Editing Dimethylaniline (section)

==Preparation==
DMA was first reported in 1850 by the German chemist [[August Wilhelm von Hofmann|A. W. Hofmann]], who prepared it by heating aniline and [[iodomethane]]:<ref>Watts, Henry, ''A Dictionary of Chemistry and the Allied Branches of Other Sciences'', Part 2, (London, England:  Longmans, Green, and Co., 1881), Methylanilines, [https://books.google.com/books?id=NfMfAQAAMAAJ&pg=PA1306 p. 1306]</ref><ref>In 1850, August Hofmann announced his synthesis of methylaniline:
*  Hofmann, A. W. (1850) [http://rstl.royalsocietypublishing.org/content/140/93.full.pdf+html "Researches regarding the molecular constitution of the volatile organic bases,"] ''Philosophical Transactions of the Royal Society of London'', '''140''' :  93–131 ;  see especially pp. 113-114.
However, in 1877, the Swiss chemist Alfred Kern (1850–1893) contended that Hofmann's reaction produced only dimethylaniline, not methylaniline:
*  Kern, A. (1877) [https://babel.hathitrust.org/cgi/pt?id=hvd.cl1hz2;view=1up;seq=205 "Ueber die Darstellung von Monomethylanilin"] (On the preparation of monomethylaniline), ''Berichte der deutschen chemischen Gesellschaft'', '''10''' :  195–199.
Hofmann found that acetic anhydride reacted only with methylaniline, not with dimethylaniline, and was thus able to show that his reaction produced both the mono- and di-methylated forms of aniline:
*  Hofmann, A. W. (1877) [https://babel.hathitrust.org/cgi/pt?id=hvd.cl1hz2;view=1up;seq=613 "Versuche über die Einwirkung des Chlor-, Brom- und Jodmethyls auf Anilin"] (Experiments on the reaction of methyl chloride, bromide and iodide with aniline), ''Berichte der deutschen chemischen Gesellschaft'', '''10''' :  591–601.</ref>
:C<sub>6</sub>H<sub>5</sub>NH<sub>2</sub>  +  2 CH<sub>3</sub>I   →   C<sub>6</sub>H<sub>5</sub>N(CH<sub>3</sub>)<sub>2</sub> + 2 [[hydrogen iodide|HI]] <!-- probably the aniline serves as base also-->
DMA is produced industrially by [[alkylation]] of [[aniline]] with [[methanol]] in the presence of an acid catalyst:<ref name=Ullmann>Kahl, Thomas ''et al.'' (2007) "Aniline" in ''Ullmann's Encyclopedia of Industrial Chemistry''. John Wiley & Sons: New York. {{doi|10.1002/14356007.a02_303}}</ref>
:C<sub>6</sub>H<sub>5</sub>NH<sub>2</sub>  +  2 [[methanol|CH<sub>3</sub>OH]]  →  C<sub>6</sub>H<sub>5</sub>N(CH<sub>3</sub>)<sub>2</sub>  +  2 H<sub>2</sub>O
Similarly, it is also prepared using [[dimethyl ether]] as the methylating agent.