I N D U S T R I A L A N D E N G I: N E E R I N G C H E M I S T R Y
888
1
loo,
~ , ~ - P E S T . ~ ID E IXXEE R\vas prepared by heating 1,3-pentadiene a t 50" C. in a sealed tube for 25 days. The yellow product boiled a t 150-177" C., nSo 1.4772. DICBCLOFESTADIESE from the United States Steel Company was redistilled, b.p. 63" C. a t 14 mm. I t s freezing point, reported by the Kational Bureau of Standards, was 28.16" C. VINYL- A~-CYCLOHEXESE (butadiene dimer), obtained from the Don- Chemical Company, was redistilled, b.p. 129" C., ny 1.4611. ~ - ~ - P I S E(11.p. S E 155' C., n y 1.1667) and camphene (m.p. 38 ' C . ) were availahle in this laboratory. DIJIETHYLACETYLE6~was prepared from 2,3-dibromohutane by the method of Kidicenus and Schmidt (f7). From 64.8 grams (0.30 mole) of 2.3-dibromobutane and 48 grams (0.86 mole) of potassium hydroxide dissolved in 232 ml. of ethanol were obtained 12.5 grams of crude product, redistilled through a n-ater-jacketed 18-inch Podbielniak column (If) to give 11.2 grams (43%) of dimethylacetylene, b.p. 27.5' C., n$5 1.3895 (literature, b, ny 1.3893). ~-PROPYLACETYLEBE AND ISOPROPYLACETYLESE Fvere obtained from the Shell Development Company. The former was report,ed to be 98.5Yc pure, b.p. 40.2" C., nLo 1.3838. Thc latter contained 107, of n-pentane but was otherwise reported to be quite pure. VISYLACETYLESE (Du Pont Company) was distilled from its toluene solution immediately before use. CARBOX DISULFIDE, reagent grade, \vas redistilled, h.p. 16.3 O C., n'," 1.6258. ETHYLX E R C A Pwas T.~ distilled, ~ b.p. 37 O C. T h e sample of a higher boiling fraction from the industrial isoprene process vas obtained from the Shell Development Company.
80z
-
V
-
-
I-
-
-
4
0 Figure 1.
8 I2 TIME IN HOURS
16
20
Effect of Residual Oxygen on Polymerization
0 , bottle flushed with isoprene
POLY3IERIZATIOS TECHNIQUE
0 , bottle flushed with isoprene, 10 ml. of air injected
c , bottle flushed
with nitrdgen for 15 seconds 3.bottle not flushed
,
1,3-Pentadiene (piperylene) was obtained as a mixture of cis and trans isomers by distillation of United Gas Improvement Company product through a 50-inch Podbielniak (11) column, b.p. 42-44' C., n'," 1.4291. Its freezingpoint, determined zt the Kational Bureau of Standards, was - 113.72' C. 1,4-Pentadiene was prepared by the following reactions: sodium Br(CH2)bBr acetate+ CHpCOO(CH?)iOCOCH3
c. 575
CHI=CHCHzCH=CH? DI.4CETATE OF PESTAMETHYLENE GLYCOL.I n a 1-liter rouiidbottomed flask equipped with a reflux condenser were placed 390 grams (1.7 moles) of pentamethylene bromide, 340 grams (3.4 moles) of freshly fused potassium acetate, and 100 ml. of glacial acetic acid, T h e mixt,ure was heated a t 170" C. for 5 hours and allowed t o cool, and 1 liter of water ]vas added. T h e potassium salts and acetic acid dissolved in the water. The organic (upper) layer was separated and distilled a t atmosphoric pressure until the temperature of the distilling vapor reached 235' C. The remainder was distilled under reduced pressure to give 124 grams (39%) of product, b.p. 83" C. a t 1 mm., nz,O 1.4261. h forerun of pentamethylene bromide and w-bromoamyl acetate was also collected. ~ , ~ - P E N T A D I EOne S E . hundred twenty-four grams (0.66 mole) of diacetate of pentamethylene glycol were passed through a hot tube filled with glass beads a t the rate of 15-20 drops per minute, according t o the method of Schniepp and Geller (14): The temperature of the tube was maintained as clasely as possible a t 575' C. The crude product (120 grams) was distilled through a 15-inch helis-packed column to give 11 grams of product boiling a t 26-28" C. T h e residual liquid \vas recycled through the hot tube two additional times, with removal of the low-boiling material each time. The total yield of 1,4pentadiene (b.p. 26-28" C.) was 24.1 grams (54%). Its freezing point, determined a t the Sational Bureau of Standards, was - 149.45" C. CYCLOPESTADIENE was prepared by the pyrolysis of recrystallized United States Steel Company's dicyclopentadiene by distillation in the presence of iron powder. The product was redistilled through a 6-inch helix-packed column, b.p. 42' C. It was used immediately. JSOPREXEDIMER(mainly dipentene) was obtained from Esso Laboratories, b.p. 169.5-171.7" C., n'," 1.4722.
Vol. 39, No. 7
'
The various impurities were tested in concentrations of 0.01, 0.10, and l . O O ~ , of the isoprene in emulsion copolymerization with styrene. The polymerization recipe was that of Craig fa), using in 8-ounce screw-cap bottles 30 grams of isoprene, 10 grams of styrene, 70 grams of soap solution (2 grams of soap in 68 grams of water), 4 nil. of 3% aqueous potassium persulfate solution, and 0.06 gram of a mixture of primary mercaptans of approximately twelve carbon atoms as a polymerization modifier ( 2 , 5,6 . 8,12). Each bottle was partially filled with the soap solution, catalyst solution, 1.33 nil. of styrene containing 0.06 gram of the mercaptan. and 30 grams of isoprene. One to two additional grams of isoprcnc x-ere then added and allowed to boil out of the mixture under the heat of an infrared lamp. The bottles were capped with a perforated cap having a GR-S (Butaprene) gasket. .The impurities dissolved in styrene were then injected through the self-sealing gasket by means of a Beeton, Diekinson, and Company 10-ml. Lurr Lok hypodermic syringe. The styrene solutions were prepared as fo1lon.s: for l . O O ~ , impurity, 10 ml. of solution ( S o . 1) of 0.45-gram impurity in 14.31 nil. of styrene; for O , l O ~ cimpurity, 9.60 nil. of solution ( S o . 2) prepared from 1.10 ml. of solution 1 added to 9.90 ml. of styrene: for 0.0l';h impurity, 9.54 ml. of solution prepared from 1.00 ml. of solution 2 added to 0.00 ml. of styrene; for controls, 9.54 ml. of styrene. The importance of adequate flushing of the bottles with excess isoprene cannot be overemphasized, as any trace of air in the bottles causes an induction period and comparisons between bottles become unreliable. The effect of air is shown in Figure 1, which also indicates that flushing the bottles n-ith nominal amounts of nitrogen is likely to be insufficient for removal of the last traces of air. Polymerizations rvere carried out by rotating the bottles end oter end a t 28 revolutions per minute in a constant temperature bath a t 50' C. T h e bottles were momentarily removed a t intervals (as indicated in the figures) for sampling by means of a 20ml. hypodermic springe equipped with a guard to prevent the plunger from bloJving out of the syringe under pressure. The bottle was shaken vigorously, a IO-ml. sample was removed, and approximately half the sample was quantitatively (by weighing syringe before and aft'er) ejected into a tared cup of aluminum foil containing 5 ml. of an ethereal solution of anti-
July 1947
INDUSTRIAL AND ENGINEERING CHEMISTRY
Percentage conversion f o r t h e individual curves can be judged f r o m t h e origin of each curve. E a c h small division on the ordinate represents a conversion of 1 0 % . Percentages of impurities a r e calculated o n t h e basis of isoprene in t h e polymerization recipe. 8 : 0 , control: 3 , 1.00% n-pentane B : 0 , control; D , 1.00% isopentane: D - , l.OOc/, cyclopentane C : 0. control: 3-, 1.00% 1-butene: 1.00% cis-2-butene: ‘ 3 . 1.00% trans-2-butene. Isobutene (1.00%) gave a curye identical with t h a t obtained with I-butene D-L: 0 , control; G , concentration of 0.01% of t h e respecti\-e i m p u r i t y ; C . concentration of 0 . 1 0 % ; 3 , concentration of 1.00%. T h e impurities for each curve are as follows: D , 1-pentene; E , trans-2-pentene: F , 2-methyl-I-butene: G. 2-methyl-2-butene; H , cyclopentene: I,3-methyl-1-butene; J , isoprene dimer; K , piperylene dimer; L , cyclopentadiene dimer
a,
889
INDUSTRIAL AND ENGINEERING CHEMISTRY
E90
osidant. This solution was prepared by dissolving 1.2 gram. of l,henyl-?-naphtliylaniine and 0.8 gram pf ,3-naplithol in 1 liter of ethyl ether. Thc, saniple was dried for 12 hours at 80" c'. and n.c.ighed t o detc~rminethe total solids. The roiivtlr4ons w r c cnlculatpd b y the follon-ing formulas:
tl 1
- 5.45
=
0.lC; impurity: 285.5 n7 1
- 5.52
= c;
converziun
tl ].Or; impurity: 286.2 1
- 6.20
=
r2
conversion
C'ontrol arid 0.01(; impurity: 285.4
)\-here tl 1
= =
c i coiiver-ion
Vol. 39, No. 7
s1o1vor than pure isoprene (curve I , Figure 2,.
attriliutid t o the structuralunit \
I
'
H
Its c,ffcct m:iy hc
'
',' T h i c ~furt1ic.r impurities which can occur i n isi~prc~iii~ froin petrolc~uni arc ieoprcsne dimer (formula B J , piperylr.ni' tlimc,i, (formula ($1, and tlicyclopentadiene (formula 1)). (Isoprene ani1 rv probably mixtures of ihescb 5tructures w i t h the other po;xible isomeric diene adducts.) These thwe impurities arcs diolcfin~but can be condertvl here a, monoolefin.. since the cloul)le lioiidi are not in close proximity i n the iiiolrculcs: /('=( \wight of the residue in the ('up .\ solution ivac prrpared for viscosity dc2tc.1mination- I,tliluting 2 nil. of the clear solution descrihed Ivith 10 nil. of h*nz t , n t ) . The flow tinic of 5 ml. of this d u t i o n through a modified 0-tn-ald viscometc)r at 2: C. v a s nirwurcd and compared \\-it li I!N, ficin time of l ~ e i i z c ~undel, ~ ~ e the same cc-inelitioiis. The, intl,:n-ic vi.'.oiitv \vas ralculiitetl from thc c~quati1~11 111
1v1 = -c
f t8
intrinsic viscosity f l o time ~ of polymer solutinii = flow time of benzene = concentr:ition of polymer, grnmc per 100 nil. of siilution
x l i p r p 171 =
t t,,
c
=
1,;vcry sct of polynlerizations was compared x i t h a control r u i i c,ontaininy no impurities and carried out simultanc~oudy. ('(invi,i.>ionrixere then plotted against time (Figures 2 and 3,. EFFECT O F I>lPC'RITlES ON POLY3IERIZATION R A T E ~ ~ T L - R I T C HYDR~OC.LRBOS.;. I~ n-Pentane, isopcntant.. i t l i d cyclopentane had no effect on the polymerization rate in conct,ntrntions of O,O1-l.OO'-c of the imprc>ne ( C I I ~ ~ F-1 and R , , Figure 21, * OI.E;FISQ. The effects of unsaturatcd hydrocarl)oni varicd :iccording to their structurc.
Oic.fins of tkre type )c=~-cII,-,
alt iiough siion-ing some
i-nriance, had in general a slight retarding effwt ranging from 1 t o 3 5 at concentrations of 1.00% of the isoprene. Impuritietested were tlie butenes and pentems (cur\-czz C to G, Figure 21. C'yclopentene appeared to retard t o a greater estent t h a n most of the other olefins (curve H , Figure 2 ) . Thiy is perlmps to be cspected. as cycloperitene is the only esaiiiple having niorc than one allylic methylene group in the molecule. ~ - l I e t l i y l - ~ - h u t t ~(formula nc -4) \vas also escr.ptiona1 in having :I much larger retarding cffc~ct than the others. Isopreni. con;:Lining 1.00$ of this impurity polymc.rized approsimati.ly 6';
.\lthougli not to he ronsidered as possible inipurities in conimerical isoprene, hoth have allylic niethinyl groups located a t their hridgehmds. Seither shoiwd any retardation of polymerization (curve A , Figure 31. The observation that isoprene dimer is a polynicrization tardcr may serve as a \varning that iioprcne and other dicnc+ should he distilled iinmediatcly before polymerization, since it is r < h -
July 1947
INDUSTRIAL AND ENGINEERING CHEMISTRY
z
0 cr) a W > z
0 0
c z w
0
cc Ld
n
TIME
IN
HOURS
891
INDUSTRIAL AND ENGINEERING CHEMISTRY
892 r
7 ,
U
the viscosit,y was l o w r , since it, represented only the polymer in solution after renioval of gcl. Figure 4 represents these trends. In polymerizations containing retarders, the intrinsic viscosity decreased with increasing rctarder concentration, the solubilities remaining conipletc. This ivas especially noticeable with the more powerful retarders, such as 1,4-pentadiene and cyclopentadiene (Table I). Thus retarders in general loner the chain length of polymers but do not usually bring about cross linking. Cross linking was apparently brought about by only one of the inipuritics tested. Thc presence of vinylacetylene caused greatly lowered
-
A
100-
*
580E
2
,
/
‘v)
/
-60z
’i
P‘
U w
a
‘a.,
E404
_ _ _ _ _-- -
--a‘
’. - I
20 -
Vol. 39. No. 7
I Figure 4. Variation with Conversion of Benzene Solubility ( A ) and Intrinsic viscosity of Soluble Portion (B1 . . of Isoprene- Styrene Copolymers
DISCUSSION
On t h e assumution that the growth and terniination of polymer chains occurs by a free radical mechanism (9),one may consider the action of reknown that dimeriaation occurs on standing, unaffected by p ~ ~ l y - tarding inipurities to be that of “inefficient chain transfer agents” merization inhibitors. (10). The substances are capable of reacting ivith growing DIOLEFINS. This section discusses those diolefins Iyhose chains to terminate their growth, but the resulting free radicals double bonds are in close enough proximity to have i n effect on are incapable of initiating new chains at a comparable rate. one another or a cumulative effect in the molecule. The fart that compounds containing the structural unit FI 1,2-Butadiene (not a likely impurity in isoprene, but more i readily available than the corresponding pentadienesj had no ef)C.=C-?” are stronger retarders than those containing the fect on the rate of polymerization (curve B , Figure 33. 1,a-Pentadiene (piperylene) had a substantial retarding effect may t)c used as indirect evidence that reunit )c=&H~(curve C, Figure 3). 1,4-Pentadiene and cyclopentadiene were the strongest retardation occurs by removal of the allylic hydrogen atoms t o tarders in the series (curves F and D, Figure 3) and arc perhaps form radicals of the type /C=C--C\. \ . / Smith and Taylor the greatest cause of unsatisfactory polymerization rates in eommercial isoprene samples. Of interest in this connection is the (15) and ot,hers (13)have shoivn that tertiary hydrogen atonis are parallel action of linoleic and linolenic acids, both containing the more rcactive than primary or secondary hydrogens. structural unit -CH4H--CHz--CH=CH--. PolymerizaThe inability of bicyrlic structures, such as dicyclopentadienc., tion systems emulsified with soaps of these acids are greatly repinene. and camphene, to ret,ard polymerization, coupled with tarded (1). the fact that they do not affect the intrinsic viscosity of the reCurve E, Figure 3, s h o w the results of adding tv-o impurities sulting polymers, indicates a lack of ready formation of free a t once. A mixture of 1,2-butadiene and 1,4pentadierie gave no radicals in this type of compound. Iiharasch, Engelmann, and greater retardation than 1,4-pentadiene alone. Urry have observed this in the case of the apocampbyl radical ( 7 ) ACETYLENES.Dimethylacetylene, n-propylacetylene, and isopropylaeetylene (curves G, H , and I, Figure 3j showed some variation in inhibitory effect, although slight in any case. VinylTABLEI. EFFECT O F 1 , 4 - P E N T A D I E S E A S D CYCLOPEST.4DIE.L’E. acetylene, on the other hand, had a marked retarding effect on O S SOLUTIOX VlSCobITIES O F ISOFRESIC-STYRESE ( 7 j 2 5 ) polymerization (curve J , Figure 3). Vinylacetylene itself is COPOLYAIERS~ I n tofr i w Polyitier i c Tisrosity at not likely to occur in isoprene from cracking processes; it was 5 Inipurity tested because it is more readily available t’han the five-carbon Irripuriiy (Based o n Isoprene) 82 ’ 3 7 Conversion enynes which might be present in isoprene. 2.63 0.00 Control 2.42 0.01 1,4-Pentadiene Sulfur compounds, such as the A~ISCELLAXEOUS IYPL‘RITIES. 1.72 0.10 1,4-F’entadiene 1.42 1.00 1,4-Pentadiene lower mercaptans and carbon disulfide, must be removed from 2 43 Control 0.00 isoprene for satisfactory polymerization (curves K and L , Figure 2 13 Cyclopentadiene 0.01 3). Curve k‘ also illustrates the effect of a higher boiling frac1 26 Cyclopentadiene 0.10 0 94 Cyclopentadiene 1.00 tion from a commercial cracking unit for isoprene. .ilthough of .ill polymers u e r e benzene soluble unknown constitution, its effect illustrates the necessity of careful fractionation of the products. TABLE11. EFFECTOF VIXYLACETYLESEox SOLCBILITY OF‘ ISOPRENE-STYRESE (75 : 25) COPOLYUERS
1\
‘
(1
EFFECT OF I&IPURITIES O S POLYXIER PROPERTIES
Benzene solubilities as an cvaluittion of cross linking and gel formation, and intrinsic viscosities as a meabure of molecular weight, were determined, on all the copolymer samples. In t’he control runs and those runs containing impurities with no cffect, the polymers were completely benzene-soluble (according t o the method described, at all conversions up to 805,. From 80 to 100cGthe solubility deereased, probably because of cross linliing of the polymer chains. The viscosity increased v-ith conversion until the benzene solubility began dtcreasinp: after that
Conver-ion,
Concn Vinylacetylene in Isoprene, v
c-10
52 71
50 88 98
/c
0 0 0 0 0
(Control) (Control) (Control) (Conrrol) (Corirrol)
Holy. In Benzene,
Conversiun,
‘7,
7c
98 99 97 79 29
56
72 60 94
Concn. Vinylacetylene i n Yoly i n Isoprene, Benzene, CI
/O
0 10 0.10 0.10 0.10
C’ ,c
(18
70 4;
2u
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
-
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:
N i n e t e e n 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 t o h a l e 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 a t 1%. At higher percentages these compounds cause a marked decrease in con\ersion. Polymer con+ersions are 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.
