Method for catalytic synthesis of piperazine and triethylenediamine from ethylenediamine under solvent-free condition

Abstract

The invention provides a method for catalytic synthesis of piperazine and triethylenediamine from ethylenediamine under a solvent-free condition. The method includes feeding pure ethylenediamine independently into a reactor, and performing catalytic conversion under a certain condition on a mesoporous/microporous composite multistage pore molecular sieve catalyst without any solvent to obtain a product needed. The piperazine and triethylenediamine are prepared by the method with high yields, a separation process is simple, energy consumption is lower, the production cost is reduced, and a difficult separation problem of azeotropes and compounds with close boiling points and a solvent recovery and purification problem are solved fundamentally. In addition, a part of or all product piperazine and a byproduct N-ethylpiperazine are recycled to increase the yield of triethylenediamine, flexible control of the yields of the piperazine and triethylenediamine is achieved while the yield of byproducts is reduced, and economic performance and competitiveness of the process are further enhanced.

Description

technical field [0001] The invention belongs to the field of chemistry and chemical engineering, and particularly relates to a method for synthesizing piperazine and triethylenediamine by gas-solid phase catalysis of ethylenediamine under a solvent-free condition. Background technique [0002] Piperazine (Piperazine, abbreviated as PIP) is an important chemical intermediate, which has extremely strong utilization value in the chemical and pharmaceutical fields, and is also widely used as a chemical raw material for surfactants, synthetic resins, and synthetic fibers. In recent years, as the most widely used polyurethane catalyst, the demand for triethylenediamine (Triethylenediamine, abbreviated as TEDA) is increasing; in addition, triethylenediamine can also be used as a catalyst for ethylene polymerization and ethylene oxide polymerization, Its derivatives can be used as corrosion inhibitors and emulsifiers. With the increasingly wide range of applications, the prices of ...

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Problems solved by technology

[0005] The use of a large number of solvents or diluents will inevitably increase the solvent recovery load, bring a lot of power, heat and other cycle consumption, and increase production costs

What's more serious is that organic amines such as ethylenediamine, PIP, and TEDA can form azeotropes with various solvents, and only the azeotropic composition of the corresponding components can be obtained under conventional atmospheric distillation. Expensive special distillation methods such as azeotropic distillation, extractive distillation or pressurized distillation, etc., for dehydration and separation of azeotropes and near-boilers, the process operation is complicated, and the equipment investment is also large

Taking ethylenediamine as an example, in azeotropic distillation, hydrocarbons such as benzene, toluene, xylene, cyclohexane, and esters such as ethyl acetate, which are commonly used as entrainers, form binary azeotropes with ethylenediamine, and form binary azeotropes with water. -Ethylenediamine forms a ternary azeotrope, and azeotropic distillation separation is very difficult; for example, US3454645 and CN101723837A disclose the extraction and rectification process of the ethylenediamine-water system of strong basic extractant and ether extractant respectively, but because For the corrosion of equipment, and the introduction and accumulation of impurities in the extractant, the process operation is extremely complicated, and the equipment investment increases

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