728 Journal of AgrimiHural Research voi. xii, No. n 



After esterification the contents of the flask are cooled, 50 c. c. of 

 ether and 150 gm. of magnesium chloride added, rotated to hasten 

 saturation, transferred to a i,ooo-c. c. pear-shaped separatory funnel 

 and allowed to stand until a clear separation is secured. The underlying 

 layer is drawn off into the original flask and the esters carefully shaken 

 out two or three times with 25 to 50 c. c. of ether and 50 c. c. of an alco- 

 holic solution of magnesium chlorid. Violent shaking causes a slow 

 separation. After the removal of the final washing, the clear, purified 

 esters are filtered through a firm, close-textured paper into a 500-c. c. 

 round-bottom "low" side-tube distillation flask. The filter is extracted 

 with ether which is run into the original globe flask containing the 

 alcoholic layer and washings from the esters. More ether is added until 

 a ready separation is obtained and the solution again transferred to 

 the separatory funnel and allowed to stand several hours to recover any 

 occluded esters which are then washed several times vath ether and 

 magnesium chlorid solution as previously described, and filtered into 

 the distillation flask containing the first portion. 



Fractionation. — A number (50) of glass beads are placed in the 

 side-neck distillation flask which is connected with a 12-inch Liebig 

 condenser and heated in a bath of superheated valve oil for distillation 

 of the esters. The exposed portion of the flask should be covered with 

 asbestos paper and the condenser filled with cold water at the outset 

 but no circulation should be permitted during the distillation. The 

 temperature should be raised slowly. After the ether and alcohol are 

 expelled, the entire distillate between 85° and ^65° C. is collected and 

 constitutes from no to 120 gm. with butter fat. 



The distillate from two portions representing 300 gm. of butter fat 

 and a number (50) of glass beads are brought into a 500-c. c. round- 

 bottom "high" side-tube distillation flask which is connected with a 

 Liebig condenser and heated as previously described. Particular care 

 should be exercised in heating the oil bath so as to insure a slow, steady 

 rise in temperature taking at least 80 minutes from the beginning of 

 the first fraction to the completion of the last. The required range of 

 every fraction must be accurately established with the apparatus em- 

 ployed by analysis (See Table I). 



The volatility of the esters and the readiness with which they hydrolyze 

 necessitates careful treatment of the fractions, which should be collected 

 in tared flasks, weighed, and the saponification and iodin numbers 

 determined as soon as possible. 



