Synthesis method of diethyl toluene diamine

Abstract

The invention discloses a method for preparing diethyltoluenediamine, which comprises the following steps: diaminotoluene and catalyst are added to a reactor; an 'aromatic amine-aluminum' catalyst system is formed after temperature rising and stirring, and ethylene is pumped into the reactor to purge the hydrogen produced by the reaction; high pressure ethylene gas is pumped in, and after complete alkylation, diphenyl ether or phenoxy biphenyl are added to dilute the reactants; the mixture is filtered, the materials at the bottom of the reactor are recycled, the filtrate is distilled, and diethyltoluenediamine is obtained. The method has the advantages that, aluminum, zinc, aluminum chloride and organic aluminum are used as the catalyst, so activity is increased, reaction pressure is lowered and reaction time is reduced; diphenyl ether or phenoxy biphenyl is added before filtration, so material viscosity can be lowered to facilitate filtration and separation, simultaneously, the 'aromatic amine-aluminum' catalyst system is not damaged; the catalyst can be recycled, so operation steps are reduced, catalyst cost is greatly lowered and environment protection is benefited.

Description

technical field [0001] The invention relates to the field of alkylation reactions of aromatic amines, in particular to a method for synthesizing diethyltoluenediamine with diaminotoluene. Background technique [0002] 3.5-diethyl-2.4(2.6)-diaminotoluene (English name: 3.5-diethl-2.4(2.6)-toluenediamine), molecular structure formula is [0003] [0004] It has a boiling point of 308°C, a freezing point of 9°C, and a viscosity of 280 centistokes at 20°C. It is a transparent amber liquid with a slight ammonia smell. It is mainly used as a hardener for polyurethane and epoxy resin and used in conjunction with E-300. It is widely used as the main chain extender and elastomer for reaction injection molding (RIM) of polyurethane and sprayed polyurethane polyurea elastomer (SPUA). Antioxidants of lubricating oil chemical intermediates, etc. [0005] According to scientific research reports, the reaction mechanism of alkylation of arylamine is: [0006] The first step: the reac...

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Problems solved by technology

[0018] In the existing method for synthesizing diethyltoluenediamine, when using inorganic aluminum as a catalyst, the time to form the catalyst system is long (generally more than 3 hours), and the material is easy to coke under high temperature and high pressure

Single use of alkylaluminum as a catalyst, alkylaluminum is expensive and highly toxic, which is not conducive to human health and environmental protection

[0019] After the alkylation reaction is completed, the alkaline aqueous solution added to the reaction material will destroy and decompose the "arylamine-aluminum" catalyst system, making it a waste residue, which not only wastes raw materials, but also causes great pollution to the environment.

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