N-Methylaniline

Physical properties

Colorless to yellow to pale brown liquid with a faint, ammonia-like odor. Odor threshold concentration is 1.7 ppm (quoted, Amoore and Hautala, 1983).

Definition

ChEBI: N-methylaniline is a methylaniline that is aniline carrying a methyl substituent at the nitrogen atom. It is a phenylalkylamine, a secondary amine and a methylaniline. It derives from an aniline.

Preparation

N-methylaniline was synthesized by the reaction of aniline with dimethyl sulfate. Dimethyl sulfate was added dropwise to the mixed solution of aniline and water below 10°C, stirred for 1 h, and then added dropwise with 30% sodium hydroxide solution. The upper layer is the organic phase, and the lower layer is extracted with benzene. After the benzene is recovered from the extract, the obtained oil lookchem-like substance is combined with the organic phase to obtain a mixture of aniline, N-methylaniline and N,N-dimethylaniline. The mixture was treated with sulfuric acid, and the aniline formed sulfate crystals which were filtered off. N,N-dimethylaniline can be converted to N-methylaniline by the following reaction.

Application

N-Methylaniline (NMA) was used in the preparation of self-assembled poly(N-methylaniline)-lignosulfonate (PNMA-LS) composite spheres with reactive silver-ion adsorbability. NMA was also used in electrodeposition of poly(N-methylaniline) (PNMA) coatings on a steel disc electrode using potentiodynamic, potentiostatic and galvanostatic techniques.

Synthesis Reference(s)

Chemical and Pharmaceutical Bulletin, 14, p. 1007, 1966 DOI: 10.1248/cpb.14.1007Journal of the American Chemical Society, 107, p. 493, 1985 DOI: 10.1021/ja00288a037Synthetic Communications, 13, p. 601, 1983 DOI: 10.1080/00397918308059535

General Description

Chemical oxidation of N-methylaniline with dichromate (oxidant) has been studied by Raman spectroscopy.

Hazard

Toxic by ingestion, inhalation, and skin absorption. Methemoglobinemia and central nervous system impairment.

Health Hazard

Recommended Personal Protective Equipment: Approved respirator; rubber gloves; splash proof goggles; Symptoms Following Exposure: Inhalation causes dizziness and headache. Ingestion causes bluish discoloration (cyanosis) of lips, ear lobes, and fingernail beds. Liquid irritates eyes. Absorption through skin produces same symptoms as for ingestion; General Treatment for Exposure: INHALATION: remove victim to fresh air and call a physician at once; administer oxygen until physician arrives. INGESTION: give large amount of water; get medical attention at once. EYES or SKIN: flush with plenty of water for at least 15 min.; if cyanosis is present, shower with soap and warm water, with special attention to scalp and finger nails; remove any contaminated clothing; Toxicity by Inhalation (Threshold Limit Value): Data not available; Short-Term Inhalation Limits: Data not available; Toxicity by Ingestion: Data not available; Late Toxicity: Data not available; Vapor (Gas) Irritant Characteristics: Data not available; Liquid or Solid Irritant Characteristics: Data not available; Odor Threshold: Data not available.

Chemical Reactivity

Reactivity with Water No reaction; Reactivity with Common Materials: May attack some forms of plastic; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Not pertinent; Inhibitor of Polymerization: Not pertinent.

Safety Profile

Poison by ingestion and intravenous routes. Moderately toxic by subcutaneous route. When heated to decomposition it emits toxic fumes of NOx.

Potential Exposure

The material is used as an intermediate in organic synthesis, as a solvent and as an acid acceptor

Carcinogenicity

N-methyl aniline (1.95 g/kg of food) given together with sodium nitrite (1.0 g/l of drinking water) to Swiss mice resulted in a 17% incidence of lung adenomas and a 14% incidence of malignant lymphomas; there were no carcinogenic effects in animals treated with Nmethyl aniline alone, suggesting that in vivo nitrosation is necessary for forming carcinogenic nitrosamines.In bacterial mutagenicity assays N-methyl aniline was negative with or without metabolic activation.

Environmental fate

Soil. Reacts slowly with humic acids or humates forming quinoidal structures (Parris, 1980).

Shipping

UN2294 N-Methylaniline, Hazard Class: 6.1; Labels: 6.1-Poisonous materials.

Purification Methods

Dry it with KOH pellets and fractionally distil it under vacuum. Acetylate, and the acetyl derivative is recrystallised to constant melting point (m 101-102o), then hydrolysed with aqueous HCl and distilled from zinc dust under reduced pressure. [Hammond & Parks J Am Chem Soc 77 340 1955, Beilstein 12 IV 241.]

Waste Disposal

Controlled incineration whereby oxides of nitrogen are removed from the effluent gas by scrubber, catalytic or thermal device.