N,N-Dimethyl-p-toluidine

light yellow liquid

N,N-Dimethyl-4-toluidine is an amine accelerator for the polymerization of e.g. dental methacrylic restorative materials

N,N-Dimethyl-p-toluidine is used as a polymerization catalyst for polyesters, acrylate and epoxy resins. It is also used as a hardener for dental cements and in adhesives. It serves as an intermediate for photographic chemicals, in industrial glues, in artificial fingernail preparations, colorants, pharmaceuticals. It reacts with vinyl ether in the presence of copper(II) chloride gives tetrahydroquinolines. Further, it is used to accelerate polymerization of ethyl methacrylate.

Synthetic Communications, 19, p. 3051, 1989 DOI: 10.1080/00397918908052700
Tetrahedron Letters, 8, p. 1849, 1967

A clear colorless liquid with an aromatic odor. Density 0.937 g / cm3 (Lancaster) and insoluble in water. Hence floats on water. Toxic by skin absorption and inhalation. Flash point 181°F. May release toxic vapors when burned.

Tends to darken upon exposure to air. Insoluble in water.

N,N-Dimethyl-p-toluidine neutralizes acids in exothermic reactions to form salts plus water. May be incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides. May generate hydrogen, a flammable gas, in combination with strong reducing agents such as hydrides.

TOXIC; inhalation, ingestion or skin contact with material may cause severe injury or death. Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Effects of contact or inhalation may be delayed. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution.

Combustible material: may burn but does not ignite readily. When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion hazards. Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated. Runoff may pollute waterways. Substance may be transported in a molten form.

N,N-Dimethyl-p-toluidine was prepared by reacting p-toluidine with methanol and POCl3 in autoclave heated up to 280° C for 3h.

Reflux for 3hours with 2 molar equivalents of Ac2O, then fractionally distil it under reduced pressure. Alternatively, dry it over BaO, distil and store it over KOH. The picrate has m 128o (from EtOH). Methods described for N,N-dimethylaniline are applicable here. [Beilstein 12 H 902, 12 III 2026, 12 IV 1874.]

The initial threshold screening level (ITSL) for n,n-dimethyl-p-toluidine (DMPT), is 28 μg/m3 based on an annual averaging time.