210 ANILINE AND ANILINE DYES. — Substituted Anilines .
hydrochloride (prepared by heating together phenol,sal-ammoniac, and hydrochloric acid), or by passingphenyl chloride or iodide and aniline vapour througha liot tube (Dusart and Baiidy).
oh) iyh.)
C 6 II 3 ,01 + U HC1 = HC1 + C 6 II 5 V-N,HC1
It is also formed by simply heating aniline hydro-chloride to 800° C., (Girard and De Laire), or bytreating aniline with potassium (not sodium), andacting on the product with phenyl bromide (Meezand Weitii).
Diphenylamine is, when pure, a solid crystallinebody, melting at 45°, and distilling without changeat 810° C. It is chiefly characterized by its powerof yielding deep blue products of great tinctorialpower on treatment with certain oxidizing agents( Vide Blue Dyes infra).
A great number of higher homologues of diphenyl-amine are known. Commercial diphenylamine ismade from a mixture of aniline and toluidine (para-and meta-), not unfrequently containing higher homo-logues: hence it may be expected to contain, inaddition to diphenylamine, the following bases: —
I’aratoluyl phenylamine, C c H 5 hN ;
Uetatoluyl phenylamine, C 6 H 5 >N ;
C 6 H 4 (CH 3 )p)
Di paratoluylamiiie, C 6 H 4 (OII 3 )p VN ;
C,;H 4 (CH ; > 1 1
Di metatoluylamine, I I 4 (C j-N;
Paratoluyl metatoluylamine,CtiH 4 (CH 3 )m j-N ;
Besides higher homologues. The existence of allthese bodies, however, has not yet been absolutelyproved: some of them have been described, but itis not yet proved that the bodies examined were notmixtures of isomerides.
c 9 h 8 )
Methyl diphenylamine, C 6 II 6 V N, has been obtained
CII 3 \ .
by 15 ardy by the action of methylic alcohol on dipheny-lamine under pressure; by the action of oxidizingagents it forms blue and violet colouring matters.
CAl
Methyl aniline, CII 3 f N. — This base is obtainable
II j
by the action of methyl chloride, bromide, or iodideon aniline, and the action of caustic alkalies on theresulting methyl plienylium salt formed (IIoemann).
c 6 h 6 1
c 6 n s ) rH ^ oil, i
h In + l = H >. N
H j 1 > H|
IJ
cn 3 | c,n s )
H j-N 4- KOH = II 2 0 - + KI -f CHAN
IJ
Methyl nitrate, also, forms much methyl aniline onheating to 100° C. with aniline; its use, however,requires caution, as dangerous accidents and explo-
sions have occurred through the volalility of the ni-trate and its detonating power, under conditions notthoroughly understood. It is producible much morecheaply by the reaction of methylic alcohol on anilinehydrochloride underpressure (Baedy, Boiiirier, andCfiappat), the reaction being
t-VD 0 B H.5l
II | CII 3 |
H IN + CH 3 ,OH = H J-N + H 2 0
HI H|
Cl J Cl J
Methyl aniline hydrochloride is thus formed, fromwhich the free base is obtainable by treatment withalkalies. Simultaneously with methyl aniline, dimethylaniline hydrochloride is usually produced in variablequantities. It seems not improbable that this reac-tion is really due to the formation of a small quantityof methyl chloride which then attacks the anilinepresent, in accordance with Hofmann’s reaction ;instead of aniline hydrochloride a mixture of anilineand sal ammoniac may be used, or a mixture of anilineand methylamine hydrochloride. When pure, methylaniline is an oily liquid, boiling at 192° C., yieldingcolouring matters in small quantities only by theaction of oxidizing agents ; when mixed with dimethylaniline, or with higher homologues, e.g., methyltoluidine, the yield is much greater.
c 6 n 6 l
Dimethyl aniline, CH,, N, is obtainable fromCII 3 J
methyl aniline by the same processes as those bywhich the latter is producible from aniline : it is aliquid, boiling at 202° C. (Lautii), at 192° C. whenperfectly pure (Hofmann).
When the salts of methyl aniline are heated in asealed tube to 850° C. for a day, they undergo a changeof the kind referred to as “change of position,”toluidine salts resulting : thus with the hydrochlorideC e HA C 6 H 4 ,CH 3 )
CH.AN,HC1 = H VN,HC1.
H i II)
It is especially noteworthy that whilst paratoluidine(solid) results in the case of methyl aniline hydro-chloride, a liquid toluidine, ajiparently metatoluidine,is formed when methyl aniline hydriodide is thustreated (Hofmann).
Similarly, when the methyl iodide of dimethylaniline (trimethyl phenylium iodide) is heated to ahigh temperature in a sealed vessel, or if dimethylaniline hydrochloride is heated to 300° C. for ten hourswith a large excess of methylic alcohol, analogouschanges result; true homologues of aniline, or deriva-tives thereof, being formed by analogous reactions of“change of position.” Thus with dimethyl anilinemethyl iodide —
Dimethyl Aniline, Dimethyl Toluidine,
Methyl iodide. Hydriodide.
C 6 H 5 ) c 6 ii 4 ,cit ;! )
ch,vn,cii 3 i = cii.An,iii =
Methyl Xylidine, Cumidine, »
Methyl iodide. Hydriodide.
I PTI ‘ N,HI = (0II 3 IN,III.
H 3 1 11 1
M J U J