Method for producing alkoxylate through microchannel reactor

Abstract

The invention relates to a method for producing alkoxylate through a microchannel reactor, and discloses a method for continuously performing alkoxylation reaction in a microreactor. According to the invention, initiator potassium alcoholate in which low molecules (the low molecules herein are mainly water and methanol) are removed and epoxide enter a microreactor, a delay line and a mixer in a liquid-phase form to perform liquid-liquid reaction, the purpose of sufficient mass transfer and heat transfer is achieved, and the liquid-liquid reaction is realized by increasing the pressure of the reaction system and adding a counterbalance valve. Compared with the alkoxylation reaction in the prior art, the method can effectively solve the heat transfer problem of such reaction, realizes fast and uniform mixing and constant reaction temperature, avoids the temperature runaway phenomenon and reduces the side reaction; the process is continuous flow reaction, and the reaction time is shortened to a few minutes, thus obviously improving the reaction efficiency and production efficiency; and the microreactor hardly has scale-up effect and is high in safety performance, thus being suitable for industrial production.

Description

technical field [0001] The invention relates to a method for producing alkoxylates by using a microchannel reactor, and belongs to the technical field of alkoxylate preparations. Background technique [0002] Alkoxylated compounds are an important class of compounds such as alkoxylated compounds of alcohols, alkoxylated compounds of phenols or phenols modified, alkoxylated compounds of carboxylic acids, alkoxylated compounds of amines Compounds, etc., can be attributed to alkoxy compounds containing active hydrogen. Alkoxy compounds can usually be prepared by stepwise addition reactions between compounds containing active hydrogen and epoxy compounds in the presence of catalysts. The products are different The mixture of polymers, that is, there is a relative molecular mass distribution in the product, which is expressed by the distribution coefficient, that is, the weight average molecular weight / number average molecular weight. The closer the distribution coefficient is to...

AI Technical Summary

Problems solved by technology

However, due to the need for materials to circulate at high temperatures in the system, and high-viscosity products, etc., often lead to problems with the sealing of the high-temperature circulation pump, carbon black enters the product, which limits the use of this type of device.

In addition, the above two generations of alkoxylation process equipment occupy a large area; the reaction rate is low, the production cycle is long, and the production capacity is small. Taking ethylene oxide as an example, the consumption of ethylene oxide per cubic meter of reactor does not exceed 300kg / h; the liquid phase material in the reactor contains a large amount of supersaturated epoxides, and the existence of such epoxides can easily cause explosions and epoxide poisoning accidents; the upper part of the reactor is enriched with a large amount of unreacted epoxides Compounds, they may self-polymerize to form by-products and local hot spots; the friction between the stirring shaft and the sealing ring and gas-phase redox oxides may also generate static electricity and local overheating, which may easily cause explosions; epoxy compounds are fed from the bottom of the reactor Or distributor feeding, when the pressure in the kettle is higher than the pressure in the epoxy compound metering tank or storage tank, it is possible to cause the catalyst-induced material to flow back to the epoxy compound metering tank or storage tank, which may cause epoxy compound Pollution and polymerization explosion of metering tanks or storage tanks; the existence of coiled pipes reduces the effective volume of the kettle, and it is difficult to overhaul and replace; and there are deficiencies in the minimum feeding amount and production capacity, gas-liquid phase reaction, and intermittent production.

CN100497438C discloses that on the basis of the original batch reactor, multi-pot series connection and overflow method are adopted to realize the continuous production of polyether polyol. Although the quality consistency of the product increases before and after, it does not solve the problem of rapid heat transfer and batch reaction molecular weight distribution in the reaction process. broad and common problems

However, domestic representative microreactor manufacturers include DOWCORNING, Guizhou Microchemical Technology Co., Ltd., Dalian Weikai Chemical Co., Ltd., etc. Their microreactor structures are different, and the alkoxylation process is quite different; this method directly The active hydride and catalyst are passed into the microreactor to produce alkoxide and water at high temperature, water and epoxide are polymerized to form diol by-product, and the solid catalyst is easy to block the microchannel; at the same time, the reaction pressure of epoxide is 0.4-2MPa It is in a gaseous state, and the effect is far worse than that of liquid-liquid mixing; moreover, the purpose of achieving uniform mixing by connecting too many microreactor units in series is likely to increase the pressure difference, reduce the mixing effect, and increase investment; this method does not mention the background The pressure valve is used to stabilize the pressure of the reaction system. Without a back pressure valve, the system pressure is low, and the gaseous epoxy is easy to overflow from the outlet of the reactor, which is not conducive to the progress of the reaction.

Images