248 Phelps and Tillotson, Jr. — Malonic Acid. 



acting for a longer time, produces a far greater amount of ester 

 than is obtained by the use of zinc chloride for a shorter time. 

 However, if, as in experiment (8), a small amount of hydro- 

 chloric acid is present with the zinc chloride, the yield is 

 increased 43 per cent over experiment (7) when zinc chloride 

 was present but no hydrochloric acid, and 5'5 per cent over 

 experiment (2), when hydrochloric acid was used with no zinc 

 chloride. In experiment (11) the use of 1 grm. of zinc chlo- 

 ride with hydrochloric acid gives an increase of 5*5 per cent 

 over experiment (2), where zinc chloride was not used. Com- 

 paring experiments (6), (8) and (15), it is apparent that under 

 similar conditions, 1 grm. of zinc chloride gives better yields than 

 0*5 grm. or 10 grm. for the shorter time, while for a longer 

 time, as shown in experiments (10) and (16), 10 grm. of zinc 

 chloride seem to give the better yield. Increasing the amount 

 of alcohol driven over in the same time, as shown in experi- 

 ments (11) and (12), gives a decided increase in the amount of 

 ester obtained, while increasing the amount of hydrochloric 

 acid to 10 per cent tends to reduce the amount of ester formed, 

 as is evident in experiments (18) and (19). In experiments 

 (1) to (4) and in certain of the others, ethyl acetate was 

 detected by its odor in the first few drops of the distillates, 

 but when the esterification was partially completed on a water 

 bath, as in experiments (5) and (22), before continuing in the 

 regular apparatus, no ethyl acetate could be detected by its 

 odor in the presence of the large mass of alcohol, and, in the 

 case of experiment (22) a better yield of ester was obtained. 

 It is possible that in experiment (5) some ester was lost during 

 the treatments under diminished pressure, as described above. 

 For all the experiments in Table II, sulphuric acid of com- 

 merce sp.gr. 1*84, and commercial alcohol, made anhydrous by 

 the method described, were used. In the experiments in series 

 A, the procedure was precisely as in the experiments of Table 

 I. In series B, malonic acid was treated with the first portion 

 of alcohol and the small amounts of sulphuric acid, shown in 

 Table II. This solution was boiled under a return condenser 

 for one hour, then the second amount of sulphuric acid was 

 added and the process of esterification completed with the 

 second portion of alcohol in the usual manner. In series C, the 

 procedure was the same as that described for experiment (5) of 

 Table I. It was found in experiment (1) of series A that 

 when malonic acid was treated in the esterification apparatus 

 in the presence of sulphuric acid, there was a distinct odor of 

 ethyl acetate in the distillate, indicating decomposition of the 

 malonic acid, or the acid ester, but when the alcoholic solution 

 was boiled under a return condenser for an hour, as in experi- 

 ment (4) of series B, the odor of ethyl acetate was not 



