JPH0770308A - Recovery method of polyoxyalkylene polyol polymerization catalyst - Google Patents

Abstract

(57) [Summary] [Object] To provide a method for recovering a cesium compound from a crude polyoxyalkylene polyol obtained by polymerizing an alkylene oxide in the presence of a cesium compound catalyst. [Structure] An aqueous solution containing a cesium salt obtained by neutralizing a crude polyoxyalkylene polyol containing a cesium compound catalyst is subjected to a metathesis reaction with an alkaline earth metal oxide, and the aqueous solution is filtered to obtain a cesium compound. to recover.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for recovering a polyoxyalkylene polyol polymerization catalyst, and particularly to a crude polyoxyalkylene polyol obtained by polymerizing alkylene oxide in the presence of a cesium compound catalyst.
The present invention relates to a method of recovering a cesium compound by neutralizing a solution by adding a mineral acid and then subjecting the obtained aqueous solution containing a cesium salt to a metathesis reaction with an alkaline earth metal oxide.

[0002]

Polyoxyalkylene polyols used as raw materials for polyurethanes are usually obtained by addition-polymerizing alkylene oxides with active hydrogen compounds in the presence of an alkaline catalyst. This addition polymerization rate improves when the concentration during the alkylene oxide addition reaction is high, when the reaction temperature is high, and when the amount of catalyst increases, but these methods simultaneously increase the amount of unsaturated bonds due to side reactions. Therefore, the quality is deteriorated.

In order to solve the above problems, a method using a cesium compound catalyst is known (USP 3,39).
3,243). However, the cesium compound is
It has the drawback of being very expensive and of poor economic efficiency when used industrially.

[0004]

An object of the present invention is to neutralize a crude polyoxyalkylene polyol obtained by polymerizing an alkylene oxide in the presence of a cesium compound catalyst with a mineral acid, and then to obtain a polyoxyalkylene from a cesium salt obtained. It is to provide a method for recovering an alkylene polyol polymerization catalyst.

[0005]

Means for Solving the Problems As a result of intensive studies for solving the above-mentioned objects, the present inventors have found that a crude polyoxyalkylene polyol is neutralized by adding water and a mineral acid, and It was found that the cesium compound should be recovered, and the present invention has been completed.

That is, according to the present invention, a crude polyoxyalkylene polyol obtained by polymerizing an alkylene oxide in the presence of a cesium compound catalyst is neutralized by adding water and a mineral acid, and the obtained cesium salt is converted into cesium. A method for recovering a polyoxyalkylene polyol polymerization catalyst, which comprises recovering a compound.

Examples of the polyoxyalkylene polyol include those having any molecular weight obtained by addition-polymerizing an alkylene oxide with a known active hydrogen compound in the presence of a cesium compound catalyst.

Known active hydrogen compounds include, for example, monohydric alcohols such as methanol, ethanol and butanol, dihydric alcohols such as propylene glycol and 1,4-butanediol, polyhydric alcohols such as glycerin, pentaerythritol, sorbitol and sugar. There are alcohols, alkanolamines such as ethylenediamine, and phenol compounds such as bisphenol A and novolac.

Examples of the cesium compound catalyst include cesium metal, cesium hydroxide and monohydrate thereof. After adding these catalysts to the active hydrogen compound or polyoxyalkylene polyol, it is desirable to heat dehydration and dealcoholation to carry out alkylene oxide addition polymerization.
In some cases, the heating dehydration and dealcoholization may be omitted and these catalysts may be used as they are.

The amount of the cesium compound catalyst used is
The range of 0.01 to 5% by weight is preferable with respect to the polyoxyalkylene polyol after the alkylene oxide addition polymerization.

Examples of the alkylene oxide include known ones such as propylene oxide, ethylene oxide, butylene oxide and styrene oxide, and these may be used in combination of two or more kinds.

The amount of alkylene oxide added is not particularly limited, but is usually in the range of 1 to 90 mol per 1 mol of the hydroxyl group in the active hydrogen compound. Further, these addition polymerizations can be carried out under known methods and conditions. For example, it is usually performed at 50 to 150 ° C.

The crude polyoxyalkylene polyol can be neutralized by adding water and a mineral acid under the condition of 50 to 120 ° C. Water is industrial water,
Ion-exchanged water, distilled water, etc. are used depending on the purpose, and the addition amount is preferably 0.05 wt% to 30 wt%. Examples of the neutralizing agent include mineral acids such as phosphoric acid, hydrochloric acid, sulfuric acid and sulfurous acid.

If necessary, after the neutralization treatment, an adsorption treatment may be carried out using an adsorbent. As the adsorbent, synthetic magnesium silicate is preferably used, and Tomix-AD600NS, Tomix-AD6
00B, Tomix AD-300 (manufactured by Tomita Pharmaceutical Co., Ltd.), Kyoward 400, Kyoward 600 (manufactured by Kyowa Chemical Industry Co., Ltd.), etc.

The method for recovering the polyoxyalkylene polyol polymerization catalyst of the present invention is as follows. To the crude polyoxyalkylene polyol obtained by polymerizing alkylene oxide in the presence of a cesium compound catalyst, water and a mineral acid are added to adjust the pH to 3.0 to 9.0. A cesium salt is obtained by dehydrating the added water. A cesium compound is recovered by subjecting an aqueous solution obtained by adding water to the salt to a metathesis reaction with an alkaline earth metal oxide and filtering the alkaline earth metal salt.

The concentration of the aqueous solution containing the cesium salt is not particularly limited, but is usually 0.01 wt% to 30 w.
Those having about t% are preferably used.

Barium oxide and calcium oxide are preferably used as the alkaline earth metal oxide.

The metathesis reaction is usually carried out at 20 to 90 ° C.

[0019]

EXAMPLES The present invention will be described below with reference to examples. Example 1 300 g of glycerin as an active hydrogen compound and 80 g of a 50% cesium hydroxide aqueous solution as a cesium compound catalyst were charged into a reactor purged with nitrogen. Then, the temperature inside the reactor was raised to 105 ° C., and the dehydration rate was set to 9 at a reduced pressure of 10 mmHg.
After continuing the dehydration until it exceeds 0%, 1360 g of propylene oxide (hereinafter abbreviated as PO) as an alkylene oxide under the conditions of an internal temperature of 105 ° C. and an internal pressure of 4 kg / cm ² G.
Was gradually charged and the reaction was completed in 150 minutes. After completion of the reaction, unreacted PO in the system was removed under reduced pressure to obtain a crude polyoxyalkylene polyol (hereinafter abbreviated as crude polyol) 1700.
g was obtained. Next, 5% by weight of water, cesium hydroxide and equimolar phosphoric acid were added to the crude polyol for neutralization. After neutralization,
The added water was removed to obtain a cesium salt. Water was added to the obtained cesium salt to prepare a 15% aqueous solution (hereinafter abbreviated as aqueous solution A), and the phosphate ion concentration was measured to be 54.5 mg / m 2.
It was l. Then, aqueous solution A and barium oxide 43.1
g was placed in a flask and stirred at 80 ° C. for 1 hour. At this time, as a result of filtering the aqueous solution, an aqueous cesium hydroxide solution containing a very small amount of cesium salt (phosphate ion concentration 1.34 mg / ml) was obtained.

[0020]

According to the method of the present invention, the polyoxyalkylene polyol polymerization catalyst can be efficiently recovered from the purified salt obtained from the crude polyoxyalkylene polyol, which contributes to the improvement of the economical efficiency.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Izugawa, Mitsui Toatsu Chemical Co., Ltd., 2-1, Tango-dori, Minami-ku, Nagoya-shi, Aichi

Claims (4)

[Claims] 1. A crude polyoxyalkylene polyol obtained by polymerizing an alkylene oxide in the presence of a cesium compound catalyst is neutralized by adding water and a mineral acid, and the cesium compound is recovered from the obtained cesium salt. A method for recovering a polyoxyalkylene polyol polymerization catalyst, which comprises: 2. The recovery method according to claim 1, wherein the cesium compound catalyst is metal cesium, or cesium hydroxide or its monohydrate. 3. The method according to claim 1, wherein the cesium compound is recovered by subjecting an aqueous solution containing a cesium salt to a metathesis reaction with an alkaline earth metal oxide. 4. The alkaline earth metal oxide is an oxide of barium or calcium.
Recovery method described.