44s
C. S . MARVEL AND G ~ R DE. ~ HARTZEX, N
tutc, tlie semicarbazone (5.4 9 . ) obtained from a portion (21 9.) of these fractions melted a t 225-227" dec.
Anal. Calcd. for CllH190N3: N, 20.07. Found: N, 19.99. T h e kctone obtained from this semicarbazone by regeneration with sulfuric acid boiled at 222' without decomposition arid had the physical constants: @D 1.47'60, dzoa 0.9617, -56.07" ( 1 d m . neat). Its infrared spectrum was identical with t h a t of dihydroverbenone produced by hydrogenating verbenone with Adams catalyst. Schulz and list t h e material as isoverbanone with t h e constants: b.p. 84" (20 mm.), d20, 0.9644, %*OD 1.4779: [ a ] -59", ~ semicarbazone, 227". Anal. Calcd. for C10H160: C, 78.89; H, 10.59. Found: C, 78.80; H, 10.47. a-Terpineol.-The major compcncnt of fractions 41 to 51 was a n alcohol. T h e residual iiifrarecl absorptim spectra after correction for the isoverbanime were essentially identic:iI with that of authentic a-terpineol. Tlie secondary alcohols present iii fractions 5,>--58were cimverted t o t h e p-nitrohcnzoates F, ;r purification. t ive rccr~~stallizatiiin from peiitane yielded an est 84-86*, [ U ] D 29.5" (c 3.8, chlor~~forni), 48" (c 3.31,beiizene).
!CON~~RIUlJ'I'ION FROM THE S O Y E S
VO!.
81
Anal. Calcd. for C17&oOl;\;: C , 67.30; li, 6.97. Found: C, 67.63: €3,7.01). T h e 3,3-dinitrohenzoatc, 1n.p. 90-91.5", \vas prepared in :t similar manner. Saponificatim of a sample of the g-nitroljenzoate (1n.p. 80-81") gave a n alcr>hol in 90yo yield. b.p. 220-221", n z " ~ 1.4843, d2".r0.9568, [ a ]2.8' ~ (c 5.4, benzene). Tlie alcohol on standing partially scilidified in long needles. One recrystallization from pentane gave a solid whicl: me!ted at 54-56'. The infrared spectrum of t h e solid alcohol was substantially equivalent t o that. o f the mixture from which it W:LS isolated. Attempts t o prepare it solid pheny1uretli;iii were linsuccessful. Anal. Calcd. for Ci;,HlsO; C, 77.87; II, 1123. Found: C, 7 i . 3 5 ; H, 11.66. Sainples c f autiieiitic isi)~,iriocainptiec,iwere pi-elmrcrl ~ J Y reduction of Ii~drosypin'icamphone by the prcicedure of Kuwata,18 arid by catalytic hydrogenation of trans-pitlocarveol.s The s z m i n g materials available were n o t optically liomogeneous; hence tlie products were semi-si)!id. I n frared s:iectra of tlie two reduction products and nf t h coho1 isolatcd froni the decomposition mixture were all siilistantially identical.
CHEMKC.4L
L4UORATORY, ~ ~ N I \ X , I < S I TOF Y ~LLIN1715]
Preparation and Aromatization of Poly-1 ,3-cyclohexadiene1 BY C. S. MARVEL AND GORDOK E. H A m z e L L 2 RECEIVED JULY 31, 1958 The polymerization of 1,3-cgclohexadiene t o a low molecular weight polymer utilizing a Ziegicr catalyst coinposed c - triisubutylalurninu~nand titanium tetrachloride is reported. Although attempted dehydrogenation of the polp-l,3-cyclohcxadietie failed t o give a complete!y aromatized p-polyphenyl rrhich could be isolated, evidence obtained from infrared spectra, analyses and X-ray diffraction stxdies confirmed the presence of p-polyphenyl in the products of t h e dehydrogenation reactions.
The lower members of the p-polyphenyl series / P LJ \1 possess remarkably high melting points, with p -- > < [ /,, quinquiphenyl and p-sexiphenyl melting without I i r 111 decomposition a t 380 and +L6O4G0, r e s p e ~ t i v e l y . ~ , ~ Numerous preparations of 1 ,3-cyclohexadiene (I) Numerous attempts have been made to obtain high molecular weight p-polyphetiyls. The Ullrnann re- have been reported, including dehydrobromination action has not been successful for the preparation of 1,2-dibromocyclohexane either with quinoline' or of p-polyphenyls larger than p-sexiphenyl.6 A with sodium ethoxide,8 dehydrobrornination of 3polyphenyl having a molecular weight of 2700- bromocyclohexene with quinoline@and pyrolysis of The most convenient 2800 has been reported from the condensation of 1,2-dia~etoxycyclohexane.~~ f)-dichlorobenzenein the presence of a liquid potas- synthesis yielding the highest purity 1,3-cyclohexasium-sodium alloy.6 However, the physical prop- diene was that involving dehydrobromination of 3erties of the polymer indicate that i t was probably broniocyclohexcne, whicli was obtained in 70-80c/;i yield from the reaction of X-broniosuccinimide and not an all-para polyphenyl Research was undertaken to determine the cyclohexene. The bromocyclohexene was heated feasibility of preparing a high molecular weight uith quinoline a t 190"to give 1,3-cyclohexadienein p-polyphenyl (111) by dehydrogenation of poly- 53-6070 yield. Vapor phase chromatography analvsis showed the product to contain a minimum of 1,3-cyclohexadiene (11). 99% 1,3-cyclohexad;cne The other preparations (1) T h e work discussed herein was supported in part by Contracts were judged less convenient and generally gave 1,3A P 33(616)-3772 and -54% with the Materials Laboratory of W r i g h t cyclohexadierie contaminated with cyclohexene Air Development Center, Wright-Patterson Air Force Base, Ohio 1,2and benzene. nehydrobromination of Reproduction of this paper in whole or i n part is permitted for any p u r po5e of the United States Government. T h e paper is abstracted from dibromocyclohexan a portion of a thesis submitted in p x t i a l fulfillment of requirem-nts for containing onily 45 tile P1i.D. degree by Gordon Ellsworth Hartzell to the Graduste Col4070 cyclohexene an lege of the University of Illinois in 1938. 7
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d
( 2 ) National Science Foundation Fellow, 1950-1958. ( 3 ) A. E. Cillnm and D. H. Hey. J . Chem..Soc., l i 7 0 (1939). (1) I
