N,N-Dimethyl-p-toluidine CAS Number: 99-97-8

**Physicochemical Properties:**

N,N-Dimethyl-p-toluidine is a colorless or pale yellow oily liquid with a rotten egg odor. It has a melting point of 130.31℃, a boiling point of 211.5-212.5℃, a density of 0.9287-0.9366 g/mL at room temperature, and a refractive index of 1.5360-1.5470. It is insoluble in water but soluble in some organic solvents, and decomposes upon exposure to light.

**Product Description:**

N,N-Dimethyl-p-toluidine is soluble in some organic solvents and decomposes upon exposure to light. It is an effective photoinitiator for acrylonitrile (AN) polymerization and can also be used in the production of self-curing dental adhesive.

**Polymerization Reaction:**

Aromatic tertiary amines, especially N,N-dimethyl-p-toluidine, are effective photoinitiators for acrylonitrile (AN) polymerization. The medium has a significant impact on the polymerization rate; a polarity results in a faster polymerization rate. Oxygen has a significant effect on polymerization; as the oxygen content increases, the polymerization induction period increases, and the polymerization rate decreases. N,N-Dimethyl-p-toluidine is generally considered a retarder for olefin polymerization, not an initiator for the photopolymerization of acrylonitrile (AN).

Polymerization Characteristics：

N,N-Dimethyl-p-toluidine cannot initiate the polymerization of acrylonitrile (AN) in the dark, but it initiates polymerization extremely rapidly under light. Figure 1 shows the photopolymerization of acrylonitrile (AN) in the presence of N,N-dimethyl-p-toluidine, naphthalene, benzophenone (BP)-triethylamine (TEA), and AClN, with polymerization rates of 0.157, 0.023, 0.139, and 0.045% min⁻¹, respectively, indicating that N,N-dimethyl-p-toluidine is a highly effective initiator for the photopolymerization of acrylonitrile (AN).

The photopolymerization of acrylonitrile (AN) initiated by N,N-dimethyl-p-toluidine proceeds via a free radical mechanism. The polymerization completely stops upon the addition of a trace amount of free radical scavenger. For example, [N,N-dimethyl-p-toluidine]-10-3M, when 200 ppm of 2,2,6,6-tetramethylpiperidinol nitroxide free radicals are added, shows no polymerization of acrylonitrile (AN) after 1.5 hours of light irradiation. However, under the same conditions without a free radical scavenger, a white precipitate of polyacrylonitrile appears within two minutes.

Applications:

As an effective photoinitiator for acrylonitrile (AN) polymerization, its polymerization rate is directly proportional to the 1.62 power of the AN concentration and the 0.62 power of the DMT concentration. This product is commonly used as an accelerator and can also be used in the synthesis of unsaturated polyesters and as an additive in adhesives.

Synthesis Method:

N,N-dimethyl-p-toluidine is synthesized at low temperature and ambient pressure using dimethyl sulfate as a methylating agent.

Uses

Used in the manufacture of self-curing dental trays

Uses

A tertiary amine that can undergo iron-catalyzed oxidative C-C coupling with phenylacetylene and benzamide in the presence of di-tert-butyl peroxide to form N,4-dimethyl-N-(3-phenylprop-2-ynyl)benzamide and N-((methyl(p-tolyl)amino)methyl)benzamide, respectively.