Method for producing N, N, N '-trimethyl-N'-hydroxyethyl ethylenediamine by using monatomic palladium/graphene catalyst

Abstract

The invention relates to a method for producing N, N, N '-trimethyl-N'-hydroxyethyl ethylenediamine by using a monatomic palladium / graphene catalyst. The methodcomprises the following steps of: by using monatomic palladium / graphene (Pd1 / graphene) as a catalyst, adding a raw material hydroxyethyl ethylenediamine and a raw material solid paraformaldehyde into a reaction kettle, heating the mixture to 110 DEG C in a hydrogen atmosphere, controlling the pressure of the reaction kettle to be 1.5-3 MPa, stirring to react for 4-6 hours, cooling to normal temperature; centrifugally separating the catalyst and reaction liquid, and rectifying the reaction liquid under reduced pressure to obtain the product N, N, N '-trimethyl-N'-hydroxyethyl ethylenediamine shown in the formula (I). All Pd atoms in the monatomic palladium / graphene catalyst are surface atoms and interface atoms, the metal atoms Pd are in maximum contact with a carrier; compared with Pd / C and nano-molecular catalysts, the monatomic palladium / graphene catalyst has higher catalytic efficiency, selectivity and stability; the dosage of the monatomic palladium / graphene catalyst is greatly reduced, the catalyst is not inactivated after being continuously used for 10 times, and the N ', N'-tetramethyldisiloxane is not inactivated after being continuously used for 10 times, and the yield of the N, N, N '-trimethyl-N'-hydroxyethyl ethylenediamine can reach 95% or above.

Description

technical field [0001] The invention belongs to the technical field of synthetic chemical engineering. In particular, a monoatomic palladium / graphene (Pd 1 / graphene) catalyst for the production of N,N,N'-trimethyl-N'-hydroxyethylethylenediamine. Background technique [0002] N,N,N'-trimethyl-N'-hydroxyethylethylenediamine is a general-purpose polyurethane foaming catalyst with good performance. It can be used in polyether soft and rigid packaging materials molded by hard balls. It is widely used in the foaming process. The hydrogen on the hydroxyl group in its structure is very active, can react with isocyanate, and is difficult to volatilize when combined into the system. It is one of the environmentally friendly catalysts that have been developed in recent years. It has been widely used in Japan, Europe, America and other countries. The market demand larger. [0003] Patent CN106748826 discloses a method for synthesizing N,N,N'-trimethyl-N'-hydroxyethylethylenediamine...

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Problems solved by technology

[0003] Patent CN106748826 discloses a method for synthesizing N,N,N'-trimethyl-N'-hydroxyethylethylenediamine using 88% formic acid as a reducing agent. The atomic utilization rate of the above preparation method is less than 44%, which will generate a large amount of CO 2 Gas, the environment is not friendly, and does not conform to the concept of green chemistry; and there is a side reaction of formic esterification, which needs to be replaced by higher temperature transesterification in the later stage, and finally the alcohol solvent used in transesterification needs to be recycled. The process is complicated and the production Low efficiency, not suitable for industrial production

Patent CN105801436 discloses a method for synthesizing N,N,N'-trimethyl-N'-hydroxyethylethylenediamine using a conventional 5% Pd / C catalyst. The amount of catalyst used is 2-5.5% of the total amount of raw materials. The yield is 86-92%, the amount of catalyst is high, the activity is low, and the effect of catalyst application is poor and the stability is low

None of the above disclosed technologies mentioned the method of efficiently and greenly synthesizing N,N,N'-trimethyl-N'-hydroxyethylethylenediamine using Pd single-atom catalysts on graphene

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