236 Proceedings of the Royal Irish Academy. 



Contrary to our expectation we experienced little difficiilty in the prepara- 

 tion of the pure esters of palmitic and stearic acids. Some of these esters 

 had heen obtained in the course of researches on esterification by Berthelot,' • 

 Herntz,^ Hanhart/ and Dufiy,* who in all cases prepared the esters by the 

 somewhat troublesome method of heating the acid with excess of alcohol in a 

 sealed tube. 



It was found by us that in every case a yield of more than ninety per cent. 

 of the theoretically obtainable quantity of the ester could be obtained in a 

 few rainutes by adding a few cubic centimetres of concentrated sulphuric 

 acid to a hot solution of the acid in an excess of the alcohol. The ester 

 separated as an oily layer on the surface of the mixture. Steric hindrance, 

 which, with acids of such high molecular weight, might be expected to 

 materially retard the formation of esters, is here prevented from controlling 

 the reaction by the separation of the ester from the solution of the alcohol 

 and the acid as a distinct liquid phase, the solubility of the ester in a given 

 quantity of alcohol and sulphuric acid being less than the quantity which 

 would be in equilibrium with free acid and alcohol at the concentrations of 

 the experiment. 



The methyl, ethyl, and propyl esters of palmitic and stearic acids were 

 prepared by this method. They wei-e oily liquids or wax-like solids of 

 moderately low melting-point and possessed a faint ester-Kke smell. They 

 were easily soluble in chloi'oform, ether, and petroleum ether. 



For the synthesis of a tertiary alcohol, the Grignard compound of the alkyl 

 or aryl halide was prepared in the usual way, and, when the solution of the 

 magnesium was complete, the ester, which had usually been kept for about 

 twenty-four hours in a vacuum desiccator, was slowly added in small fragments. 

 As each piece was dropped in, a slight efifervescence occurred ; and the ester 

 was dissolved in about one minute. Time was given for each fragment to 

 dissolve before the addition of another, the addition of the ester usually 

 occupying about half an hour. "\^Tien the contents of the flask had been left 

 standing for about twelve hours, the magnesium compound was decomposed 

 with ice-cold water, hydrochloric acid was added to dissolve the basic 

 magnesium compound which separated, and the organic substances were 

 extracted with ether from the mixture in the flask. PinaUy, the alcohol was 

 freed from unchanged ester by evaporating with alcoholic potash and extract- 

 ing with petroleum ether. In the earlier experiments, the addition of the 

 ester was effected by dropping a solution of the compound in dry ether into 

 the Grignard reagent ; but the method described above was found to be more 



' Jahresbericht, 1853, pp. 447 and 502. ^ Jahresbericht, 1853, p. 447. 



» Jiid,, 1858, p. 301 . * Annalen, Ixxxviii, p. 292. 



