Aug., 1946
CONDENSATION OF ALKYLCHLORIDES WITH POLYCHLORO~LEFINS
[CONTRIBUTION FROM THE
1655
RESEARCH AND DEVELOPMENT LABORATORIES, ~ J N I V E R S A LOIL PRODUCTS C O M P A S Y ]
Condensation of Saturated Halides with Unsaturated Compounds. 111. Condensation of Alkyl Chlorides with Polychloroof e h s l BY LOIJISSCHMERLING I n the second paper of this series2i t was shown gether with a smaller amount of its dehydrothat alkyl halides may be condensed with rnono- chlorination product, trichloropentene. Since the haloolefins to produce dihaloalkanes, metal halides product formed by the addition of hydrogen of the Friedel--Crafts type serving as catalysts. chloride to trichloroethylene in the presence of The present paper furnishes examples of the con- aluminum chloride a t 50" contains 1,1,1,2- and densation of some alkyl chlorides with di- and tri- 1,1,2,2-tetrachloroethanein the ratio of 5:1,5 chloroolefins in the presence of aluminum chlo- i t is probable that the tetrachloropentane was ride. As in the previous c a ~ e s ,the ~ , reaction ~ :tp- chiefly 1,1,1,2-tetrachloro-3-methylbutane. The parently involves the addition of the alkyl group trichloropentene was either 1,1,2-trichloro-3-methand the chlorine atom to the double bond of the yl-1-butene or 1,1,l-trichloro-3-rnethyl-2-butene. olefinic compound, the chlorine adding to the car- (CH,),CHCl + ClCH=CCIz ----f bon atom that holds the smaller number of hydrogen atoms. The condensation of either n- or isopropyl ch.10ride with 1,2-dichloroethylene in the presence of Ethyl chloride could not be condensed with aluminum chloride gave the same trichloropen- cis-dichloroethylene. The only product isolated tane, presumably 1,1,2-trichloro-3-methylbutane. from the reaction of these chlorides was 1,1,2Intermediate isomerization of the primary propyl trichloroethane formed by addition of hydrogen chloride to the secondary compound is indi- chloride t o the dichloroethylene. Similar results ~ a t e d . More ~ than twice the yield oi the tri- were observed previously2 in a n attempt to conchloride was obtained when cir-dichloroethylene dense ethyl chloride with vinyl chloride. rather than its trans isomer was used. The difference in reactivity between the cis Experimental and trans forms of the dichloroethylene was even The experimental procedures will be summarized very more apparent when they were condensed with briefly since they were similar to those previously det-bu tyl chloride. Thus, 1,1,2-trichloro-3,3-di- scribed2 for the analogous reactions of alkyl halides with methylbutane was obtained in up t o 75yoyield by monohaloolefins. In Method T, the catalyst was added to the reactants in the reaction with cis-dichloroethylene and in a large "test-tube" cooled to about -65" and the mixture not more. than 276 yield by the reaction with the then allowed t o warm up to the reaction temperature and maintained at that point by intermittent cooling and trans isomer. while being shaken manually. In Method B , the The fact that two different trichloroheptanes warming, mixture of reactants and catalyst in a glass liner was were formed b:y the reaction of t-butyl chloride sealed into an Ipatieff-type rotating autoclave which was with 1,2-dichloro-2-propene and with 1,2-di- then heated at the indicated temperature for four hours. It was observed that the yield of product could often be chloro-1-propene supports the assumption that increased (within limits) by increasing the amount of the products were 1,2,2- and 2,2,3-trichloro-4,4- catalyst used. Thus, when 1 g. (0 03 molar proportion) of dimethylpentane, respectively. A smaller yield aluminum chloride was added to 26 g. each (approximately of product was obtained with the 1,2-dichloro-l- molar proportions) of t-butyl chloride and cis-dichloropropene, probably because i t was a mixture of ethylene a t -40", l i t t l e r e a c 9 occurred; the mixture was permitted to warm up to 0 , a t which point the catalyst the cis- and tra;m-isomers. forming an orange solution. After standing a t 0 When the third dichloropropene, namely, 1,3- dissolved, to 23' for three hours, the product was a clear red solution dichloro- 1-propene was contacted with t-butyl which on being worked up in the usual manner yielded the chloride in the presence of aluminum chloride, a trichlorohexane in 21yo of the theoretical yield. On the poor yield of trichloroheptane (presumably 1,2,3- other hand, when 5 g. (0.07 molar proportion) of aluminum chloride was added t o 50 g. each (approximately molar trichloro - 4,4 - dimethylpentane and/or 1,1-di- proportions) of the reactants a t -65", there was a vigorous chloro 2-chloro-methyl-3,3-dimethylbutane) was reaction and the temperature rose to - 10"in about thirty obtained. The principal reaction was the di- seconds and to + l o " in another thirty seconds despite the that the reaction vessel was immersed in a Dry Icemerization of the dichloropropene to tetrachloro- fact acetone-bath. The product was a mixture of dark redhexene . brown liquid and white, undissolved aluminum chloride Condensation. of isopropyl chloride with tri- powder. The temperature dropped to -40" in a few chloroethylene yielded tetrachloropentane to- minutes. The mixture was then maintained a t -15 to (1) Presented before the Division of Organic Chemistry of the American Chemical Society at the Atlantic City meeting, April, 1El46. (2) L. Schmerling, Trns JOURNAL, 68, 1650 (1946). (3) L. Schmerling, ibid., 67, 1152 (1945). (4) Compare reaction of ?a- and isopropyl chloride with ethylene
(ref. 3).
-5" by intermittent warming and cooling for fifteen minutes during which time the remainder of the catalyst went
(5) E. Mueller and C. Hoenn, J. p i o k l Chem.. 133, 289 (1932) See also M. S. Kharasch, S. C. Kluger and F R . Mayo, J . Org. Chcm., 4, 428 (1939),who indicate that with ferric chloride as catalyst at room temperature, the product is 1 , l , I ,2-tetrachloroethane.
LOUISSCHMERLINO
1650
Vol. 68
TABLE I CONDENSATION O F ALKYLCHLORIDES WITH POLYCHLORO6LEFINS
c
-
_
I
_
~
Alkyl chloride
Method
T T T T T T T T T T
RCl
g.
~-P~CI i-I'rC1 n-PrCl t-Bu(31 t-HuCl t-IluCl i-E'rC1 t-I3~(31 t-BuC1 t-Elu(LI1
35 31 45 50 26 26
--
Reactants Chloroolefin-Formula
---
C-CHCI=CHC~* t-CHCl=CHCld c-CHCl=CHCl c-CHCl=CHCl c-CHCl=CHCl t-CHCl=CHCl CH,=CHCl-CH~Cl' CH,=CHCI-CHzCl CHCI=CHCI-CHI' CHCl=CH~-CII~Cl'
AICI:,
Temp.,
g.
g.
OC.
25
2 2 6
40 50 50 26 26
0 to3V
0 t o 23 0 to 15 -15 to + I 0 0 to23 0 to23 0 to 18 -10 to -10 -20 to -10 -10 to -10
5 1
Duration, hr.
0.1 .I?
.8 .3 3.0 5.0 .8 .5
--Chief Comp. no.
-
Higher-
product F.
A"
6.
26
