1053 



A fiirtlier purification of the ester by crystallisation was under- 

 taken. A large vessel full of water was placed in a liay box. When 

 the ester was placed in the water its temperature was 36° and after 

 24 hours, 32°. After repeated crystallisations the melting point of 

 the ester was 34°. 8 — 34°. 9. The determination was made by heating 

 the ester in a testtube provided with an air-jacket in a bath at 45°. 

 A thermometer reading to '/„ ^^ ^ degree was placed in the sub- 

 stance, and the readings plotted on a curve. 



The following temperatures are given as the melting-point of this 

 ester: 33°'), 36°') near 36°'), 34°*), while Schimmel and Co. found 

 36° for the ester from Wartara-oil, and 34° -35° for their own 

 preparations^). From this ester 16.5 gr. synthetic cinnamic acid was 

 prepared according to Erlenmkyer. The first portion separated from 

 the solution of the sodium salt; about 1 gr., was found on testing 

 with ether to be Eklenmeyer's synthetic cinnamic acid. 



Purification of cinnamic acid hy cri/stallisation from water. 



200 gr. cinnamic acid prepared from the roots of Alpinia Malac- 

 censis, was dissolved by boiling iii about 16 litres of water. On the 

 following day the crystallised acid was filtered off and again dissolved 

 in 16 litres of water. This procedure was repeated ten times. The 

 quantity of cinnamic acid had then been reduced to about 40 gr. 

 20 gr. of this product was then recrystallised four times from water 

 and from the final product synthetic cinnamic acid was prepared 

 by the method indicated by Eklenmeyer. 



From 17 gr. of the synthetic acid the first fraction, about J gr., 

 was separated and was deposited from ether in well formed thin 

 plates of cinnamic acid. These were larger and thinner than those 

 given by the original acid and were to some extent superposed. 

 Curved edges were not shown. The substance was thus not identical 

 with so-called synthetic cinnamic acid according to Erlenmeyer. 



Purification of cinnamic acid by crystallisation from d6 "/„ alcohol. 



860 gr. cinnamic acid, separated from the ethereal oil was dis- 

 solved in J 720 c.c. hot alcohol, and after filtration the solution was 

 made to crystallise by cooling and stirring. In this way a mass of 



1) Anschütz and Kinnicutt, Ber. 11, 1220. 



2) Weger. Ann. 221. 74. 



3) VAN ROMBURGH, 1. C 



*) Ultée, Mededeeling v. h. Alg. Proefstation at Salatiga II, N*^. 45. 



6) GiLDEMEiSTER and Hoffmann, Die aeth. Oele, 2e Aufl. I, 522. 



