Phelps and Hubbard — Esterification of Succinic Acid. 369 



may still be active in holding back the completion of the 

 reaction in which the normal ester is formed. Fischer's best 

 yield was 73*9 per cent of that theoretically possible. 



In the work here described the attempt has been made to 

 reduce the proportion of water, the presence of which may 

 retard the completion of the action, by introducing the vapor 

 of alcohol charged with dry hydrochloric acid into the solution 

 of succinic acid in alcohol also charged with hydrochloric acid, 

 and allowing the alcohol, water, and hydrochloric acid to pass 

 out from the hot solution to a condenser. 



In every experiment recorded in the table, alcohol charged 

 with dry hydrochloric acid was boiled in a 500 cm3 flask fitted 

 with a separating funnel and an outlet tube, and passed in 

 vapor to the bottom of a 250 cm3 sideneck flask containing a 

 definite weight of succinic acid and a definite volume of alco- 

 hol charged with a definite weight of dry hydrochloric acid. 

 The temperature of the mixture in the sideneck flask was 

 kept between 100° and 110° by heating the flask in a bath of 

 sulphuric acid* and potassium sulphate, and this temperature 

 was indicated by a thermometer dipping in the mixture and held 

 in a two-bored stopper fitted to the sideneck flask and carrying 

 also the glass tube for the introduction of the vapor. The vapor 

 liberated in the sideneck flask passed through the sideneck to 

 a condenser and was collected as the liquid distillate. This 

 distillate contained whatever ester may have passed along with 

 the hydrochloric acid, alcohol and water mixture. As succinic 

 ester boils at 213°"3 and as the temperature in the sideneck 

 flask was maintained between 100° and 110°, the amount of 

 succinic ester in the distillate was necessarily a small part of 

 the total ester produced in the reaction. 



The mass of ester with its impurities from the sideneck flask 

 was poured into a separating funnel containing a little ice, the 

 last traces of the liquid being transferred from the flask to the 

 funnel by successive rinsings with ether. The impure ester in 

 the funnel was treated with an excess of dissolved sodium car- 

 bonate, and the water solution was drained off from the super- 

 natant mixture. This mixture was washed free from sodium 

 carbonate with a water solution of sodium chloride of sufficient 

 density to separate it easily from the mixture. To recover any 

 portion of the ester carried along in the water solution of sodium 

 carbonate and the washwater containing sodium chloride, each 

 solution was shaken out separately three times with fresh por- 

 tions of ether which were added to the main portion of the 

 mixture. These mixtures of ester in the etherial solutions were 

 gathered in a 250 cm3 sideneck flask connected with a 100 cm3 side- 

 *H. Scudder, Jour. Am. Chem. Soc, xxv, 161, 1903, 



