INDUSTRIAL AND ENGINEERING CHEMISTRY
July 1947
ACKKOWLEDGRZENT
The authors wish t o express their thanks to the following men for their cooperation in various phases of this work: 11. TI-. Boyer, Louisiana Division of the Standard Oil Company of XeLv Jersey: L. J. Briggs and F. D . Rossini, Sational Bureau of Standards; 0. IT. Burke, Jr., Rubber Reserve Company; F. A. Gilbert, Buffalo Electro-Chemical Company; E. 1.Lute, Dow Chemical Company; and R. W. llillar, Shell Development ComDanv. This investigation Tvas carried out under the srionsorship of the Office of Rubber Reserve, Reconstruction Finance Corporation, in connection xvith the government synthetic rubber program. .
I
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LITERATURE CITED
(1) Blackburn, W.E., and Shepherd. D . d.,prirate communication. ( 2 ) Craig, D., U. S.Patent 2,362,052 (Nov. 7, 1944). (3) Fryling, C. F., IKD. ENG.CHEM?., . ~ N . A L ED., . 16, 1 (1944). (4) Gilbert, F. A , , private communication. (5) Heisig, G. B., and Davis, H. hl., J . Am. Chem. SOC.,57, 339 (1935). (6) I. G. Farbenindustrie *L-G., Brit. Patent 519,730 (dpril 4. 1940).
893
( 7 ) Kharasch, M. S.,Engelmann, F., and Urry, W. H., J . Am. Chem. SOC.,65, 2428 (1943). (8) Kolthoff, I. AI., and Dale, IT.J., J . Am. Chem. Soc., 67, 1672 (1945). (9) Marvel, C. S., and Horning, E. C., "Organic Chemistry." 2nd ed., pp. 771-7, New York, John Wiley & Sons, Inc., 1943. (10) Mayo, F. R., J . Am. Chem. SOC.,65, 2324 (1943). (11) Podbielniak, IV. J., IND.ESG. CHEM.,r l s . 4 ~ED., . 3, 177 (1931). (12) Price, C. C., and Adams, C. E., J . Am. Chcm. SOC.,67, 1674 (1945). (13) Itice, F. O.,and Rice, K. K., "Aliphatic Free liadicals," p . 7 5 , Baltimore, Johns Hopkins Press, 1935. (14) Schniepp, L. E., and Geller, H. H., J . Am. Chem. SOC.,67, 54 (19453. (15) Smith, J . O., Jr., and Taylor, H. S., J . Chem. Phys., 7, 390 (1939). (16) Staudinger, H., and Heuer, W., Ber., 67, 1164 (1934); Staudinger, H., and Heusemann, E.. Ibid.. 68, 1618 (1935); Staudinger, H., Heuer, IT., and Heusemann, E., Trans. Faraday SOC.,32, 323 (1936); hIarvel, C. S., and Horning, E. C., in Gilman's "Organic Chemistry," 2nd ed., p . 706, New York, John %ley & Sons, Inc., 1943. (17) Wislicenus, J., and Schmidt, P., .4nn., 313,210 (1900).
Effects of Impurities on Copolymerization of Butadiene and Styrene J
ROBERT L. FRANK, JAAIES R . BLEGEN, G. ESLER ISSKEEP, AND PALL V. SMITH University of Illinois, Urbana, Ill.
S
U1IEROUS authors (cited by Frank et d.,
cessive crystallizations followed by a flash distillation. T h e crystallizing point of the final product was -30.65 * 0.004' C. This material was considered t o be well over 99.9500 pure. It was stored a t 0' C. until used. n-DoDEcYL A~RCAPTAN. Very pure n-dodecyl bromide was obtained from Columbia Organic Chemicals, Inc. From 500 grams (2.00 moles) of this substance xere prepared 500 grams (77%) of ndodecyl isothiouronium cliloride by the method of Urquhart, Gates, and Connor (j),m.p. 124-125" C. nDodecyl mercaptan was obtained by hydrolysis of 500 grams (1.51 moles) of the isothiouronium salt and distilled through a 50-inch Podbielniak fractionating column ( 4 ) in a stream of pure nitrogen. The yield Tvas 247 grams (79% from t h e salt, 61% from n-dodecyl bromide), b.p. 117-118" C. a t 7 mm., na0 1.4589. Imperometric titration of the mercaptan showed a purity of 99.5%. STEARICACID. Thirty-five pounds of specially prepared stearic acid were obtained from Armour 8: Company. Analyses, carried o u t in the laboratories of t h e Goodyear Tire 8: Rubber Company, Inc., were as follo~vs:
Nineteen possible impurities in butadiene and st?rene were added in \arjing amounts to mixtures of butadiene and styrene, and their effects on polymerization rates of the mixtures were determined. In amounts of 1% or less of the monomers used, thk following appear to hale no effect i n emulsion poljmerization: ethjlbenzene, o-xylene, phenjlacetylene, methjlphenjlcarbinol, acetophenone, aceTaldeh>de, propjlene, allene, isoprene, and ethj 1acetylene. The butenes and straight-chain pentenes show some retardation at 1%. At higher percentages these compounds cause a marked decrease in con\ersion. Polymer con+ersionsare lo^ ered sharply h j 1,5-pentadiene and less marhedlj bj l-+injl-A3-c~clohexene.p-Dirinylbenh a \ e little or no effect on the zene and Finjlacetjlene (17~) polymerization rates, but the, do cause cross linhing in ~. the polymers.
2 ) have pointed out the import,ant influence nhich impurities may h a r e on the course of polymerizgtion reactions. This was recognized in the development of butadiene-styrene copolymers, and the present work was undertaken t o extend the knon-ledge on the influence of impurities in butadienes t y r e n e cop o 1y m e r i z a t ion recipes. I n the present Jvork nineteen possible impurities in butadiene and styrene m r e added in varvina " - amounts to the monomers, and their effects on polymerization rat('*, solubilities, and solution viscosities were deterniined T h e importance of using mat,erials of the highest purity in work of this kind has been pointed out in the preceding paper ( 2 ) . I n the present n-ork the same care was taken in the purification of all the starting materials, including the impurities added. STARTING MATERIALS
BUTADIESE. The butadiene used n-as Phillips research grade, above 99.90% pure, with a total amount of peroxides, aldehydes, acetylenes, and nonvolatile impurities of less t h a n O.OITg. T h e butadiene x a s inhibited with tert-butylcatechol and was used by condensing the gas directly from the cylinder in which it was delivered. STYREKE.Highly purified styrene was obtained from t h e Monsanto Chemical Company. It was prepared by three suc-
Acid number mg. KOH/gram acid Theoretical a'cid number of stear/c,acid, Theoretical acid number of palmltlc 3Cld Iodine n u m b e r , m g . iodine/grani acid Peroxide valuc, p.p.In. active oxygen/gram acid
194.5 197.4 218.8 2.85 22
SODILX HYDROXIDE.T h e sodium hydroxide used for preparing the soap was Baker and Adamson, U.S.P. grade. POTASSICM PERSULFATE.3fallinckrodt analytical reagent having a nitrogen analysis of 0.001% was used throughout the investigation.
INDUSTRIAL AND ENGINEERING CHEMISTRY
894
TABLE
Vol. 39, No. 7
I. EFFECT OF IjrTESF, Z.~TIOS OF
A S D PEXTICXES O S COPOLYMERIB ~ T A D I E SASD E STTREXE
Added t o Butadiene
Tc
Impurity Control 1-Rurene
?-Butene
Control Coiiver;ion minus C'onver-ion with I m p u r i t y "
0 : 01 0 10 1 00 15.00
0 01 1.00
15 00
0
" 0
4
1.0 1.2
'6
2 0 1 !I 0 ,n
2 2 2 1
1 1 1 !I
