Electrophilic Substitution at Saturated Carbon. XI. Steric Course of the

Donald J. Cram, and Paul Haberfield ... Jean M. J. Fréchet, Man-kit Leung, and Edward J. Urankar , C. Grant Willson, James F. Cameron, Scott A. MacDo...
0 downloads 0 Views 1MB Size
2354

DONALD J. CRAMAND PAUL HABERFIELD

lTul. 53

The basic aqueous layer was acidified with concentrated TABLE I hydrochloric acid and the acid liberated was extracted with SAPUNIFICATIOX KATE OF ETHYL CYCLOHEXATECARBOXpetroleum ether. The crude acid recovered from the YLATE IN 70Oj, ETHAXOL AT 25.2' petroleum ether layer in the usual manner melted a t 107Base, 30 ml. of 0.2206 N NaOH; ester equivalent, 1.0341 g. 112", raised to 115-117' by one recrystallization from pequench acid, 10 ml. of 0.05043 N HCl, indicator, phenoltroleum ether (b.p. 30-60"). I t s infrared spectrum was phthalein; back titration alkali, 0.05651 N NaOH; a = identical with that of the pure cis-acid (lit.6 m.p. 117-118'), 0.03308 mole/l. indicating that little i f a n y epimerization had occurred Titer, in the saponification. ml. of k X 104, Kinetic Saponification Runs.-The alkali solution for the a - x, Reaction, 1 /mole/ Time, NaOH X, kinetic runs was prepared by diluting exactly 30 ml. of G7 sec. iec. 0.05G51 A' mole/l. mole/]. /c standardized 0.2 .I7 carbonate-free aqueous sodium hyZero 3.07 0,03305 0 .. 0 droxide to 100 ml. by means of absolute ethanol in a volu10175 4.21 0.00644 ,02664 19.5 7.19 metric flask. An amount of ester exactly equivalent to 30 ml. of the alkali was weighed out in a small weighing 1,3892 4.56 ,02466 ,00842 25.5 7.39 bottle, transferred to a 100-ml. volumetric flask and made 17474 4.79 ,02336 ,00970 29.3 7.21 up to the mark with absolute ethanol after prior addition 5.03 20673 ,02201 ,01107 33.5 7.34 of exactly 30 ml. of boiled distilled water. Both solutions 22701 5.14 ,02138 .01170 35.4 7.26 then were placed in a thermostat at 25.2" for a t least 60 minutes and then mixed by pouring them through a wide15624 5.27 ,02065 .01243 37.6 7.13