Preparation method of ethylene glycol monoether

Abstract

The invention provides a preparation method of ethylene glycol monoether, which comprises the following step: by taking ethylene oxide and low-carbon fatty alcohol as raw materials and triethylamine as a catalyst, reacting in a rectifying tower to prepare the ethylene glycol monoether. The preparation method of ethylene glycol monobutyl ether disclosed by one embodiment of the invention has the advantages of being simple, easy to implement, green, environmentally friendly and capable of realizing large-scale production.

Description

technical field [0001] The invention relates to ethylene glycol monoether, in particular to a preparation method of ethylene glycol monoether. Background technique [0002] Ethylene glycol monoether is an important derivative of ethylene oxide. It is an environmentally friendly solvent with excellent performance and is widely used in industrial fields such as ink, paint, leather and brake fluid. Industrially, glycol ether products are mainly synthesized by ethoxylation reaction using ethylene oxide and low-carbon alcohol as raw materials under the action of a catalyst. Taking the reaction of alcohol (expressed in ROH) and ethylene oxide (EO) as an example, the ethoxylation reaction can be expressed as: [0003] ROH+EO→RO(EO) 1 h [0004] RO(EO) 1 H+EO→RO(EO) 2 h [0005] RO(EO) 2 H+EO→RO(EO) 3 h [0006] ······ [0007] ROH+nEO→RO(EO) n h [0008] The above ethoxylation reaction will generate a series of ethoxylated homologues with different addition numbers of e...

AI Technical Summary

Problems solved by technology

[0011] There are many advantages in the synthesis of ethylene glycol monoether by reactive distillation, but the selection of catalysts is relatively difficult and complicated

When selecting the most widely used alkali metal catalysts in industry, such as KOH, NaOH and sodium alkoxide, there are three technical bottlenecks: (1) if the raw material contains moisture, the active component of the catalyst, the alcohol oxyanion, is very easy to react with water. reaction, which will lead to a serious reduction in catalyst activity, and moisture will accumulate in the tower at the same time, requiring additional water removal facilities; (2) Since the inorganic base is not volatile, the catalyst is difficult to recover and reuse, which not only affects the economics of the device, but also It will cause environmental problems such as solid waste treatment; (3) the alkaline catalyst in the product needs to be neutralized, and the salt in the product will affect the quality of the product

[0012] When selecting the solid catalyst, that is, when adopting the heterogeneous reaction rectification process, although the limitation of the homogeneous reaction process may be overcome, there are still many problems: (1) the molding of the solid base catalyst and the placement in the tower are not necessary. Mature and effective method; (2) The deactivation problem of the catalyst will lead to the long-term stable operation of the device; (3) The vapor-liquid-solid three-phase mass transfer in the reactive distillation column is complicated, especially the surface heterogeneity of the solid catalyst The mass transfer mechanism and reaction mechanism will be difficult to determine due to internal diffusion problems

When a tubular reactor is used, the existence of non-condensable gas in the tube will lead to a severe decrease in the heat transfer rate, which will be a huge safety hazard

In addition, if too much ethylene is generated during the reaction process, the flow pattern of the fluid in the tube will be a gas-liquid two-phase flow, which will cause flow pattern disorder and cause serious back-mixing of the material in the tube

Therefore, although the use of triethylamine catalyst has its advantages, if the reactor is not properly selected, it is difficult to achieve the purpose of large-scale industrialized safe production

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