Method for preparing pentamethyldipropylene triamine

Abstract

The invention provides a method for preparing pentamethyldipropylene triamine. The method comprises the following steps: (1) performing a reaction on 3-dimethylaminopropylamine and acrylonitrile so asto form a 3-[[3-(dimethylamino)propyl]amino]propionitrile reaction solution, and performing separation so as to obtain a 3-[[3-((dimethylamino)propyl]amino]propionitrile pure product; (2) performinga hydrogenation reaction on 3-[[3-(dimethylamino)propyl]amino]propionitrile, hydrogen and a solvent under the action of a catalyst so as to obtain a N'-(3-aminopropyl)-N,N-dimethyl-1,3-propylene diamine reaction solution; and (3) performing a methylation reaction on the N'-(3-aminopropyl)-N,N-dimethyl-1,3-propylene diamine reaction solution obtained in the step (2), formaldehyde and hydrogen underthe action of a catalyst so as to obtain pentamethyldipropylene triamine. The method has the advantages of cheap and easily available starting materials, good selectivity to the product and high product yield, and the method is economical and effective, and has industrialization prospects.

Description

technical field [0001] The present invention relates to a kind of preparation method of polyurethane catalyst, more specifically relate to a kind of preparation method of pentamethyldipropylene triamine. Background technique [0002] Pentamethyldipropylenetriamine is a balanced polyurethane foaming catalyst, which is widely used in soft foam and rigid foam fields, and has been used in polyurethane field for a long time. Its characteristics are: 1. Catalyze foaming and gel reaction; 2. Provide more open-cell foam; 3. Can produce softer foam in high water formula; 4. Can reduce foam in flexible foam molding foam Foam peeling; 5. In terms of hard foam, it can reduce the fragility of the foam and improve the adhesion. [0003] The production routes of pentamethyldipropylene triamine reported in literature are few at present, mainly contain two, the first route is Liang, Hong-Chang (Journal of the American Chemical Society, 124 (16), 4170-4171) 2002 The Eschweiler-Clarke reacti...

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Problems solved by technology

[0008] The advantage of this method is that the raw materials are relatively cheap, and the disadvantages are: 1. The product of the first step is dicyanide, so the hydrogenation difficulty of the second step is relatively large, and there are many by-products, which are mainly aminonitrile and diimine according to literature reports. , piperazines, under optimal conditions, the selectivity of N-(3-aminopropyl)-N-methylpropane-1,3-diamine is only 85%, and the yield of the final product is only 67%. %; 2. In addition, each step of this method is not separated, which will cause the separation difficulty of the product to increase; 3. The odor of the raw material methylamine is relatively large, which is likely to cause environmental problems; Complex, low degree of automation, high labor intensity, high probability of safety accidents

[0009] Therefore, it is necessary to find a new production method of pentamethyldipropylenetriamine to solve the problems of high raw material cost, low product yield and difficult separation of impurities in the traditional process

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