ELECTROSYXTHESIS. 307 



acids, ethoxy-acids, chloro-acids, bromo-acids, unsaturated 

 acids, and aromatic acids have all been tried, but instead 

 of yielding synthetic products, or unsaturated compounds 

 formed in accordance with equation IV., they only yield 

 oxidation products, of a nature depending" on the chemical 

 characteristics of the acid electrolysed. The removal of 

 hydrogen from a compound, or the introduction in its stead 

 of chlorine, bromine, or a partially oxidised radical, seems to 

 offer a point of attack for the active oxygen, which, even 

 in the most favourable circumstances, is always produced 

 at the anode, the whole molecule being then destroyed with 

 formation of carbon monoxide, carbon dioxide, aldehydes, 

 unsaturated hydrocarbons, etc. 



The effect of various external conditions on the reactions 

 taking place at the anode has been investigated by T. S. 

 Murray, who subjected the electrolysis of potassium acetate 

 solutions to an exhaustive examination. He found that the 

 concentration of the solution and the size of the anode 

 exercised an influence on the electrosynthesis precisely in 

 accordance with the view expressed on p. 304. With a 

 solution containing 0*5 per cent, of potassium acetate, the 

 ethane produced was only equal to 0*3 per cent, of that 

 theoretically obtainable from the current ; with a 2 per cent, 

 solution, the yield had increased to over 50 per cent., and 

 with a 60 per cent, solution, it reached 80 per cent, of the 

 theoretical amount. The effect of current strength was 

 similar but not so marked. A current of 0*045 amperes 

 gave a yield of 25 per cent., a current of o'6 amperes, 69 

 per cent, and a current of 5*2 amperes, Si per cent. The 

 size of the anode is of great importance in determining the 

 quantity of synthetic products formed. With a current of 

 2 amperes, and the surface of the anode 100 times greater 

 than the surface of the cathode, the yield of ethane was 27 

 per cent, of the theoretical amount : with the same current 

 but the electrodes reversed, so that the former anode 

 became the cathode, and vice versa, the yield rose to 88 

 per cent. The highest yield obtained in any case was 91 

 per cent. The temperature of the solution greatly affects 

 the action at the anode. Thus, other conditions being the 



