290 Phelps, Palmer and Smillie — Ester Formation. 



Art. XXXII. — Researches on the Influence of Catalytic 

 Agents in Ester Formation. The Effect of Certain Sulphates 

 on Benzoic and Succinic Acids ; by I. K. Phelps, H. E. 

 Palmer, and P. Smillie. 



[Contributions from the Kent Chemical Laboratory of Yale Univ. — clxxxviii.] 



In a former work* published in this Journal it has been shown 

 that almost theoretical yields of succinic ethyl ester may be 

 obtained by passing alcoholic vapor charged with dry hydro- 

 chloric acid into the flask containing the succinic acid. In a 

 somewhat later paperf in this series of researches on esters, 

 under the direction of one of us, it has been shown that theoret- 

 ical yields of benzoic ethyl ester may be obtained from benzoic 

 acid, using sulphuric acid as a catalyzer, while if no catalyzer 

 be present, only a trace of the ester is produced under con- 

 ditions otherwise precisely similar. Bogojawlensky^: has stud- 

 ied the effect of various inorganic sulphates on the esterification 

 of a number of organic acids, using as the indication of esteri- 

 fication the amount of ester produced by heating the mixture 

 of acid, alcohol, and catalyzer on a return condenser. In the 

 case of benzoic acid he obtained a yield of 92 per cent with a 

 mixture of 30 grams of copper sulphate and 1 gram of sul- 

 phuric acid, while with sulphuric acid alone he obtained a yield 

 of only 65 per cent, and with copper sulphate alone no ester 

 whatever was formed. 



In the work to be described the effect of various acid sul- 

 phates on the esterification of succinic and benzoic acids has 

 been studied. Pure succinic acid was prepared by heating on 

 a return condenser succinic ester, which boiled within 0'2°, 

 with an equal volume of water and a few drops of nitric acid, 

 and recrystallizing from water the pure succinic acid formed, 

 as has been described in a previous paper§ in this Journal. 

 In the case of the benzoic acid, the pure acid of commerce was 

 'used. The apparatus was the same as that illustrated and de- 

 scribed in an earlier paper | in this Journal on the esterification 

 of succinic acid. In all of the work absolute alcohol which 

 had been made as free from water as possible by repeated dis- 

 tillations over lime was used. In all cases 40 cm3 of the abso- 

 lute alcohol were put into the second flask together with the 

 benzoic or succinic acid and catalyzer, and the remainder of the 

 alcohol as vapor was run into the second flask from the first dur- 

 ing the intervals of time indicated in the tables, the temper- 

 ature of the mixture in the second flask being kept by means 

 of an acid sulphate bath at 100°-110° during the action. 



* This Journal, xxiii, 368. f This Journal, xxv, 39, 



^Berichte, xxxviii, 3344. §This Journal, xxiii, 211. 



fl This Journal, xxiv, 194. 



