Process for producing polyether polyol

Abstract

A process for producing at a high efficiency with high selectivity a polyether polyol reduced in coloration through the dehydrating condensation of a polyol. In producing a polyether polyol through the dehydrating condensation of a polyol, a solid acid catalyst satisfying at least one of the following (1) to (3) is used: (1) the acidity function H0 as measured by Hammett's indicator adsorption method is larger than -3; (2) in analysis by temperature programmed ammonia desorption (TPD), the amount of ammonia desorbed in the region of 100-350 DEG C is at least 60% of the amount of ammonia desorbed in the whole test region (25-700 DEG C region); and (3) in a thermogravimetric (TG) analysis, the amount of water desorbed in the region of 32-250 DEG C is 3 wt.% or larger based on the basis weight.

Description

technical field [0001] The present invention relates to a method for producing polyether polyols by dehydration condensation reaction of polyols. Specifically, it relates to a method for efficiently producing polyether polyol with little coloration by carrying out the reaction in the presence of a catalyst having specific acid properties. Background technique [0002] Polyether polyols are polymers that have a wide range of uses, for example, uses as raw materials for soft segments such as elastic fibers or plastic elastomers. As typical polyether polyols, polyethylene glycol, poly(1,2-propylene glycol), polytetramethylene ether glycol, and the like are known. Among these, poly(1,2-propylene glycol) is liquid at room temperature, is easy to handle, and is inexpensive, so it is widely used. However, since poly(1,2-propylene glycol) has primary and secondary hydroxyl groups, the difference in the physical properties of these hydroxyl groups is a problem depending on the appl...

AI Technical Summary

Problems solved by technology

[0006] Among these, inorganic acids such as iodine, hydroiodic acid, or sulfuric acid, organic acids such as p-toluenesulfonic acid, organic sulfonic acids, heteropolyacids, etc. are acid catalysts of a uniform system, but when using an acid catalyst of a uniform system, due to acid The catalyst shows strong acid properties, the reactor used for the polymerization reaction is corroded, and the metal component is eluted due to the corrosion of the reactor, and there is a problem of polyether polyol coloring of products containing the eluted metal component in the polyether polyol

In addition, in order to prevent corrosion, it is necessary to use glass or glass-lined reactors, or to use reactors made of high-grade materials such as Hastelloy corrosion-resistant high-nickel alloy (Hasterloy), which will increase the size of the equipment or the construction cost. is the big problem

In addition, when a homogeneous catalyst is used, the end of the polyether polyol of the product contains an ester of an acid derived from the catalyst, and hydrolysis of the ester is sometimes necessary, resulting in a large number of steps and the problem of wastewater treatment.

In addition, since polyether polyols contain uniform acid catalysts, these acid catalysts must be removed by neutralization, washing, etc., and the problem is that the purification process of polyether polyols must be carried out.

[0008] As solid acid catalysts that can be used in the dehydration condensation reaction of polyols, resins, activated clays, and zeolites having perfluoroalkylsulfonic acid groups in the side chains are listed in the above-mentioned references, but they are used for polyols. During the dehydration condensation reaction, there are the following problems: there are many side reaction products such as alkanol, the selectivity of polyether polyol is very low, and the coloring of polyether polyol itself is serious, which is not at a practical level.