Method for continuously producing polycarbonate-polyether polyol in channelization mode through liquid phase method

Abstract

The invention discloses a method for continuously producing polycarbonate-polyether polyol in a channelization mode by a liquid phase method, wherein the method comprises the following steps: (1) pumping a raw material from an inlet of a channelization reactor, making an initiator, an epoxy compound and carbon dioxide contact in the channelization reactor in the presence of a catalyst, and carrying out polymerization reaction; and (2) enabling part or all of the polymerization reaction product material flow in the step (1) to flow through a cooling section group, separating out part of polycarbonate-polyether polyol, and continuing to carry out polymerization reaction on the rest of the polymerization reaction product material flow in the channelization reactor, or circulating back to thestep (1), wherein the catalyst is a zinc-cobalt double-metal cyanide complex catalyst obtained by reacting water-soluble metal salts of zinc and cobalt in a water-soluble solvent, when the catalyst issynthesized, the catalyst is modified by mixed acid, and the organic acid is selected from any one or more of succinic acid, glutaric acid, phthalic acid, iminodiacetic acid, pyromellitic acid and butane tetracarboxylic acid.

Description

technical field [0001] The invention relates to the field of synthesis of polycarbonate-polyether polyols, in particular to a method for continuous production of polycarbonate-polyether polyols through liquid-phase pipelines. Background technique [0002] Polycarbonate-polyether polyol is a kind of polyol with carbonate group in the molecule and hydroxyl group at the end of the molecular chain. carbon dioxide (CO 2 ) and epoxy compound regulation copolymerization method is CO 2 Adding an initiator during the copolymerization reaction with epoxide, and controlling the molecular weight of the product by controlling the chain transfer of the reaction. Carbon dioxide, one of the main greenhouse gases, has attracted attention as a carbon-resource that can replace traditional fossil fuels for the synthesis of many important chemicals due to its cheap, easy-to-obtain, non-toxic and non-flammable advantages. Studies have shown that 20wt% CO 2 CO 2 Compared with the preparation ...

AI Technical Summary

Problems solved by technology

[0005] The first is about catalyzer, when adopting zinc-cobalt DMC catalyzer to synthesize polycarbonate-polyether polyol, the problem of existence is, in industry, add catalyzer and the epoxy monomer mass ratio of adding will at least ≤ 1 / 1000 (namely When the catalyst dosage is less than or equal to 1000ppm, that is, 0.1wt%, the overall production cost and catalyst residual cost are relatively low and have economic value

Or there are very few that still maintain a weak activity, but the reaction time is greatly prolonged (more than 12 hours) to obtain a polymer. This is due to the fact that the reaction time is actually caused by a higher proportion of the initiator. The time of the activation process of the substance (extended by several hours)

It takes longer reaction time and more energy consumption, which increases the production cost

[0006] The second is about the initiator. In addition to the catalyst, when using zinc-cobalt DMC catalyst to synthesize polycarbonate-polyether polyol, under the condition of a higher proportion of initiator addition, the synthesized polycarbonate-polyether polyol structure The structural proportion of polycarbonate will be reduced (<50%), that is, the fixation rate of carbon dioxide will be reduced

Because the addition of a higher proportion of initiator will cause a large number of catalyst active sites to be quenched or occupied, the macroscopic manifestation is that the catalyst activity is reduced or even deactivated

The reduction of the carbon dioxide fixation rate indicates that the proportion of the low-cost carbon dioxide raw material in the polymer is reduced, which means that the proportion of the higher-cost epoxide is increased, which leads to an increase in the production cost of the polymer on the one hand, and on the other hand, is beneficial to energy saving and emission reduction. (Consumption of CO2) is also less effective

If the temperature is too high, the content of carbonate chains will be low, the molecular weight distribution will be broadened, and the proportion of by-product cyclic carbonate will increase, which will reduce the quality of the product

[0018] Although a small number of continuous flow processes have been developed, there are problems: there is inevitably an amplification effect, which brings many uncertainties for further industrial applications; The reaction time is used to increase the conversion rate, resulting in a decrease in production efficiency

The large and uncertain amplification effect will bring many disadvantages to the industrial application of the process. For example, when scaling up to industrialization, only multiple step-by-step amplification methods can be adopted, and in order to obtain results consistent with the laboratory scale, It is necessary to re-adjust and optimize the process conditions and parameters every time the amplification process is carried out, which will greatly consume manpower and material resources and project development time; Achieve good results on a laboratory scale; at the same time, the large and uncertain amplification effect will affect the stability and reliability of the process, resulting in unstable product quality and difficult to control; in addition, this will also bring potential safety risks to the production process

[0020] Another disadvantage of the semi-batch or batch process is that the process has to be stopped in order to remove the product, thus resulting in a loss of time

[0021] In summary, how to increase the content of carbonate units, reduce the proportion of by-product cyclic carbonate in the crude product, increase the molecular weight of the polycarbonate-polyether polyol of the polymerization product while reducing the relative molecular mass distribution coefficient, and solve the problem of large-scale production The magnification effect is an urgent problem for those skilled in the art, and there is no solution to solve the above three technical problems at the same time in the art

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