Ryan and Dillon — On the Hydrocarbons of Beesioax. 109 



extracted by petroleum ether from the residue were assumed to consist 



entirely of hydrocarbons. 



The results obtained by this method present, however, discrepancies, 



which become apparent on examining the figures for any one of the many 



samples analysed. Thus in a wax from the department of Somme they 



found : — 



Ester number .... 72-22 

 Cerotic acid .... 14-87 per cent. 



Palmitic acid . . . 32 - 95 „ „ 



" Melissyl alcohol" .' . . 52-64 „ 



Hydrocarbons .... 13-39 „ „ 

 Volume of hydrogen from 1 gram of wax 535 c.cs. 



Now, the ester number of a wax, that is the number of milligrams of 

 potash required to hydrolyse the esters in 1 gram of the wax, is very simply 

 related to the volume of hydrogen evolved, when 1 gram of the wax is heated 

 to 250° C. with potash lime. 



The equations for the reactions being : — 



E . CtLOOC . K' + KOH = E . CH 2 OH + KOOC . R', 

 E . CH 2 OH + KOH = E . COOK + 2H 2 , 



it follows that one gram-molecule of the ester E . CH 2 OOC . E', or of the 



alcohol E . CH 2 OH will evolve 44-52 litres of hydrogen, at normal temperature 



and pressure, when heated with potash-lime. If M is the molecular weight 



of the ester or alcohol, then the number of cubic centimetres of hydrogen 



44520 

 evolved from 1 gram of the ester or alcohol is , and since 56 - 15 



grams of potash are required to hydrolyse 1 gram-molecule of the ester, we 



have — - = 56-15, where " e " is the ester number, and finally 



_ e x 44 520 

 1000 x 5615 C " C " 



The volume of hydrogen theoretically obtainable from 1 gram of the wax, 

 the analysis of which is given above, is 57'25 c.c, and the volume actually 

 found by A. and P. Buisine was 53-5 c.c. Since the volume of the hydrogen 

 evolved was only 93-45 per cent, of the theoretical, it follows that 6-55 per 

 cent, of the alcohols from which the esters are derived evolved no hydrogen. 

 This may have been due to incompleteness of the reaction, or to the presence 

 of alcohols other than primary in the esters, or to both these causes. 



s2 



