Method of continuously preparing pentamethyldiethylenetriamine and catalyst system for method

Abstract

The invention discloses a method of continuously preparing pentamethyldiethylenetriamine and a catalyst system for the method. The method includes: subjecting diethylenetriamine, a solvent, hydrogen and formaldehyde to reaction in a two-stage fixed-bed reactor under certain reaction temperature, pressure and space velocity to obtain pentamethyldiethylenetriamine reacted liquid; the first stage ofreactor is filled with a supported copper-based catalyst, with reaction temperature controlled to 60-100 DEG C; the second stage of reactor is filled with a supported palladium-based catalyst, with reaction temperature controlled to 100-130 DEG C. The different catalysts and different reaction conditions are employed to carry out two-stage reaction; amide byproducts can be effectively decreased; the yield of pentamethyldiethylenetriamine is increased accordingly. The fixed-bed continuous process is employed herein; serial problems due to the catalysts crushed and entering a reacted liquid post-treatment system can be avoided; the method herein has the advantages of high automation level, low labor intensity, good process operational safety, low production cost and the like, and is suitablefor industrial large-scale production.

Description

technical field [0001] The present invention relates to a kind of preparation method of polyurethane catalyst, more specifically relate to a kind of method for continuously preparing pentamethyldiethylenetriamine and the catalyst system for this method. Background technique [0002] Pentamethyldiethylenetriamine is a colorless to pale yellow clear liquid, easily soluble in water. It is a highly active catalyst for polyurethane reaction. It mainly catalyzes foaming reaction and is also used to balance overall foaming and gelling reactions. It is widely used in various polyurethane rigid foams, including polyisocyanurate sheet rigid foams. Due to its strong foaming effect, it can improve the foam flow, thus improving the production process and improving the quality of the product. It is often shared with N,N-dimethylcyclohexylamine, etc. The production methods of pentamethyldiethylenetriamine include formaldehyde formic acid method and formaldehyde hydrogenation method. ...

AI Technical Summary

Problems solved by technology

The disadvantage of this invention is that the reaction time is particularly long, the yield of pentamethyldiethylenetriamine is on the low side, and the amount of catalyst is large in addition, relative to the quality of diethylenetriamine, it is 4%-8%, and the toxic nickel Catalyst, can have an impact on the environment

[0012] (1) Intermediates trimethyldiethylenetriamine and tetramethyldiethylenetriamine are easy to form formamides, which leads to low yield of pentamethyldiethylenetriamine on the one hand, and on the other hand, this recombination Partial tar can stick to reboiler coils, affecting heat transfer and causing some engineering problems

[0013] (2) The process for preparing pentamethyldiethylenetriamine adopts a batch process, the operation process is complicated, the degree of automation is low, the reaction time is long, and in the post-treatment process of the reaction solution, due to the entrainment of the catalyst, the product is prone to decomposition, which will cause the product losses and some security issues

[0014] (3) The raw materials of the reaction have high requirements on the material or the components of the catalyst are harmful to the environment

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