Conductivity of Organic Acids in Ethyl Alcohol. 143 



tends to decrease the conductivity of the ethylmalonic acid. Propylma- 

 lonic acid has uniformly higher conductivity than ethylmalonic, and the 

 conductivity of the dipropyl acid is uniformly higher than that of the 

 diethyl. Just as diethylmalonic acid has smaller conductivity than 

 ethylmalonic, so dipropylmalonic acid has smaller conductivity than 

 propylmalonic. 



Butylmalonic and allylmalonic acids, at the dilution in question, 

 have smaller conductivities than malonic acid itself; but as the dilution 

 increases, the conductivity of allylmalonic acid becomes greater than 

 that of malonic acid. 



Benzylmalonic acid has greater conductivity than malonic, but 

 less than ethylmalonic acid. This is especially interesting, in consid- 

 eration of the fact that, in general, a phenyl derivative of an acid has 

 much greater conductivity than the corresponding methyl derivative; 

 e. g., the conductivity of acetic acid in alcohol is so small that it can not 

 be accurately measured. On the other hand, benzoic acid has a conduc- 

 tivity of 0.014. Again, benzilic acid having the formula 



CeHsv /OH 



C 

 C 6 H 5 X/ 



has a much greater conductivity than the corresponding methyl deriva 

 tive, oxyisobutyric acid 



CH 3 \ /OH 

 C 



This is in keeping with the results obtained for these acids in aqueous 

 solution, 1 and with the general observation that the replacement of a 

 methyl group by a phenyl group increases the conductivity. 



Phenylpropiolic acid, C 6 H 5 C = C COOH, has a conductivity many 

 times larger than that of cinnamic acid 



C 6 H 5 -CH = CH-COOH 



This is in accord with what was found for these same acids in aqueous 

 solutions. 



Take the following series: 



Benzoic acid ............ CsHsCOOH 1.3.5 dinitrobenzoic acid. . .C 6 H3(NO 2 ) 2 COOH 



m-chlorbenzoic acid ..... C 6 H 4 C1COOH o-toluic acid ............ C 6 H 4 CH 3 COOH 



m-nitrobenzoic acid ..... C 6 H 4 NO 2 COOH p-toluic acid ............ C 6 H 4 CH 3 COOH 



The conductivities of benzoic acid and of orthotoluic acid are about 

 equal, whereas the conductivity of p-toluic acid is very much less. 

 That the same relation holds also for other substituent groups may 



Carnegie Inst. Wash. Pub. 170, 115, 132 (1912). 



