Method for continuous preparation of pentamethyldiethylenetriamine and catalyst system for the method

Abstract

The invention discloses a method for continuously preparing pentamethyldiethylenetriamine and a catalyst system used in the method. The method comprises: mixing diethylenetriamine, a solvent, hydrogen, and formaldehyde at a certain reaction temperature, pressure, Pass through two-stage fixed-bed reactors under space velocity conditions to obtain pentamethyldiethylenetriamine reaction liquid. The first-stage reactor is filled with supported copper-based catalyst, and the reaction temperature is controlled at 60-100°C; the second-stage reactor is filled with supported palladium-based catalyst, and the reaction temperature is controlled at 100-130°C. By adopting two-stage reactions with different catalysts and different reaction conditions, the generation of by-products of amides can be effectively reduced, thereby increasing the yield of pentamethyldiethylenetriamine. In addition, the present invention adopts a fixed bed continuous process, which can avoid a series of problems caused by catalyst crushing into the reaction liquid post-treatment system. This process has the advantages of high degree of automation, low labor intensity, safe process operation, and low production cost. It is suitable for Industrialized mass 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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