Method for preparing low hydroxyl value alkyl capped polyether

Abstract

A preparation method of terminated alkyl polyether with low hydroxyl value belongs to the preparation technical field of terminated alkyl polyether, which is characterized in that the invention uses alkyl polyether with low hydroxyl value as raw material to process alcohol salinization reaction with alcohol salinization agent, after the reaction, adding alkyl sulfate blocking agent to continue the reaction to obtain terminated alkyl polyether with low hydroxyl value, wherein the alcohol salinization agent is solid alkali and alkali water solution, the mol ration of alkyl polyether with low hydroxyl value and alcohol salinization agent is 1:1-3, the mol ratio of alkyl polyether with low hydroxyl value and alkyl sulfate is 1:1-3. The invention confirms that alkali can be reacted with polyether completely in polyether with high viscosity and low hydroxyl value to generate alkoxide and avoid completely dissolving solid alkali, while solid alkali can be released slowly when adds alkyl sulfate to avoid over high alkalinity of the reaction system, thereby reducing side effect, confirming reaction selectivity, blocking efficiency and improving product quality.

Description

technical field [0001] The invention relates to a preparation method of a low hydroxyl value alkyl-terminated polyether, which belongs to the technical field of preparation of an alkyl-terminated polyether. Background technique [0002] Since all the hydroxyl groups in the molecular chain of the alkyl-terminated polyether are substituted by alkyl groups, compared with the polyether containing hydroxyl groups, its oil solubility, chemical stability to strong alkali, degradation performance, etc. are greatly improved, thus showing a unique function. Alkyl-terminated polyether is mainly used in the following aspects: Utilizing the good heat resistance of alkyl-terminated polyether, it can be used in the oil agent for high-speed spinning of chemical fibers; it can also be used as an additive for high-temperature-resistant lubricating oil or heat conduction oil; it can be used in strong alkaline detergent formulations due to its stability to strong alkali; in addition, in the po...

AI Technical Summary

Problems solved by technology

If it reacts with alkyl sulfate in the presence of solid potassium hydroxide or sodium hydroxide to form a capped polyether, it is difficult for solid potassium hydroxide or sodium hydroxide to react in polyether due to the high viscosity and less hydroxyl groups of the polyether. Dissolved and the reaction cannot proceed smoothly, even if the amount of alkali and alkyl sulfate is increased, the reaction of alkoxide and alkyl sulfate to prepare capped polyether cannot be fully carried out

[0005] If the reaction is carried out in an alkali solution, although the polyether can fully contact with the alkali, the hydrolysis side reaction of the alkyl sulfate in the aqueous alkali solution will occur due to the presence of a large amount of water in the reaction system, so this method is usually used Sufficient end-capping efficiency can only be ensured by increasing the amount of end-capping agent used in large quantities, but this will cause many negative effects. First, the increase in the amount of end-capping agent will lead to an increase in cost; secondly, it will increase the difficulty of wastewater treatment. The environment has a serious impact; again, it increases the difficulty of production control

[0006] Chinese patent CN100999576A proposes a method for preparing alkyl-terminated polyethers from polyethers whose molecular chain ends are secondary hydroxyl groups with low reactivity

And adopt the alcoholic solution of sodium methylate, the alcoholic solution of potassium methylate, solid sodium methylate, the mixture of any one or more than one of solid potassium methylate as alcoholate reagent, its basicity is bigger than potassium hydroxide and sodium hydroxide, The destructive effect on polyether is enhanced, and the color of the product will be deepened at the same time, and the cost of raw materials will increase, and the difficulty of environmental protection and post-processing will increase.

[0007] Therefore, these existing alkyl-terminated polyether preparation methods are usually not suitable for high-molecular-weight polyethers with lower hydroxyl value and higher viscosity.

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