A kind of method for preparing pentamethyldipropylene triamine

Abstract

The invention provides a method for preparing pentamethyldipropylene triamine. The method comprises the following steps: (1) 3-dimethylaminopropylamine and acrylonitrile are reacted to generate 3-[[3-(dimethylamino)propyl]amino]propionitrile reaction solution, and 3-[[3 -(dimethylamino)propyl]amino]propionitrile pure product; (2) adding 3-[[3-(dimethylamino)propyl]amino]propionitrile to hydrogen and solvent under the action of a catalyst; Hydrogen reaction obtains N'-(3-aminopropyl)-N,N-dimethyl-1,3-propanediamine reaction solution; (3) N'-(3-aminopropyl) obtained in step (2) base)-N,N-dimethyl-1,3-propylenediamine reaction solution and formaldehyde and hydrogen undergo methylation reaction under the action of a catalyst to obtain pentamethyldipropylenetriamine. The method has the advantages of cheap and easy-to-obtain starting materials, good product selectivity, high product yield, economical and effective method, and industrialization prospect.

Description

technical field [0001] The invention relates to a preparation method of a polyurethane catalyst, and more particularly to a preparation method of pentamethyldipropylene triamine. Background technique [0002] Pentamethyldipropylene triamine is a balanced polyurethane foaming catalyst, which is widely used in the field of flexible and rigid foam, and has been used in the field of polyurethane for a long time. Its characteristics are: 1. catalyzes foaming and gelation reactions; 2. provides more open-cell foam; 3. produces softer foam in high-water formulations; 4. reduces Foam peeling; 5. In terms of hard foam, it can reduce the fragility of the foam and improve the adhesion. [0003] There are few production routes of pentamethyldipropylene triamine reported in the literature at present, there are mainly two routes, the first route is Liang, Hong-Chang (Journal of the American Chemical Society, 124(16), 4170-4171) 2002 The Eschweiler-Clarke reaction that reported in 2010 g...

AI Technical Summary

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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