leads to loss in electrical resis tivity, is one of the shortcomings of these dielectrics, es pecially since only very minor degradation could cause serious breakdown in electrical equipment. The purpose of this study was to determine what factors are involved in degradation and what, can be done to prevent the degradation. This study re sulted from customer requests for higher stability in Aroclors in order that better electric equipment might be produced. II . SUMMARY Since the stability of Aroclors depends upon the degree of -chlorination, the variation of Aroclor structure as it affects stability was determined by ultraviolet absorption spectra. The variation between fractions- of fractionated Aroclor 12*42 and of unfractioned Aroclor 125*1 was studied by ultra violet absorption spectra, The thermal degradation of frac tionated 12*12 was measured at 250C. and the amount of hydro gen chloride liberated was determined. Aroclor 12*12 was degraded by ultraviolet light in vacuo and the decrease in electrical resistivity with Irradiation time was measured. It was possible to remove the conducting material and restore the resistivity to its original value by passing the degraded material over activated alumina. How ever- further exposure of the purified n.-celor to radiation again lowered the resistivity. The plot of resistivity ver sus time of irradiation resembled a conductivity versus con centration curve for a weak electrolyte. The resistivity of the photo-degraded Arcelor reached a constant value after ap proximately 2*1 hours irradiation but degradation evidently continued since the yellow color increased with time of irradiation. oome information on the conducting material produced in Aroclor degradation was obtained by adding various types of compounds which could act as precursors for the conducting material and observing the effects of these additives when the mixture is irradiated. Possible precursors were used 0690371 HARTOLDMON0005077 because the conducting material could not be isolated from the degraded mixture. Additional information on the degradation mechanism was obtained by prototype studies using chlorobenzene. As a re sult a reasonable mechanism has been postulated for the photodegradatlon of Aroclor and other halogenated aromatic compounds. The effectiveness of several organometallic compounds as photostablllzers for Aroclor was measured; of those tested, tetraethyl lead was the most effective. HI. CONCLUSIONS The loss of electrical resistivity is caused by the photodegradat.lon of the Aroclor molecule Itself but may also be affected tc a minor extent by trace impurities. The amount of degradation is small but nevertheless sufficient to cause the resistivity to decrease below an acceptable minimum. The thermal degradation of Aroclors is minor compared to the photochemical degradation. Thermal treatment causes re lease of a small amount of hydrogen chloride initially, but this evolution ceases after a short time. Such behavior is attributed to thermal degradation of impurities. If Aroclor is irradiated then exposed to a thermal treatment, appre ciably more hydrogen chloride is liberated. This indicates that the hydrogen chloride is developed by a photoreaction and that the photodegraded material is more unstable than Aroclor itself. The primary reaction occurring ir. '-e photodegradation of Aroclor or other halogenated aromatic compound at wave lengths greater than 2800 8 is the hemolytic cleavage of the carbon-chlorine bond to give an aromatic or aromatic-substi tuted free radical and a free chlorine atom. This free chlcr ine atom car. enter into further reactions in a number of ways The chlorine atom can abstract a hydrogen atom and form hy drogen chloride or it may form an addition compound with Aroclor or a halogenated aromatic compound. The loss of resistivity can be attributed to the forma tion of hydrogen chloride and a conducting chlorine addition compound which contains a number of phenyl groups attached to an aliphatic or allcycllc carbon bearing a chlorine. As such a complex possesses sufficient planarity for resonance 0690372 3. stabilization,, a stable carbonlum ion can be formed in the Aroclor medium. Aroclors cannot be completely stabilized by additives which scavenge hydrogen chloride since the conductivity is only partially due to liberated hydrogen chloride. The pro posed degradation mechanism indicates that the free chlorine atom and its reactions are responsible for the loss of resis tivity. Elimination of chlorine atoms before they react will stabilize Aroclor against photodegradatlon. Stabilization by the use of metallic organic compounds, such as tetraethyl lead or diphenyl dibuty] tin, offers some possibility. The ultraviolet absorption spectra for Aroclors show the characteristic, absorption due to resonance of the coplanar benzene rings except for those Aroclors that possess resonance restricting ortho substitution. Aroclors will degrade photochemical 1y regardless of the purity of the sample since the Aroclor molecule Itself is unstable. No amount of purification will stabilize the Aroclor. Stabilization can only be accomplished by the use of additives. The rate of degradation of Aroclors is accelerated by the addition of impurities such as phenyl alkanes or chlorinesubstituted phenyl alkanes. The degradation of chlorobenzene, a prototype for Aroclor, shows the formation of hydrogen chloride and the loss of elec trical resistivity due to the formation of chlorine addition compounds which eventually lead to highly substituted phenyl alkanes. The mechanism of the chlorobenzene photodegradation is considered representative of Aroci.. degradation. IV. UdK.'i AND APPLICATIONS Aroclors may be stabilized by certain metallic organic compounds. Tetraethyl lead exhibits the greatest stabilizing effect of many compounds tested but leads to a slight precip itate. This additive, as well as similar ones, should be fur ther evaluated and its possible use as a phctostabillzer should be brought to the attention of our customers. V. REFERENCES' A. Literature References 1. Berberieh, L. J., and Friedman, P., Ind . Eng. Char. AO, 117 (1948). 0690373 2. Hantzch, A., and Jochem, E,, Per. 34, 3337 (1901) 3. Noyes, W. A., Organic Synthe sis , Vol . 2, page 108 4. Brown, H. C., and Fletcher, E. A., J. Am. Chem. Soc. 73, 2808 (1951). 5. Ziegler, K., and Mathes, W., Ann. 479,. HI (1930) 6. Pray, H.A.A., J. Phys. Cbem. 30, 1477 (1926). 7. Lindsey, R. V., Jr., and Ingraham, J. N., J. Am. Chem. Soc. 75, 5613 (1953). B. Patent References 1. Jcnkino, R. L. (to Monsanto), 'J.S. 2,578,559. December XI, 1951- "Stabilization of halogenated organic compounds with dibutyl dipher.yl tin." 2. Clark, F. M. (to General Electric), U.S. 2,468,544. April 26, 1949. "Stabilized halogenated coraposl- tions and electrical devices." 5- Jenkins, R. L. (to Monsanto), U.S. 2,646,403. July 21, 1953. "Halogenated aromatic hydrocarbon dielectrics. 4. Hardy, E. E. (to Monsanto), U.S. 2,566,196. August 28, 1951. "Chlorinated aromatic dielec trics." 5. Carothers, i'. H. (to Dv'-nt), U.S. 2,008,003. July 16, 1935' "Lead phenolate." 6. Mack, G. P. (to Advance Solvents), U.S. 2,628,211. February 10, 1953. "PVC resins stabilized with polystannoxanediol esters." C. Reference to Previous Work at Monsanto 1. 'White, W. A., and Ruehrwein, R. A., Central Re search Report No. 543, January 11, 1949. "Light stability of electrical resistivity of Aroclor 1254. 0690379 VI. EXPERIMENTAL WORK A. Raw Materials All Aroclor sarapj.es used in these experiments were supplied by the Inorganic Division at Anniston, Alabama. The following Aroclors were used: Aroclor 1221 Aroclor 12J2 Aroclor 1242 Aroclor 1248 Aroclor 1254 Aroclor 1260 Aroclor 1262 Aroclor 1268 Lot 47-741 Lots lr2 and 170 Lot 1705 Lot 1851 Lot 1379 Lot 16 Lot 18. The sources of the stabilizers, precursors, etc. are given in Tables IV and VI. All materials synthesized in this laboratory for these experiments are noted in these Tables and the syntheses are described elsewhere in tills report. B. Apparatus 1 . Aroclor degradation a. Thermal degradation Tills apparatus, shown in Pig. 1, consists of a pot furnace containing Dow Corning Fluid 200 as an oil bath, a bubbler tube containing the Aroclor sample, and an HC1 trap containing standardized NaOH. Nitrogen was bubbled through the oil bath to prevent polymerizetion and through the sample bubbler tube to sweep the HC1 over j,,co the HC1 trap. Knobs were bluwn on the HC1 trap to give the gas bubbles longer contact time with the NaOH solution. b, Photochemical degradation In the preliminary irradiations the samples, contained in a beaker and stirred with a magnetic stirrer, were irradiated by an S4 lamp, placed about 8 in. from the beaker. A reflecting baffle was placed around the entire set-up. A calculation from the specific extinction coefficient of Aroclor 1242 showed that 50% of the light of 3000 ft was absorbed in a distance of 1^**.. Therefore, an 0690375 I I HARTOLDMON0005081 6. apparatus was set up, as shown in Fig. 2, in which an ever changing film of Aroclor could bo irradiated. This appara tus consisted of an irradiation box with an elliptical re flecting surface inside. The sample tube wan placed at one focal point of the ellipse and rotated by a motor to form a thin film on the wall of the sample tube. A 3-A nun lamp was placed at the other focal point of the elliptical reflec ting surface. Two fans on the back of the apparatus pulled air through the box, thereby cooling the sample tube. 2, Continuous primary degradation of chlorobenr.ene An attempt was made to degrade and to collect continuously the primary degradation products of chloroben zene, without further degrading them. The apparatus used, shown in Fig. 3, consisted of a 200-ml. round-bottom distil lation flask, a distillation column, a condenser, a quartz irradiation zone, a return line and trap and an AH-b sun lamp. The flask was sealed to the distillation column and the return trap and was fitted with a thermometer well and filling tube. The chlorobenzene was charged to the flask, which was then sealed off under vacuum. The distillation column was wrapped with asbestos tape, while the flack, con denser and trap were protected from irradiation by tin foil; thus, only the quartz irradiation zone was exposed to light. An elliptical reflecting shield was placed around the irra` diation zone and the AH-A lamp and the apparatus was covered from above with tin foil. This increased the efficiency of the AH-A lamp. The inner tube in the irradiation zone caused the distillate to spread in a thin film. 3. Resistivity measurements The resistivities were isured with a General Radio Megohm bridge, Type 544B. The three conductivity cells, made by J. C. Balsbaugh Co., had an approximate cap acity with air as the dielectric of f. and cell con stants of 35, 555 and 574 ems. respectively. All resistivi ties were measured at 25 + .03 C. C. Experiments 1 . Thermal degradation Thermal degradation experiments wore carried out at 250C. on various Aroclors as shown in Table I and at 2!l3C. on various fractions of Aroclor 1242 as shown in Table II . The sample to be evaluated was placed in the ap paratus, Fig. 1, and brought to the desired temperature. 0690376 V HARTOLDMON0005082 7. Nitrogen was passed through the sample to sweep the HC1 lib- erated by the thermal degradation into the HC1 trap. After various heating cycles, as shown in Tables I and II, tne sampie of 0.02N NaOH in the HC1 trap was removed and acidified with 2 ml. of 0.9N HNO3. Tnen, 2 ml. of O.OlBN AgNOj was added and the chloride ion was determined turbidimctrically. It was found that hydrogen chloride was only evolved during tho first J-l/2 hrs. and that additional heating produced no more hydrogen chloride. The additional 1-1/2 hr. or a total of 5 hrs. heating was adopted to insure complete removal of all hydrogen chloride. Aroclor 1242, Lot 170, was photodegraded in air for 240 hrs. and then thermally degraded at 243C. for 5 hrs. The photodegraded Aroclor liberated 22.6 x 10' g. of HC1 per gram of Aroclor during the above thermal degradation, compared to 2.13 x 10' g. of HC1 when this Aroclor was sub jected to heat alone. 2, Ultraviolet absorption spectra The ultraviolet absorption spectra of Aroclors 1221, 1232, 1242, 1248, 1254, 1260, 1262 and 1268 and vari ous fractions of Aroclors 1242 and 1254 were measured with a Cary Recording Ultraviolet Spectrophotometer. These spectra were measured on approximately 0.000655 solutions of the Aroclors in absolute alcohol using a 1-cm. cell. The re sults are shown in Rigs. 4-10 expressed as specific extinc tion coefficient versus wave length in rry^'s. The specific extinction coefficient is defined as ' S ; f ' K = log Io4 / or ____ optical density / be coll ..ickncss in ems x cone. In g./liter The ultraviolet absorption spectra were also measured on sev eral lots of Aroclor 1242 submitted by Anniston. The results are shown in Table III for Aroclor 1242, Lots 166, 170, 174, 179, l8l. These results are tabulated since plots of extinc tion coefficients vs. wave length were 30 similar that little or no difference was detectable. The slight differences be tween lots are more clearly shown in the Table giving optical density and specific extinction coefficient for each wave length. 3. Photodegradation Aroclor 1242 was photodegraded in air for 100 hrs., 0690377 1 HARTOLDMON0005083 8. in the f.lrst photodegradation apparatus described above. Dur ing this treatment the volume resistivity of the Aroclor changed from 9.7 x lcA* ohm ems. to 1.4 x 1011 ohm. ems. A 50^ solution of the degraded Aroclor in heptane was then sep arated chromatographicaliy by passage through a column of activated alumina. A very dark yellow band appeared at the top of the column while the Aroclor-hcptane solution wa3 clear, resembling unirradiated Aroclor. After the heptane was distilled off, the recovered Aroclor 1242 had a resistiv ity of 1.2 x 1012 ohm ems. The recovered Aroclor was again exposed to the S-4 lamp for 240 hrs. and the irradiated sam ple was recovered as described; its resistivity was 1.3 x 1011 ohm. ems. The isolation of the degraded material from Aroclor which was adsorbed on alumina was attempted by treat ment of the column with heptane. After JO washes with hep tane, the eluate still contained 0.0118 g. Aroclor 1242/ liter, wlille the brown layer had not moved during elution. Other solvents ranging in polarity from hydrocarbons to water were tried as eluants but none was effective. Since these washings did not separate the adsorbed material, isolation of the degraded materials by this method was abandoned. Aroclor 1242 was irradiated in vacuo for a total of 210 hrs. by the S-4 lamp in the elliptical irradiation apparatus (Fig. 2). At intervals samples were removed and the resistivity was measured. A plot of resistivities vs. time of irradiation is shown in Fig. 11. The initial resis tivity of 1 x lO^2 ohm ems. dropped rapidly during the first 24 hrs. of irradiation but the drop thereafter was only slight, The final resistivity after 210 hrs. exposure was 1 x 10^1 ohm ems. The resistivity stability of Aroclor 1?6? was compared with that of Aroclor 1242 upon irradiation for onehalf and for five hrs. Benzene (29>;S by weight) was added to the Aroclor 1262 to facilitate handling. The measured re sistivities (ohm ems.) are as follows: | j ' Aroclor 1242 Aroclor 1262, 265? benzene Initial 7.7 x 10n 1/2 hr. 6.9 x 1010 5 hrs. 9.9 x 109 1.2 x 1012 2.1 x 10n 7.3 x 1010 0690378 HARTOLDMON0005084 9. It was considered that Aroclor could contain some impurities which would lead to the formation of conducting materials on irradiation and that such impurities might be oxygen-, nitrogen-, or sulfur-containing compounds which should be removable by washing with cone. H^SOi^. Aroclor 1242, Lot 152, was extracted three times with cone. H2SO4 and then washed with water, alcoholic KOH and finally with distilled water until the washings were neutral. The Aroclor was dried by a vacuum technique. Its resistivity was 1.93 x 101 ohmems. compared to 7.7 x 10^1 ohm ems. The Aroclor was then passed over alumina, and the resistivity rose to 8.2 x 1CA? ohm ems. The HgSO/j-washed Aroclor was irradiated 20 hrs. by the S-4 lamp and the resistivity dropped to 1.9 x 10^ ohm ems. compared to a resistivity of 2.5 x 10^0 ohm ems. for un treated Aroclor after 20 hrs, irradiation. From those re sults it was concluded that acid washing did not affect the degradation. The photodegradation of Aroclor 1242 in the pres ence of diphenyl picryl hydrazy] (DrPH) was also followed by its change in resistivity. Very little change was observed since the conductivity of the DPPH was high, causing low initial resistivity. 4. Effect of added impurities Phenyl-substituted methyl chlorides have been shown to be electrolytes in non-aqueous media (A.5) and it was considered likely that this type of compound could be material formed upon irradiation of Aroclor. It was further thought that this type of conducting material could be formed from small amounts of impurities, such as phenyl alkanes or their chlorinated derivatives, which could be present in Aroclor. For example, It is known wiat stilbene is an im purity in raw biphenyl . Accordingly a number of compounds were added to Aroclor at a concentration of 0.5^ to determine if the loss of resistivity would be accelerated upon irradiation in the presence of these additives. It was believed that such ex periments might reveal the kind of impurity that could be acting as a precursor for the conducting substance. The Aroclor solutions were irradiated for 5 hrs. by the S-4 lamp, samples being removed after 1/2 hr. for resistivity measure ments. The results of these additives are shown in Table IV. Compounds of the trlphenylnethyl chloride type were shown to be conductors in an Aroclor media by measuring 0690379 HARTOLDMON0005085 10. the resistivities of Aroclor 121*2, Lot 170, containing vari ous concentrations of triphenylmethyl chloride (up to 0.3750 at 25C. The plot of concentration of triphenylmethyl chlor ide vs. resistivities is shown in Fig. 12. The resemblance of this curve to the conductivity curve of a weak electrolyte indicates that triphenylmethyl chloride acts as a weak elec trolyte i.n Aroclor. It was considered that the presence of a substance containing an excess of electrons might be essen tial for the stabilization of the carbonium ions; however, when this was tried, using benzophenone as the source of ex cess electrons, a negligible effect on the resistivity re sulted, which indicated that the carbonium ion needed no further stabilization. Aroclor 1242 could contain as an impurity a small amount of a substance bearing an excess of electrons which could stabilize the carbonium ion formed upon addition of triphenylmethyl chloride. Such an impurity, if present, should be removable by cone. HpSOij. If it is necessary to have a compound bearing an excess of electrons in order to stabilize triphenylmethyl chloride, then HpSOA-washed Aroclor should not conduct when triphenylmethyl chloride is added. Acid washed and dried Aroclor 1242 containing added triphenyl methyl chloride had the following resistivities: Wt. % foCCl Resistivity at 25C. 0.000 0.0652 0.314 2.1 X 1012 0hm ems . 2.4 x 109 ohm ems. 3.7 10 ohm ems. 5. Reduction of resistivity by hydrogen chloride Hydrogen chloride has been reported to be a con ducting material in Arcelor (A.l). Further measurements on the conductivity of hydrogen chloride in Aroclor were made by modifying a Balsbaugh conductivity cell so that dry hydrogen chloride gas was bubbled directly into the cell containing Aroclor 1242 and the resistivities of the solution were fol lowed as a function of time. The results and conditions of the experiments are shown in Table 7. In 10 minutes the re sistivity had dropped from 5 x 10^2 ohm ems. to 2.4 x 10l0 ohm ems., at which point the minimum resistivity level had been reached and additional hydrogen chloride bubbling did 0690380 I I HARTOLDMON0005086 not further decrease the resistivity. The cell wa3 heated to 100C. and dry nitrogen was bubbled through the Aroclor to sweep out the entrained hydrogen chloride. The reslstlvlty returned to 2.0 x 10*2 ohm cms., or essentially the orlginal value. Aroclor 1242 was photodegraded until its resis tivity was 7.8 x 109 ohm cms. Nitrogen was bubbled through this degraded Aroclor in the conductivity cell at 100C. The resistivity level after the bubbling was 4.4 x 10^ ohm cms. Hydrogen chloride was added to chlorobenzene and the resistivity was measured. The addition of HC1 reduced the resistivity from 3.2 x lcA2 ohm cms. to 6.3 x 108 ohm cms., but bubbling nitrogen through the solution (that is. sweeping out the HCl) raised the resistivity to 1.5 x 10-Li ohm cms. Failure of the chlorobenzene to return to its orig inal resistivity may be partially due to dissolved hydrogen chloride, since no heat was applied during the nitrogen sweeping. 6. Chlorobenzene reactions a. Reaction of chlorobenzene with benzenedlazonium chloride Since benzenediazoniun chloride splits ther mally to give a phenyl radical and a chlorine atom, its re action products in the presence of chlorobenzene should be similar to products obtained during chlorobenzene`photodegra dation. This is based on the assumption that the primary photochemical reaction of chlorobenzene is the homolytlc cleavage of the carbon-chlorine bond. To 150 ml. of distilleu chlorobenzene In a 300 ml. flask 28.5 g. benzenediazonium chloride was added. The reaction mixture was allowed to stand for four weeks at room temperature, protected from atmospheric moisture by a calcium chloride drying tube. The rate of reaction was so slow that very small bubbles of nitrogen could be seen coming off only occasionally. After four weeks at room temperature, reaction was allowed'to continue for 16 hours at 45C. and 24 hours at 50C. The reaction at the elevated temperatures was carried out in a bomb room, by remote control. After the above treatment, the excess ben zene! j azonium chloride was filtered off. Hydrogen chloride was identified as one of the reaction products. The filtrate 0690381 ) : HARTOLDMON0005087 1?. wan distilled by a high-vacuum and low-temperature distilla tion and separated into three fractions. The refractive in dices of the fractions were as follows: Number 1 Number 2 Number 3 Distilled chlorobenzene 1.5095 1.5212 1.5215 1 .5211* The fractions and the residue were analysed by infrared and the results showed little or no difference between samples. b. Photodegradation of chlorobenzene The continuous irradiation apparatus shown in Fig. 3 was charged with 150 ml. of distilled chloroben zene. The liquid was frozen with liquid nitrogen and the ap paratus was evacuated. The freezing, pumping and thawing cy cle W3S continued until all dissolved gases were removed. The liquid and apparatus was finally pumped to a pressure of 1 x 10-5 mm. of Hg and sealed off. The liquid was distilled from the reservoir, condensed in the irradiation zone and then re turned to the reservoir. This continuous distillation and irradiation was continued for' 482 hours. Initial boiling point of the chlorobenzene was 50C., and the final boiling point was 60C. The reaction mixture was analyzed by lnfrared and ultraviolet. The ultraviolet spectra of irradiated chlorobenzene and the reaction products of chlorobenzene and benzenediazonlum chloride showed strong absorption at 287 ms*', attributed to an addition compounu f chlorobenzene and chlor 'ere not significant c. Chlorine addition to chlorobenzene An addition compound of chlorine to chlorobenzene was made by filling a 500-ml. flask with chlorine and adding 10 ml. of distilled chlorobenzene. The flask was stoppered and Irradiated by an AH-4 lamp for a short time. The liquid was freei of the excess chlorine by a Ic.w-temperature distillation. An ultraviolet spectrum of this addition mixture, compared with that of chlorobenzene, shewed a very strong absorption at 287ryn- . 0690382 HARTOLDMON0005088 13. Infrared spectra of (l) photodcgraded chloro benzene, (2) benzenediazonlum chloride-chlorobenzenc reaction product and (?) chlorobenzene with known addition compounds showed (Fig. l4) a slight shoulder on the C-H aromatic band, which indicated that an aliphatic or alicycllc structure Is present in all mixtures. 7. Stabilizers The stabilizing effects of various additives were determined by measuring the volume resistivities of the Aroclor containing the additive before and after 5 hours ir radiation. All irradiations were carried out in the irradia tion apparatus shown in Fig. 2. The concentration of the additive was 0.1# by weight unless noted otherwise. The com pounds tested and the resistivities of Aroclor containing them are shown in Tabic VI. 6. Syntheses of compounds a. Triethanolamine borate Triethanolamine borate was syntnesized from triethanolamine and boric acid In 68# yield, using the method described by H. C. Brown and E. A. Fletcher (A.4). b. Trlsdlbutylstannanedlol Trisdibutylstannanediol was prepared by hy drolyzing dlbutyl tin diacetate by steam. This procedure Is described In U.S. Patent 2,628,211 (B.6) Issued to Mack of Advance Solvents & Chemical Corp. c. Triethyl lead phenolate Triethyl read phenolate was prepared by the action of tetraethyl lead upon phencl as described by Carothers in U.S. Patent 2,008,00? (B.5). d. Chlorinated dlphenylmethane Dlphenylmethane was vacuum distilled through a Vigreux column pressure and the fraction boiling at 132C./ 14 mm. was collected; Nfp - 1.5734 (Njy = 1.5788A reported). The purified dlphenylmethane was chlorinated by bubbling chlorine gas through 3-4.5 g- of the hydrocarbon at a rate of 1/3 mole per hour, with the temperature maintained at 120C. Iron clippings were used as a catalyst. In order to prevent 0690383 HARTOLDMON0005089 J chlorination by a free radical mechanism, light was elimina ted from the glass tube reactor by Immersing It In a sand bath surrounded by a steel casing. After 4-1/2 hours, the chlorination was stopped, the product was distilled and the distillate was collected at 1J0-152C ./1-5 mm., b ,p .=130C ./ 1 mm. Anal. Calc, for CvsHnCl: C, 77.41; H, 5-46; Cl, 17.1?. FouncH C;"W.'64; H, 5.91; Cl, 13-45 (by diff.). The tarry residue was dissolved in benzene and extracted with water. The benzene solution was distilled to remove the water and solvent. The dry product was a fine brown powder melting near 95C. (not sharp) was obtained. Analysis showed 9-25$ chlorine. e. Chlorinated trlphenylmethane Triphenylmethane (10.8 g.) was chlorinated in the same manner as the proceeding synthesis. The temperature was allowed to reach 142C. After 1-1/2 hours, the chlorine flow was stopped and the material crystallized Into a dark reddish brown mass upon cooling. Anal. Calc, for CioHmCl: C, 82.16; H, 5.41; Cl, 12.43. FouncTi C7~35774; H, 6.56; Cl, 6.7 (by diff.). In both of the above reactions the desired degree of chlorination was not reached; however, it was thought that some of the desired product was present. f. Benzenedi&zonlum chloride Benzenedlazonium chloride was prepared accord lng to Har.tzch and Joch (A.2) by reaction of amyl nitrite with aniline hydrochloride. The amyl nitrite was prepared as described by Noyes (A.3). In this synthesis 38 g. (0.55 moles) C.P. sodium nitrite was dissolved in 150 cc. of water and cooled to 0C. To this cooled mixture a solution con taining 10 cc. water, 13.6 cc. cone. Hg30i| and 44 g. n-arayl alcohol was added dropwlse in 1-1/2 hours. The water layer was separated and the amyl nitrite was washed with sodium bicarbonate and sodium chloride solutions and finally was dried over anhydrous sodium sulfate. A mechanically stirred mixture of ?2 g. of aniline hydrochloride dissolved in 60 ml. of glacial acetic acid was cooled to 0C. To this was added during 2 hours 0690384 HARTOLDMON0005090 15. 25 g of amyl nitrite. The benzenedlazonium chloride was precipitated by slowly dropping In anhydrous ether (two vol umes of ether to one of solution). This addition required 3-1/4 hours. The precipitated diazonlum compound was fil tered off and washed with anhydrous ether until free of ace tic acid. The benzenedlazonium chloride could be stored un der other but at no time was it allowed to be dry. Benzene dlazonium chloride is explosive and must be handled with extreme care. VII. DISCUSSION A. Thermal Degradation of Aroclors Aroclors 1221, 1232, 1242, 1248 and 1254 were ther mally degraded at 250C. and all liberated hydrogen chloride. It is seen from Table I that 1221, 1232 and 1242 liberate approximately the same amount of hydrogen chloride, while less is liberated from Aroclors 1248 and 1254. Apparently the higher Aroclors are more stable to thermal degradation. Since any of the Aroclors contains a mixture of compounds of various degrees of chlorination, it is reasonable to ex pect that all would produce some degradation products. It seems that 1242 contains such a possible combination as to give maximum degradation. The Research Laboratory at Anniston, Alabama, frac tionated Aroclor 1242 into ton fractions and these fractions were thermally degraded at 250C. for 5 hours (Table XI). Only the first three fractions liberated hydrogen chloride, the greatest amount being liberated from the first fraction. Fraction No. 4 showed only a slight trace of hydrogen chlor ide while higher fractions liberated none at all. It was also significant that hydrogen chloride was no longer liberated from any of the samples after approxi mately the first 3-1/2 hours. These data would indicate that the degradation by some trace impurity was securing and after depletion of this material no further thermal degrada tion took place during this heating cycle. When these frac tions were photodegraded and then heated, additional hydro gen chloride was liberated. These data would Indicate that unstable impurities could be formed within the Aroclor as a result of photodegradation or aging and that the less of re sistivity could be attributed to products arising from the Aroclor molecule itself. 0690385 HARTOLDMON0005091 16. Thermal degradation studies on fractionated Aroclor 1254 were not performed but it is expected that results simi lar to those with Aroclor 1242 would have been obtained; that is, hydrogen chloride would have been released in the early fractions, but not from the higher boiling fractions. B. Ultraviolet Spectra of Aroclors The plots of specific extinction coefficient against wave length in millimicrons (Figs, 4 and 5) for Aroclors 1221, 12J>2, 12a2, 1248, 1254, 1250, 1262 and 1268 show a gradual decrease in the absorption band at 246 which disappears in Aroclor 1248 and those higher. This absorption band is due to coplanarity resonance between the benzene rings. It is absent In Aroclors higher than 1248, in which coplanarity resonance is hindered by ortho chlorination: even one chlor ine atom in the ortho position is sufficient to eliminate tills resonance. The ultraviolet absorption spectra of fractionated Aroclor 1242 show little difference between fractions, with the exception of Fraction No. 1: the absorption curve for Fraction No. 1 shows little absorption due to coplanarity resonance, whereas curves for other fractions show a strong band at . This fraction also liberated the greatest quantity of hydrogen chloride during thermal degradation. The ultraviolet absorption spectra of various lots cf Aroclor 1242 show little or no difference between lots. C . Fhctodegradatlon of Aroclors It is shown in Fig II that the resistivity of Aroclor 1242 rapidly decreases during irradiation, but reaches an es sentially constant lev . after approximately 24 hours. The shape of this plot resembles the plot of conductivity versus concentration for a weak electrolyte. Even though the resis tivity readies a constant value, degradation continues since the color continues to darken. The colored material can be adsorbed from the Aroclor bv activated alumina and the resistivity of the recovered Aroclor is thereby restored to its original high value. Fur ther exposure of the purified Aroclor to irradiation causes a further decrease in resistivity. If this colored extract from the Arcelor is added to untreated Aroclor, a drop in the resistivity occurs, showing that the conducting material is contained in the colored extract. 0690386 t HARTOLDMON0005092 17. It was shown that hydrogen chloride in Arcelor lowers its resistivity but that hydrogen chloride can be freed from the Aroclor by bubbling nitrogen through the Arocj.or, thereby restoring the original high resistivity. I'hotodcgraded Arcelor could not be returned to its original resistivity by bubbling nitrogen through the degraded Aroclor at 100C. for a period of 24 hours. Since the resistivity was restored partially by this treatment, it is believed the hydrogen chloride wa,3 re moved but some other conducting material remained. These re sults indicate that the conducting materials in degraded Aroclor could be hydrogen chloride and some high-boiling material. Photodegradation of Aroclor takes place in the pres ence or absence of oxygen with loss of resistivity; however, the reduction of resistivity is more pronounced in the ab sence of oxygen. All experiments in this study were carried out in the absence of oxygen. Trace impurities are always a possible source of de gradation reactions in any system. Impurities were consid ered to be present in the Aroclor and these were considered to be nitrogen-, sulfur- or oxygen-containing compounds which should be removable by concentrated H0SO4 washes. After sev eral treatments with concentrated H2SO4, the purified Aroclor underwent photodegradation with loss of electrical resistivi ty at essentially the same rate as unpurified Aroclor. These data indicate that the degradation products were being devel oped from the Aroclor itself. ' The thermal degradations indicated that hydrogen chloride was produced from some Impurity and after depletion of this Impurity, no further hydrogen chloride was liberated. To determine the source of the degradation, Aroclor 1242, Lot 170, was irradiated and then heated. The amount of hydrogen chloride liberated from this Aroclor was ten times greater than from Aroclor subjected to thermal degradation alone. It is concluded that a thermally unstable compound which liber ates hydrogen chloride is produced in the photodegradation, and it is also reasonable to believe that the Aroclor con tains traces of such a compound, developed during handling and storage. Determination of the chemical constitution of the conducting material was attempted by first isolating the ma terial on activated alumina. The color was removed from the degraded Aroclor and the resistivity was restored by the alumina adsorption purification. However, the .material was 1 1 0690387 HARTOLDMON0005093 18. so tightly bound to the alumina that it. could not be com pletely eluted. After 50 washes with heptane, the heptane still showed 0.0118 g. of Aroclor per liter, indicating some original Aroclor on the alumina. The alumina was then eluted with ethanol and finally with 0.1N KOH. Even after all these treatments, the colored band remained on the alumina. Other materials for adsorbing the conducting material were tried (silica gel, sugar, charcoal, etc.) but without success. Since it could not be ascertained whether some reaction oc curred with the alumina and since the colored material could not be completely eluted from the alumina, this method of Isolating the conducting material was abandoned. Extraction of the photodegraded Aroclor was tried with cone. HpSOt). The acid washings were diluted with water and the temperature was kept below 50C. The benzene extract of the acid washings yielded a brown, waxy material, the infrared and ultraviolet spectra of which were anomalous. Since attempts to isolate and identify the conducting material had failed, it was considered possible that Insight as to the nature of the precursor for the conducting material might be obtained by addition of various types of compounds to the Aroclor. The additives tried are described in Sect. VI-C-'J. P. Effect of Addition of Impurities Phenyl-substituted methyl chlorides have been shown to be electrolytes in non-aqueous solvents (A.5), and it is possible that compounds of this type would be the conducting material in Aroclor. This possibility was explored by adding trlphenylinethyl chloride to Aroclor and following the resis tivity as a function of concentration. The resulting curve was similar to the equivalent conductance curve for a weak electrolyte. For such compounds to be conductors they must have resonance stabilization of the carbonium ion or there must be present some trace materials possessing an excess of elec trons for stabilization. Benzophenono is known to act as a stabilizer for carbonium ions. However, the addition of benzophenono to Aroclor containing a small amount of triphenylmethyl chloride does net further lower the resistivity of the mixture. If stabilization of the carbonium lor. had required the presence of ar. excess of electrons, then the addition of benzephenone should have lowered the resistivity considerably. It was concluded that substances such as 0690388 , HARTOLDMON0005094 19. triphenylmcthyl chloride posses sufficient resonance stabil ization to render the carbonium Ion stable. If phenyl-substituted aliphatl. .hlorlde compounds are the conductors formed in irradiated Aroclor, the ques tion arises whether these compounds are formed from impuri ties or from Aroclor itself. It was thought that the ef fects of various phenyl-substituted methanes and their chlor ine derivatives (Table IV) on Aroclor resistivity would give some idea of the nature of the precursor for the conducting material in Aroclor. A comparison of the drop in resistivity of Aroclor upon irradiation in the presence of the various additives with that of the Aroclor alone reveals that all of the additives accelerate the loss of resistivity. It is therefore concluded that, in general, a phenyl alkane can be a precursor for conducting material. It is not necessary for the phenyl alkane to be chlorinated initially, as the disso ciating chlorine atom, which leads to conduction by the as sumed conducting material, is added to the precursor during the photochemical reactions. Addition of phenyl alkane chlorides, for example, causes decrease in the resistivity, even without irradiation. It is known that the greater the phenyl substitution on the aliphatic chlorine-bearing car bon, the greater is the conductivity. . Carbonium ion must be planar in order to be stable. Compounds produced in the degradation of Aroclor could pos sess a number of phenyl groups and could possess sufficient planarity for resonance stabilization of the carbonium ion. However, if the ortho positions are filled in Aroclor, then the compounds produced could not arrange themselves into a planar configuration and therefore no conducting material could be produced through the formation of carbonium ions. The fact that Aroclor 126? {62% chlorinated) is more stable than Aroclor 12t2 {'^2% chlorinated) indicates that less con ducting material is formed when the ortho position is blocked. Since Aroclor 1262 contains some molecules that are not chlorinated in the ortho position, it is expected that some degradation should occur. The higher degree of chlorination aids in the photostability of the Aroclors due to restric tion of the resonance and thus reduces the concentration of the carbonium. ion formed. The photedegradation of Arcelor -undoubtedly proceeds via a free radical mechanism.. An attempt was made tc follow the rate of generation of the free radicals by reaction with diphenyl plcryl hydrazyl (DPPH) dissolved in Aroclor and ob serving the change in resistivity with time. The diphenyl 0690389 1 i HARTOLDMON0005095 20. plcryl hydrazyl solution was placed in a special cell ar ranged so that the irradiation took place in a portion of the cell where light could not strike the metal, surfaces of the electrodes. Significant results were, not obtained since the PPPH had some initial conductivity and degradation pro duced only a very small change in the resistivity. No fur ther work was done to purify the DPPH. The study with possible precursors had given some insight into how conducting substances could be formed but determination of the actual compound vas difficult due to the complexity of the Aroclors. These complications led to the use of a prototype, chlorobenzene, for further identi fication of the conducting material. E. Prototype Studies Chlorobenzene has an absorption band at approximate ly 2200 ?i due to the cleavage of the carbon-chlorine bond. This is measured on very dilute solutions. In pure chloro benzene this absorption is shifted to higher wave lengths and the absorption is apparently sufficient at wave lengths above JOCO $ to cause some degradation, since it was shown that the resistivity of pure chlorobenzene was lowered by irradiation. As with Aroclor 12b2, it was not possible to restore photedegraded chlorobenzene to its original high resistivity by bubbling dry nitrogen through the degraded material. An attempt to remove the conducting material by freezing, evac uation, thawing, refreezing and re-evaluation was not effec tive . Fractionation of photodegraded chlorobenzene yielded a dark residue as the final fraction. The infrared spectrum of this residue, compared to that of chlorobenzene, indicated a shift in the CK absorption band, attributable to a trace of aliphatic or alicycllc carbon. There were also indications of para and neta substitution. Ultraviolet spectra show a strong absorption at 287 . The logical photodissociation of chlorobenzene would be the homclytlc cleavage of the C-Cl bond tc give a phenyl radical and a chlorine atom ao the primary reaction. To test these reactions, the thermal degradation of ber.zenedlazonlum chloride in presence of chlorobenzene was studied since sev eral workers (A.6,7) have shown that benzenedlazcnlum chloride 0690390 1 I I I HARTOLDMON0005096 Is thermally unstable and the reaction is as follows: (^jj + 2 4 Cl- Considerable proof exists for this reaction and the resulting products formed through the free radical mechanism. If such radicals are produced thermally, then the reaction of these radicals with chlorobenzene should produce the same products as the photodegradation of chlorobenzene if the primary re action is the homolytlc cleavage of the carbon-chlorine bond. The ultraviolet and infrared spectra of the products of the reaction of the dlazonium chloride with chlorobenzene were similar to spectra of photodegraded chlorobenzene. Lir.doey and Ingraham (A.8) have studied the photo degradation of 1-chlorocyclohexene and have concluded that the primary reaction Is the homolytlc cleavage of the carbonchlorine bond. They found cyclohexene, cls-1,2-dlchlorocyclohexane, 3,31 -dichloro-1,11 -bl-2-cyclohexenyl and 3(1'-cyclohexenyl)-l-chlorocyclohexene as reaction products. These products show that all possibilities are formed from the radicals and that the chlorine atom can add to the double bond In the cyclohexene ring. Prom these results it is rea sonable to expect that aromatic comprunds such as chlorobenzene could undergo essentially the same types of reactlons, especially the homolytlc cleavage of the carbon-chlorine bond plus the addition of the chlorine to the aromatic ring. Such reactions would be expected to take place to a lesser extent with the aromatic compounds, however. It is seer, in Pig. 13 that the ultraviolet spectra of (l) a chlorine addition compound of chlorobenzene (Curve B), (?) the reaction products of benzenediazonium chloride (with chlorobenzene (curve A) and (3) irradiated chlorobenzene show a characteristic absorption band .near 285 my~ , when compared with the spectrum of distilled chlorobenzene. The Infrared spectra of these three preparations plus the spectrum of chlorobenzene are shown in Pig. 1A. Curve I In Fig. 1A shows only the characteristic C-H absorption cf anaromatic group in the 3-3/^' region. Curves II, III and IVshow similar absorption plus an additional absorption at slightly longer wave lengths, attributable to the presence of addition compounds. It is to bo noted In Curve III, Pig. lA, that the ' . : f | t i 1 J 1 I I 1 I I J 0690391 HARTOLDMON0005097 residue from photodegraded chlorobenzene (Curve B, Fig. 13) shows considerable shift, indicating that the addition prod ucts are concentrated in the higher boiling residue. Also the resistivity of all the treated chlorobenzene mixtures are low. From these data, it can be concluded that the con ducting materia] arises from the chlorine addition compounds which contain some aliphatic carbons bearing a chlorine atom. From the data and those of Lindsey and Ingraham (A.7) it is possible to write a mechanism for the photodegradation of chlorobenzene as follows, to account for the behavior of chlorobenzene under photodegradativo conditions: (1) + Cl Cl + (-0 ci- + -Cl HC1 + I -^1 Reaction (l) is the hemolytic cleavage of C-Cl bond and represents the primary reaction. Reaction (2) shows the addition of the chlorine atom to the benzene ring. Reaction (3) shows the reaction cf the addition complex with phenyl radicals, to produce a compound which could possess sufficient resonance energy so that the carbonlum ion would be stable. The exact nature of the conducting material was not identi fied. With such radicals produced in the primary reaction, hydrogen chloride could be produced by the action of a chlorine atom, with a hydrogen on the ring. Ir. any case the 0690392 HARTOLDMON0005098 conducting material in the chlorobenr.ene degradation mur.t arise from secondary reactions of Die chlorine atom. The phenyl radicals are free to enter into other re actions, which could produce color or polyphenyl a but it is not considered possible that they could produce conducting materials. The reaction of Aroclors and other chlorinated organic compounds could be expected to follow a similar pattern. F. Arcelor Stabilization From the postulated mechanism for the degradation of chlorobenzene, it is seen that elimination of the free chlor ine atom in essential if the Arcelor is to be successfully stabilized. Stabilizers must have the following character istics : (l) The stabilizer must be a non-conductor. (f) The stabilizer must react rapidly with chlorine atoms . (3) The resulting product must be non-conducting. Stabilizers for Aroclor which operate by scavenging the hy drogen chloride liberated cannot be expected to do an effic ient stabilization Job since they are ineffective in prevents ing the formation of the chlorine addition complex. Although not investigated here to any extent, another effective stabilization method could be the elimination of the primary reaction by screening out that radiation which causes the cleavage of the C-Cl bond. From the results listed in Table VI it is seen that tetraethyl lead was the most effective stabilizer tested. A slight precipitate occurred with this stabilizer which might affect its use. Diphenyl dibutyl tin was not quite so effective. Compounds such as Uvir.ul A90, 2-dodecyl-9,10anthraqulnone and Ponsul Yellow could only act as ultra violet screening agents and would not be effective in remov ing the hydrogen chloride or the chlorine atoms. None of these additives was an effective stabilizer. A number of the additives tried as stabilizers caused an initial decrease in resistivities of the Aroclor, but it is suspected that in many cases this is due to trace impuri ties which are conductors. 0690393 HARTOLDMON0005099 It has recently been found at Anniston that phenoxypropenc oxide is a good thermal stabiliser and is not covered by adverse patents. This compound was evaluated as'a light stabilizer but was found to be ineffective. Many of the additives that were found to be photo stabilizers for Aroclors are covered by patents, which claim such compounds as hydrogen chloride scavengers but which do not cover photostabilization. VIII. RECOMMENDATIONS Aroclors can be stabilized by certain metal lo-organlo. compounds such as tetraethyl lead. It is net certain what effects this compound will have on electrical equipment since a slight precipitate was formed during photodegrada tion of Aroclor' containing it. It is to be pointed out that the degradations in this study represent accelerated and more severe degradation conditions than those obtained under use conditions. General Electric holds the basic patent on the addition of compounds of RXM type to chlorinated biphenyls. It is also felt that G.E. has never studied the effect of this additive in Aroclor under photodegradatlve conditions since their original intent was a hydrogen chloride scaven ger. The effect of.tetraethyl lead as a pnotostabllizer for Aroclors should be brought to the attention of General Electric. Monsanto holds the patent on diphenyl dlbutyl tin as an additive for Aroclor. Although this compound is not as effective as tetraethyl lead, it docs exhibit a marked photostabilizing action and further evaluation is in order. The search for a more efficient stabilizer should be continued with attention to those compounds which will react readily with free chlorinators. Additional Aroclor degradation studies should place more emphasis on prototype studies since with a prototype the number of product possibilities is reduced. From the data of this study, it is seen that the mechanism of degra dation for the Aroclor prototype, chlorobenzene, is given from reasonably good evidence but has not been absolutely proved. Further study cn the proof of this mechanism is in dicated. Studies should include a positive identification of the products, quantum yields, and the wave length ranges effective in degradation. 0690394 HARTOLDMONOOQ5100 Emphasis should not be placed solely upon purification of Aroclors as a means of stabilization since degradation has been shown to arise from Aroclor itself. IX. DESCRIPTION OF RECOMMENDED PROCESS Not applicable. X. PATENT STATUS A disclosure on the use of tetraethyl lead as a photo stabilizer was submitted, but it is expected that this will be in direct comflict with a previous patent issued to Clark of General Electric (B.2). Diphenyl dlbutyl tin is protected by a Monsanto patent (8-1). XI . COST ESTIMATES Not. applicable. XII. ANALYTICAL PROCEDURE The Balsbaugh conductivity cells must be subjected to a very rigorous cleaning procedure. This procedure was recom mended by the research group from Anniston and is also that used by General Electric. Unless the cells arc thoroughly cleaned an described belcw reproducible results cannot be obtained. The cleaning procedure recommended is as follows: (1) Drain cell and fill with trichlorobenzene and heat at 100C. for 15 minutes. (2) Drain hot trichlorobenzene and rinse with cold trlchlorotenzene. (3) Rinse at least twice with methanol. (1|) Rinse with water. (3) Fill with a saturated solution of trisodium, phosphate and heat at 10CC. for 15 minutes. (0) Rinse with distilled water several times and dry ir. an oven at 120C. for at least 1 hour. 0690395 Ij i HARTOLDMONOOQ5101 26. The resistance of the Balsbaugh cell shows a drift with time after the voltage from the Megohm bridge is applied across the cell. This is due probably to polarization of the electrodes. The A.S.T.M. recommends that the voltage be ap plied for one minute and then the resistance be measured. Drift after one minute has been found to cause less than 10$ change in the resistance. All resistivities were measured after the voltage had been applied for one minute. Care must be exercised in handling the cell in order to keep electrical leakage as low as possible when measuring these very high resistances. The amount of hydrogen chloride liberated from the Aroclor was determined turbldlmctrlcally by precipitating the chlor ine as silver chloride and observing the quantity of light scattered at 90 by a Debye light scattering Instrument. The amount scattered was compared with a calibration chart for determination of chloride ion present. XIII. TOXICITY AND HAZARDS The stabilizers used for Aroclors consist chiefly of met.allo organic compounds such as tetraethyl lead or diphenyl dibutyl tin. These compounds are toxic and care should be exercised in handling them. XIV. ACKNOWLEDGMENT The assistance of Miss 'Jim, Messrs. Beasecker and Loucks of the Spectrographic Group is acknowledged. Many helpful discussions were held with Drs. Johns and Ruehrweir. and their suggestions were particularly valuable. Frof. Fuoss also contributed much to the discussions. XV. APPENDIX This report covers work recorded in the following note book pages: 257780 2577814.87 261937 270638 2706143-50 275151-59 275161 275171 275173-75 275181-82 2751814-95 275197-20C 279851-80 279885-87 0690396 * HARTOLDMONOOQ5102 Notebook pages continued. 279890-94 279896-900 280906-50 284652-54 284655-62 284664-68 284675 284693 287901-04 289905 289909 289912-13 289916 239928 289924 289928 289936-50 294004-05 294007 294009-20 294041 204046-47 297678 27. i jo \i 0690397 HARTOLDMONOOQ5103 TABLE I THERMAL DEGRADATION OF AROCLORS AT 250C. Aroclor 1221 123? 1242 Lot 13? 12*, 8 g. of HCl/g. x 10*-' 3.34 6.73 11.07 3-91 6.42 9.81 5.96 9.58 13.00 . 3.61 5. LA 8.48 3.43 7.96 6.43 Heating Time 1 hr 2 hr 5 hr 1 hr 2 hr 5 hr ' 1 hr 2 hr 5 hr 1 hr 2 hr 5 hr 1 hr 2 hr. 5 hr, 1 0690398 HARTOLDMONOOQ5104 TABLE II THERMAL DEGRADATION OF FRACTIONATED AROCLOR 124? AT g*QC.1,g Fraction 1 2 3 5 6 7 8 9 10 ill bottom Wt. of Charge 1.6 9-5 10.0 10.0 10.1 10.1 10.il . 10.'5 10.3 11 .A 2. a B.F. Range C./mm. ^ 146-169/ 10-11 mm. 168-186/ 11-26 mm. 169-196/ 26-1)0 mm. 138-157 157-159 159 159-162 162-167 154-177 177-197 R. HCl/g.. Aroclor 6.6 x 10`6 O.36 X 10-6 0.35 x 10"6 Very slight trace 0 0 0 0 0 0 1 The Aroclor was fractionated by the Inorganic Di vision at Anniston. ^ All samples were heated 5 hrs. t5 t2A3C. with Np bubbling through them. Pressure is 3 mm. except as noted. 0690399 T HARTOLDMONOOQ5105 ULTRAVIOLET ABSORPTION SPECTRA OF AROCLOR 1292 Aroclor 1292, Lot 3 66 Q3C>.SO x 3 0-3 p./l /\ 0. D. 220 1.25 2^0 .68 2 9o .985 250 .99 ?6o .32 270 .163 280 .070 290 .03 Specific Extinction Coefficient 79.11 93.09 30.70 27.85 20.25 10.32 9.93 1 .90 Arcelor 123*2, Lot 170 C^10.2 x 10-2 p./l. A o. D. 220 .392 230 .970 ?90 .33 250 .312 260 .21 270 .108 280 .050 290 .015 Specific Extinction Coefficient 87..95 96,,08 32., 35 30, 59 20, 59 10 59 9 90 1 A7 0690400 HARTOLDMONOOQ5106 TABLE III fContd.) ULTRAVIOLET ABSORPTION SPECTRA OF AROCLOR 1242 Aroclor 1242, Lot 174 014.9 x 10-3 g./i. X 0. D. 220 230 240 230 2o0 270 280 290 1.335 .71 .49 .44 .163 . 067 .031 1242, Lot 179 0^14,6 x 10-3 g,/l, X 0. D. op 0 230 240 250 260 270 280 290 1.36 .725 50 .455 33 .16 .07 .033 Aroclor 1242, Lot 181 C-l8.1 x 10-3 , X 0. D. 1.63 230 .695 2'-0 .60 250 55 200 .40 270 .19 280 .090 290 035 Specific Extinction Coefficient 89.60 47.65 32.88 29.53 21,47 10.94 4.50 2.08 Specific Extinction Coefficient 91.89 48.99 33.78 30.74 22.30 10.81 4.73 2.23 Specific Extinction Coefficient 92.82 49.45 33-15 30.39 22.10 10.50 4.97 1.93 0690401 I HARTOLDMONOOQ5107 TABLE IV EFFECT OF VARIOUS ADDITIVES AS IMPURITIES IN AR0CL0R12'i2 Ti'ccursor . 0.5 Wt. % p-Chlorotoluene o-Chlorotoluene Toluene Aroc.lcr 124? Trano Stllbcne Benzyl Chloride Chlorinated tripheny line thane Di p)'. e r.y 1 me b h a nn Chlorinated diphenyImethane Chlorinated diphenylmethane Tri phony Ime t!:ane Trini.eny Irr.e thy 1 Chloride Source of Additive E. K. E. K. C. R. Monsanto E. K. Gen. Chem. E. K, (Liq.) (Solid) E. K. E. K. Resistlvity in Ota-cm. At Start After 1/2 hr. After 5 hr. Irradiation Irradiation 2.0 X 1012 4.2 X 1012 3.0 X 1012 7.7 X ion 1.5 X 101-2 3.5 X ioi 3.J4 x 1010 4.8 X ioio 4.7 x loio 6.9 x ioio 1 .0 x 1011 1.9 x 1010 3.3 X 10i0 1.5 X ioio 1.3 X ioio 9.9 X 109 9.8 X 109 7.9 X 109 6.0 X 109 1 .7 X 1012 4. 6 x 109 6.1 x 1010 3.2 X 109 2.0 X 109 5-3 X ion 5.3 x 1010 1 .0 X 109 1.9 X lei? 5-5 X ion CD 1.0 x ioio 10? 1.0 X 109 5.0 X 10** I * Synthesized during this investigation ** c.369 wt. %. \ 0690402 HARTOLDMONOOQ5108 TARLE V EFFECT OF DISSOLVED HCl CN THE RESISTIVITY OF AROCLOR 1242 Treatment START HC1 bubbled through at 250. until resistivity became constant N'2 bubbled through at 100C. for 2.5 hra. N bubbled through at 25C . for 16 hra, No bubbled through at lt'0c . for 4 hrs . Np bubbled through at 100C. for 5 hrs. Resistivity of Non-Irradlatcd Aroclor 5 x 1012 ohm-cm. Resistivity of Irradiated Aroclor 7.8 x 109 ohm-cm. 2.4 x lO^ohm-cm. 5.6 x lO^ohra-cm. 2.0 x 10^^ohm-cm. 1.0 x lO^chm-cm. Not treated 2.2 x 109 ohm-cm. 5.8 x 10-*-Oohm-om. -4.4 x lO^^ohm-crri. 0690403 ' . HARTOLDMONOOQ5109 TABLE VI STABILIZATION OF RESISTIVITY OF AROCLOR 129? CONTAINING EXPERIMENTAL STABILIZERS** Stabilizer Nc no Tetraethyl lead Diphenyl dibutyl tin IH-2-ethylhexyl phenyl phosphate Dibutyl tin dllaurat.e Triethanolamine borate* B.Ia(2-ethyl hexyl)benzene phocphonate Diphenyl tin oxide Triphenylstibinc D3butyl tin salicylate Eenzalnzine Dibasic, lead phosphite Barium-Cadmium laurate Piacetate of dlanhydrotrisdlbutyl stannanediol* Tetraethyl silicane Tetrabenzyl silicane Source Ethyl Corp. Metal and Thermite C. R. C. R. C. R. Metal and Therm!te E. K. C. H. Mathiesr.n Natl.Lead Forro C. R. c. r. Volume Resistivities at 23C. in ohm-cms. Before After 5 hrs. Irradiation 1.0 x lol? 1 .7 x 1012 5.0 x 1011 1.0 x 10l 9.3 x IOU 7.0 x 1010 1.65 x 1011 -- 5.86 x 10-11 7.6 x 10l 1.46 x 1011 3.2 x 1010 9.9 x 101P Insoluble -- 1.79 x 10n 8.6 x 10 9.3 x IOU 2.25 x 10l 7-9 x lOl1 8.65 x 109 Insoluble Insoluble 5.75 x 101C -_ 1.39 x 10-2 I.06 x iclp 1.27 x 1;12 3.3 x ic9 li 0690404 HARTOLDMONOOQ5110 TABLE VI (Contd . ) STABILIZATION OF RESISTIVITY OF AROCLOR 1242 CONTAINING EXPERIMENTAL STABILIZERS** Stabilizer Source Volume Resistivities at 25C lr. ohm-cms. 3efore After 5 hrs Irradiation Dibutyl tin maleate Metal and Thermite Triphenyl phosphite C. R. Diphenyl picryl hydrazyl Harvard General Dyestuff Corp. Uvlnul A9C 0.5 wt. % 2-dcdecyl 9-10ar.thraquinonc C. R . 0.15 wt. 76 aluminum isopropylate Ms thieson Pon.sul Yellow C . R. Phenyl salicylate c. R . 1.0 wt. ; d-llir.cner.e T^tranr.onyl g^r^niurt E. K. r> R. Hexapher.yl dlgernane R. Epcsidized Soybeanoil , Du Pont Triethyl lead phenolate 0.5 wt. % Finer,e C. R. 0.5 wt. % Metal & Thermite's RS 31 Phenoxy propene oxide 3.6 x 10-1-1 - 2.48 x 1011 2.3 x 109 A.2 x 109 1.3 x 1010 6.8 X 109 1.2 x 1011 3.8 x 108 2.5 x 1012 1.8 x 109 2.A x 10n 1.5 x 1010* 1.43 x 10n 1 .5 x 1010 / ~~ 8.9 x 1011 4.7 x 1C1C 8.6 x 109 C.R. - Chemical Research stock - source -unknown made in Laboratory previo sly. * 20 hrs. Irradiation. ** Stabilizer concentration was C.l^ unless otherwise noted. 0690405 I HARTOLDMONOOQ5111 Fig. / THERMAL DEGRADATION APPARATUS 0690406 HARTOLDMONOOQ5112 Fig. 2 PHOTOCHEMICAL DEGRADATION APPARATUS 0690407 f HARTOLDMONOOQ5113 Defoliation Column AH- 4 Sunlamp Fig. 3 CONTINUOUS PHOTOCHEMICAL DEGRADATION APPARATUS for CHLOROBENZENE 0690908 HARTOLDMONOOQ5114 c'^o Fig. 4 ABSORPTION ULTRavlOLET SPEC TRfi nf aRpCi nR^ 0690409 HARTOLDMONOOQ5115 /~/svc/~/o/v C o.t `/r / c / * s r/ '*<>' 0690910 HARTOLDMONOOQ5116 0690411 HARTOLDMONOOQ5117 i f / r / c /-/oa/ \ 0690412 HARTOLDMONOOQ5118 160 ' ISO 140 120 too BO Fig. 8 ULTRAVIOLET ABSORPTION SPECTRUM FRACTIONATED ARCLOR 1242 FROM ANNISTON :; ! FRACTION BIO : Specific Extinction Coefficient 0690413 HARTOLDMONOOQ5119 Fig. 9 : 42 'r&nt'/oj.er WabQ&*}r/Osv Ovecr-v/j ?W/?cr/o/y/?/-> /Avacw? /.*$*? Frociton * I O--a-- Frodio n tt 2 Fraction* 3. Fraction 4*4 0690<tl<* HARTOLDMONOOQ5120 s-* 7- /a/ c r/G M ,'So /to Is lo * />o V\; : k lVyj 40 * Jo FiQ-IQ .(/tr&fit'/oLtf/ /?& jo/p />r/<?/v J/^/rcr/p/? ''ZSS i A yt4. 0690415 HARTOLDMONOOQ5121 Sftt. n 1 R e s is tiv i7 / jd O ~ Ohm --cms iO 20 3C 4C 5C 60 70 80 90 100 HO 120 130 140 150 160 170 ISO 1*0 200 210 Irradiation Timeinhojrs 0690916 HARTOLDMONOOQ5122 Volume R e sistivity HARTOLDMONOOQ5123 HARTOLDMONOOQ5124 HARTOLDMONOOQ5125