JP2006089581A - Method for producing polyether polyol - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a production method in which a time required for production of polyether polyol is short and the amount of monools produced as by-products when an alkylene oxide is polymerized is slight. <P>SOLUTION: In the method for producing the polyether polyol by carrying out addition polymerization of an active hydrogen-containing compound with an alkylene oxide by using potassium hydroxide as a catalyst, sodium content in the potassium hydroxide is ≤100 ppm and purity of potassium hydroxide is ≥90%. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a polyether polyol. Specifically, the present invention relates to a method for producing a polyether polyol by adding an alkylene oxide to an active hydrogen-containing compound using a specific catalyst.

  The polyether polyol is obtained by adding alkylene oxide to an active hydrogen-containing compound in the presence of an alkali metal hydroxide catalyst. In general, potassium hydroxide is used as the alkali metal hydroxide catalyst, and the reaction temperature is 60 to 100 ° C. while the reaction temperature is 60 to 100 ° C. while the alkylene oxide is continuously charged into the reactor charged with the active hydrogen-containing compound as a polymerization initiator. The reaction is carried out under a pressure of 0.4 to 0.5 MPa until a predetermined molecular weight is obtained to obtain a crude polyether polyol. Next, the potassium alcoholate in the crude polyether polyol is hydrolyzed, filtered with an adsorbent, or neutralized with an aqueous solution of an acid such as a mineral acid or an organic acid, dehydrated and dried, and the precipitated potassium salt is filtered, or The crude polyether polyol is produced through a post-treatment purification step by washing with water and drying.

In order to increase the productivity of the polyether polyol, methods for increasing the concentration of alkylene oxide during the reaction, the reaction temperature, and increasing the amount of the catalyst are known. However, according to these methods, for example, in the case of propylene oxide (PO), PO is ring-opened by alkali to produce propenyl alcohol, which is further converted to allyl alcohol by a rearrangement reaction, and PO is added to these. The production rate of by-product monool having an allyl group or a propenyl group at the terminal increases, and the production amount also increases. Since this by-product monool has a lower molecular weight and a wider molecular weight distribution than the main polyether polyol, the molecular weight distribution of the entire polyether polyol is greatly broadened, and the functional group amount (OH group amount) is prevented from being lowered. Therefore, a polyurethane resin using a polyether polyol having a large amount of by-product monool is accompanied by undesirable effects such as an increase in hysteresis, a decrease in hardness, and an increase in permanent compression strain, regardless of foam or elastomer.
As a polymerization catalyst capable of suppressing the production of by-product monool and speeding up the production of polyether polyol, double metal cyanide complex (for example, Patent Document 1), cesium hydroxide (for example, Patent Document 2) ) Has been proposed.
Japanese Patent Laid-Open No. 3-14812 JP-A-8-134202

However, when double metal cyanide complex is used, when addition polymerization of ethylene oxide is performed after PO addition, once double metal cyanide complex is removed, polymerization is performed again using alkali metal hydroxide or its alkoxide. There are problems such as necessity.
When a cesium hydroxide catalyst is used, addition polymerization of propylene oxide is effective only in the reaction temperature range of 60 to 98 ° C., and is not efficient from the viewpoint of productivity. Cesium has a large molecular weight, so its effect per weight is small, and removal after the reaction becomes difficult. It is very expensive and has a problem from the viewpoint of cost performance.
There has been a demand for a production method in which the time required for producing the polyether polyol is short and the amount of by-product monol during the alkylene oxide polymerization is small.

As a result of intensive studies to solve the above problems, the present inventors have found that a secondary potassium having an allyl group or propenyl group at the end even when PO is added by raising the reaction temperature by using a specific potassium hydroxide catalyst. It has been found that the amount of raw monool does not increase.
That is, the present invention provides a method for producing a polyether polyol by addition polymerization of an alkylene oxide to an active hydrogen-containing compound using potassium hydroxide as a catalyst, wherein the sodium content in the potassium hydroxide is 100 ppm or less, and A method for producing a polyether polyol, wherein the purity is 90% or more.

The method for producing the polyether polyol of the present invention has the following effects.
(1) It is excellent in productivity without requiring an extra process or an unnecessarily long reaction time.
(2) The amount of by-product monool is small, and even when PO is added, the amount of by-product monool having an allyl group or propenyl group at the end is small, and the reaction product using the polyether polyol has reduced physical properties. Few.

  As the active hydrogen-containing compound in the present invention, a hydroxyl group-containing compound, an amino group-containing compound, a carboxyl group-containing compound, a thiol group-containing compound, a phosphoric acid compound; a compound having two or more active hydrogen-containing functional groups in the molecule; A mixture of two or more of these may be mentioned.

Examples of the hydroxyl group-containing compound include monovalent alcohols, divalent to octavalent polyhydric alcohols, phenols, and polyhydric phenols.
Specifically, monohydric alcohols such as methanol, ethanol, butanol, octanol, lauryl alcohol, oleyl alcohol; ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,4-butanediol, 1,6-hexanediol , 3-methylpentanediol, diethylene glycol, neopentyl glycol, 1,4-bis (hydroxymethyl) cyclohexane, 1,4-bis (hydroxyethyl) benzene, 2,2-bis (4,4′-hydroxycyclohexyl) propane Dihydric alcohols such as glycerin and trimethylolpropane; pentaerythritol, diglycerin, α-methylglucoside, sorbitol, xylit, mannitol, dipentaerythritol, glucose, 4- to 8-hydric alcohols such as lactose and sucrose; phenols such as phenol and cresol; polyhydric phenols such as pyrogallol, catechol and hydroquinone; bisphenols such as bisphenol A, bisphenol F and bisphenol S; polybutadiene polyol; castor oil type Polyols: (co) polymers of hydroxyalkyl (meth) acrylates, polyfunctional (2-100) polyols such as polyvinyl alcohols, and the like.

  Examples of the amino group-containing compound include amines, polyamines, and amino alcohols. Specifically, ammonia, C1-C20 alkylamines (butylamine, etc.), monoamines such as aniline; aliphatic polyamines such as ethylenediamine, trimethylenediamine, hexamethylenediamine, diethylenetriamine; piperazine, N-aminoethyl Heterocyclic polyamines such as piperazine; alicyclic polyamines such as dicyclohexylmethanediamine and isophoronediamine; phenylenediamine, tolylenediamine, diethyltolylenediamine, xylylenediamine, diphenylmethanediamine, diphenyletherdiamine, polyphenylmethanepolyamine Aromatic alcohols such as monoethanolamine, diethanolamine, triethanolamine, triisopropanolamine, etc. (in this case alcohol Both amines and amines are active hydrogens); polyamide polyamines obtained by condensation of dicarboxylic acids with excess polyamines; polyether polyamines; hydrazines (hydrazine, monoalkylhydrazines, etc.), dihydrazides (succinic acid dihydrazide) Adipic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, etc.), guanidines (butyl guanidine, 1-cyanoguanidine, etc.); dicyandiamide, etc .; and mixtures of two or more thereof.

Examples of the carboxyl group-containing compound include aliphatic monocarboxylic acids such as acetic acid and propionic acid; aromatic monocarboxylic acids such as benzoic acid; aliphatic polycarboxylic acids such as succinic acid and adipic acid; phthalic acid, terephthalic acid, tri Aromatic polycarboxylic acids such as merit acid; polycarboxylic acid polymers (functional group number: 2 to 100) such as (co) polymer of acrylic acid, and the like.
Examples of the polythiol compound of the thiol group-containing compound include divalent to octavalent polyvalent thiols. Specific examples include ethylenedithiol, propylenedithiol, 1,3-butylenedithiol, 1,4-butanedithiol, 1,6-hexanedithiol, 3-methylpentanedithiol, and the like.
Examples of phosphoric acid compounds include phosphoric acid, phosphorous acid, and phosphonic acid.
Moreover, the compound which added the following alkylene oxide to the said active hydrogen containing compound by the conventionally well-known method (for example, 1-100 mol) can also be used as an active hydrogen containing compound.
Of these active hydrogen-containing compounds, alcohols are preferred, and 2 to 8 valent alcohols are more preferred.

Examples of the alkylene oxide in the present invention include adjacent alkylene oxides having 2 to 8 carbon atoms such as ethylene oxide, propylene oxide, butylene oxide, and styrene oxide, and one or more of them are used. Block addition polymerization or random addition polymerization may be used. Propylene oxide is preferred, and more preferably 70% by weight or more of propylene oxide. When propylene oxide is 70% by weight or more, the amount of by-product monool having an allyl group or propenyl group at the terminal is small even when addition polymerization is carried out by raising the reaction temperature in order to increase productivity, and polyether polyol is used. The reaction product has little decrease in physical properties.
The number of moles of alkylene oxide added is preferably 12 to 40 moles, more preferably 15 to 35 moles per active hydrogen. When the addition mole number is 12 to 40 moles, the above-mentioned effect is remarkable when the addition polymerization is carried out by raising the reaction temperature in order to increase the productivity.

The potassium hydroxide used in the production method of the present invention must have a sodium content of 100 ppm or less and a potassium hydroxide purity of 90% or more.
Commercially available commercial products of potassium hydroxide usually contain a trace amount of metal components such as lithium, sodium, potassium, cesium, rubidium, calcium, magnesium, barium, strontium, aluminum, and iron. Sodium in particular is abundant and is usually contained at a level of 1,000 ppm or more.
The sodium content in potassium hydroxide used in the method of the present invention is 100 ppm or less, preferably 80 ppm or less, more preferably 50 ppm or less. When the sodium content exceeds 100 ppm, the performance as an alkylene oxide polymerization catalyst is deteriorated, and particularly when the polymerization is carried out by raising the reaction temperature, the amount of by-product monool during propylene oxide polymerization is remarkably increased.

The purity of potassium hydroxide used in the method of the present invention is 90% or more, preferably 92% or more, more preferably 95% or more. When the purity is less than 90%, the performance as an alkylene oxide polymerization catalyst is lowered.
The purity of the alkali metal hydroxide can be measured in accordance with the purity measurement method of the following JIS-K8574 potassium hydroxide (reagent).
About 2 g of a sample is weighed to a 0.1 mg unit in an Erlenmeyer flask, dissolved in 50 ml of ion-exchanged water, and titrated with 1N hydrochloric acid using phenolphthalein as an indicator until it becomes colorless from red. The calculation formula is purity (%) = 0.05611 × titer (ml) × titrant titer × 100 / sample amount (g), and is calculated from the titer of hydrochloric acid. Further, the purity can be calculated by setting the coefficient 0.05611 to 0.04000 for sodium hydroxide and 0.14992 for cesium hydroxide.
Under normal handling methods, hydroxide is highly hygroscopic and absorbs carbon dioxide in the air to form potassium carbonate, which tends to lower its purity, so it has been stored for a long time in humid places and in the air. Not only does the activity decrease, but also the potassium hydroxide concentration per gram, that is, the alkali number, decreases, so the reaction rate is affected and the productivity decreases.

  The amount of potassium hydroxide used in the present invention is preferably in the range of 0.05 to 0.5 mol, more preferably 0.1 to 0.3 mol, relative to 1 mol of the active hydrogen-containing compound. When potassium hydroxide is 0.05 mol or more with respect to 1 mol of the active hydrogen-containing compound, the alkylene oxide polymerization rate does not decrease, and when it is 0.5 mol or less, the by-product monool content in the polyether polyol Less.

In addition, the catalyst performance is affected by any metal, but the sodium content is particularly important. The amount of lithium, cesium, rubidium, calcium, magnesium, barium, strontium, aluminum, and iron detected is less than 10 ppm, and the performance of the polymerization catalyst is not significantly affected. The amount of trace.
Analysis of these metals is performed by a conventionally known method such as ion chromatography, atomic absorption analysis, or IPC method.

Potassium hydroxide may be used in a dry state before use or may be used in the form of an aqueous solution.
The reaction temperature is preferably 105 to 130 ° C, more preferably 110 to 120 ° C. The reaction pressure is preferably 0.5 MPa or less, and more preferably 0.4 MPa or less. When the reaction temperature is 105 to 130 ° C. and the reaction pressure is 0.5 MPa or less, the productivity of the polyether polyol is improved.
Particularly in the production method of the present invention, the amount of potassium hydroxide used is 0.05 mol to 0.5 mol with respect to 1 mol of the active hydrogen-containing compound, the reaction temperature is 105 to 130 ° C., and the reaction pressure is 0.5 MPa. When 12 to 40 moles of alkylene oxide is added to one active hydrogen of an active hydrogen-containing compound under the following conditions, the productivity of polyether polyol is improved and the by-product monool content is represented by the general formula. Since it decreases so that (1) is satisfied, it is preferable.
By-product monool content (%) ≦ 0.011 × MW−7.656 (1)
[MW is alkylene oxide addition molecular weight per active hydrogen of active hydrogen-containing compound]
In particular, when the alkylene oxide is propylene oxide, the monool produced as a by-product tends to be a monool having an allyl group or a propenyl group at the terminal.

  After completion of the reaction, a known method, for example, a method in which water and a mineral acid such as hydrochloric acid or phosphoric acid or an organic acid such as acetic acid are added, dehydrated and dried, and the precipitated catalyst salt is removed by filtration. A polyether polyol is obtained by removing the catalyst by an adsorption removal method in contact with an adsorbent, a water washing removal method in which water or water and an organic solvent are used to extract the catalyst, or an ion exchange method using an ion exchange resin. .

  Examples of the present invention will be shown below to clarify aspects of the present invention. For the comparison of the reaction rates, the time required until the pressure became constant was used.

Moreover, the analysis of the polyether polyol was performed according to JIS K-1557.
The amount of monool produced as a by-product is obtained from the following formula from the degree of unsaturation derived from the terminal allyl group or propenyl group and the measured hydroxyl value.
Monool content (%) = 56100 × unsaturation × 100 / {1000 × (hydroxyl value + unsaturation × 56.1)}
The degree of unsaturation can be obtained from the mercuric acetate method or NMR in the above JIS K-1557, but was conducted by the mercuric acetate method.
As the potassium hydroxide of the present invention, Merck (A) and Toagosei (B) were used in the form of a 50% aqueous solution. Table 1 shows the metal content compositions of the potassium hydroxide catalysts (A) and (B) used and the metal content compositions of sodium hydroxide (C), potassium hydroxide (D) and cesium hydroxide (E) used in Comparative Examples. It was shown to. The sodium hydroxide used in the comparative example was a 50% aqueous solution manufactured by Wako Pure Chemical Industries, the potassium hydroxide was manufactured by Nippon Soda Co., Ltd., and the cesium hydroxide was manufactured by Kemetal Co.
The volatile content was measured with a gas chromatograph.

Example 1
Polymerization (1): 92 parts of glycerin and 3 parts of a 50% aqueous solution of the catalyst (A) were charged into an autoclave, and after substituting with nitrogen, vacuum dehydration was performed at 120 ° C. for 60 minutes to reduce the water content to 0.1 wt% or less. Next, at 120 to 130 ° C., 522 parts of propylene oxide (3 mol per hydroxyl group) was injected in about 3 hours, and the reaction was continued at the same temperature for 2 hours until the volatile content was 0.1% or less. Ether was obtained.
Polymerization (2): 72 parts of the crude polyether obtained in polymerization (1) was charged into an autoclave as an initiator, and 3.2 parts of a 50% aqueous solution of catalyst (A) was added. It was vacuum dehydrated for 60 minutes to make the water content 0.05 wt% or less. Next, at 110 to 120 ° C., 632 parts of propylene oxide (31 mol per hydroxyl group) was injected in about 4 hours, and the reaction was continued at the same temperature until the volatile content was 0.1% or less. Obtained. It took 2 hours for the pressure to drop and become constant. The measured hydroxyl value was 30.9 mgKOH / g, and the measured unsaturation value was 0.050 meq. / G. The amount of residual propylene oxide was a trace amount. The crude polyether polyol containing the catalyst was purified by adding water and an alkali adsorbent “KYOWARD 600” (manufactured by Kyowa Chemical Industry Co., Ltd.), adsorption treatment, filtration and drying. The charge ratio and the charge amount are as shown in Table 2.

Example 2
The operation was performed in the same manner as in Example 1 except that a 50% aqueous solution of the catalyst (B) was used instead of the 50% aqueous solution of the catalyst (A). The charging ratio and the charging amount are as shown in Table 2.

Comparative Examples 1-3
The same operation and conditions as in Example 1 were performed based on Tables 1 and 2.

    trace: Trace amount detected (10 ppm or less), ND: Not detected (1 ppm or less)

The production method of the present invention is suitable for improving the productivity of polyether polyol and obtaining a polyether polyol with a small amount of by-produced monool. The obtained polyether polyol can be used widely as a raw material for surfactants in addition to being used as a raw material for polyurethane resins such as soft and hard polyurethane foams, elastomers, paints, sealing materials, flooring materials, adhesives and the like.

Claims (3)

In a method for producing a polyether polyol by addition polymerization of an alkylene oxide to an active hydrogen-containing compound using potassium hydroxide as a catalyst, the sodium content in the potassium hydroxide is 100 ppm or less and the purity of the potassium hydroxide is 90% or more A process for producing a polyether polyol, characterized in that The method for producing a polyether polyol according to claim 1, wherein the alkylene oxide contains 70% by weight or more of propylene oxide. In the above addition polymerization, the amount of potassium hydroxide used is 0.05 mol to 0.5 mol with respect to 1 mol of the active hydrogen-containing compound, the reaction temperature is 105 to 130 ° C., and the reaction pressure is 0.5 MPa or less. The monool content by-produced when 12 to 40 moles of alkylene oxide is added to one active hydrogen of the active hydrogen-containing compound under the conditions satisfies the following general formula (1). The manufacturing method of the polyether polyol of Claim 1 or 2.
By-product monool content (%) ≦ 0.011 × MW-7.656 (1)
[MW is alkylene oxide addition molecular weight per active hydrogen of active hydrogen-containing compound]