CATALYSIS BY

OF

SALTS S.

IN S.

p-ELIMINATION NONAQUEOUS

Yufit

and

REACTION MEDIA

I. A.

UDC 542.97

Esikova

The effect of salts on the p-elimination rate of alcohol f r o m 3 - c a r b e t h o x y - 4 - e t h o x y - 2 - p e n t a n o n e (I) in AcOH was r e p o r t e d previously and certain considerations were e x p r e s s e d regarding the possible raechanism of their action [1]. The effect of salts can be a s s o c i a t e d both with a change in the catalytic p r o p e r t i e s of AcOH and with salt c a t a l y s i s . To solve this p r o b l e m the reaction was studied in an inert medium. The starting substrate (D is stable on prolonged heating in benzene (80~ The addition to a benzene solution of (I) (0.1 m o l e / l i t e r ) of the anhydrous Li and Mg p e r e h l o r a t e s , Li, Na, and K acetates, and Li and K c h l o r i d e s , in an amount of 0.01 m o l e / l i t e r exerts a catalytic effect, as a r e s u l t of which only the elimination products are formed, namely 3 - c a r b e t h o x y - 3 - p e n t e n - 2 - o n e and ethanol. The taken salts are found in the bottom phase, and their concentration in the benzene solution was 10-4-10 -3 m o l e / l i t e r . Mg p e r c h l o r a t e , and the Li p e r c h l o r a t e and acetate, exhibit the highest catalytic activity. The obs e r v e d elimination rate constant in the p r e s e n c e of Mg p e r c h l o r a t e is 4.5 9 10 -4 sec -1, which is m o r e than 30 times g r e a t e r than the specific elimination rate when using the same amount of AcOH. We postulate that the elimination p r o c e s s is a c c o m p l i s h e d in the liquid phase via the intermediate complex of the c a t a l y s t and s u b s t r a t e . The obtained data make it possible to a s s u m e that salt catalysis takes place in the p - e l i m ination reaction. LITERATURE 1.

CITED

S. S. Yuf!t and I. A. Esikova, Dokl. Akad. Nauk SSSR, 217, 394 (1974).

N. D. Zelinskii Institute of Organic C h e m i s t r y , A c a d e m y of Sciences of the USSR, Moscow. T r a n s lated f r o m Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, p. 2134, September, 1975. Original a r t i c l e submitted June 9, 1975.

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