TRANSACTIONS OP SECTION B. 169 



acetic acid. During tlie production of tlae acetone and alcohol the ratio of 

 acetic to butyric acid increases gradually, so that, when the fermentation is 

 completed, the volatile acids in the mash are 4 or 5 parts of acetic and one part 

 of butyric acid. 



The fluctuations in the relative amounts of the two acide present in the 

 mash would indicate that the acids are intimately connected with the produc- 

 tion of acetone and ?i-butyl alcohol, especially as the formation of the latter 

 substances may be suj)pressed almost completely by conducting a fermentation 

 in presence of calcium carbonate. Under these conditions the main products 

 formed are acetic and butyric acids. These acids are obtained in the ratio 

 of t«n moiecules of acetic to nine molecules of butyric. Using these piroportions, 

 and assum.ing that 7i-butyl alcohol and acetone are formed from the acids with- 

 out any appreciable side reactions, 7i-butyl alcohol and acetone should be pro- 

 duced in the ratio of 2-3 parts by weight of the former to one of the latter. 

 Such a result is in accordance with the actual yields obtained. It seems likely, 

 therefore, that the ?i-butyl alcohol is produced from the butyric acid. In 

 support of such a view, several facts are adduced ; the decrease of the amount 

 of butyric acid in the mash is coincident with the formation of 7i-butyl alcohol ; 

 the hypothesis is in agreement with experimental data given by Buchner and 

 Meisenheimer (Bar., 1908, 41, 1410) ; the reduction of butyric acid to butyr- 

 aldehyde has been observed to be brought about by certain extracts ; the addi- 

 tion of butyric and propionic acids results in the formation of n-butyl and 

 n-propyl alcohols respectively; n-butyric acid has been observed in most fermen- 

 tations in which n-butyl alcohol is obtained. 



It is also probable that the acetic acid is an intermediate substance in the 

 formation of the acetone, since the decrease in the amount of this acid in 

 the mash during the fermentation is much slower than that of butyric acid. 

 The amomit of acetone produced is only half that of the alcohol. Also on 

 adding acetic acid to the fermenting mash it is found that the added acid is 

 converted principally into acetone. The fatty acid is best added periodically 

 some hours after the maximum acidity of the mash has been reached, in such 

 a manner as to maintain a figure for the acidity of the mash equal to the 

 maximum acidity obtained in a normal fermentation. 



There is produced also in the fermentation a small amount of ethyl alcohol. 

 It is not yet determined whether this is obtained in a side reaction, or whether 

 it is due to the presence of some impurity. 



The two volatile fatty acids in the mash appear to be attacked, each in a 

 different manner, the butyric acid undergoing a reducing action, while the 

 acetic acid is condensed to acetone. To account for this difference it ijs sug- 

 gested that the formation of dipropyl ketone by condensation from the butyric 

 acid may be prevented owing to the increased steric hindrance imposed by the 

 presence of large groups. 



3. Intramolecular Rearrangement of the Alkylarylamines . 

 By Joseph Eeilly, M.A., D.Sc, and Wilfred J. Hickinbottom. 



The intramolecular change brought about by heating the hydrochlorides of 

 the alkylaniiines under pressure is well known (Hofmann, Ber., 1872, S, 720). It 

 is now shown that not only the hydrochloride but also certain addition compounds 

 of the secondary and tertiary amines with metallic salts are capable of under- 

 going this change on heating. Compounds of the type B.RCl^ (where B 

 represents one molecule of a monovalent base, and R one atom of a divalent 

 metal), produced by the addition of chlorides of zinc, cobalt, and cadmium, to the 

 secondary amines, readily yield alkyl nuclear substituted amines, on heating 

 undei- pressure. Unless the assumption is made that these double compounds 

 readily split off hydrogen chloride, it is difficult to reconcile these facts with 

 the view that methyl chloride is an intermediate product in the formation of 

 |j-toluidine from methylaniline double salts. 



In the alkylarylamines each group occupies a definite space and has a cer- 

 tain definite vibration path. If a change of conditions occurs each group will 

 tend to occupy a position in which the vibration is least restricted. This may 

 occur simply on heating, or by combination or reaction with another compound. 



