JP2006342344A - Method for producing polyether polyol - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a polyether polyol having a high degree of polymerization in good yield by the dehydration condensation of a polyol. <P>SOLUTION: The method for producing the polyether polyol by a dehydration condensation reaction of a polyol containing 50 mole% or more of 1,3-propandiol, wherein the reaction is carried out in the presence of a compound of a metal selected from the metals belonging to 4 or 13 Group and an acid catalyst. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a polyether polyol, and more particularly to a method for producing a polyether polyol by a dehydration condensation reaction of the polyol.

  Polyether polyol is a polymer having a wide range of uses including raw materials for soft segments such as elastic fibers and plastic elastomers. Typical examples of the polyether polyol include polyethylene glycol, poly (1,2-propanediol), polytetramethylene ether glycol, and the like. In particular, poly (1,2-propanediol) is widely used because it is liquid at room temperature, easy to handle and inexpensive. However, since poly (1,2-propanediol) has a primary hydroxyl group and a secondary hydroxyl group, the difference in physical properties of these hydroxyl groups becomes a problem depending on the application. On the other hand, polytrimethylene ether glycol, which is a dehydration condensate of 1,3-propanediol, has recently attracted attention because it has only primary hydroxyl groups and a low melting point.

  The polyether polyol can generally be produced by a dehydration condensation reaction of a corresponding polyol. However, ethylene glycol, 1,4-butanediol, 1,5-pentanediol, and the like generate 5-membered or 6-membered cyclic ethers, that is, 1,4-dioxane, tetrahydrofuran, and tetrahydropyran, respectively, upon dehydration condensation. . Therefore, a polyether polyol corresponding to a polymer of ethylene glycol and 1,4-butanediol is produced by ring-opening polymerization of a corresponding cyclic ether, that is, ethylene oxide and tetrahydrofuran. A polyether polyol corresponding to a polymer of 1,5-pentanediol is difficult to obtain because tetrahydropyran, which is a cyclic ether, is thermodynamically advantageous.

  An acid catalyst is generally used for the production of a polyether polyol by a dehydration condensation reaction of a polyol. Catalysts include iodine; inorganic acids such as hydrogen iodide and sulfuric acid; organic acids such as para-toluene sulfonic acid; resins having perfluoroalkyl sulfonic acid groups in the side chain, sulfuric acid, activated clay, zeolite, organic sulfonic acid, heteropoly Combinations of acids and the like with cuprous chloride have been proposed. As a reaction method, there has also been proposed a method in which a dehydration condensation reaction is first performed in a nitrogen atmosphere and then a dehydration condensation reaction is performed under reduced pressure (see Patent Document 1). On the other hand, as a method for improving the polymerization rate and coloring, a method in which a reaction is carried out in the presence of a catalyst comprising an acid and a base has been proposed (see Patent Document 2).

US Patent Application Publication No. 2002/0007043 International Publication No. 2004/048440 Pamphlet

  According to the study by the present inventors, in the case of the above-described conventional method, it is necessary to perform a reaction at a high temperature or a long time in order to produce a polyether polyol having a high degree of polymerization, and the resulting polyether polyol is colored. There is a problem of doing. In addition, when a method of reacting in the presence of a catalyst comprising an acid and a base is used, the polymerization rate is improved and the chromaticity is improved, but there is a problem that the polymerization rate is industrially insufficient. Therefore, the present invention is intended to provide a method for producing a polyether polyol having a high degree of polymerization in a short time by dehydrating condensation of the polyether polyol under mild conditions.

  According to the present invention, when a polyether polyol is produced by a dehydration condensation reaction of a polyol, the reaction is carried out in the coexistence of an acid catalyst and at least one metal compound selected from the group consisting of Group 4 and Group 13. The inventors have found a method for efficiently producing a polyether polyol having a high degree of polymerization, and have completed the present invention.

  That is, the gist of the present invention is that at least one metal selected from the group consisting of Group 4 and Group 13 when producing a polyether polyol by a dehydration condensation reaction of a polyol containing 50 mol% or more of 1,3-propanediol. The present invention relates to a method for producing a polyether polyol, wherein the reaction is carried out in the presence of a compound of the above and an acid catalyst.

  According to the present invention, it is possible to provide a method for producing a polyether polyol having a high degree of polymerization in a short time by dehydrating condensation of a polyether polyol under mild conditions.

  Hereinafter, the present invention will be described in detail. However, the description of the constituent elements described below is a representative example of embodiments of the present invention, and the present invention is not limited to these contents.

<Catalyst>
In the present invention, when a polyether polyol is produced by a dehydration condensation polymerization reaction of a polyol, the groups 4 and 13 of the long periodic table (based on the group 18 system recommended by IUPAC in 1989, the same applies hereinafter). And at least one metal compound selected from the group consisting of an acid and an acid as a catalyst.

(1) Metal compound catalyst:
Examples of the Group 4 and Group 13 metals constituting the metal compound in the present invention include titanium, zirconium, hafnium, aluminum, gallium, indium, and thallium. Among these, titanium, zirconium, aluminum, and gallium are preferable in terms of accelerating the dehydration condensation reaction of polyol, and aluminum is particularly preferable in terms of availability and low cost.

  In using Group 4 and / or Group 13 metals, those in which a metal salt is formed of these metals and an acid are preferred. Specific examples of the metal compound selected from the group consisting of Group 4 and Group 13 include inorganic acid salts and organic acid salts, and specific examples include sulfates, hydrogen sulfates, halides, and phosphoric acids. Salts of mineral acids such as salts, hydrogen phosphates and borates, organic sulfonates such as trifluoromethanesulfonate, paratoluenesulfonate and methanesulfonate, carboxylates such as formate and acetate Etc. Further, in the reaction system, when a metal compound selected from Group 4 and / or Group 13 and an acid catalyst described below coexist, the acid forming these metal compounds and the acid of the acid catalyst are the same. Is preferred.

  In this case, an acid catalyst and a metal compound selected from the group consisting of Group 4 and Group 13 may be used. However, a metal carbonate, hydrogen carbonate, water selected from the group consisting of Group 4 and Group 13 may be used. A desired acid catalyst and a metal compound of a metal and an acid selected from the group consisting of Group 4 and Group 13 can also be prepared by reacting an oxide, a simple metal, or the like with an excess acid catalyst. For example, it is possible to react a group 4 and / or 13 metal carbonate with sulfuric acid in a polyol which is a reaction substrate to obtain a liquid containing sulfuric acid and a group 4 and / or 13 metal salt of sulfuric acid.

  These catalysts can be used alone or as a mixed catalyst of two or more. The amount of the metal compound selected from the group consisting of Group 4 and Group 13 used for the production is as follows. That is, the lower limit is usually 0.01 mol%, preferably 0.02 mol%, more preferably 0.05 mol%, in terms of metal atoms, relative to the polyol of the raw material. Moreover, an upper limit is 1.0 mol% normally, Preferably it is 0.9 mol%, More preferably, it is 0.7 mol%, Most preferably, it is 0.5 mol%. When the amount of the metal compound used is too large, the reaction rate does not increase, and separation of the metal catalyst tends to be difficult in the post-treatment process. When the amount is too small, the reaction rate does not increase.

(2) Acid catalyst:
As the acid catalyst used in the present invention, any of those conventionally known to produce an ether bond by a dehydration condensation reaction of an alcoholic hydroxyl group can be used. The acid may be either one that dissolves in the reaction system and acts as a homogeneous catalyst, or one that acts as a heterogeneous catalyst without being dissolved. Examples of such acids include heteropolyacids such as sulfuric acid, phosphoric acid, fluorosulfuric acid, and phosphotungstic acid, methanesulfonic acid, trifluoromethanesulfonic acid, octanessulfonic acid, 1,1,2,2-tetrafluoro Alkyl sulfonic acids such as ethane sulfonic acid, which may be fluorinated, benzene sulfonic acids and benzene sulfonic acids which may have an alkyl side chain in the ring, for example, aryl sulfonic acids such as para-toluene sulfonic acid, etc. Examples of the latter include activated clay, zeolite, metal composite oxides such as silica-alumina and silica-zirconia, and resins having perfluoroalkyl sulfonic acid groups in the side chain. Among these, sulfuric acid, phosphoric acid, benzenesulfonic acid, paratoluenesulfonic acid, and the like are preferable, and sulfuric acid is most preferable because it is easily available and inexpensive.

  The amount of the acid catalyst used is as follows. That is, the lower limit is usually 0.001 times by weight, preferably 0.002 times by weight, and the upper limit is usually 0.3 times by weight, preferably 0.2 times by weight with respect to the raw material polyol. If the acid acts as a homogeneous catalyst, the lower limit is usually 0.0005 times by weight, preferably 0.001 times by weight, and the upper limit is usually 0.2 times by weight, preferably 0.1 times by weight.

  The amount of the acid catalyst used for the metal compound selected from the group consisting of Group 4 and Group 13 is as follows. That is, the lower limit is usually 0.01 equivalents, preferably 0.02 equivalents, more preferably 0.05 equivalents. The upper limit is usually 1.0 equivalent, preferably 0.9 equivalent, more preferably 0.7 equivalent, and particularly preferably 0.5 equivalent. When this ratio is too large, the reaction rate does not increase, and removal of the metal catalyst tends to be difficult in the post-treatment process, and when it is too small, the reaction rate does not increase.

  In addition, when using an acid that acts as a heterogeneous catalyst such as a resin having a perfluoroalkyl sulfonic acid group in the side chain in a continuous reaction, it is not taken out together with the reaction solution into the reaction apparatus. It is possible to adopt a method in which the material polyol is retained and the raw material polyol is continuously supplied thereto. In this case, usually, the following proportion of raw material polyol is supplied to the acid staying in the reactor in one hour. That is, the lower limit of the supply amount is usually 0.1 times by weight, preferably 1 time by weight, and the upper limit of the supply amount is usually 10,000 times by weight, preferably 1000 times by weight. In this case, the equivalent ratio of the metal compound selected from the group consisting of Group 4 or Group 13 to the acid in the reactor may decrease over time. A metal compound selected from the group consisting of Group 13 is supplied, and an equivalent ratio of the compound of at least one metal selected from the group consisting of Group 4 and Group 13 to the acid is maintained at a desired value.

<Raw material polyol>
The polyol used as a raw material for the polyether polyol is 1,3-propanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol, 1, It is preferable to use a diol having two primary hydroxyl groups such as 7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,4-cyclohexanedimethanol and the like. . However, even if it is a diol having two primary hydroxyl groups, ethylene glycol, 1,4-butanediol, 1,5-pentanediol and the like generate cyclic ether ethers by the dehydration condensation reaction as described above. The raw material for the method of the present invention is not preferable. Usually, these polyols are used alone, but can be used as a mixture of two or more polyols if desired.

  However, in the present invention, 1,3-propanediol needs to be 50 mol% or more based on the total polyol of the raw material. The content of 1,3-propanediol with respect to the total polyol of the raw material is preferably 60 mol% or more, more preferably 70 mol% or more. The upper limit is 100 mol%. When the content of 1,3-propanediol is too small, the time required for producing a high molecular weight product tends to be long.

  Moreover, the oligomer of the 2-9 mer obtained by the dehydration condensation reaction of the main diol can be used together with these diols. Furthermore, triol or higher polyols such as trimethylolethane, trimethylolpropane, pentaerythritol, or oligomers of these polyols can be used in combination. However, even in these cases, 1,3-propanediol accounts for 50 mol% or more. Usually, except for those that produce a 5- or 6-membered cyclic ether by a dehydration condensation reaction such as 1,4-butanediol and 1,5-pentanediol, the number of carbon atoms having 2 primary hydroxyl groups is 3 to 10 Or a mixture of this with another polyol and the proportion of the other polyol being less than 50 mol% is subjected to the reaction. Preferably, a diol selected from the group consisting of 1,3-propanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, or 1,3-propanediol And other polyols in which the ratio of the other polyols is less than 50 mol% is subjected to the reaction.

<Method for producing polyether polyol>
The production of the polyether polyol by the dehydration condensation reaction of the polyol according to the method of the present invention can be carried out either batchwise or continuously. In the case of a batch system, a raw material polyol and catalyst acid and a metal compound selected from the group consisting of Group 4 and Group 13 may be charged into a reactor and reacted with stirring. In the case of a continuous reaction, for example, a raw material polyol and a catalyst are continuously supplied from one end of a reaction apparatus or a flow type reaction apparatus in which a large number of stirring tanks are connected in series, and the inside of the apparatus is a piston flow or a mode close to this. The method can be used in which the reaction solution is continuously extracted from the other end.

  The temperature of the dehydration condensation reaction is as follows. That is, the lower limit is usually 120 ° C., preferably 140 ° C., more preferably 150 ° C., and the upper limit is usually 250 ° C., preferably 200 ° C., more preferably 190 ° C. If this temperature is too high, coloring tends to deteriorate, and if it is too low, the reaction rate tends not to increase.

  The reaction is preferably carried out in an inert gas atmosphere such as nitrogen or argon. The reaction pressure is arbitrary as long as the reaction system is maintained in a liquid phase, and is usually carried out under normal pressure. If desired, the reaction may be carried out under reduced pressure or an inert gas may be circulated through the reaction system in order to promote elimination of water produced by the reaction from the reaction system.

  The reaction time varies depending on the amount of catalyst used, the reaction temperature, and the desired yield and physical properties of the dehydration condensate to be produced, but is as follows. That is, the lower limit is usually 0.5 hours, preferably 1 hour, and the upper limit is usually 50 hours, preferably 20 hours. The reaction is usually carried out without solvent, but a solvent can be used if desired. The solvent may be appropriately selected from organic solvents used for usual organic synthesis reactions in consideration of vapor pressure under reaction conditions, stability, solubility of raw materials and products, and the like.

  Separation and recovery of the produced polyether polyol from the reaction system can be performed by a conventional method. When an acid that acts as a heterogeneous catalyst is used, first, the suspended acid is removed from the reaction solution by filtration or centrifugation. Next, the low-boiling oligomer or at least one metal compound selected from the group consisting of Group 4 and Group 13 is removed by distillation or water extraction to obtain the target polyether polyol. When an acid that acts as a homogeneous catalyst is used, first, water is added to the reaction solution, and then a polyether polyol layer and an acid, at least one metal compound and oligomer selected from the group consisting of groups 4 and 13, etc. The aqueous layer containing is separated.

  In addition, since a part of polyether polyol forms the acid and ester which were used as a catalyst, after adding water to a reaction liquid, it heats and hydrolyzes an ester and makes it separate. In this case, when an organic solvent having an affinity for both the polyether polyol and water is used together with water, hydrolysis can be promoted. Further, when the polyether polyol has a high viscosity and the operability of the layer separation is not good, it is also preferable to use an organic solvent that has an affinity for the polyether polyol and can be easily separated from the polyether polyol by distillation. . The polyether polyol phase obtained by the layer separation is distilled to distill off the remaining water and organic solvent to obtain the target polyether polyol. In addition, when an acid remains in the polyether polyol phase obtained by the layer separation, the remaining acid is removed by washing with water or an alkaline aqueous solution or treating with a solid base such as calcium hydroxide. Then use for distillation. The obtained polyether polyol is usually stored in an inert gas atmosphere such as nitrogen or argon.

<Physical properties of polyether polyol>
The number average molecular weight of the polyether polyol of the present invention can be adjusted by the type of catalyst used and the amount of catalyst. The lower limit of the number average molecular weight is usually 80, preferably 600, more preferably 1000, and the upper limit is usually 10,000, preferably 7000, more preferably 5000. The number average molecular weight indicates an average molecular weight per molecule. The Hazen color number of the polyether polyol is preferably closer to 0. The upper limit of the Hazen color number is usually 500, preferably 400, and more preferably 200.

<Use of polyether polyol>
The polytrimethylene ether glycol obtained by the method of the present invention can be used for applications such as elastic fibers, thermoplastic polyester elastomers, thermoplastic polyurethane elastomers, and coating materials.

  Hereinafter, the present invention will be described more specifically with reference to examples.

<Yield calculation method>
The yield calculation method is as follows.
Yield (%) = (Weight of polytrimethylene glycol after polymerization) 100 / {Weight of charged 1,3-propanediol− (Weight of charged 1,3-propanediol) 18/76}

<Molecular weight>
The molecular weight of the polyether polyol after the polymerization reaction was measured by a nuclear magnetic resonance method (NMR). The sample was dissolved in chloroform-d (manufactured by ALDRICH, TMS 0.03 v / v%, 99.8 + atom% D, lot: 09904PB), and analyzed with a ¹ H-NMR apparatus (AVANCE400 (400 MHz, manufactured by BRUKER)). Sulfuric acid esters were produced, and the molecular weights when all of them were hydrolyzed were determined by the following formula (ppm is based on TMS).

  Molecular weight = 58 (3.4 to 3.7 ppm methylene peak integrated value) / (3.8 ppm methylene peak integrated value + 4.3 to 4.4 ppm methylene peak integrated value) +18

<Hazen color number>
The degree of coloration of the polyether polyol is represented by the Hazen color number defined in the standard of the Hazen color number American Public Health Association (APHA). The Hazen color number was determined by colorimetry according to JIS K0071-1 using a standard solution prepared by diluting APHA color number standard solution (N0.500) manufactured by Kishida Chemical Co., Ltd. The color difference meter was a colorimetric color difference meter ZE-2000 manufactured by Nippon Denshoku Industries Co., Ltd., and the cell thickness was measured under the condition of 10 mm.

Example 1:
<Distillation purification of 1,3-propanediol>
In a 1 L eggplant flask equipped with a reflux condenser and a stirrer, in a nitrogen atmosphere, 500.0 g of 1,3-propanediol (Aldrich reagent, purity 98%, Batch # 04427AB), 500.0 g of demineralized water, 6.78 g concentrated sulfuric acid (95%) was charged. The flask was placed in an oil bath and heated to reflux for 8 hours. The flask was removed from the oil bath and allowed to cool to room temperature, and then an aqueous sodium hydroxide solution (dissolved 5.26 g of sodium hydroxide in 10 g of demineralized water) was gradually added while stirring. After filtering through a 4 m filter to remove insoluble matters, the filtrate was heated to 80 ° C. and water was distilled off under reduced pressure. The reaction liquid cooled to room temperature was transferred to a 1 L four-necked flask, and water remaining at about 100 ° C. was completely removed under reduced pressure. Subsequently, simple distillation was performed at about 100 ° C. under reduced pressure, 20 g of the first fraction was discarded, and 380 g of a distillate was recovered.

<Dehydration condensation reaction of 1,3-propanediol>
50 g of 1,3-propanediol purified by the above method was charged into a 100 mL four-necked flask equipped with a distillation tube, a nitrogen introduction tube, a mercury thermometer, and a stirrer while supplying nitrogen at 100 NmL / min. To this was added 0.207 g of aluminum sulfate (14-18 hydrate), and then 0.678 g of concentrated sulfuric acid (95%) was gradually added while stirring. The flask was immersed in an oil bath and heated, and the liquid temperature in the flask reached 170 ° C. in about 1 hour. The reaction was started when the liquid temperature in the flask reached 170 ° C., and then the reaction was continued for 8 hours while maintaining the liquid temperature at 170 to 172 ° C. The water produced by the reaction was distilled off accompanying nitrogen. The reaction solution was allowed to cool to room temperature, transferred to a 300 mL two-necked flask containing 50 g of demineralized water using 50 g of 1-butanol, and gently refluxed for 2 hours to hydrolyze the sulfate ester. After cooling to room temperature and cooling, the lower layer (water layer) separated into two layers was removed. After adding 50 ml of water to the upper layer (oil layer) and stirring, the operation of leaving still and removing the water layer was performed once to wash the oil layer with water. 1-Butanol and water were distilled off under reduced pressure by heating to 60 ° C. The obtained oil layer was vacuum-dried in an oil bath at 60 ° C. for 3 hours to obtain polytrimethylene ether glycol, which was used to measure the Hazen color number.

Comparative Example 1:
Polytrimethylene ether glycol was obtained in the same manner as in Example 1 except that aluminum sulfate was not added. The results are shown in Table 1.

Comparative Example 2:
Polytrimethylene ether glycol was obtained in exactly the same manner as in Example 1 except that 0.0348 g of sodium carbonate was used instead of aluminum sulfate. The results are shown in Table 1.

Example 2:
Polytrimethylene ether glycol was obtained in the same manner as in Example 1 except that the amount of concentrated sulfuric acid (95%) added was changed to 0.577 g. The results are shown in Table 1.

Example 3:
Polytrimethylene ether glycol was obtained in exactly the same manner as in Example 1 except that 0.247 g of gallium sulfate (18 hydrate) was used instead of aluminum sulfate. The results are shown in Table 1.

Example 4:
Polytrimethylene ether glycol was obtained in exactly the same manner as in Example 1 except that 0.217 g of titanium (IV) sulfate (4-6 hydrate) was used instead of aluminum sulfate. The results are shown in Table 1.

Example 5:
The amount of polysulfuric acid (95%) added was 0.664 g, and polytritriglycerin was exactly the same as in Example 1 except that 0.0234 g of zirconium (IV) sulfate (tetrahydrate) was used instead of aluminum sulfate. Methylene ether glycol was obtained. The results are shown in Table 1. As shown in Table 1, according to the method of the present invention, a polyether polyol having a high degree of polymerization can be obtained in a high yield.

Claims (3)

  Presence of at least one metal compound selected from the group consisting of Group 4 and Group 13 and an acid catalyst when producing a polyether polyol by a dehydration condensation reaction of a polyol containing 50 mol% or more of 1,3-propanediol A method for producing a polyether polyol, wherein the reaction is carried out below.   The method for producing a polyether polyol according to claim 1, wherein the abundance of the metal compound is 0.01 mol% or more in terms of metal atoms with respect to the polyol used as a raw material.   The method for producing a polyether polyol according to claim 1 or 2, wherein the reaction is performed at 120 ° C or higher and 250 ° C or lower.