JPS60212425A - Production of polyol - Google Patents

Abstract

PURPOSE:An alkylene oxide is allowed to react with aqueous sucrose in the presence of an alkali catalyst, dehydrated, then further alkylene oxide is allowed to react to give a polyol which can be suitably used as a starting material of polyurethane, because it is low in diol content. CONSTITUTION:Aqueous raw sugar is decolorized and about 60-70wt% of aqueous sucrose before crystallization process is used in the following reaction. The resultant solution is allowed to react with an alkylene oxide of 2-4 carbon atoms such as ethylene oxide in the presence of an alkali catalyst such as an alkali metal hydroxide or alkali metal carbonate, then the reaction product is dehydrated lower than 1wt% water content. Further, an alkylene oxide of the same or different kind is allowed to react, thus giving the objective polyol.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a polyol comprising a sucrose-alkylene oxide adduct, or a polyol mixture containing the polyol.

Polyols consisting of cibosugar-alkylene oxide adducts are well known as raw materials for polyurethanes such as polyurethane foams. Relatively small amounts of alkylene oxide adducts are used primarily as raw materials for rigid polyurethane foams, and relatively large amounts of fullylene oxide adducts are used primarily as raw materials for flexible or semi-rigid polyurethane foams. Sucrose is an octavalent initiator with eight hydroxyl groups per molecule. In the present invention, an initiator is a functional group to which an alkylene oxide can be added (hydroxyl group,
Amino group.

refers to a starting material that has an imino group (such as an imino group). Sucrose is a compound that has a high melting point and is easily decomposed, and is easily colored due to decomposition, especially in the presence of an alkali catalyst.

In order to add alkylene oxide to sucrose, it is necessary to dissolve sucrose in a solvent.

There are two types of solvents: solvents to which alkylene oxides can be added, such as water and polyvalent initiators, and inert solvents, such as hydrocarbon solvents. The former is usually used. In particular, sucrose-alkylene oxide adducts are rarely used alone as polyurethane raw materials, but are often used as a mixture with alkylene oxide adducts of functional polyvalent initiators. A widely used method is to add an alkylene oxide to a mixed initiator with a multivalent initiator. Water is a divalent initiator, and diols are produced by the reaction between water and alkylene oxide. Polyols consisting of sucrose-alkylene oxide adducts, particularly mixtures containing the polyols with alkylene oxide adducts of polyvalent initiators other than sucrose, are mainly divided into two types depending on their use. Those with a relatively low molecular weight, that is, those with a relatively high hydroxyl value, are suitable as raw materials for rigid polyurethane foam, and the hydroxyl value in this case is in the range of about 300 to 700. On the other hand, those having a relatively high molecular weight, that is, a relatively low hydroxyl value, are mainly used as raw materials for flexible or semi-rigid polyurethane foams, and the hydroxyl value in this case is in the range of about 20 to 150.

The sucrose used as a raw material for the production of sucrose-alkylene oxide adducts was powdered or granular refined sugar.

However, from an economic point of view, it is considered that cruder (that is, nearly unrefined) raw materials are more advantageous. Therefore, it is conceivable to use unrefined sucrose such as raw sugar, but since raw sugar is significantly colored, the color of the alkylene oxide adduct obtained from it is of little practical value unless the color of the alkylene oxide adduct is also significantly decolored. Therefore, the present inventor investigated the use of sugar water obtained by decolorizing an aqueous solution of original axes and which is in the pre-crystallization stage. Sugar water, also called molasses, is an aqueous solution of purified sucrose that has been purified from a raw aqueous solution through a purification process that includes a decolorization process using activated carbon, ion exchange resin, etc., and is in a stage before the crystallization process. The sugar water in the normal sugar refining method has a sucrose concentration of approximately 8
0 to 70% by weight, pure sugar rate approximately 85% or more, color value (RBtl
) of about 80 or less, but the sugar water in the present invention is not necessarily limited to these values.If SIV water is used as a raw material for the above polyol, it is economical because it does not undergo a crystallization process. A polyol with excellent properties can be obtained, and since it is purified sucrose, it is thought that there are fewer problems due to coloration and impurities.

The biggest problem in using the above sugar water is that a large amount of water coexists. As mentioned above, the method of adding alkylene oxide to sucrose using water as a solvent is conventionally known. A polyol mixture obtained by adding an alkali catalyst to sugar water and reacting it with alkylene oxide contains a large amount of diol. In other words, even if the sugar water has a high sucrose concentration, the amount of water is extremely large considering the molar ratio of sucrose to water. Therefore, a large amount of diol is produced by alkylene oxide addition, and the molecular weight of the diol is low. . Siliceous sugar-alkylene oxide adducts containing a large amount of such low molecular weight diols lose the polyfunctionality (that is, octavalent) characteristic of sucrose-alkylene oxide adducts, and are not used as raw materials for polyurethane foam. is inappropriate. Furthermore, there is no known method for effectively separating this low molecular weight diol from the sucrose-alkylene oxide adduct.

One of the conventionally known methods for solving the above problems
One is to dissolve sucrose in water, add an alkali catalyst, add a relatively small amount of fullkylene oxide, dehydrate, and then add alkylene oxide to achieve the desired sucrose-alkylene oxide addition. It is a method of manufacturing a product, and is described, for example, in Japanese Patent Publication No. 39-3590. Since this method uses powdered to granular sucrose dissolved in water, it is economically disadvantageous compared to the case where the above-mentioned sugar water is used. Moreover, according to the studies conducted by the present inventors, it has been found that the above-mentioned problems caused by water have not been satisfactorily solved. That is, in the above-mentioned known method, the water content in the reaction product after addition of alkylene oxide in the first stage is about 10% by weight.
Although dehydration is carried out until the amount of diol is reduced, it is difficult to sufficiently avoid the formation of the diol with this degree of dehydration. According to the study of the present inventors, more sufficient dehydration is necessary to prevent the formation of diols, and dehydration after the addition of alkylene oxide in the first step is sufficient to reduce the water content in the reaction product to about 1% by weight or less. In particular, it has been found that it is necessary to reduce the content to about 0.5% by weight or less.

The first aspect of the present invention is a method for producing a sucrose-fulkylene oxide adduct that produces less diol using this sugar water, that is, the presence of an alkaline catalyst in a sugar water with a sucrose concentration of about 50 to 70% by weight. A method characterized in that sucrose is reacted with less than about 1.0 equivalent of alkylene oxide, then dehydrated until the water content in the reaction mixture becomes about 1% by weight or less, and then further reacted with alkylene oxide. A method for producing a polyol comprising a sugar-fulkylene oxide adduct.

As mentioned above, sucrose-alkylene oxide adducts are often used as a mixture with a polyvalent initiator other than sucrose before the alkylene oxide reaction; this mixture is a combination of sucrose and a liquid polyvalent initiator. It is often produced by adding an alkylene oxide to a mixing initiator consisting of a mixture. This liquid multivalent initiator acts as a solvent for sucrose, and in this case, it is not substantially used as a solvent. One example of a multivalent initiator is glycerin. Although water is sometimes used as a solvent for the alkaline catalyst or as an auxiliary solvent in very small amounts, the amount never exceeds about 5% by weight of the reaction system before the alkylene oxide reaction. For example, sucrose is described in Japanese Patent Publications No. 40-10060 and Japanese Patent Publication No. 45-38839.

A method is described in which a mixture of glycerin, an alkaline catalyst, and a very small amount of water is reacted with an alkylene oxide. In addition, when producing a high-molecular-weight polyol, additional caustic alkali is added as a catalyst to a polyol mixture containing a relatively low-molecular-weight sucrose-alkylene oxide adduct. A method of further reacting with alkylene oxide after removing water is also known (for example, see Japanese Patent Publication No. 44194/1983). However, this water is in a very small amount and does not participate in the reaction with the alkylene oxide. As described above, in the conventional method of reacting alkylene oxide with sucrose using a liquid multivalent initiator as a solvent, water was not substantially used as a solvent. We also considered the use of sugar water. It is thought that a mixed initiator equivalent to the known method described above can be produced by mixing a liquid multivalent initiator such as glycerin with sugar water and then sufficiently dehydrating it. If the amount is high, there is a high risk that solid sucrose will precipitate due to dehydration. The presence of solid sucrose tends to cause bulk purchasing of sucrose and also tends to be a problem in reaction operation.As a result of various studies, the present inventors have developed a method for reacting alkylene oxide with a mixed initiator of sugar water and a polyvalent initiator. Even when letting
It has been found that a method in which the mixture is reacted with a certain amount of fullkylene oxide, dehydrated, and further reacted with alkylene oxide solves the above problems and is also excellent in economical efficiency. The second invention relates to this method, namely, adding less than about 1.0 equivalents to sucrose to a mixture of a sugar water with a sucrose concentration of about 50 to 70% by weight and a polyvalent initiator in the presence of an alkaline catalyst. A method for producing a polyol containing a sucrose-fulkylene oxide adduct, which comprises reacting an alkylene oxide, then dehydrating the reaction mixture until the water content is about 1% by weight or less, and then reacting the alkylene oxide. , is.

These two inventions will be explained below.

In the present invention, the term "sugar water" refers to an aqueous solution of sucrose that has been purified in the sugar refining industry through a purification process including a decolorization process and is in a stage before the crystallization process. The sugar concentration, pure sugar percentage, and color value are preferably within the above ranges, but are not necessarily limited to these values. A particularly preferred sucrose concentration is about 60
~70% by weight, and the color value is about 60 or less. As the alkali catalyst, alkali metal compounds such as alkali metal hydroxides and alkali metal carbonates which are commonly used in alkylene oxide addition reactions are suitable, and potassium or sodium hydroxides are particularly preferred. The amount of alkaline catalyst used is not particularly limited, but for sucrose,
or about 0.01 to 10% by weight based on the mixture of sucrose and polyvalent initiator, particularly about 0.1 to 5% by weight.
The alkaline catalyst, preferably in weight %, can also be used additionally during the reaction. For example, after the alkylene oxide is reacted in the first stage, an alkali catalyst can be added to perform dehydration. In addition, particularly when producing a high molecular weight polyol, an alkali catalyst may be added during the subsequent alkylene oxide reaction, and preferably the alkylene oxide reaction may be continued after dehydration. The purpose of adding this alkali catalyst is to prevent the catalyst concentration in the system from decreasing as the reaction of alkylene oxide with sucrose etc. progresses, thereby preventing the reaction rate from decreasing. Therefore, in the step of reacting alkylene oxide, it is desirable to adjust the alkali catalyst concentration to be within the above range based on the total of sucrose, polyvalent initiator, and their alkylene oxide adducts present in the reaction system. .

It is necessary that the reaction amount of alkylene oxide before dehydration is less than about 1.0 equivalent relative to sucrose. That is, less than about 8.0 moles of alkylene oxide are used per mole of sucrose. The lower limit is preferably about 0.3 equivalent when no multivalent initiator is present, and about 0.1 equivalent when a multivalent initiator is present. In either case, the preferred reaction amount of alkylene oxide is about 0.1-0, g
equivalent, particularly about 0.4 to 0.8 equivalent. In addition,
When sucrose and a polyvalent initiator coexist, the alkylene oxide in the present invention reacts equally with both. For example, in the case of an equimolar mixture of sucrose and a trivalent initiator, 8711 of the alkylene oxide reacts with the sucrose and 3711 reacts with the trivalent initiator in a molar ratio. Therefore, in the second invention, the reaction amount of alkylene oxide with respect to sucrose refers to the amount distributed in this ratio.

Polyhydric initiators include polyhydric alcohols, aflecanolamine, mono- or polyamines, polyhydric phenols, and alkyleneoxytoyed additions thereof. A functional group having a hydrogen atom reactive with fullkylene oxide, such as an amino group, an imino group, or a phenolic hydroxyl group, reacts with an alkylene oxide to produce an alcoholic hydroxyl group.

Therefore, after the functional groups of polyvalent icositators having these functional groups are converted into alcoholic hydroxyl groups, the sequential addition reaction of alkylene oxides proceeds in the presence of an alkali catalyst, similar to polyhydric alcohols. Therefore, the above polyhydric alcohols, alkanolamines, mono- or polyamines to which alkylene oxide has been added in advance,
Polyvalent phenols can also be used as polyvalent initiators. In some cases, the sucrose-alkylene oxide adduct itself can be used as a polyvalent initiator to produce even higher molecular weight sucrose-alkylene oxide adducts, and sucrose itself can be used as a polyvalent initiator. . A preferred multivalent initiator is a multivalent initiator that is liquid at room temperature. However, polyvalent initiators that are solid at room temperature can also be used as long as the resulting mixture of fullylene oxide adducts is liquid after the mixture of sugar water and polyvalent initiators is reacted with the alkylene oxide in the first stage. The polyvalent initiator may be a diol produced by the reaction of water and alkylene oxide, because when using a pre-produced diol, the alkylene oxide reacts with water during the reaction and the diol produced This is because the reaction between the diol and fullkylene oxide proceeds from the beginning of the reaction, producing an alkylene oxide adduct with the desired molecular weight. The functional number of the polyvalent initiator, ie, the number of reactive hydrogen atoms, is preferably 2 to 8, particularly preferably 3 or 4. Moreover, two or more types of multivalent initiators can also be used in combination.

Examples of the polyvalent initiator include the following compounds and their alkylene oxide 4=1 adducts.

Particularly preferred multivalent initiators are polyvalent initiators that are liquid at room temperature, and are polyols that are liquid at room temperature, such as polyhydric alcohols that are liquid at room temperature, alkanolamines that are liquid at room temperature, and polyols that are liquid at room temperature or other alkylene oxide adducts thereof. . Particularly preferred multivalent initiators are glycerin, monoethanolamine, jetanolamine, and triethanolamine.

Polyhydric alcohols: ethylene glycol, diethylene gelcol, propylene glycol, dipropylene glycol, glycerin, trimethylolpropane, pentaerythritol, diglycerin, dextrose, sorbitol.

Aliamines: mono-, di-, or triethanolamine, mono-, di-, or tripropylamine.

Mono- or polyamines: ethylene diamine, tolylene diamine, diaminodiphenylmethane.

Polyhydric phenols; bisphenol A, bisphenol S
, Novolac.

The mixing ratio of the sugar water and the polyvalent initiator as described above is not particularly limited, but the number of moles of the polyvalent initiator per 1 mole of sucrose in the sugar water is approximately 0.1.
~20 mol is appropriate, and about 0.5 to 10 mol is particularly preferred.The zero-reactive degree is usually 60 to 150 O.If the zero-reactant degree is too high, coloring may occur due to decomposition of sucrose. It becomes easier. In addition, the reaction between water and fullkylene oxide becomes more likely to occur. A more preferable reaction temperature in the first stage is about 70-120"0. In the second stage reaction, since there is no risk of reaction between water and alkylene oxide, a reaction temperature higher than this preferred reaction temperature can be adopted. However, , preferably within the range of about 80 to 150'0 in order to prevent coloring and the like.

After the first stage reaction is completed, a new multivalent initiator can be added if necessary. If this multivalent initiator does not contain water, it may be added before the subsequent reaction after dehydration.However, the multivalent initiator added at this stage is liquid at room temperature, but after dehydration It is preferable that it is soluble in the reaction mixture. Even if no new polyvalent initiator is added, the reaction mixture after dehydration is preferably a liquid containing no solids at least at the reaction temperature, i.e., even if unreacted sucrose remains. It is preferable that the compound is also dissolved in the reaction system. Therefore, it is preferable to adjust the reaction amount of monoalkylene oxide to sucrose in the first-stage reaction from this point of view as well.If a liquid polyvalent initiator is used in combination, unreacted sucrose is dehydrated after the first-stage reaction. It hardly remains in such a large amount that it precipitates as a solid, and there is almost no possibility that such a problem will occur even at the lower limit of the amount of fullylene oxide reacted in the first stage.

The sugar solution or the mixture of the sugar solution and the polyvalent initiator is reacted with less than about 1.0 equivalents of alkylene oxide relative to sucrose in the presence of an alkali catalyst, followed by dehydration. If the dehydration occurs after the alkylene oxide has been further reacted, that is, if the dehydration is carried out after the reaction of about 1.0 equivalent or more of fullylene oxide with respect to sucrose, a non-negligible amount of alkylene oxide may be present in the reaction mixture. amount of diol is produced. A polyol containing a large amount of such by-product diols is not preferable as a raw material for polyurethane, and causes problems such as deterioration of the physical properties of the resulting polyurethane. Dehydration must be carried out until the water content in the reaction mixture is about 1% by weight or less. More preferably, the amount is reduced to about 0.5% by weight or less, especially about 0.2% by weight or less. If there is a large amount of residual moisture, a large amount of diol similar to the above will be produced as a by-product in the subsequent reaction. Dehydration is usually carried out by vacuum spilling, but is not limited to this method.

After the dehydration is completed, the alkylene oxide reaction is carried out again.

The amount of alkylene oxide reacted in the latter stage can be arbitrarily changed depending on the molecular weight of the desired product. However, the final amount of alkylene oxide reacted with sucrose (i.e., the total amount of alkylene oxide in the first and second stages) must be at least about 1.0 equivalent or more relative to sucrose, regardless of the amount reacted in the first stage. is necessary. Also.

Even when a multivalent initiator is used in combination, the final amount of alkylene oxide reacted with the multivalent initiator is preferably about 1.0 equivalent or more. That is, it is preferable that the final reaction amount of alkylene oxide is about 1.0 equivalent or more based on the total amount of sucrose and polyvalent initiator.

Note that even if a relatively large amount of alkylene oxide is reacted in the first stage, the amount of alkylene oxide reacted in the second stage is preferably at least 0.2 equivalent or more, particularly at least 0.4 equivalent, relative to sucrose. The upper limit of the amount of fullkylene oxide reacted in the latter stage, which is preferably above, varies depending on the molecular weight of the target polyol. The required molecular weight of the polyol used as a raw material for polyurethane varies depending on the number of hydroxyl groups in the polyol, and the degree of molecular size is usually expressed by the hydroxyl value. The hydroxyl value of a polyol is proportional to the reciprocal of the molecular weight when the number of hydroxyl groups is the same. In the case of a mixture of two or more types of polyols, the average hydroxyl value is adopted. 0 A polyol consisting of a sucrose-fulkylene oxide adduct obtained by the present invention and a mixture of the polyol and a polyvalent initiator-alkylene oxide adduct. The hydroxyl value of is preferably about 300 to 700. That is, it is a polyol mainly used as a raw material for rigid polyurethane foam. The second preferred one is a polyol having a hydroxyl value of 20 to 150, which is a polyol mainly used as a raw material for flexible or semi-rigid polyurethane foam. However, the polyols obtained by the present invention are not limited to these two types, and may have other hydroxyl values.

The alkylene oxide is preferably an alkylene oxide having 2 to 4 carbon atoms. However, this alkylene oxide and a small amount of other alkylene oxide or monoepoxide other than alkylene oxide can also be used together. Examples of the alkylene oxide having 2 to 4 carbon atoms include ethylene oxide, propylene oxide, 1-, 2-, and Haku. 3-butylene oxide, particularly propylene oxide and ethylene oxide are preferred; as alkylene oxide 1
If only seeds are used, propylene oxide is preferably used. When two or more types are used, a combination of propylene oxide and ethylene oxide is preferred. When two or more alkylene oxides are used,
Alternatively, when an alkylene oxide and another epoxide are used, they can be mixed and reacted, or they can be reacted separately and sequentially, or both methods can be combined. When reacting sequentially, different types of alkylene oxides may be reacted in the first reaction and the second reaction, or they can be reacted sequentially in one of the reactions (particularly the second reaction).

When propylene oxide and ethylene oxide are reacted, substantially only propylene oxide is reacted in the first reaction, or in large excess in terms of molar ratio (for example, 8
It is preferable to react propylene oxide (0% or more) with a small amount of ethylene oxide. This is because the oxyethylene group produced by the reaction of ethylene oxide is hydrophilic, so it may be difficult to sufficiently remove water from the product of the previous reaction, which contains a large proportion of oxyethylene groups. Since such a risk does not occur in the subsequent reaction after dehydration, a large amount of ethylene oxide can be reacted,
It is also possible to produce hydrophilic polyols with a high proportion of oxyethylene groups. However, in the present invention, the proportion of propylene oxide in all alkylene oxides used in the reaction is preferably about 80 to 100 mol%.

After completion of the subsequent reaction, the product is preferably purified by a conventional method, particularly preferably to sufficiently remove the alkali catalyst used. Purification is usually carried out by neutralizing with an acid and removing the generated alkali metal salts by filtration or the like. As the acid, in addition to mineral acids, acid salts and solid acids are also used. In addition, water may be used in this purification, and in this case, dehydration is also required.The present invention will be explained in detail with reference to Examples below, but the present invention is limited only to these Examples. It is not something that will be done. In fact, the sugar water used was the sucrose aqueous solution extracted from the sugar manufacturing process as described above.

Example 1 The sucrose temperature was about 64% (wt%,
The same applies below) to 534.4g of sugar water (1 mole of sucrose)
Approximately 3.1 g of 8% caustic potassium aqueous solution (KO against sucrose)
After adding 5.80 mol of propylene oxide at 80°C, the moisture content was 0.15%.
Dehydration was performed under reduced pressure until . Further at 120℃5.
After adding 57 mol of propylene oxide and neutralizing and removing caustic potash, a polyol having a hydroxyl value of about 450 was obtained. The viscosity (25°C) of this polyol is 34.500 cp,
The chromaticity was Gardner 4, which was no different from the equivalent polyol obtained by conventional methods.

Example 2 A 5 fL autoclave was charged with sugar water with a sucrose temperature of about 84% in an amount equivalent to 1 mole of sucrose, 2.15 moles of triethanolamine, and 48% caustic potassium in an amount equivalent to KOHO, f17% for these initiators. 6.
After adding 26 mol of propylene oxide, the mixture was dehydrated under reduced pressure until the water content became 0.13%. Furthermore, 120
After adding 7.83 mol of propylene oxide at 0.degree. C., caustic potash was removed to obtain a polyol having a hydroxyl value of about 548. The viscosity (25℃) of this polyol is 13,200c
p, chromaticity was Gardner 8, and there was no difference from equivalent polyols obtained by conventional methods.

Example 3 A 59% autoclave was charged with sugar water with a sucrose temperature of about 84% in an amount equivalent to 1 mol of sucrose, 2.61 mol of glycerin, and a 48% aqueous solution of caustic potassium in an amount equivalent to 0.78% KOH for these initiators. After adding 7.11 mol of propylene oxide at 80℃, the water content was 0.12
It was dehydrated under reduced pressure until it became %.

Further, 25.33 mol of propylene oxide was added at 120°C, and then caustic potash was removed to obtain a polyol with a hydroxyl value of about 386. This polyol had a viscosity (at 25° C.) of 1,800 cp and a chromaticity of Gardner 4, which was no different from an equivalent polyol obtained by a conventional method.

Example 4 In a 5 fL autoclave, sugar water with a sucrose temperature of about 64% was added in an amount equivalent to 1 mol of sucrose, 1.82 mol of glycerin, and 0.04 mol of a polyol with a molecular weight of about 1500 consisting of a pre-produced glycerin-propylene oxide adduct. (
Box) and 48% caustic potash were charged to these initiators in an amount equivalent to 2,111% KOH, and heated to 80°C.
After adding 7.55 mol of propylene oxide, dehydration was carried out under reduced pressure until the water content was 0.10%, and the mixture was further heated at 120°C.
40.45 mol of propylene oxide was added.

95% caustic potassium was added to the obtained polyol in an amount such that KOH to the polyol was 3.08%, and the mixture was heated at 130°C.
After adding 18.87 moles of propylene oxide and subsequently adding 112.23 moles of ethylene oxide, caustic potash was removed to obtain a polyol having a hydroxyl value of 31.

The viscosity (25° C.) of this polyol was 1.300 cp, and the chromaticity was 80 in APHA, and there was almost no difference from the equivalent polyol obtained by the conventional method.

Claims (1)

[Scope of Claims] 1. Presence of an alkaline catalyst in sugar water with a sucrose concentration of about 50 to 70% by weight. Dosucrose is reacted with less than about 1.0 equivalent of alkylene oxide, and then water in the reaction mixture is reduced to about 1.0 equivalent.
1. A method for producing a polyol comprising a sucrose-alkylene oxytoy monoadduct, which comprises dehydrating the polyol to a weight % or less and then reacting it with an alkylene oxide. 2. Presence of an alkaline catalyst in a mixture of sugar water with a sucrose concentration of about 50 to 70% by weight and a polyvalent initiator, reacting less than about 1.0 equivalents of alkylene oxide with dosucrose;
A method for producing a polyol containing a sucrose-alkylene oxide adduct, which comprises dehydrating the reaction mixture until the water content becomes about 1% by weight or less, and then reacting with an alkylene oxide.