1872.] 



transformation of Aniline into Toluidine. 



55 



Salts of methylaniline (experiments were made with the chlorhydrate 

 and iodhydrate) may be heated to 220° or 230° for hours without under- 

 going any alteration ; but if the temperature be raised to the melting- 

 point of lead (335°), the methyl group in the ammonia fragment passes 

 over to the benzol nucleus, methylaniline being converted into toluidine. 

 C 6 H 5 . CH 3 . UN . HC1 = (C 6 H 4 . CH 3 ) HEN . HOI. 



It is not necessary for this purpose to prepare methylaniline in the 

 pure state. If a mixture of 1 molecule of pure aniline chlorhydrate and 

 1 molecule of methylic alcohol be heated for some hours to 230°-250°, a 

 yellow transparent resinous mass of the consistency of honey is formed, 

 which is principally methylaniline chlorhydrate. 



C 6 H 5 . HHN . HC1 + CH 3 . OH = C 6 H 5 . CH 3 . HN . HC1 + H 2 0. 



After a day's exposure to a temperature of 335° the contents of the 

 digestion-tubes are perfectly altered. In place of a transparent viscous 

 resin, they now contain a solid beautifully crystalline mass ; the secon- 

 dary salt has been converted into a primary one. The crystalline mass, 

 unless the temperature has been too high, dissolves in water almost 

 without a residue ; on addition of alkali to this solution an oily base is 

 separated, which rises as a brownish layer to the surface of the liquid. 

 If this oily layer be distilled in a current of steam, a colourless liquid 

 passes, which, partly in the cooler, partly in the receiver, solidifies to a 

 white crystalline mass of toluidine. There are but few secondary pro- 

 ducts formed in this reaction. 



Toluidine thus obtained, when recrystallized from water, has the 

 melting-point 45°. Though scarcely necessary, it was identified by a 

 platinum determination, which gave the value corresponding to the 

 formula 



2[(C 6 H 4 .CH 3 )H 2 N.HCl].PtCl 4 . 



It deserves to be noticed that methylaniline iodhydrate, when heated 

 like the chlorhydrate, yielded no solid, but liquid toluidine. I must leave 

 it undecided which of the two liquid toluidines was formed in this case. 



The observations rapidly sketched in this note invite to new experi- 

 ments in a variety of directions. Is it possible to obtain by similar pro- 

 cesses homologues of the monamines of other classes, perhaps even 

 of some of the bases contained in the organism r of plants and animals ? 

 Already I have commenced the study of naphthylamine, the behaviour of 

 which will be particularly interesting in more than one respect. According 

 to some observations published upon this subject, the preparation of 

 methylated naphthylamines would appear to present some difficulty ; but 

 by working at moderate temperatures, mono- and dimethylated naphthyl- 

 amine, as well as the quartary ammonium base, are readily procured. 

 The salts of these compounds are remarkable for their power of crys- 

 tallization ; I have not yet found time to examine their behaviour under 

 the influence of heat. 



