阅读说明：本技术 一种甲基封端聚醚的合成方法 (Synthetic method of methyl-terminated polyether ) 是由 王雨 房连顺 董晓红 贾正仁 陆国玲 于 2020-08-14 设计创作，主要内容包括：一种甲基封端聚醚的合成方法,属于化学合成技术领域,将聚醚和醇盐化试剂混合进行醇盐化反应,将上述反应物与一氯甲烷混合进行Williamson反应,取得甲基封端聚醚粗品,再将甲基封端聚醚粗品与水混合,经中和、抽真空脱水、过滤,取得甲基封端聚醚,本发明具有较高的封端效率、产品色泽浅、后处理简单、无污染、产率高、产品质量稳定的特点。(A process for synthesizing methyl-terminated polyether includes such steps as mixing polyether with alcohol alkylating reagent, alcohol alkylating reaction, mixing the resultant with chloromethane, Williamson reaction to obtain coarse product of methyl-terminated polyether, mixing the coarse product of methyl-terminated polyether with water, neutralizing, vacuumizing, dewatering and filtering.)

1. A synthetic method of methyl terminated polyether is characterized by comprising the following steps:

1) mixing polyether and an alcohol salinization reagent, stirring for an alcohol salinization reaction for 1-2 hours under the conditions that the temperature is 40-60 ℃ and the vacuum degree is-0.085-0.1 MPa, and obtaining a reactant; the molecular weight of the polyether is 200-4200;

2) mixing the reactant with methane chloride, stirring at the temperature of 50-95 ℃ and the pressure of 0.3-0.4 MPa, and carrying out Williamson reaction for 4-6 hours to obtain a methyl-terminated polyether crude product;

3) mixing the methyl-terminated polyether crude product with water, neutralizing, vacuumizing, dehydrating and filtering to obtain the methyl-terminated polyether.

2. The method for synthesizing methyl terminated polyether according to claim 1, wherein the alcoholizing agent is sodium hydroxide, potassium hydroxide or 50-80% sodium hydroxide aqueous solution, 50-80% potassium hydroxide aqueous solution.

3. The method for synthesizing methyl-terminated polyether according to claim 1 or 2, wherein the feeding molar ratio of the polyether to the alcohol alkylating agent is 1: 1.2-2.5.

4. The method for synthesizing methyl-terminated polyether according to claim 1, wherein the feeding molar ratio of the polyether to the monochloromethane is 1: 1.3-1.6.

5. The method for synthesizing methyl terminated polyether according to claim 1, wherein a reaction kettle with a turbo crusher arranged inside and a horizontal tank arranged at the bottom is adopted during the alcoholization reaction.

6. The method for synthesizing methyl-terminated polyether according to claim 1, wherein a dynamic stirring mixing reaction kettle equipped with a multi-stage stirring kettle with high shear and multi-stage paddle stirring is used in the Williamson reaction.

Technical Field

The invention belongs to the technical field of chemical synthesis, and particularly relates to a preparation process of alkyl terminated polyether.

Background

The hydroxyl in the molecular chain of the alkyl-terminated polyether is substituted by alkyl, so compared with polyether containing hydroxyl, the oil solubility, the chemical stability to strong alkali, the degradation performance and the like of the alkyl-terminated polyether are greatly improved, and the alkyl-terminated polyether shows unique functions. Alkyl-terminated polyethers find application mainly in the following areas: the good heat resistance of the alkyl terminated polyether can be used in an oiling agent for high-speed spinning of chemical fibers, and can also be used as an additive in high-temperature-resistant lubricating oil or heat-conducting oil; the stability of the detergent to strong alkali is utilized, so that the detergent can be used in a strong alkali detergent formula; in addition, alkyl-terminated polyethers are excellent cell openers and silicone foam levelers in the polyurethane industry.

The synthesis technology of the prior alkyl-terminated polyether, such as the synthesis methods disclosed in patent documents CN101445434, CN101497560, CN1311265, etc., generally comprises the steps of reacting hydroxyl in a polyether molecular chain with an alkoxide reagent to generate alkoxide, and then reacting with the corresponding alkyl-terminated polyether. The alkoxide reagent generally includes two types: one type is potassium hydroxide, sodium hydroxide or a mixture of the two; the other type is one of potassium methoxide and sodium methoxide or a mixture of the two. The blocking agent is mainly two kinds of alkyl halide and alkyl sulfate. The post-treatment process of the end-capped polyether comprises neutralization, water washing and filtration. The process for synthesizing the alkyl terminated polyether has the following defects: (1) in the synthesis method disclosed in CN101497560, when sodium methoxide and potassium methoxide are used as alkoxide reagents, methanol is generated in the reaction process, and the polyether can fully react to generate corresponding alkoxide only by removing methanol under vacuum condition, if methanol is not sufficiently removed, the reaction activity of polyether will be affected, the capping rate will be affected, and meanwhile, the cost is inevitably increased and the process is complicated for the treatment of toxic gas methanol. (2) When one or a mixture of two of solid potassium hydroxide and sodium hydroxide is used as an alkoxide reagent in the synthesis method disclosed in CN101445434, sometimes the reaction rate is slow and the reaction is incomplete because the polyether has a large molecular weight and the solid-liquid ratio is difficult to mix in production, and especially secondary capping is needed for a large molecular weight because the capping rate is not high, which increases the cost. (3) The alkyl sulfate used in the synthesis method disclosed in CN1311265 belongs to a highly toxic substance, and although the cost of the alkyl sulfate used as an alkylating reagent is relatively low, the low utilization rate thereof causes that the alkyl sulfate ether must be greatly excessive to ensure that the product has high end-capping efficiency, and more importantly, the alkyl sulfate has serious environmental pollution, and obviously, the alkyl sulfate used as an end-capping reagent does not meet the requirements of modern green chemical industry.

In conclusion, the existing preparation method of alkyl-terminated polyether does not meet the process requirements of environmental protection.

Disclosure of Invention

The invention aims to provide a synthetic method of methyl terminated polyether, which has the advantages of higher terminating efficiency, light product color, simple post-treatment, no pollution, high yield and stable product quality.

The invention comprises the following steps:

1) mixing polyether and an alcohol salinization reagent, stirring for an alcohol salinization reaction for 1-2 hours under the conditions that the temperature is 40-60 ℃ and the vacuum degree is-0.085-0.1 MPa, and obtaining a reactant; the molecular weight of the polyether is 200-4200;

2) mixing the reactant with methane chloride, stirring at the temperature of 50-95 ℃ and the pressure of 0.3-0.4 MPa, and carrying out Williamson reaction for 4-6 hours to obtain a methyl-terminated polyether crude product;

3) mixing the methyl-terminated polyether crude product with water, neutralizing, vacuumizing, dehydrating and filtering to obtain the methyl-terminated polyether.

The methyl-terminated polyether prepared by the invention is prepared by reacting polyether with a molecular chain containing hydroxyl with monochloromethane, wherein the polyether with the molecular chain containing hydroxyl has the following general formula:

wherein: r is C₁～C₂₀The carbon chain group of (1): r₁Is H, methyl or ethyl: r₂Is methyl or ethyl; m + n is less than or equal to 60; the polyether chain segment is homopolymerized, randomly copolymerized or block copolymerized.

The methyl terminated polyether prepared has the following general formula:

。

the invention relates to a method for preparing methyl terminated polyether by taking alkali as an alcohol salinization reagent and methane chloride as a terminating agent.

The methyl terminated polyether prepared by the method has the characteristics of higher terminating efficiency, light product color, simple post-treatment, no pollution and high yield.

Furthermore, the alcoholization reagent of the present invention is sodium hydroxide, potassium hydroxide or sodium hydroxide aqueous solution with a concentration of 50% to 80%, potassium hydroxide aqueous solution with a concentration of 50% to 80%. According to the invention, sodium hydroxide, potassium hydroxide or high-concentration sodium hydroxide aqueous solution and high-concentration potassium hydroxide aqueous solution are reasonably selected as alkoxide reagents, polyether is better contacted with the alkoxide reagents with the assistance of a turbine crusher, the reaction is more sufficient, and no methanol is generated in the process of generating alkoxide through reaction, so that no pollution is caused to the environment.

The feeding molar ratio of the polyether to the alcohol salinization reagent is 1: 1.2-2.5. The method for increasing the feeding molar ratio of the alkoxide reagent can improve the collision probability of the alkoxide reagent and the hydroxyl of the polyether, promote the generation of alkoxide and be beneficial to the end capping reaction of the polyether. When the feeding amount of the alcohol salinization reagent is less than a certain molar ratio, the end capping reaction is not easy to be complete, the hydroxyl value of the capped polyether is still large, and the application of subsequent products can be influenced, such as acid and alkali resistance, high temperature resistance, more foams easily generated and the like. When the feeding molar ratio of the alcohol salinization reagent reaches a certain proportion, the feeding molar ratio of the alcohol salinization reagent is increased, the end capping effect is not obviously influenced, the polyether is easy to generate oxidation reaction due to excessive alkali addition, the product is dark in color, and the post-treatment difficulty is increased due to the fact that a large amount of salt is generated by the reaction.

When the charging amount of the monochloromethane is less than a certain molar ratio, the blocking reaction is not easy to be complete, the blocking rate is low, active hydroxyl groups still exist at the tail ends of polyether molecular chains, and the terminal hydroxyl groups can generate chemical reactions such as oxidation or dehydration at high temperature. When the mole ratio of the monochloromethane is up to a certain proportion, the mole ratio of the monochloromethane is increased, the end-capping effect is not obviously affected, and the excessive monochloromethane can increase the environmental pollution. Therefore, the feeding molar ratio of the polyether to the monochloromethane is 1: 1.3-1.6.

During the alcohol salinization reaction, a reaction kettle with a turbine crusher arranged inside and a horizontal tank arranged at the bottom is adopted. The turbine crusher is additionally arranged in the reaction kettle, and during reaction, a crushing rotor consisting of a cutter head is supported on bearing seats of left and right end covers to rotate at a high speed, so that alkali and polyether are subjected to multiple mechanism actions such as extrusion, tearing, collision, shearing and the like between the wall body of the inner cavity and the blades, and the crushing aim is achieved; simultaneously, the two ends of the rotor rotate at high speed, eddy reaction is formed between the inlet and the outlet through the cavity, the transmission power of the crushed particles is increased, the crushed particles are crushed and refined through spiral punching, the polyether and the alcohol salinization reagent are contacted more fully, the reaction rate is high, the reaction time is shortened, the reaction is more complete, the end capping rate is high, and the color and luster of the product are light. The turbine switch is additionally arranged at the bottom end in the reaction kettle, and is convenient to control. And because the input amount of two materials, namely sodium salt and methane chloride generated by the alcohol salinization reaction must be kept at a certain ratio, a horizontal tank is additionally arranged at the bottom of the reaction kettle to buffer the materials, and the liquid level speed of the horizontal tank is controlled by a pump.

In the Williamson reaction, a dynamic stirring mixing reaction kettle equipped with a multi-stage stirring kettle with high shear and multi-layer paddle stirring is adopted. A dynamic stirring and mixing kettle is selected as a Williamson reaction reactor, the reaction occurs in a dynamic multistage stirring kettle, sodium salt and methane chloride respectively enter a mixing stirrer with high shear and multilayer paddle stirring according to the proportion, the methane chloride enters from the lower side of the mixing stirrer, and the sodium salt is conveyed into the dynamic mixer from a front horizontal tank through a gear pump. The kettle is internally connected with a vertical and downward stirring shaft, the shaft is provided with an air-inflation stirring device consisting of an air suction impeller, a plurality of layers of rotating stators and a stator cover plate, and the air-inflation stirring device consists of a straight blade impeller and a stirring rod with a straight bladeThe multilayer stirring mechanism composed of axial flow impellers at the inclination angle can be used for carrying out high shear and multilayer slurry stirring in a kettle, the generated high shear force can reduce the particle size, no circulating dead angle exists in the stirring process, the working efficiency is high, the energy consumption is low, the materials are fully mixed, the reaction speed is high, the reaction is more complete, the end-capping rate is high and reaches more than 96 percent, the product color is light, the color number is less than 30^#。

Detailed Description

The capping efficiency is defined in the following examples:

。

the product yield is defined as:

。