picrate of 2-ethyl-3-methylindole. The yields of all thczr fractions were too small for further investigation.
summary The non-catalytic hydrogenolysis of carbazole for different lengths of time a t 450' and a t cold hydrogen pressures of about 1ROO p.s.i. has shnwn the following : 1. The carbazole is quite resistant to reaction and is only decomposed to the extent of 48'01, under the most severe conditions. 2 . The primary reaction is, in all probability, the formation of unidentifiable reactive fragments
[CONTRIBU rrO\
FROM THh RESEARCH
which polymerize into undistillable ether-soluble products. 3. The heterocyclic nitrogen is quite resistant to removal since 5% is the maximum amount found in the reaction gases. 4. The nitrogen in the gaseous products increases slowly with an increase in the time of hydrogenolysis and appears initially as ammonia. Yj. Benzene, aniline, methane and ethane are minor products of the hydrogenolysis. s1 9TE COLLEGE,
LAEIORATORIBS, K-25 PLANT,
&BIDE
RECEIVED DECEMBER 9, 1949
PA.
AXD CARBVX CHEMICALS DIVISIOY
LTs~ox CARRIDE AWI) CARSOX CORPORATION 1
Reactions of Polyfluoro Olefins. 111.' Preparation of Polyflmro EthersJ BY
JOHN
T. HARK, K ~ R E. L RAPP, Roy L.PRUETT,CARL T. BAFINER, J. DONALD GIBSON.\m ROBERTH.L.WFt.:RTS. I K .
Saturated palyffuoroalkyl ethers have been prepared by the base-catalyzed addition oi alcohols to polyfluoro olefins. Saturated and unsatuated aryl polyfhoroalkyl ethers have been prepared by the action of alkali metal aryloxides on poIychbropoIyfiumoethanes and propanesfi Park, Sharrah and Lacher' have obtained 1,2-dialkoxy-3,3,4,$-tetr~uorocyclobutenes by what they regard as a metathetical reaction of metal alkoxides and hexaff uorocyclobutene. This paper describes the preparation of several of these previously reported polpfluoro ethers and several unreported ones, and a study of the mechanism of the reaction between hcxafluorocydobutene and alcohols. Chlorotrifluoroethyl ethers were prepared by the method of Park, et n1.j The yields and physical constants are shown in Table 1. alytical results for all new compounds arc. given in Table 111. Samples were prepared for analysis and for the determ ion of physical properties by careful fractio The finding of Park, Sharrah and Lacher' that only the dialkoxy cyclobutenes were formed by the reaction of alcohols and hexafluarocyclobutene in the presence of potassium hydroxide in the bubble tube has been substantiated. How ever, when potassium hydroxide was the catalyst for the reaction in a closed system a large proportion of the product was the monoalkoxy butene, 314,5
(1) The previous paper in this series is: Pruett, Barr, Rapp, Bahner, Gibson and Lafferty, THISJOURNAL, '?e,3646 (1960). (1) This document is based on work performed for the Atomic Energy Commissio and Carbon Chemicals Division, Union Carbide and ( 3 ) Hanford and Rigby. ent2,409,274 (ISM); cf. E. I. du Patent 583,874 (1947). 4) Miller, Pager and Griswold, THZS JOURNAL, 70, 431 (1948) 5 ) Park, Vail, Lea and Laeher, ibrd., 70, 1550 (1948) 412 (194 6) =Bee and Bolt, I n d . Errs. Chcm., 2 P a k , Sharrah and T,achrr, THISJOVRXAI. 71.
m,
even 111 the presence of a large excess of almhol. Renzyltrimethylammonium hydroxide cataiyst gave predominantly the monoether in either the bubble tube or a closed system. In contrast to the instability during storage which was reported7 and found for the dialkoxy butenes, these monoalkoxy compounds were relatively stable. The reaction of phenolic compounds with hexafluorocyclobutene in ether solution, using tertiary amines as catalysts, gave only the monoaryloxy butenes. Because of their failure to obtain saturated ethers from the reaction of metal alkoxides and hexafluorocyclobutene, Park and associates' have proposed a vinylic substitution mechanism far this reaction, supported by an extrapolation from thermodynamic data which they had obtained. I t has been proposed,',' however, that the reactions of thiols and amines with hexafluorocyclobutene proceed by an addition mechanism analogous to the reactions of other polyfluoro olefins. A saturated bis-(butylthio)-pentafluorocyclobutane of the structure to be expected from an addition mechanism has been reported. The more stable unsaturated products were thought to have been formed by the loss of hvdrogen fluoride from the saturated addition protiUCii
Dur-iiig this work the ~iresence of hydrvgeir fluoride was noted many times during the purification of the products, and an effort was made t o isolate a corresponding saturated mono- or dialkoxy substituted cyclobutane. I n every case decomposition occurred before the material could be obtained in a pure state. Quantities of hydrogen fluoride were formed by this spontaneous decomposition of the products within a few hours after their formation. It was found repeatedly,
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