254 Phelps and Eddy — Purification of Esters. 



chloric acid of commerce or l cm3 of concentrated sulphuric acid 

 of commerce, 10 cm3 of alcohol nearly absolute and an excess — 

 10 grm. — of either pure potassium carbonate of commerce or 

 the same freshly fused and cooled before introducing into 

 the ester mixed with impurities. These impurities are pres- 

 ent here in larger proportion than would be expected if the 

 ester were produced according to the procedure referred to 

 earlier in this paper. The Claisen flask was connected for dis- 

 tillation under diminished pressure with a second Claisen flask 

 of 100 cm3 capacity used as a receiver. To secure a current of 

 air through the apparatus during the entire operation an open 

 glass tube was used in place of the usual capillary tube. The 

 100 cm3 Claisen was connected either directly or with a glass 

 tube held through a rubber stopper to the larger Claisen, the 

 side neck of which was very short, in the same manner as has 



Ester 





Alcohol HOI H 2 S0 4 



KaCO, 



Organic acid 





Recovered 



No. 



cm 3 . 



cm<*. 



cm 3 . 



grm. 



2 grm. 



75 grm. 



grm. 



( 1) 



10 



2 





10 



Succinic 



Succinic 



74-40 



( 2) 



10 



2 





10 



Succinic 



Succinic 



74-67 



( 3) 



10 





1 



10 



Succinic 



Succinic 



74-41 



( 4) 



10 





1 



10 



Succinic 



Succinic 



74-56 



( 5) 



10 



2 





10 



Malonic 



Malonic 



74-24 



( 6) 



10 



2 





10 



Malonic 



Malonic 



74-20 



( ?) 



10 





1 



10 



Malonic 



Malonic 



74-31 



( 8) 



10 





1 



10 



Malonic 



Malonic 



74-27 



( 9) 



10 



2 





10 



Benzoic 



Benzoic 



74-55 



(10) 



10 



2 





10 



Benzoic 



Benzoic 



75-00 



(11) 



10 





1 



10 



Benzoic 



Benzoic 



74-60 



(12) 



10 





1 



10 



Benzoic 



Benzoic 



74-67 



been described in a former paper* for the distillation of a sub- 

 stance where loss of some of it in the side neck of the flask might 

 otherwise be expected. The 250 cm3 flask was then heated 

 under diminished pressure by means of an acid potassium sul- 

 phate bath at a temperature of 100°-110° for about an hour, or 

 until no further evolution of carbon dioxide indicated that the 

 acid was completely neutralized, while at the same time a cur- 

 rent of water was allowed to strike the receiver constantly 

 during neutralization to condense all products possible. The 

 temperature of the acid bath was then raised and the ester 

 carefully distilled into the receiver, taking care by raising the 

 temperature of the bath and flaming to remove the flnal traces 

 of the ester held on the side wall of the flask. The contents 



*This Journal, ■ xxiv, 479. 



