Meta-toluidine

Examjdes.—Aniline is rapidly tribrominated at room temperature, the end point is very sharp, and this estimation of aniline is preferable to the nitrous acid method. At ordinary temperature ortho- and para-toluidines are dibrominated and meta-toluidine is tribrominated. Dimethylaniline is monobrominated at 0°—5°, dibrominated at 40°—50° and tribrominated at 60°—70°, an interesting example of the effect of temperature. Sulphanilic acid at 60°—70° yields tribromoaniline, and at this temperature p-nitroaniline reacts quantitatively. Phenol at about 22° yields tribromophenol. For reference to the estimation of m-diamines, m-dihydroxy compounds, R salt, cresols, p nitroaniline, diphenylamine, p-nitrophenol, and other notes, see J. S. C. I., 41, 161. 

Synonyms/Trade Names 3-Amino-1-methylbenzene, 1-Aminophenylmethane, m-Aminotoluene, 3-Methylaniline, 3-Methylbenzenamine, 3-Toluidine, meta-Toluidine, m-Tolylamine ... 

Odor limit is above TLV. Alcohol consumption increases toxic effects. Depending on the degree of exposure, regular medical checkups are advisable. Effects on blood due to formation of methemoglobin. Special first aid required in the event of poisoning antidotes must be available (with instructions). The measures on this card also apply to meta-toluidine. 

Red lake C n. Family of organic acid azo pigments prepared by coupling the diazo-nium salt of ortho-chloro-meta-toluidine-para-sulfonic acid with /i-naphthol. 

Fujita et al. [68] have polymerized ortho- and meta-toluidines on gold-plated quartz plate electrolytically in an aqueous medium under nitrogen atmosphere. Oxidative polymerization was typically carried out in 1.0 M HCl solution containing 0.5 M monomer at a constant potential of +0.75 V (versus Ag-AgCl) using... 

Thyssen, A. Hochfeld, A. Schultze, J.W., "Investigations of the Anodic Polymerisation of Ortho- and Meta- Toluidine with the EQMB", p. 151 in Plocharski, J. Roth, S. (Eds.), Materials Science Forum, 42, Trans Tech Publications, Switzerland (1989). 

If pure isomers are required, the ortho and meta compounds can be prepared by indirect methods. o-Nitrotoluene can be obtained by treating 2,4-dinitrotoluene with ammonium sulfide followed by diazotization and boiling with ethanol. / -Nitrotoluene can be prepared from -toluidine by acetylation, nitration deacetylation, diazotization, and boiling with ethanol. A fairly pure -nitrotoluene, which has been isolated from the isomeric mixture, can be purified further by repeated crystallization. 

Figure 21. Conversion of substituted anilines (OT, MT, and PT are respective ortho-, meta-, and para-toluidine, PA = p-anisidine, and PAA = p-aminoacetophenone), corresponding mono-N-methylated anilines selectivity and yield obtained on Cu0.5Zn0.5Fe204 at 300oC with methanol. Only in the case of PAA, feed with CH30H PAA = 6 was employed to avoid solubility problem, and in all other cases a CH30H Sub. Amline H20 = 3 1 1 was maintained. Reprinted from Applied Catalysis A General, 320, Vijayaraj M., et al., 2007, 64-68 with permission from Elsevier.

Toxicology. ort/ o-Toluidine causes anoxia due to the formation of methemoglobin and hematuria xA-toluidine hydrochloride is carcinogenic in experimental animals. The meta-and para-isomers are assumed to produce comparable toxic effects however, meta-tolrriAine seems to have no carcinogenic activity. 

Rats survived an 8-hour exposure to concentrated vapor. Animals exposed to from 6 to 23 ppm for several hours developed mild methemoglobinemia. In the eye of a rabbit, the liquid caused a severe burn. Excessive drying of the skin may result from repeated or prolonged contact. The meta- and para-isomers of toluidine show the same toxicity profile and dose range as ort/jo-toluidine similar effects from exposure are expected, although these isomers have not been tested as extensively as o-toluidine. ... 

Cheever, K.L., Richards, D.E. Plotnick, H.B. (1980) Metabohsm of ortho-, meta-, and para-toluidine in the adnlt male rat. Toxicol, appl. Pharmacol, 57, 361-369 Cheever, K.L., DeBord D.G, Sweaiengin, T.F. Booth-Jones, A.D. (1992) ortho-Toluidine blood protein addnets HPLC analysis with fluoreseenee deteetion after a single dose in the adult male rat. Fundam. appl Toxicol, 18, 522-531 Chemfinder (2000) ortiho-Toluidine Hydrochloride [http //www.ehemfinder.com/result.asp] Chemieal Information Serviees (1999) Directory of World Chemical Producers (Version 99.1.0) [CD-ROM], Dallas, TX... 

Since many ligands are organic compounds which have possibilities for isomerism, the resulting complexes can show isomerism from this source. Examples of isomeric ligands are 1,2-diaminopropane ( propylenediamine, pn) and 1,3-diaminopropane C trimethylenediamine, tn) or ortho-, meta-, and pcra-toluidine fCH3C6H4NH2). 

The 0-, M- and P-Toluidino-Diazido-Copper Complexes. (N3)2Cu.C7H7NH2 mw 254.78 N 38.49% grn-brn cryst mp, ortho-123° (explds), meta- 157-60°(explds), para- 135° (explds). Sol in ethylenediamine and acids. Prepn is by reacting Cu(II) azide with the appropriate toluidine isomer. The isomers have an impact sensy of 10cm, using a 1-kg wt Refs 1) Beil, not found 2) Gmelin, Syst Nr 60, Teil B, Lieferung 1 (1958) 3) A. Cirulis... 

In contrast to the ortho and meta isomers, a substantial fraction of p-toluidine can be converted into toluene (45% yield) the ether is also obtained (20% yield).10 13 A para methyl group apparently facilitates replacement of the diazo group by hydrogen. 

Amide ion is a strong nucleophile, attacking at either end of the weak, reactive benzyne triple bond. Subsequent protonation gives toluidine. About half of the product results from attack by the amide ion at the meta carbon, and about half from attack at the para carbon. 

Aromatic amines are often acetylated before nitration. Examples include the nitration of p-acetotoluide and 2-acety]aminonaphthalene, the products being 3-nitro-p-acetotoluide (90%) and l-nitro-2-acetylamino-naphthalene (49%), respectively. The p-tolylsulfonyl derivative is readily formed and hydrolyzed after nitration. On the other hand, if unacetylated and in the presence of a large excess of sulfuric acid, p-toluidine gives mainly 2-nitro-p-toluidine (71%), the arylammon um ion being meta-directing. 

Homologous Amines. Toluidines.—The amino derivatives of the homologues of benzene are formed by the same kind of reactions as those for preparing aniline, viz., the reduction of the homologous mono-nitro compounds. The- amino toluenes in which the amino group is substituted in the benzene ring are known as toluidines, and there are, of course, three isomeric compounds, orthoj meta and para. In the ordinary nitration of toluene the ortho and para compounds are formed. By indirect methods (p. 532) the meta-nitro toluene may also be prepared. These nitro compounds by reduction yield the corresponding toluidines. 

Rearrangement of Alkyl Anilines.—Both mono-methyl aniline and di-methyl aniline undergo an interesting rearrangement when their salts are heated in sealed tubes to 250°-350°. The mono-methyl aniline yields a mixture of ortho- and para-toluidines while the dimethyl aniline yields first a mixture of ortho- and para-mono-methyl toluidines and then finally from each of these intermediates there is obtained unsymmetrical meta-xylidine only. 

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