214 Proceedings of the Royal Irish Academy. 



B. Condensation of Aldehydes with. Hethylethylketone in the Presence of Acids. 



1. Action of Benzaldehyde on Methylethylketone in the Presence of Alcoholic 



Hydrochloric Acid. 

 A solution of 5 c.es. of iuethylethylketone and 17i c.cs. of benzaldehyde 

 in 20 c.cs. of alcohol, which had been previously saturated with gaseous 

 hydrochloric acid, was allowed to stand in a stoppered flask for several days. 

 The oil which separated was dissolved in a mixture of chloroform and 

 alcohoL The crystals which were formed were filtered and recrystallized 

 from chloroform and alcohoL "When dried at 110° G, the substance melted 

 at 156 c C. 



The same compound can be obtained by the action of benzaldehyde. 

 in the presence of alcoholic hydrochloric acid on either a-benzylidene- 

 methylethylketone or the condensation-product which melts at Sl c -83 c C. 



2. Action of Benzaldehyde on a-Benzylidene-Methylethylketone in the Presence 



of Alcoholic Hydrochloric Acid. 



A solution of 2 grams of a-benzylidene-methylethylketone and 2 - 7 grams 

 of benzaldehyde in 20 c.cs. of alcoholic hydrochloric acid rapidly turned a 

 reddish colour, and gradually deposited an oily substance, which in the course 

 of a few days solidified. The parent liquid was decanted, and the residue was 

 recrystallized a couple of times from chloroform and alcohoL "When dried 

 the colourless, crystalline solid melted at 156 : C. 



3. Action of Benzaldehyde on ' tsat ion-Product C xi H xt 2 in the Presence 



Alcoholic Hydrochloric Acid. 

 Equimolecular quantities of the condensation-product Ci S Hi S 2 and 

 benzaldehyde were dissolved in alcoholic hydrochloric acid, and the solution 

 was let stand in a stoppered flask for a few days. From the solution, which 

 turned a reddish colour, a copious separation of crystals occurred. The solid 

 was filtered and recrystallized from chloroform and alcohol. 



After drying at 110" C. it melted at 156 c C. and gave on analysis the 

 following results : — 



01876 substance gave 0-6120 C0 2 and 0-1043 H 2 G 

 corresponding to C 890 H 62 

 C^H-,,0 requires C 892 H 60. 

 The compound crystallizes from chloroform and alcohol in short rectangular 

 prisms, which are sparingly soluble in ether or alcohol, and readily soluble iu 

 chloroform. 



