Synthetic method for 2-methyl-4-methoxydiphenylamine

Abstract

The invention discloses a synthetic method for 2-methyl-4-methoxydiphenylamine. The synthetic method comprises the following steps: (1) successively adding orthochlorobenzoic acid, a copper catalyst,an acid binding agent, and a mixed solvent of toluene and DMF into a reaction vessel, carrying out heating to a reflux state, then performing stirring and mixing for 10-20 min, dropwise adding 2-methyl-4-methoxyaniline into the reaction vessel, continuing a reflux reaction for 6 to 10 h after the addition is completed, separating water produced by the reaction by using an oil-water separator during the reflux reaction, neutralizing excess alkaline liquor after the reaction is completed, performing extraction with toluene, washing an extracted organic phase, carrying out distilling to remove toluene, and performing concentration and vacuum drying to obtain an intermediate product; and (2) subjecting the obtained intermediate to heating and decarboxylation in a methanol system so as to obtain the target product 2-methyl-4 -methoxydiphenylamine. The synthetic method of the invention improves the conversion efficiency and selectivity of the reaction, increases the conversion rate of raw materials, generates little process wastewater, and has low production cost.

Description

technical field [0001] The invention relates to the technical field of organic synthesis, in particular to a synthesis technology of 2-methyl-4-methoxydiphenylamine. Background technique [0002] 2-Methyl-4-methoxydiphenylamine is mainly used as an important intermediate of pressure-sensitive dyes, medicines, rubbers, and pesticides. [0003] The synthesis technology of 2-methyl-4-methoxydiphenylamine reported in the literature is mainly as follows: adopt 2-methyl-4-methoxyaniline and halogenated benzoic acid to add acid-binding agent to produce condensation reaction in toluene The target product was obtained, and the system was negatively pressured to remove water during the reaction process. After pickling and washing with water three times, the target product is obtained, and the product 2-methyl-4-methoxydiphenylamine is obtained after decarboxylation. The product yield of this preparation process is about 84%. Since the salt generated by the reaction with the acid-bi...

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Problems solved by technology

Since the salt generated by the reaction with the acid-binding agent is insoluble in toluene, adding all the acid-binding agent at one time will produce a large amount of solids in the system, or even agglomerate, which will seriously affect the smooth progress of the experiment, resulting in incomplete conversion of raw materials and low product yield. And the recovery of unreacted raw materials is time-consuming and labor-intensive, and the excess alkali and salt in the product need to be washed many times, and the process wastewater is more, resulting in high production costs; the reaction requires high-vacuum distillation and water separation, so the process energy consumption is high; Negative pressure, the boiling point of the material is lowered, and the reflux temperature of the system is lower, resulting in a slower reaction

Therefore, this preparation process is difficult to carry out industrialization promotion at present