Phelps and Hubbard — Esterification of Succinic Acid. 373 



is not surprising when it is remembered that the larger part 

 of the water liberated is found early in the reaction and that 

 the effect of the continued distillation would be naturally more 

 in evidence at that time. Thus the yield of experiment (3), 

 in which 150 cm3 of the charged alcohol were used, is 8 per cent 

 greater in half the reaction time than that of experiment (1), 

 in which 100 cm3 of the same mixture were employed ; while 

 the difference between the yield of (6) from 250 em3 of the 

 charged alcohol and that of (10) from 350 cm3 of the similarly 

 charged alcohol is 1*1 per cent. In (12) of B w 7 ith purer acid 

 and alcohol of greater concentration the process gives the same 

 yield as in (10). 



Increase in the amount of dry hydrochloric acid with which 

 the alcohol is charged is effective in increasing the yield. 

 From (18) it appears that a current of dry hydrochloric acid 

 has such an effect. This appears when (18) is compared with 

 (17), and, more strikingly when compared with (5), where the 

 differences are largely the concentration of the hydrochloric 

 acid with a gain of 4 per cent in the yield of (18). 



In the experiments of series C the process of forming the 

 ester was conducted in two stages in an attempt to cause the 

 esterification of the final portions of the succinic acid more 

 advantageously. It is obvious from the work recorded in 

 series A and series P> that it is comparatively easy to cause the 

 esterification of a little more than 90 per cent of the acid. In 

 experiment (19), after the first portion of alcohol — 200 om3 — of 

 highest purity charged with dry gaseous hydrochloric acid in 

 the proportion of 10 grams to the liter had acted upon the 

 commercial succinic acid in the manner described above, a 

 fresh portion of alcohol — : 150 cm3 — containing 10 per cent of 

 dry hydrochloric acid gas was put with the ester solution and 

 the whole was heated at the boiling point for an hour with a 

 return condenser in an attempt to learn whether a fresh mass 

 of the absolute alcohol hydrochloric acid mixture containing 

 10 per cent of hydrochloric acid could serve sufficiently as a 

 dehydrating agent to allow the completion of the reaction. It 

 does not seem evident that the second treatment is markedly 

 advantageous in completing the reaction. Its effect, if any- 

 thing, is slight. In case of experiment (20), after completing 

 esterification of the pure acid so far as possible with 200 cm3 of 

 the purest alcohol with hydrochloric acid in the usual way, 

 20Qcm3 more f i\ ie same alcohol with 10 per cent of hydro- 

 chloric acid was driven through the ester as in the first half of 

 the procedure. The effect of this second treatment is not 

 apparently of marked advantage in esterifying the final por- 



Am. Jour. Sci.— Fourth Series, Vol. XXIII, No. 137. — May, 1907. 

 26 



