Document Lg85boLGLQzYONqYgjv0ynyr5

ORGANIC CHEMICALS DIVISION RESEA Report No. P-688 Job No. 2-02-750.01 5040 TENTATIVE PROCESS FOR CONTINUOUS CHLORINATION OF BIPHENYL March 25, 1956 R, A. Simone HONS 061664 'f St. Louie Research Report No. P-688 Maroh 23, 1956 f' TENTATIVE PROCESS FOR CONTINUOUS CHLORINATION OF BIPHENYL Job No. 2-02-750.01-3040 Monsanto Chemical Company Organic Chemicals Division St. Louis Research Department Work done by: A. M. Ellenburg R. A. Simone Written by: R. A. Simone MCNS 061665 DISTRIBUTION OF REPORT NO. P-688 1. File 2. Mr. A. M. Ellenburg 5. Mr. H. K. Nason - file 4. Duplicate File 5. Circulate: Associate and Assistant Research Directors - Safe Deposit 6. Mr. R. A. Simone 7. Anniston Plant - Stds. Dept. 8. Anniston Plant - Stds. Dept. 9. Anniston Plant - Stds. Dept. 10. Monsanto Chemicals Limited - England 11. Monsanto Chemicals Limited - England 12. Extra 15. Extra 14. Extra This report contains confidential information which is the property of the Monsanto Chemical Company and which shall be disclosed only to duly authorized persons. The recipient Is held accountable for the filing and safe custody of the report, which must be returned on demand. HONS 061666 1. INTRODUCTION- The Anniston production group requested that the Research Department investigate the possibility of producing Aroclors (chlorinated biphenyl) by a continuous process in order to Increase the production efficiency over the present batch operation. The advantages that should be realized by continuous manufacture are increased production, decreased labor costs, and product uniformity. The object of the research laboratory work was to develop a continuous operation that would produce Aroclors favorable in quality to batch processed material. Satisfactory continuously produced Aroclor 1242 and 1254 have been demonstrated in the laboratory. The process reported herein is for the continuous production of Aroclors 1142, 1146, 1154, and 1160 and is based on laboratory work. SYNOPSIS OP PROCESS Aroclors are manufactured continuously by a four stage chlorin ation of biphenyl in the presence of iron catalyst and at elevated temperatures. Biphenyl and chlorine gas are introduced into the first ohlorinator at controlled rates. The overflow from the first stage ohlorinator flows into the second stage reactor and is further chlorinated under controlled conditions and discharged into the third stage, etc. The process is controlled in such a manner that the overflow product from the fourth stage is of the required chlorination level for the crude Aroclor desired, as indicate^ by specific gravity measurement. The different Aroclors are made by varying the ratio of the chlorine to biphenyl and chlorinated biphenyl in the four stages. The crude Aroclors are further processed to refined material in the same manner as in the present Aroclor manufacture. By-product HC1 is absorbed in water for the production of muriatic acid. BILL OF MATERIALS ' The materials theoretically required for 100 pounds of various orude Aroclors are as follows: Aroclor Chlorine - Lbs. Biphenyl - Lbs 1142 1148 1154 ll60 84.9 96.6 109-7 120.0 58.7 40.4 The raw materials used in the continuous chlorination are the same as in the present Aroclor batch process consisting of biphenyl. MGNS 061667 2. chlorine, and iron turnings catalyst. The theoretical feeds for the continuous production of Aroclors 1142, 1148, 1154, and 1160 are given in Table I of the appendix of this report. EQUIPMENT LIST The continuous chlorination process makes use of the present chlorlnators which are 3' I.D. x 16' vertical tanks equipped with cooling colls, chlorine distributors, circulating pumps, biphenyl inlets and off-gas lines. The following additions and modifications will be necessary for conversion to satisfactory continuous operation; Biphenyl Feed Pump - This pump should be capable of accurately delivering molten biphenyl at rates from 1300 to 3400 pounds per hour against the hydrostatic head in the first stage chlorinator. Auxilllary equipment, such as a flow recorder and line thermocouple should be Installed to assure accurate biphenyl feed. Lines to and from the pump must be steam traced or Jaoketed to avoid freezing. Chlorlnators - The first three chlorlnators should be elevated to the proper levels to assure discharge by gravity of the overflow from one stage to the next. That is, the differential in adjacent reactor levels should be sufficient to overcome the hydrostatio pressure in the receiving reactor, which will contain material of a higher gravity. The gravity differential will be greatest in the manufacture of Aroclor 1160. If the proper elevation of the . ohlorlnator is not feasible, transfer pumps will be necessary in the overflow lines. The overflow outlets should be set at the 700 gallon level of each chlorinator. Cooling capacity must be sufficient to maintain desired temperature control. Biphenyl should be Introduced into the first chlorinator well below the surfaoe in order to avoid short circuiting. The overflow line to the succeeding stages should likewise be extended to the lower region of reactors. The lower ends of these dip pipes should be perforated to aid in mixing with chlorinator material. Each overflow line should be equipped with a sampling cock. Agitation is accomplished with the circulating pump presently installed. Each chlorinator should be equipped to allow conversion to batch operation with a minimum of effort. Chlorine Peed Regulators - The chlorine feed to each stage should be accurately controlled as indicated by the specific gravities of the overflow streams. This will require the monitoring of each overflow stream with an automatic gravity recording and regulating device which is capable of proportional control of the chlorine valves. The controller should be so located as to keep lag at a minimum. In addition, the chlorine feed line of each stage should HONS 061668 Ft7+ urc. I- F/o w /ay ram v Four Staye Oonf/Auous (TA/or/s?urso/i of HONS 06166 -nr ur- e. JT D/c/jram of Co/irs/iuous Ch/or/nvT/ofi Sta/je. 1 Cye/oe- Se^>ctf'e\ tot' HONS 061670 3. be equipped with a flowrator capable of measuring flows of 500 to 800 pounds per hour. The main chlorine line feeding all stages should be equipped with a pressure regulator. Cyolone Separators - Each chlorlnator should be equipped with a cyolone separator to remove sublimed or entrained material from the off-gas. The separated material is dropped back to the chlorlnator, with the return line extending below the surface of the chlorlnator liquid. The return line outside the chlorlnator should be steam ^traced. A sampling outlet on the exit line to the absorber will be neoessary to determine chlorine efficiency. PROCESS IN DETAIL Instrumentated Operation The four chlorlnators are charged with biphenyl, the amount depending on the Aroclor to be produced. Allowance should be made for the molar expansion of biphenyl upon batoh chlorination In each reactor. The biphenyl in each stage Is chlorinated batohwise to the desired level for the Aroclor to be produced as listed In Table I. When the proper gravity is obtained In each stage, the liquid surface should be at the overflow level. The gravity controls are then adjusted to the proper setting. The biphenyl delivery Is set at the required feed for the corresponding Aroclor to be produced as listed In Table 1. The continuous operation is then started by simultaneous feed of biphenyl and ohlorlne. The gravity of each overflow line should be determined periodically by hydrometer to cheok the operation of the gravity recorder-controllers. The temperature of each stage should be held uniformly. Manual Operation During the plant demonstration run, It Is contemplated at present that the chlorination will not be fully Instrumentated and chlorine flow will have to be manually controlled, based on flowrator readings. If the flowrators are calibrated against the hydrostatic pressure expected in each chlorlnator, the process Is started In the same manner as described under "Instrumentated Operation", with the gravity of the overflow streams being determined manually every half hour. The ohlorlne feeds are adjusted accordingly by operation of the ohlorlne valves. The malntalnance of uniform reactor temperatures Is important In order to avoid flowrator fluctuations due to the temperature-gravity relationship. In oaBe the flowrators cannot be accurately calibrated against the hydrostatlo pressures expected In the chlorlnators, the correct feed will have to be determined by trial and error. In order to avoid production of off-grade material due to poor control, the operation should'be started stagewise. Biphenyl is oharged to the first stage and chlorinated batchwlse to the desired level. Continuous MOWS 061671 4. operation ie then started and the correct chlorine feed is determined as indicated by the proper uniform overflow gravity. The overflow is discharged into the second stage reactor until nearly overflowing. The flowrator reading Is noted and the operation stopped. The second stage is then chlorinated batchwlse to the desired gravity. Continuous operation is then resumed and the correct chlorine feed is determined for the second stage in the same manner. The procedure is repeated until all four stages are operating continuously at the desired chlorination levels. When the ohlorlne feeds are determined in this manner, the gravity of the overflow gravities should remain relatively constant, providing that reactor temperatures and chlorine pressure are uniform. DISCUSSION OF IMPORTANT VARIABLES The stagewlse startup for manual operation is reoommended in cases where chlorine feed cannot be accurately predetermined. If startup of all four stages were attempted without accurate knowledge of chlorine feed, control of the over-all operation would be extremely difficult and before the system could be brought into balance, considerable material of Incorrect gravity overflowing from the fourth stage could be produced. The suggested feeds listed in Table I are theoretical and assume 100# utilization of chlorine, biphenyl, and chlorinated biphenyl. Allowance for any entrainment losses and chlorine inefficiency will have to be made in practice. The suggested feeds in Table I give four production rates for each Aroolor. Each rate results in a different sojourn which will influence the character of the final product. These differences may be minor but should be determined by infrared analysis when shifting from one rate to another. Two alternatives are given in Table I for production of Aroolor at the 2400 and 2800 pounds of ohlorlne per hour over-all rates. In one case the chlorine feed is distributed equally to each stage and in the other the feed is staggered, with the first two stages operating at below over-all average chlorine feeds. The latter alternative is suggested if sublimation and entrainment becomes a severe problem at high chlorination rates in the first and seoond stages. When production demands require the manufacture of a different Aroolor them previously produced, two possible situations may arise. The required Aroclor may be of a higher or lower chlorination stage than the one previously manufactured. In case the required Aroclor is higher, the individual stages are chlorinated batchwlse to the proper levels before continuous operation is started. An intermediate Aroclor will be discharged from the system during the batch ohlorlnatlons due to molar expansion. When a lower Aroclor is required, the fourth stage is pumped out and processed to finished goods. The first three stages are then pumped forward and adjusted batchwlse to the correct gravity before continuous operation is resumed. If a shift HONS 061672 5. from Aroclor 1160 to 1142 or 1148 were required, the third stage would also have, to be drained. An alternative when such a shift Is necessary would be to chlorinate the third stage batchwise to Aroclor ll60 and drain the reactor. The overflow should be closed during the batoh chlorination to avoid overflow due to molar expansion. The product from the fourth stage should not be considered truly representative of a continuous operation until at least 3500 gallons have been discharged. The Intermediate material will be partially composed of varying degrees of batch material, MATERIAL SPECIFICATIONS, ANALYTICAL METHODS The raw, orude and finished material specifications are the same as those given by present product specifications. The analytical methods for finished Aroolors are the same presently used on present production. In addition. Infrared spectra of 10# carbon disulfide solutions of finished Aroclors are to be run by the St. Louis Research Department during the Initial continuous production of eaoh produot or whenever sojourn time for any Aroolor Is Initially changed. TOXICITY AND HAZARDS Chlorine - Chlorine is an extremely toxic gas. The allowable concentration for an eight hour day is reported to be from 0.35 to 2 parts per million. High concentrations causes pneumonitis and edema of the lungs. An exposure of 1000 ppm is rapidly fatal. However, sufficient warning of its presence Is given since the gas is detectable by odor at a concentration of 3.5 ppm, and 15.1 ppm gives throat Irritation. Respiratory equipment should be available to those working on chlorination equipment. Reference: Sax, N. I., "Handbook of Dangerous Chemicals", Rheinhold Publishing Company7 Mew York, 1951, P. 93. Biphenyl - Large concentration of biphenyl vapors causes intoxication. Respiratory equipment should be worn when working In contaot with its vapors. The material Is flammable and should be kept away from areas of acute fire hazard. Reference: Opus Cit., p. 151. Chlorinated Biphenyl (Aroclors) - Aroclors can give rise to dermatitis when contacted with the skin. Inhalation of vapors is usually followed by systemgSic poisoning. The liver is affected by serious exposure to vapors. Toxicity Increases with Increasing degree of chlorination. The proper protective clothing should be worn when handling Aroclors. Respiratory equipment should be used when vapor contact is anticipated. HONS 061673 6. Reference: Opus Cit., p. 92 These materials have teen handled for many years In Monsanto so no difficulty is expected In the operation of this process. R. A. Simone Approved: A. M. Ellenburg dm 3-28-56 HONS 061674 7. APPENDIX (1) Physical Constants Sheet for Biphenyl. (2) Graph I - Percent Chlorine vs. Specific Gravity for Chlorinated Biphenyl. (3) Table I - Suggested Feeds for the Continuous Chlorination of Biphenyl. HONS 061675 w Pi' .* *: J"j '.j-lf V'* -\t. `-'"s-'.t&f* ^ *r.f / ' ...name jJJ J..../.....;'i,.-. . ....... .. ... iS*' V>:- Formula ' , ' * ..CCe.HHii.aCC.aHfle. .`;. _iX'|>5ran>c________ .._ ___ ___Konoolinlo Mol ucui.ar Jwlfcht . _i lift. 29L Hulling point at. 700mm ......^......ie55C. .Rubber Band- jlnt.firdt. Tables _J>WJAn*' sslnt-.aJld^ _'_ JUS _xpy*t\ui/ipit_RoiDt_........' ,,69j0oC. ....; .. ......... J69'p._____ *fywx file #13T,,.U?3 .j*Svann curve* _ . Int.CrlWTatilfiJi. 89lut4o_n ^>o_lnt ___________ ' _ . Specific gravity 77/^0 Pfin. gra.vA.tjr J 3?0/a *C., ..U JO.9895 Jl.PJU____ .1. Refractive lndox $ .T7A*C.. -)0--.1.569?2. - Jot.Crlt.T6W%; _f *9 a ` .S '' n rt ti Viscosity i 100*C Vikcpaity 0 .7 0*0, 12fl.8 8*y. Sec. . 31,*..:". . *.... B*ann f11#137A| " , n X-'"- , _*'"..** JL29*20 -429-5. dyne/c* tnt.Cm.Tabl*s_ ^Solubility, in rater.80.C._--.1liiaoliible____ . law_____ '....... _ __ | .Solubility. Jt- . Seidell ,, J ._ssa.uwxi.w_ir>.8 /100 g,. toltentj Seidell . .Ben*en9;e_27;9'-C.___ ____ ,J13? 4./10Q g. solvent Seidell.... (Heptane 26.5*0.: ________ ^5.I^g./IDO g. solvent -Seidell . Klash point *F (method^_ 223>552??,* -" coploesne*dupoup Fire_ point *F _ ___ ' XS[!>?jO. -Dan. ... _____1 _. Meet of comt>u8tlonK|t-eel(13V bar gM. mol ..JL504..-A. jtnt.Crlt. Sables Uat-vplJ!..Qf.vs -d..69^2*5..Jl90. 9 BTD per. lb. .. eSvann tile #137A Spool rip hu.jL ) 40*C...____ 1.6X. Joule/ga.. xnt. Crlt '. tables. C r 11 i c It omper at u re____ ______ Critical pressure ____ Pounds por gal. 0 . JJ *C P,.?3. Xbe... per j*l, _ . 8ww tile #137A 1^303 sa.,8- gm.-.cal .per. gm___ lXange. Handboolc (53.1 BTU/lb.J -iWt' Toxicity (give reference) (x) Dr.Kolsaatei*, Anniaton nebCg, Report .Copy .In.Jtx, Xflula j^itcian'a file 4 2)|. fem:i!ax.^B0Hade.tt7 ^.Btathetla Dru^l J.!! ..pH Bdltloa,. P-.19-: WflWla Jlrilrf*.' AS i/. .o- _* * *'"r* HONS 061676 MQNS 061677 TABLE I Suggested Approximate Operating Conditions of 4 Stage Continuous - lOOjf Chlorination of Aroclors - 700 Gal. Chlorlnator Volume Cla Peed Llq. Peed Outage Sp. Gr. Chlor. Sojourn Aroclor Stage Lb3./Hr. Lbs./Hr. Lbs./Hr. at 90C. Temp. C. Hrs. 1142 1 2 3 4 500 500 500 500 1353 1593 I.092 110 3.9 1593 1836 1.184 120 3-7 1836 2079 1.268 130 3.4 2079 2323 1.332 140 3.2 1142 1 600 1625 1917 I.O92 110 3.3 2 600 19X7 2208 1.184 120 3.1 3 600 2208 2500 1.268 130 2.8 4 600 , 2500 2791 1.332 140 2.7 1142 1142 1 2 3 4 1 2 3 4 400 500 700 800 700 700 700 700 1625 1819 1.054 110 3.3 1819 2062 1.140 120 3.2 2062 2402 1.236 130 2.9 2402 2791 1.332 140 2.7 1896 2236 2576 2916 2236 2576 2916 3256 I.092 1.184 1.268 1.332 110 2.8 120 2.6 130 2.4 140 2.3 1142 *o * 1142 o 1 2 3 4 1 2 3 4 500 700 800 800 800 800 800 800 1896 2139 1.056 110 2.8 2139 2479 1.156 120 2.7 ?47Q 2868 1.256 130 2.5 2868 3256 1.332 140 2.3 2166 2555 I.092 110 2.5 2555 2943 1.184 120 2.3 2943 3332 1.268 130 2.1 3332 3721 1.332 140 2.0 CD Total Sojourn 14.2 % Clp 15.65' 27.17 36.00 43.00 11.9 15.65 27-17 36.00 43-00 12.1 10.99 21.82 33-30 43.00 10.1 15.65 27.17 36.00 43.00 10.3 11.69 24.20 34.87 43.00 15.65 27.17 36.00 9-0 43.00 MCNS 0 6 1 6 7 9 TABUS I (Cont.) Page 2 Cla Peed Aroclor Stage Lbs./Hr. 1148 1 2 3 4 500 500 500 500 1148 1 2 3 4 600 600 600 600 1148 1 2 3 4 400 500 700 800 1148 1 2 3 4 700 700 700 700 1148 1 2 3 4 500 700 800 800 1148 1 2 3 4 8oo 800 800 800 Liq. Feed Lbs./Hr. 1111 1354 1597 1840 1334 1626 1917 2209 1334 1528 1771 2111 1557 1897 2237 2577 1557 1800 2140 2529 1778 2167 2556 2945 Outage Lbs./Hr. 1354 3.597 1840 2083 1626 1917 2209 2500 1528 1771 2111 2500 1897 2237 2557 2917 1800 2140 2529 2917 2167 2556 2945 3334 Sp. Gr. at 90C. 1.110 1.226 1.314 1.396 1.110 1.226 1.314 1.396 1.068 1.168 1.284 1.396 1.110 1.226 1.314 1.396 1.076 1.190 1.300 1.396 1.110 1.226 1.314 1.396 Chlor. Temp. C. 110 120 130 140 110 120 130 140 110 120 130 140 110 120 130 l4o 110 120 130 l4o 110 120 130 140 Sojourn Hr. 4.7 4.0 4.0 3.8 3.? 3.4 3-4 3.2 4.0 3.8 3.5 3.2 3.4 2.9 2.9 2.7 3.2 3.2 2.9 2.7 2.9 2-5 2.5 2.4 Total % Sojourn Cl2 16.5 18.46 31.91 40.76 48.00 13.9 18.46 31.91 40.76 48.00 14.5 13.10 25.41 37.90 48.00 11.9 18.46 31.91 40.76 48.00 12.0 13.89 28.04 39.54 48.00 10.3 18.46 31.91 40.76 48.00 TABUS X (Cont.) Page 3 8B 8 fm 88WR Cl2 Feed Aroclor Stage Lbs./Hr. 1154 1 2 3 4 500 500 500 500 1154 1 2 3 4 600 600 600 600 1154 1 2 3 4 400 500 700 800 1154 1 2 3 4 700 700 700 700 1154 1 2 34 500 700 800 800 1154 O O' Oao' 1 2 3 4 800 800 800 800 Liq. Feed Lbs ./tar. 846 1089 1332 1575 1016 1308 1599 1891 1016 1210 1453 1793 1185 1525 1865 2205 1185 1428 1768 2157 1354 1743 2132 2521 Outage Lbs./Hr. 1089 1332 1575 1818 1308 im 2182 1210 1453 1793 2182 1525 1865 2205 2545 1428 1768 2157 2545 1743 2132 2521 2916 Sp. Gr. at 90C. 1.156 1.280 1.156 1.280 i: 1.096 1.216 1.354 1.486 1.156 1.280 1.102 1.244 L 1.156 1.280 1.390 1.486 Chlor. Temp. C. 110 120 140 150 no 120 140 150 no 120 140 150 no 120 140 150 no 120 140 150 no 120 140 150 Sojourn Hr. 6.1 5.5 5.0 4.6 5.1 4.6 4.2 3-8 5-2 4.8 4.3 3.8 4.4 3-9 3.6 3.3 4.5 4.0 3.6 3.3 3-8 3.5 3-1 2.9 Total * Sojourn Cla 21.2 23-96/ 37.54 47.62 55-00 17.7 17.8 23. 37. 47. 55. 16. 50. 44. 55. 15.2 23. 37. 47. 55. 17. TV. 15.4 55. 13.3 23. 37. 47. 55. TABIE I (Cont.) Page 4 CI2 Peed Aroclor Stage Lbs./Hr. 1160 1 2 3 4 500 500 500 500 1160 1 2 3 4 600 600 600 600 1160 1 2 3 4 400 500 700 800 1160 1 2 3 4 700 700 700 700 1160 1 2 3 4 500 700 800 800 1160 1 2 3 4 800 800 800 800 Llq. Peed Lbs./Hr. 695 938 1181 1424 834 1126 1417 1709 834 1028 1271 l6ll 973 1313 1653 1993 973 1216 1556 19*5 1112 1501 1890 2279 Outage Lbs./Hr, 938 ll8l 1424 1667 1226 1417 1709 2000 1028 1271 1611 2000 1313 1653 1993 2333 1216 1556 19*5 2333 1501 1890 2279 2668 Sp. Gr. at 90C. 1.176 1.326 1.456 1.562 1.176 1.326 1.456 1.562 1.118 1.260 1.416 1.562 1.176 1.326 1.456 1.562 1.126 1.288 1.440 1.562 1.176 1.326 1.456 1.562 Chlor. Temp. C. 110 120 140 150 110 120 140 150 110 120 140 150 110 120 140 150 110 120 140 150 110 120 140 150 Sojourn Hr. 7.3 6.5 5.8 5-3 5.6 5.* 4.8 4.4 6.5 5.7 5.0 4.4 5-2 4.6 4.1 3.8 5.3 4.8 4.2 3-8 4.5 4.0 3-6 3-3 Total % Sojourn Cl2 24.9 26.65 42.3* 52.67 60.00 20.2 26.65 42.34 52.67 60.00 21.6 19-*5 35.40 49.66 60.00 17.7 18.1 26.65 42.34 52.67 60.00 20.56 38.56 51.41 60.00 15.4 26.65 42.3* 52.67 60.00 HONS 061681