Method for producing propylene glycol mono-methyl ether with energy conservation

Abstract

The invention relates to a method for producing propylene glycol mono-methyl ether with energy conservation, which comprises the following steps: mixing propylene epoxide, methanol and a catalyst (sodium methoxide or potassium methoxide) in a preset ratio in a static mixer; preheating to a set temperature with vapor generated by absorbing reaction heat in a preheater; heating with foreign vapor with the temperature higher than 160DEG C in a heater for pre-reaction; continuously reacting materials in a tube pass of a pressureproof tube type heat exchanger; vaporizing hot water in a shell pass with surplus heat released in the reaction; and performing the subsequent routine refining process of separation and purification on materials on the outlet of the tube pass of the tube type heat exchanger to produce the propylene glycol mono-methyl ether. The method can timely remove heat released in etherification, the heat is converted to a heat source for preheating the raw materials, and the method can produce the propylene glycol mono-methyl ether with energy conservation. The heat exchange makes the temperature rise in the reaction controlled in a narrow range, so the selectivity of generated 1-methoxy-2-propanol can be improved and the quality of the product is improved.

Description

(1) Technical field [0001] The invention relates to a method for producing propylene glycol methyl ether, in particular to a method for making full use of reaction heat to save energy, control the degree of reaction, and improve the selectivity of target products. It belongs to the technical field of organic chemical product manufacturing. (2) Background technology [0002] The molecular structure of propylene glycol methyl ether has both lipophilic covalent ether bonds and hydrophilic alcoholic hydroxyl groups, so it has good solubility to oily and water-based resins. Its hydroxyl group is also reactive, and it can also undergo esterification reaction with lower fatty acids to further produce esters with good solubility. Its melting point is very low at -97°C, and it is liquid at room temperature or even at low temperature, making it easy to transport and use. It has a moderate boiling point and a boiling range of (117-125) °C, and can be produced by heating with steam. M...

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Problems solved by technology

[0027] The purpose of the present invention is to overcome the problem of improving the selectivity of 1-methoxy-2-propanol by suppressing the temperature rise in the reaction stage without considering the recovery of reaction heat in the existing propylene glycol methyl ether production technology, and to provide a Or potassium alkoxide is used as a catalyst, and the etherification reaction of propylene oxide and methanol is carried out in a pressure-resistant shell and tube reactor, so that hot water is converted into steam, and the heat released by the etherification reaction is removed in time, and converted into a reversible raw material A heat source for preheating, so that the temperature rise of the reaction is controlled within a narrow range, so as to improve the energy-saving production of propylene glycol methyl ether with primary ether selectivity.

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