1052 



from which, merely by allowing to stand, a large portion of the 

 ester separated out in crystals. It was jnirified by melting and by 

 allowing it to recrystallise slowly at the prevailing temperature 

 rabout 25—30°). The portion which still remained liqnid after 24 

 honrs was removed by draining. This procednre was repeated nnlil 

 the ester solidified entirely within 24 honrs. Its melting point mea- 

 snred on an Anschntz thermometer placed in the substance was 

 34° (a trace of water was present). 



From 28 gr. of this ester a yield of 7.7. gr. of benzaldehyde was 

 obtained, which gave 4.25 gr. of cinnamic acid, while more than 

 3 gr. of benzaldehyde were separated which had not taken part in 

 the reaction'). Only 177o of the cpiantity of cinnamic acid used is 

 thus recovered as synthetic product. The synthetic acid was recrys- 

 tallised from boiling water lo free it from a small amonnt of brown 

 impnrity. On treatment with elher well developed crystals ()f f<-cin- 

 namic acid were obtained with stiaight edges and sharp angles. 

 The product, like the acid previously obtained, showed none of the 

 properties which Erlknmkykh ascribes to the so-called synthetic 

 cinnamic acid. 



16 gr. of synthetic product were then prepared from the ester 

 by Ert.enmeyer's method, and from this 1 gr. was separated by 

 dissolving in an insnf!icient cpiaiility of a boiling solntion of caustic 

 soda. This last product crystallized from ether in thin transi)areiit 

 superposed glittering plates showing iridescence. Of these several had 

 curved edges. From benzene solution large thin plates with partly 

 curved edges separated out which under the influence of light gave 

 ^.'-trnxillic acid. On cooling the hot petrol solution locally small 

 curved needles were obtained, which on exposure to light were trans- 

 formed into ,*-truxiliic acid. The properties of the first portion agree 

 with those of synthetic cinnamic acid as given by Erlenmeykr, 

 wdiereas, according to the method of preparation, heterocinnamic 

 acid should have resulted. 



That in this case so-called synthetic cinnamic acid was obtained, 

 while the original oil treated in the same way gave a product in 

 which these properties were not yet fully developed, must probably 

 be attributed to the quantities of the cinnamic acid used, 9 gr. and 

 16 gr., from which the first fractious were prepared. 



It may also be pointed out that so-called synthetic cinnamic acid 

 apparently occurs in tAvo forms, an «- and a ^-form. This fact is 

 not mentioned by Ehlknmeyer. 



1) These figures are the means of eight preparations. 



