Document GK9o9ek00gg1EaXx9vr7LN7R7

4.4 :T P * Mi> INTERIM REPORT DEGRADATION OF ARCCLOR^ IAL i *4 TO CHEMICAL CCMPANY RESEARCH AND ENGINEERING DIVISION Chemical Research Department Dayton, Ohio ;t4 I 4 This . report and i"4r^'Con contained iha-el-s ^ -. rf ., . of i MONSANTO CHEMICAL COMPANY t ' . 11 i ^-40,V2 :lr-H4*||ff;|4> ' *1 July. 29, 1S5 i?f ffi 4 4V. A* Pit mfmm DSW 620732 WWSK iW* STLCOPCB4094760 STLCOPCB4094761 If*'*' OF CONTENTS m. Page No, I. INTRODUCTION II. SUMMARY III. CONCLUSIONS IV. USES AND APPLICATIONS V. REFERENCES A. Literature References 3. Patent References C. Reference tc Previous Work a' Monsanto VI. EXPERIMENTAL WORK A. Raw Materials B. Apparatus 1. Arcelor degradation 2. Continuous primary degradation of chlorobenzene 3. Resistivity measurements C. Experiments ' 1. Thermal degradation 2. Ultraviolet absorption spectra 3- Photodegradation A. Effect of added impurities 5. Reduction of resistivity by hydrogen chloride 6. Chlorobenzene reactions ' 7 Stabilizers 8. Syntheses of compounds ;: 1ik t > ' . * i f* ; 4, DSWi STLCOPCB4094762 VII. miw' If ft ptf* *.T`- Page No. DISCUSSION i' ? A- A' *$ *<v 3 * V A. Thermal Degradation of Aroclors B. Ultraviolet Spectra of Aroclors C. Fhotodegradatlon of Aroclors D. Effect of Addition of Impurities E. Prototype Studies , F. Aroclor Stabilization ' 15 VIII. RECOMMENDATIONS IX. DESCRIPTION OF RECOMMENDED PROCESS X. .PATENT STATUS XI. COST ESTIMATES XII. ANALYTICAL PROCEDURE XIII. TOXICITY AND HAZARDS XIV. ACKNOWLEDGMENT XV. APPENDIX = 4if 1?|ii%A\11 f i &i* ** ; DSW 620735 {-------------- ** STLCOPCB4094763 STLCOPCB4094764 STLCOPCB4094765 3 5**-iilw 10DI .1 . * 4i f " Mbnsahtofmanufactures large quintitles of chlorinated bi-' phenyls (Aroolor series 12),which/Sre1 sold as dielectric1 ' ' fluids. Research to improve the Aroclors is part of a con tinuing program within Monsanto for better products. Degrad ation of 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 :f ArccIor3 depends upcr. the degree of -chlorination, the variation of Aroclor structure as it affects stability was determined by ultraviolet absorption scec tra. The variation between fractions of fractionated Arcclcr 12A2 ana of unfracticr.ed Arcclcr 125^ was studied by ultra violet absorption spectra. The thermal degradation cf frac tionated 12^2 was measured at oOC. and the amount of hydro gen chloride liberated was determined. Arcelor 12^2 was degr by ultraviolet light in vacuo and the decrease in elect L resistivity with i: radiation time was measured. It wa ssible to remove the conducting material and restore the -tivlty to its origir .aI value by passing the degraded r. Lai over activated ai umina. How- ever further exposure cf verified Arcclcr to : adiation again lowered the resist! . The plot of rests ivity ver- sus time of irradiation r eserr.bL1ed a conductivity ersus cor.- :entration curve a we a ectrolyte. The res stivity cf the photodegraded Arcclcr reached a constant vaiu after ap- preximately 2 b hours lrra; i a tier, but degradation vider.tly continued since the yells.; color increased with t me of irradiation. t i litj $ fome information or. the conducting, material produced iin; it f * | * Aro'clOT' degradation was obtained by adding various types of ; compounds' which could act as precursors for the conducting it material land, observing the ;:x~ec ^ .these additives .when, iPoaslt i!sors were! tI iit. ..L?j- . DSW 620738 STLCOPCB4094766 jeecause? th6-<35!Mu5^i?i^?ffiSttfe?33EBB3S'5rd n*c the,'degraded mixture4. f-'rg ' Additionaifinforin^J?^:< ^ degradation?mecl' obtained by prototype 'stdle3" iing chlorobenzene ,|||? suit a reasonable mechanism* has-^ )'een postulated for*4 51 m . ;wds\ a|re- pho- todegradation of Aroclor-`and other halogenated aromatic compounds. **{. : -&ri #>- . .*; ?'<$#-< * ; The effectiveness of"several organometallic compounds as photostabilizers for Aroclor was measured; of those tested, tetraethyl lead was the moat effective. III. CONCLUSIONS ' The loss of electrical resistivity is caused by the pho todegradation 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 degradatlpn 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. ' s r ' J + The primary reaction occurring In the photodegradation of Aroclor or other halogenated aromatic compound at wave lengths greater than 2000 % Is the homolytlc cleavage of the carbon-chlorine bond to give, an aromatic or aromatic-substi tuted free radical and a free chlorine atom. This free chlor ine atom can 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 fan .addition compound .with Aroclor or a halogenated aromatic ^cor.Dound. ' . $ Thg loss. ^i tloh of hydrogen'chiorl' ' compound which contains STLCOPCB4094767 Stabilization, a stable carbonium ion can be, __ . i. ' t^ )clorjnedium.|i ^ . t- - :- ~ . \ . - ''' ' Aroclors cannot be completely stabilized by additives \ 41 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 photodegradation. Stabilization by the use cf metallic organic compounds, such as tetraethyl lead or diphenyl dibutyl 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 resonancerestricting ortho substitution. Aroclors will degrade phctcchemically regardless of the purity of the sample since the Aroclor molecule itself unstable. No amount of purification will stabilize the Aroclor. Stabilization can only be accomplished by the use of additives. ' The rate cf 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, shews 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 Aroclor degradation. U3Ei> AN Aroclors may be stabilize compounds. Tetraethyl V~ effect -of many compounds tested but leads to a slight precip- | itate. This additive, as well as similar ones, should be fur ls ther evaluated and Its possible use as a photostabilizer .|Mjbl|oulc$ b4 brought fto the attention cf ioiir feuitomeirs | f STLCOPCB4094768 1W HantzchffA|>J.asgif;Joehem, EY, Ber;T34 >"13337:1(1901)4 r-y- f W^tmtK f * f3. Noyes, w.| A^OTgsua<fc|Synthe^Ls,sVol.|sf, ^page 108. f I / : " ff I ll ; I i - " i ' V 4 4. Brown, H. C. , and "Fletcher, ET'A., J. Am. Chem. 3oc. 73, 2808 (1951). 5. Ziegler, K., and Mathes, W., Ann. 479, 111 (1930). 6. Pray, H.A.A., J. Phys. Chem. 30, 1477 (1926). 7. Lindsey, R. V., Jr., and Ingraham, J. N., J nJTl . Chem. Soc. 75, 5613 (1953). B. Patent References Jenkins, R. L. (to Monsanto), U.S. 2,578,359. December 11, 1951- "Stabilization of halogenated organic compounds with dibutyl diphenyl tin." Clark, F. M. (to General Electric), U.S. 2,468,544. April 26, 1949. "Stabilized halogenated ccmpositions. and electrical devices." Jenkins, R. L. (to Monsanto), U.S. 2,646,403. July 21, 1953- "Halogenated aromatic hydrocarbon dielectrics. Hardy, E. E. (to Monsanto), U.S. 2,566,196. August 28, 1951. "Chlorinated aromatic dielec trics . " Carothers, W. H. (to Dupont), U.S. 2,008,003. July 16, 1935- "Lead phenolate." Mack, G. P. (to Advance Solvents), U.S. 2,628,211. February 10, 1953- "PVC resins stabilized with polyscannoxanediol esters." Reference to Previous Work at Monsanto white, W. A., and Ruehrweln, R.A., Central Re search Report No. ,543a January, 11, 1949..i. "Light stability of electrical*rfelistivity of (Aroclor r 1254. " i ,L i f f '" If DSW 620741 STLCOPCB4094769 Aroclor 1221 Aroclor 1232 Aroclor 1242 Aroclor 1248 Aroclor 1254 Aroclor 1260 Aroclor 1262 Aroclor 1268 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 this report. Apparatus Aroclor degradation Thermal degradati This 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 cil bath tc prevent polymerization and through the sample bubbler tube to sweep the KC1 over into the HC1 trap. Knobs were blown on the HC1 trap to give the gas bubbles longer contact time with the NsCH 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 i t beaker. A reflecting baffle was placed around the entire set-up-, i f ^ " I M | ; ` I* " ^calculation from, the specific ^242 showed;that 505o Of STLCOPCB4094770 . apparatus was sexoifpyas shown in.?Pig^72T-SLnl,Whlch art ver| ^Fchanging-film oftefeoclor could bel irradlafedis: Thlssappara? -V-tus consisted- o-f an-irrad.i.a.t.ion .boxn Elliptical re-t im T- fleeting surface inside. The sample ^ubefwail placed at one i focal point of the ellipse and rotated by fa motor to form a thin film on the wall of the sample tube. A S-4 sun 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-4 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 tnon sealed off under vacuum. The distillation column was wrapped, with asbestos tape, while the flask, con denser and trap were protected from irradiation by tin fell; thus, only the quartz irradiation zene was exposed to light. An elliptical reflecting shield was placed around the -irra.- : ` diatior. zone and the AH-A lamp and the apparatus was covered from above with tin foil. This increased the efficiency of the AH-4 lamp. The inner tube in the irradiation zone caused the distillate to spread in a thin film. 3. Resistivity measurements The resistivities were measured with a General Radio Megohm bridge. Type 54AB. The three conductivity cells, made by J. C. Baiscaugh Co., had an approximate cap acity with air as the dielectric of f. and cell con- 3tants of 550, 555 and 574 ems. respectively. All resistivi ties were measured at 25 + .03 C. '` STLCOPCB4094771 SgenfMa^^iassedr tfirovigh tSS sample to sweepS th^idi^llb-- . K ^ f wiMiCied b^t^thermalldeKradatlon Into the HC1 .^rafa^^fter-' - '-***1^3"heating cycles,*as shb|rriin Tables I and It^the sam- fpf 0.02N.NaOH in the HC1 trap was removed and acidified with 2 ml. of 0.9N HNOj. Thenji 2 ml. of 0.018N AgNOj was added and the chloride ion waa determined turbidimetrically. It was found that hydrogen chloride was only evolved during the first 3-1/2 hrs. and that additional heating produced no m 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. i 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 10-6 Qf HOI per gram of Aroclor during the above thermal degradation, compared to 2.13 x 10-D g. of HC1 when this Aroclor was sub jected to heat alone. 2. Ultraviolet absorption spectra The ultraviole t absorption spectra of Aroclors 1221, 1232, 1242, 1248, 12 54, 1260, 12o2 and 1268 and various fractions`of Aroclors 1242 and 1254 were measured with a Cary Recording Ultraviolet Spectrophotometer. These spectra were measured on apcroxima tely 0.0006$ solutions of the Aroclors in absolute alcoh ol using a 1-crn. cell. The resuits are shown in Figs. 4 10 expressed as specific extinctlon coefficient versus wa ve length In rn/*-^ 1 s . The specific extinction coefficient is defined as K log or optical density :ell thickn ss in cms x ccnc. in g./liter The ultraviolet absorption spectra were aloe measured on sev eral lots of Aroclor 1242 submitted by Annistcr.. The results are shown in Table III for Aroclor 1242, Lots 166, 170, 174, 179 l8i. These results are tabulated since plots of extinc tion coefficients vs. wave length were so similar that little or no difference was detectable. The slight differences be tween lots are jnore clearly shown in the Table glylngioptical density and sj|ebificf extinction coefficient for eacrf wave * length'. ! ! '' ;3S 1 11 xtodeggadatilor Ho DSW 620744 ' 1 ' i|,.ray*V STLCOPCB4094772 in the .-S') >todegradationpiMara&i3 described ab<v8_._,,,r. V ing ^thi3|treatmen-VtsJ tt-h.Veio^volume |reSl's1 ArObfjpF f ? i changed from 9.7 x 1011 ohm ` ioi^ohm.lcajaf; IA ' 50$ solution of the degraded Aroclb^SLn iheptane was 'then sep arated chromatographically by passage through a column* of activated alumina. A very dark yellow band appeared at`the top of the column while the Aroclor-heptane solution was : clear, resembling unirradiated Aroclor. After the heptane was distilled off, the recovered Aroclor 1242 had a resistiv ity of 1.2 x 1012 ohm cms. 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 loll chm. cms. The Isolation of the degraded material from Aroclor which was adsorbe d on alumina was attempted by treatment of the column with h eptane. After 50 washes with heptane, the eluate still co ntained 0.0118 g. Aroclor 1242/ liter, while the brown la yer 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 1012 ohm cms. 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 cms. The resistivity stability of Aroclor 1262 was compared with that of Aroclor 1242 upon irradiation for onehalf and for five hrs. Benzene (25$ by weight) wa3 added to the Aroclor 12o2 to facilitate handling. The measured re sistivities (ohm cms.) are as follows: Initial 1/2 hr. > . 5 hrs; s:,, . . i , ., {.it i n t 1j1Mm ttt1 mr tf-*ytt * cldr^ 1-242 v ^ 7.7 x I011 6.9 x 1010 '9.9 x 109. f. " " , .j; 1 75$ Aroclor 1262,; ii|2 r DSW 620745 E&; STLCOPCB4094773 tisl ^ Itrwa8^onsiderea'that Aroclor could contain Some tieslwhich woulcl, leSd^to the formation of conducting* f mit$riaIeforf irradiation iand'that such impurities might bet If s oxygen-^ nitrogen-,^ or; suijurr-containing compounds which B4 should be removable by washing with cone. H23O4. 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 ohmcms. compared to 7.7 x loll ohm ems. The Aroclor was then passed over alumina, and the resistivity rose to 8.2 x 1012 ohm ems. The H2S04-washed Aroclor was irradiated 20 hrs. by the S-4 lamp and the resistivity dropped to 1.9 x lO^O ohm ems. compared to a resistivity of 2.5 x 1010 ohm ems. for un treated Aroclor after 20 hrs. irradiation. From these re sults it was concluded that acid washing did not affect the degradation. The phetedegradatien of Aroclcr 1242 in the pres ence of diphenyl plcryl hydrazyl (DPPH) was also followed by its change in resistivity. Very little change was observed 3ince the conductivity of the DPPH was nigh, causing low initial resistivity. 4. Effect of added impurities Phenyl-substituted methyl chlorides have been 3howr. to be electrolytes in nor.-aqueous media (A.5) and it was considered likely that thi3 type cf compound could be material formed upon irradiation of Aroclcr. 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 that stilbene is an im purity in raw biphenyl. Accordingly a number cf compounds were added to Aroclcr at a concentration of C.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 t Aroclor solutions were irradiated for 5 hrs. by the S-4 lamp, t' samples beings removed aft<rtl/2 hri for resistivity measure It 1 ments The ^results of fthebe additives are shown in Table IV. III ` mss* triphenylnethyl chloride. lip nedJ DSW 620746 t'-W* W-' W>; STLCOPCB4094774 lit: ^ | dip| '' 4--V :> I _ ^ ^gw*ng<uj>v ^Lg^aj' ?Lof 17C. ^ ous concentrations .of Triphenylmethyl chlorld^f.nip4toIXjP.37^). at 25C. The plot of concentration of triphehygaeth^r^hioride vs. resistivities is shown in Fig. 12.t ^Theffi'eseB^^nce : of this curve to the conductivity curve of a 'weak;:ele^w6lyte Indicates that triphenylmethyl chloride acts as V weak'elec trolyte in 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. HpSOz;. If it is necessary to have a compound bearing an excess cf electrons in order to stabilize triphenylmethyl chloride, then HgSOl^-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: ;s Wt. % foCCl Resistivity at 25C. 2.1 x 10*2 cms_ 2.4 x 1q9 ohm ems. 3.7 x 10 ohm ems. 5. Reduction of resistivity by hydrogen chloride Hydrogen chloride has been reported to be a .con ducting material in Aroclor (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 t Aroclor 1242 and the resistivities of the solution were fol lowed ^as a(function of time. The results and condiTicfrisiofi | the* experiments are shown in Table V. In 10 minutesrthe?re* slstlvity had'dropped from 5 x 1012 ohm ems. to 2;4 x ,10|P ohm ems., at which point the minimum reslstlvlty^ie.ve] . bqep jmdjj.^ldj.tlynplihydrjpgen^.ahior* ' "* if DSW 620747 STLCOPCB4094775 >was^heafce& nitrogen was bubbled through the Aroelor out the; entrained hydrogen chloridef The-resistivi-J ^l^turned to 2.0 x lO*2 ohm cms., or essentially the orig- ? inal* value. f ` Aroclcr 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 lO^O ohm cms. Hydrogen chloride was added to chlorobenzene and the resis tlvity was measured. The addi tlon of HCl reduced the resis tlvity from 3.2 x lO^2 ohm cms . to 6.3 x 108 ohm cms., but bubbling nitrogen through the solution (that is. sweeping out the HCl) raised the resist lvity to 1.5 x lOll ohm cms. Failure of the chlorobenzene to return to its orig inal resi stlvlty may be partially due t o dissolved hydrogen chloride, since no heat was applied dur ing the nitrogen sweeping. Chlorobenzene reactions a- Reaction of chlorobenzene with benzenedldzonlum chloride Since benzer.ediazonium 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'photodegraaatlon. This is based on the assumption that the primary photochemical reaction of chlorobenzene is the homolytlc cleavage of the carbon-chlorine bend. To lpO mi. of distilled chlorobenzene in a 300 ml. flask 23.5 g. benzenediazonium chloride was added. Tne 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 3een 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 carriedjOut in a bomb room, by remote control, . * | ; 1. j * 5 1' f * After the above treatment, the excess be zenediazonium;chloride, was filtered off. STLCOPCB4094776 tlon and separated into three fractions. | The refractive^ dices of the fractions were as follows: f ?" ?, * ' v$ * - 1 ' u"k2r5- ? i' Number 1 Number 2 Number 3 Distilled chlorobenzene 1.5095 1.5212 1.5215 1.5214 Che fractions and the residue were analyzed by infrared and :he results showed little or no difference between samples. b. Photodegradaticn of chlorobenzene The continuous irradiation appara tus shown was charged with lpC ml. of distilled hlcroben- :er.e .r.e liquid was frozen w ith liquid nitrogen and the ap- :ara tu: w a s evacuated. The fr eezing, pumping and thawing cy- wa; r.tlr.ued `until all di ssclved gases were remcved. The .iqt..id and apparatus was final ly pumped to a pres sure of 1 x " rrs, `-V'.e re: a-j f Hg and sealed off. The liquid was di stilled from oir, condensed in th e irradiation zone and then rethe reservoir. This continuous distill atlcr. and ill r. was continued for -62 hours. Initial boiling r r.e chlorobenzene was 50C., and the fin boiling point wa; 60C. The reaction mixture was analyzed by infra red and ultraviolet. The ultraviolet spectra of irradiated chlorobenzene and the reaction products of chlorobenzene and ber.zenediazonium chloride shewed strong absorption at 237 npM^, attributed tc an addition compound of chlorobenzene and chlor ine. Infrared analyses were r.ot significant. c. Chlorine addition to chlorobenzene An addition compound of chlorine to chloro benzene was made by filling a 5C0-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 freed of the excess chlorine by a low-tempera ture distillation)!. | fto luitraviciet-'spectrum of; titis :addltioh mixture, compared with `that of chlorobenzene, showed a very strong absorption at 26 ibi*. STLCOPCB4094777 * '"spect `or fodegrac benzene; dlazonium chloride-chlogobenzene reaetlpn 4- produe t fahd^jS^pj iWbenzene with known ^addition compounds; showed (. Pig_ , ,' |light shoulder on thefec|H aromatic band, 3 which Indicated! Shaf^an aliphatic or allcyclic 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 Table VI. 6. Syntheses of compounds a. Triethanolamine borate - Triethanolamine borate was synthesized from triethanolamine and boric acid in 68$ yield, using the method described by H. C.*Brown and E. A. Fletcher (A.U). b. Trlsdlbutylstannar.edlol Trlsdibutylstanr.anediol was prepared by hy drolyzing dibutyl 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. Trlethyl lead phenolate Trlethyi lead pher.olate was prepared by the action of tetraethyl lead upon phenol as described by Carothers ` :ir. U.S. Patent 2,008,003 (3.5). i 't ' d. Chlorinated dlpr.er.ylmethane - .Dlphenylmethar.e was vacuum distilled through a Vigreux column| pressure and the fraction boiling at 1J2C./ lh mm. was collected* Nfp =.1.5734 (nA7 = |1.5758% reportedV.* f * The purified' adjmeriylmethane was chlorinatedfby* bubbling: f. _ ? chlorine gas thrpughf 34-. 5 g. of the hydrocarbon;at a rate of* 1/3 mole per hour STLCOPCB4094778 Jhlorination by a free radical mechanism/ light"was el_.___ . . , ted from the glass tube reactor by. immersing it in a sajidifc|' j 4A -I bath surrounded by a steel'casing: After 4-1/2 hours//the^t : ; 1 4 chlorination was stopped, the product was distilled and*the' '' v % distillate was collected at 130-152C ./1-5 mm., b .p .=130QC./ 1 mm. Anal. Calcc. for Ct^iiCI: C, 77.41; H, 5.^6; Cl, 17.13. Found! C, dO -64; H, 5.91; Cl, 13.^5 (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 Trlphenylmethane (10.0 g.) was chlorinated in the same manner as the preceedir.g synthesis. The temperature was allowed to reach 142C. After 1-1/2 hours, the chlorine flow was stopped and the material crystallized ir.tc a dark reddish brown mass upon ceding. Anal Calc, for C19H15CI: C, 02.16; H, 5.4l; Cl , 12.43. Found! C, 06.74; H, 0.56; 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. Ber.zenediazoniun chloride Benzenedlazcr.lum chloride was prepared accord ing to Hantzch and Jochem (A.2) by reaction of amyl nitrite with aniline hydrochloride. The amyl nitrite was prepared as described by Noyes (A.3). In this synthesis 33 g. (0.55 moles) C.P. sodium nitrite was dissolved in 15C cc. of water and ceded to 0C. To this cooled mixture a solution con taining 10 cc. water, 13.6 cc. cone. and 44 g. n-anyl alcohol was added dropwise 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* ovjer anhydrous sodium sulfate. t . it i . r -- 'h ' . -_ * *) A mechanically stirred mixture of 22 g. .of* aniline hydrochloride dissolved in 60 ml. of glacial *aj:4tii: ted to this jWks. added during 21 . , ah h. fc i. A ir. -r . b ; DSW 620751 STLCOPCB4094779 f4 - I/ 1% k 1 > " vi.3 precipitated by slowly dropping in "anhydrous ether fttwc unes of^etherf tcldnfelof1#solution) . t' This4.addition' requlSedl I 3-1/4 hours. iThe(precipitated diazonium compound was f^LS.-' tered off: and washed`with anhydrous ether until free of `ace tic acid. The berizenediazonium chloride could be stored un der ether but at no time was it allowed to be dry. Benzene- diazonium 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 thermally 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 Aroclc rs 1248 and 1254. Apparently the higher Aroclors are more stable to thermal degradation, Since any of the Aroclors con tains a mixture of compounds cf various degrees of chlorin ation, it is reasonable to expect that all wouldproduce s ome 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 ten fractions and these fractions were thermally degraded at 250cC. for 5 hours (Table II). Only the first three fractions liberated hydrogen chloride, the greatest amount being liberated from the first fraction. Fraction No. 4 shewed 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 occuringand 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 cpuM ,be|formed ^within ^the Aroclor aa,a|*g result *of|photbdegra*datlpn pr aging and that the loss of Ire- ?? sistivlty*could be attributed to products arising from the * ` Aroclor mqlecule iit3.elf, ' t ' ti 1 i. DSW 620752 T T - '!* T? ' STLCOPCB4094780 H % il ^ tion studle^on fractionated ^Aroclor^i ^125^Mre|i\ot ^performed but it is expected that results simi lar 'tofthose 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 specifi c extinction coefficient against wave length in millimicrons (Figs. 4 and 5^ for Aroclors 1221, 12^2, 1242, 1248, 1254, 1250 , 1262 and 1268 show a gradual decrease in the absorption b and at 246 which disappears in Aroclor 1248 and those hi gher. This absorption band is due to coplanarity resonance between the benzene rings. It is absent in Aroclors higher than 1248, in which ccplanarlty resonance is hindered hy ort ho chlorination: even one chlor- lne atom in the ortho positi cn is sufficient to eliminate this resonance. The ultraviolet absorption spectra o:' fractionated Arcclcr 1242 show little difference between fractions, with the exception of Fraction No. 1: the absorption curve for Fraction No. 1 shows little absorption due tc coplanarity resonance, whereas' curves for other fractions show a strong band at ny* This fraction also liberated the sate: quantity of hydrogen Lcride during thermal degradation. rhe ultraviolet absorption spectre :f Aroclor 1242 show ttle or r.c- diffe: various lots ;etween lets. C. Phctodegradatlcn of Aroclors It is 3hcwn lr. Fig. 11 that the resistivity of Arcclcr 1242 rapidly decreases during irradiation, but reaches an es sentially constant level after approximately 2-> hours. The of this plot r concentration for a weak electrolyte. Sven though the resis tivity reaches a >. cr.star.t value, degradation continues since the color continues to darken. The eclcred material can be adsorbed from the Arccloi by activated alumina ar.d the resistivity of the recovered Arcelor;is thereby restored to its original high value. Fur ther jexgqsjice f-the purified Aroclor to? irradiation causes further decrease in resistivity. If this colored extract Aroclor is added tc untreated Aroclor, a drop in STLCOPCB4094781 It was shown tha its1 resistivity but tha|?i gentchloride_ gerf chloride ih^rocior^iojjers^ f .~v the Aroclor by bubbling! en Ithrough the? AOpclor, thereby : restoring the original hlg' ^ sistivltyPhotodegraded Aroclor could not be returned to'its , riginal 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 was re moved but some other conducting material remained. These re sults indicate that tie conducting materials in degraded Aroclor could be hydrogen chloride and some high-boiling material. lift Photodegradation of Aroclor takes place in the pres ence or absence c.f oxygen with loss of resistivity; however, the reduction of r-sistlvity is more pronounced in the ab sence of oxygen. All experiments in this study were carried ^ut in the absence of oxygen. Trace impurities are always a pcssi ble source of de gradation reactions In any system. Inpurit les were considarea to be present in the Aroclor and these were considered to be nitrogen-, sulfur- or oxygen-contain ng compounds which should be removable by concentrated HpSO^ w ashes. After several treatments with concentrated H2SC4, th e purified Aroclor underwent photodegradation with loss cf ele ctrical reslstlvity at essentially the same rate as unpurlfi ed Aroclor. These data indicate that the degradation products were being develoced 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,, Lo* 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 t:.at a thermally unstable, compound which liber ates hydrogen chloride is ^produced in the photodegradation, and it is also reasonable tojbelieve that the Aroclor con tains traces of sue., a compound, developed during handling and storage. -; | i - . ; * $ t Determination ofI TO^fChiifi'cil? cc?nsBit4feon of fthi 1 i f conducting material was attempted by first isolating the'ma terial pn activated aluminajTb^ cplor ,was removed f~om|.the ideil .Art; clt Ena at fchel `ate $iI V; DSW 620754 STLCOPCB4094782 I*%' % fHK' ?iy^oundlt6 She"alumina that it could not be eomitely ^elu^d.|^Aflter|50 washes with heptane1, the heptane stilr showedr0.0118^g.f 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. H2SO4. The acid washings were diluted 5:1 with water and the temperature was kept below 5CC. 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 cf various types of 'compounds; to the Aroclor. The additives tried are described in Se; VI-C-4. D. Effect of Addition of Impurities Phenyl-substituted methyl chlorides have beer, 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 triphenylmethyl 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 carbor.ium ion or there must be present some trace materials possessing an excess of elec trons for stabilization. Ber.zophenone is known to act as a stabilizer for carbonium ions. However, the addition cf benzophenone to Aroclor containing a small, amount of trii pheoyl&ethyl ^hldi(id(| d<^es not further lower tfte resistivity ' of* theFmlxture / flf |tabilizatlon of the carbcni'im lor. had required the presence' of. an .excess of electrons, then the STLCOPCB4094783 triphenylmethy1 chloride posses izatlon to render the |carb|)niura ion Jstabl^'.^lp|;,;, ff i| 7 $: . .^ ... t... . If phenyl-substituted aliphatic'^hloiTide compounds v ' 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 Arcelor 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. is known that the greater the phenyl substitution on the aliphatic chlorine-bearing car bon, the greater is the conductivity. Cartcniur. ion must be planar in order to be stable. Compounds produced ir. the degradation of Aroclor could pos sess a number of phenyl groups and could possess sufficient planarity for resonance stabilization of the carbcr.iun icr.. 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 ior.s. The fact that Aroclor 1262 {62% chlorinated) is more stable than Aroclor 12^2 chlorinated) indicates that less con- ducting material is ermed when the ortho position is blocked. 1262 contains some molecules that are not chlorinated lr. the ortho posi t is expected that seme degradation should occur. The higher degree1of chlorination aids in the rhetestability of the Aroclors due to restric tion of the resonance and thus reduces the concentration of the carbcr.iurr. ion formed. :: _ STLCOPCB4094784 Utllfl * M1 ^W rr*4pr piTfryFfiydrlz^T'nibiutlon was placed in a special clT-`ar-* ranged so that .the irradiation took place in a portion of ' the cell wh^reflight could not strike the metal surfaces"ofv the electrodes." Significant results were, not obtained since ? the DPPH 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 wa3 difficult due to the complexity of the Aroclors. These complications led to the use cf a prototype, chlorobenzene, for further identi fication of the conducting material. E. Prototype Studies Chlorobenzene has an a'cscrptior. band at approximate ly 2200 due to the cleavage of the carbcn-chlorir.e bond. This is measured or. very dilute solutions. In pure chloro benzene this absorption is shif'ied tc higher wave lengths and the absorption is apparently sufficient at wave lengths above JCCC % to cause seme degradation, since it was shown that the resistivity of pure chlorobenzene was lowered by irradiation. As with Aroclcr 12-2, it was .net possible to restore phetedegraded chlorobenzene tc its original high resistivity by bubbling dry nitrogen through the degraded material. An attempt tc remove the conducting material by freezing, evac uation, thawing, refreezing and re-evaluatlcr. was not effec tive . Fractior.atlof. of phetedegraded chlorobenzene yielded residue as the final fraction. The infrared spectrum residue, compared to that cf chlcrcter.zene, indicated in the CH absorption band, attributable to a trace of Le or allcyclic carbon. There were also indications of para and meta substitution, Ultraviolet scectra shew a strong absorption at 26? -. ' The logical phetodissociation of chlorobenzene would be the homolytic cleavage cf the C-Cl bond tc give a phenyl radical, and^a hlorine aterr. as the primary reactlop., 4 To^ test ' these reactions,. *the thermal degradation of benzenediazonium1 chloride in presence of chlorobenzene was studied since sev-` eral workersI(A.6,7) have shown that benzenediazonium chloride Ait DSW 620757 STLCOPCB4094785 1 S/ N-N ^| n-C1 ji tf'lSfsffS-lS-- iw'f.i*-t M,,$, |#,, :,,Hf-! $ y\J f 5 ^ '? . f I I + N2 *+ Cl*: VX ) ' i- 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 cf the products of the reaction of the diazonlum chloride with chlorobenzene were similar to spectra of photodegraded chlorobenzene. Lindsey and Ingraham (A.8) have studied the photodegraaatior. of 1-chlorocyc lohexene and have concluded that the primary reaction is the hemolytic cleavage of the carbcr.chlorlne bend. They found cyclohexene, cis-1,2-dlchlorocyclohexane, 3,31-dichlcro-1,11-bi-2-cyclohexenyl and 3(11-cyclohexer.yl )-l-chlorccyclohexene as reaction products. These products show that all possibilities are formed from the radicals and that the chlorine atom can add to the double bend in the cyclohexene ring. From these results it is rea sonable to expect that aromatic compounds such as chloro benzene could undergo essentially the same types of reac tions, especially the hemolytic cleavage of the carbon-chlorine bond plus the addition of the chlorine to the aromatic ring. 3uch reactions would be expected to take place to a lesser extent with the aromatic compounds, however. It is seen in Fig. 13 that the ultraviolet spectra of (1) chlorine addition compound of chlorobenzene (Curve 3), (2) th reaction .products of benzenediazonium chloride (. with chlorobenzene (Curve A) ar.d (3) irradiated chlorobenzene show a characteristic absorption band near 285 m, when compared with the spectrum of distilled chlorobenzene.^ The infrared spectra of these three preparations plus the spectrum of chlorobenzene are shown in Fig. 14. Curve I in Flg.il^ shows . only the characteristic C:-H absorption of; an aromatic group * irf the' 3-5/4*> 'regionT Cuirrvvees IT, illl and! IV %hoW tslmilaif ab- sorption plus aniadditional absorption at slightly longer wave lengths,.attributable to the presence,of4addition com- unds* . It is & * t* 1 SW 620758 STLCOPCB4094786 .. - . ir6B6 TYlcft^^B^Fi 'show^Ilnt^erabie shift, indicating|that the addition prod ucts {are^ffnceritrated in thef higher boiling residue. Also1: g^She resistivity of all the ;treated chlorobenzene mixtures !Tare iWf'-f From these data, it: can be fconcluded that the con ducting material 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 photodegradative conditions: V (2) + hi/ + Cl r^V1 Cl I \y Cl- HC1 If . , : -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 r : - (J) shows .the reaction of the addition complex with phenyl | I | I -radical^ to produce a compound which, could possess sufficient 1|| ikl. tre3onaxice energy, s<x that, the tcarbpnlum ion would be stable, f * f f Sff 4v|Thd Wxijbi Mature* the conducting material was not identi- * v ` Jfied. With such radicals produced in the primary reaction, fr.ydrpgaiichloride! could baproduced py -the action of a . ipa* iny^cai the.` i f h' ' I ; ft f ri DSW 620759 t xokm r mwi if STLCOPCB4094787 I ~b % f I'ponSucting 'material iJiiQie 'chlorobenzene algrgjxJ I'Brl^e fromiBepondary reactions o| the chlcj^ng11* st > !#: ;> The phenyl radicals are free to enter! actions, which could produce color or polyphenyls1 Ss# 4Tireit 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. I ' F. Aroclor Stabilization From the postulated mechanism for the degradation cf chlorobenzene, it is seen that elimination of the free chlor ine atom is essential if the Aroclor is to be successfully stabilized. Stabilizers must have the following character istics : fl) The stabilizer must be a non-conductor. (2! The stab.illiizer 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 prevent ing the formation of the chlorine addition complex. Although net investigated here to any extent, another effective stabilization method could be the elimination of the primary reaction by screening cut that radlatlon{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 A30, 2-dodecyl-9,10- , a.nthraquinor.e and Ponsul Yellow could only act as^ ultra violet screening agents and would not be effectiv* in |remov- ingithe hydrogen chloride or the chlorine atoma. I Ithepe fedditives was an effective^ stabilizer;; i ; % v A number of the additives tried ass stabll an iLniitlalkdecrease in reslati) caused f1 iff! li DSW 620760 STLCOPCB4094788 r*; ..................... ...jtfL _ ^^ rec&ffi3^pgf]|gh-'found at^'Anniston that pHehoxy- Dto^n^1 |xlde is a|gootp thermal stabilizer and is not covered pV adVerse patents^ mLsfbompound was evaluated as'a light ^stabilizer but'was*found to be ineffective. 1 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 metallo-organic compounds such as tetraethyl lead. It is net certain what effects thi3 compound will have on electrical equipment since a slight precipitate was formed during photodegradatlon of Arcelor containing it. It is to be pointed cut that the degradations in this study represent accelerated and mere severe degradation conditions than those obtained under use conditions. General Electric holds the basic patent or. the addition of compounds of RXM type to chlorinated biphenyls. It is also felt that G.E. has never studied the effect cf this additive in Arcelor under photodegradatlve conditions since their original intent was a hydrogen chloride scaven ger. The effect of.tetraethyl lead as a photostabilizer for Aroclors should be brought to the attention of General Electric . Monsanto holds the patent on diphenyl dibutyl tin as an additive for Aroclor. Although this compound is not as effective as tetraethyl lead, it does exhibit a marked photostabilizing action and further evaluation is in order. The search for a more efficient stabilizer should be continued with attention to these compounds which will read readily with free chlorlnatcrs. i `.Additional Aroclor degradation studies should place more emphasis on prototype studies since with a prototype the number of product possibilities is reduced. From the of this study, it is seen that the mechanism of degra3n for the Aroclor prototype, chlorobenzene, is given r Reasonably |good evidence but has*noft b.een absolutely d.? `Further' study %nfthe proof`of this'mechanism is in- lica^ed. Studies should Include a positive Identification ie products; quantum yields, and thei wave .length ranges Midn d gradatiAMkt i *|g Mftwf ` ' it ti DSW 620761 iTf T. W V- STLCOPCB4094789 4.> I f% ?.? &npWs"ls WiaPPtr Il^pfacecf sdleijfSpSnW^^fl Aroclors as a meafi^Sf stabilization since degradation^hs -< i been shown to arlS# from Aroclor Itself j i" " ' ft. IX. DESCRIPTION OP RECCMMENDED PROCESS Not applicable. JiJ li X. FATENT STATUS A disclosure on the use of tetraethyl lead as a photostafcillzer 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 dibutyl tin is nrctected by a Monsanto patent (5.1). ` XI. COST ESTIMATES Net applicable. XII ANALYTICAL PRCCEDUR] The Balobaugh 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 are thoroughly ' cleaned as described below reproducible results cannot be obtained. The cleaning procedure recommended is as follows: (l) Drain cell and fill with trlchlcrcbenzer.e and heat at ICC0; 1 c: 15 minutes (2) Drain hot trichlorcber.oene and rinse with cold trichlcrobenoer.e . I -? I (^3) Rinse at least twice with methanol. (4) Rinse with water. fi-ft-* , t ' If | ., I< (5) Fill/with a saturated solution of tri sodium] phosphate and heat at 100C. xor i* i < an? oven 'a* DSW 620762 STLCOPCB4094790 ...^Balsbaugh "celiflhdws a drift with ttoe|a'fter. the voltage from the Megohm, bridge is .applied aorOssf thie^ceii This "is due probably tojpolarizaticn of the electrode's. ? The; A.SfT.M. recommends thatfthe voltage be ap plied for cnetminute 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 cf hydrogen chloride liberated from the Aroclor was determined turbldimetrically 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 Arcclors consist chiefly of metallo 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 Ulm, Messrs. Beasecker and Loucks of the Spectrographic Group is acknowledged. Many helpful discussions were held with Brs . Johns and Ruehrwein and their suggestions were particularly valuable. Frcf. Fucss alsc contributed much to the discussions. XV. APPENDIX i This report covers work recorded in the following note took pages: ; . .. .. r : J . ' 257780 V 270638 ; i .tivm 275171 27547S-75 * k 275181-82 275184-95 !5m-2p0 i ' DSW 620763 STLCOPCB4094791 STLCOPCB4094792 STLCOPCB4094793 THERMAL DEGRADATION OP FRACTIONATED i AROCLOR 1242 A--T----2--4--3OnC. 1,2 5* Fraction Wt. % of Charge 4.6 9.5 - i Still bottom .0.0 .0.1 .V . i. .C. 4 C.3 0.3 .1.4 2.4 B. ?. Range C ./mm, 4? 146-169/ 10-11 mm. 168-186/ 11-26 mm. 169-196/ 26-40 mm. 138-157 157-159 159 155-162 162-167 154-177 177-197 0 a^ X g. HCl/g. Aroclor 6.6 x t e-6 C.35 X .-6 Very sli; 0 vj 0 0 0 - The Aroclor was fractionated by the Inorganic Division at Anniston. "p , t i i a i s t. i. All samples were heated, 5 .hr 3 .at '* * - f * * ? * fe^3C. with Np bubbling* througk them. ^4||te?ure is . 3 mm. except, as noted . " ` ` fcj i j Sl;l ?J f; , f 1| 1j tI DSW 620766 w ___ . STLCOPCB4094794 Y `I ' V. ' -t ' % * * *. * -it - " y - -i-* sf J^ '- f-4' iW- '^'- STLCOPCB4094795 STLCOPCB4094796 JTT>F ' ;f. ipH*- Precursor, 0.5 wt. % p-Chlorotoluene o-Ghlorotoluene Toluene Aroclcr 1242 Trans Stilbene Benzyl Chloride Chlorinated triphenyIce thane Dip he r.y Ice thane Chlorinated dipher.y Ice thane Chlorinated dipher.y Ice thane TripuenyIcethane Tripher.ylcethyl Chloride & VIDUS' ADDII VS" jfit infoiln i f .! Source of Additive -cm^ ;' ' ; After 1/2 hr. After 5 hr. At Start " Irradiation Irradiation E. K. E. K. ' 2.0 x 1012f 4.2 x 1012 C. R. 3.0 x 1012 Monsanto E. K. 7.7 x 101! 1.5 x lO^2 Ger.. Chec. 3-5 x 10l 3.4 x 1010 4.0 x 1010 4.7 X 1010 6.9 x 10IO 1.0 x 1011 1.9 x 10IO 3.3 x 1C10 1.5 X 1010 1.3 X 1010 9.9 X 109 9.8 X 109 7.9 X 13 3 E. K. 6.0 x 109 1.7 x 1012 4.6 x 109 6.1 x 1010 3.0 X 109 2.2 x 10? (Liq.) 5.3 x 10H 5.3 x 101C 1.0 x 10'9 (Sol id i E. K. - - j x lC-'-2 5.5 x 1011 1.0 x 1010 8.3 x, lo9 1.0 x 1q9 Wm 1 .r>V ( 5.0 x 108** : i I * , * Synthesized during thi3 investigation. **'0.369 Wt. %. ;t | t* } 111 i .t f.M ill f>t * V- . ? *, i l&t? m DSW 620769 Tm f STLCOPCB4094797 STLCOPCB4094798 " f *1 STivm ofiarc CONTAINING EXPERIMENTALISTABILIzIr^^ ' ft ' 4f. Stabilizer Source /blume Resistivities at 25C. in ohm-cms. ; Before After 5 hr8. Irradiation None Tetraethyl x^ad Diphenyldibutyl tin Di-2-ethylhexyl phenyl phosphate Dibutyl tin dllaurate Triethanolamine borate* 31s(2-ethylhexyl Jbenzer.e phosphorate Diphenyl tin oxide Triphenylstibine Dibutyl tin salicylate Benzalazine Dibasic lead phosphite Barium-Cadmium laurate Qiacetate of dlanhydro- trisdibutyl stannanediol* * t # Hf- ? M i ? 15 f Tetraethyl silicane f ' ' Eetraber il silicane Ethyl Corp. Metal and Thermite C. R. C. R. C. R. Metal and Thermite E. K. " C. R. Mathiescn Natl.lead Ferro ;c. M r. f&. R 1.0 x 1012 1.7 x 1012 5.0 x 1011 1.65 x 1C11 5.66 x 1011 1.46 x ID11 9.9 x 10l Insoluble * 1,7; x 10n 3.3 x 1011 7.9 x 10-1 Insoluble *t Insoluble .25 x 1G1C ;.c5 x 109 5-J5*4'io?2 I -- 1.`39 ^lQ12 1.06 X 101C 1I ~ , x ip9 i DSW 620771 STLCOPCB4094799 Difcutyl tin maleate Triphenyl phosphite Diphenyl picryl hydrazyl General Dyestuff C Uvinul i*9C 0.5 wt. 2-dodeeyl 9-10anthraquinone 0.15 wt. aluminum isopropylate Pcr.sul Yellow :. R. Phenyl salicylate C. R. 1.0 wt. d-limcnene E. K. Tetraphenyl germanium Hexaphenyl digerr.ar.e 1 *,, EpcsidizedsScybeanoil . C. R. Z. R. Du Pont Triethyl lead phenc-late Pinenei ' 0 *'5^ w ifif ^ lietil MlhermliPe11 RS ^1 STLCOPCB4094800 STLCOPCB4094801 STLCOPCB4094802 STLCOPCB4094803 STLCOPCB4094804 STLCOPCB4094805 STLCOPCB4094806 STLCOPCB4094807 STLCOPCB4094809 f STLCOPCB4094810 STLCOPCB4094811 STLCOPCB4094813 STLCOPCB4094814