KR20140048439A - Method for preparation of anhydrosugar alcohols by using polyol as reaction diluent - Google Patents

Abstract

The present invention relates to a method for preparing an anhydrosugar alcohol by using polyol as a reaction diluent, and more specifically, in a method for converting hydrogenated sugar to anhydrosugar alcohol by a dehydration reaction, to a method for preparing the anhydrosugar alcohol which adds polyol as a diluent in a dehydration reaction and inhibits side reactions resulting from a concentration associated with the progress of the dehydration reaction, thereby improving a conversion rate.

Description

METHODS FOR PREPARATION OF ANHYDROSUGAR ALCOHOLS BY USING POLYOL AS REACTION DILUENT}

The present invention relates to a method for producing anhydrosugar alcohols using a polyol as a reaction diluent, and more particularly, to a dehydration reaction by adding a polyol as a diluent during dehydration in a method of converting hydrogenated sugars to anhydrosugar alcohols. It relates to a method for producing anhydrosugar alcohols that can improve the conversion rate by inhibiting side reactions due to concentration as the process proceeds.

Hydrogenated sugar (also referred to as " sugar alcohol ") refers to a compound obtained by adding hydrogen to a reducing end group of a saccharide, generally HOCH ₂ (CHOH) _n CH ₂ OH (where n is an integer of 2 to 5 ), And classified into tetritol, pentitol, hexitol and heptitol (C 4, 5, 6 and 7, respectively), depending on the number of carbon atoms. Among them, hexitol having 6 carbon atoms includes sorbitol, mannitol, iditol, galactitol and the like, and sorbitol and mannitol are particularly useful substances.

Anhydrosugar alcohol has a diol form with two hydroxyl groups in the molecule and can be prepared by utilizing hexitol derived from starch (for example, Korean Patent No. 10-1079518, Korean Patent Laid- -2012-0066904). Since alcohol-free alcohol is an eco-friendly substance derived from renewable natural resources, there has been much interest for a long time and studies on the manufacturing method have been carried out. Among these alcohol-free alcohols, isosorbide prepared from sorbitol has the widest industrial application currently.

The use of anhydrous alcohol is widely used in the treatment of cardiovascular diseases, patches, adhesives, oral cleansers and the like, solvents for compositions in the cosmetics industry, and emulsifiers in the food industry. In addition, it is possible to increase the glass transition temperature of a polymer substance such as polyester, PET, polycarbonate, polyurethane, and epoxy resin, to improve the strength of these materials, and to be an environmentally friendly material derived from natural materials. useful. It is also known to be used as an environmentally friendly solvent for adhesives, environmentally friendly plasticizers, biodegradable polymers, and water-soluble lacquers.

As such, alcohol-free alcohol has attracted a great deal of attention due to its versatility and its use in real industry is increasing. However, since the conventional method for producing alcohol-free alcohol has a high catalyst cost for dehydration and low conversion and distillation and purification yields, a technology capable of producing alcohol-free alcohol in a more inexpensive and simple manner Is being developed.

The present invention is to solve the problems of the prior art described above, anhydrosugar alcohol that can improve the conversion rate to anhydrosugar alcohol by a simple method of adding a polyol as a diluent during the dehydration reaction, without modification or addition of existing equipment It is a technical problem to provide a manufacturing method of the present invention.

In order to solve the above technical problem, the present invention, in the method of producing anhydrosugar alcohol comprising the step of dehydrating the hydrogenated sugar to anhydrosugar alcohol, the dehydration reaction is carried out in the presence of a polyol as a reaction diluent It provides a method characterized by.

According to the present invention, an anhydrosugar alcohol conversion rate can be improved by suppressing side reactions due to concentration due to the progress of the dehydration reaction by a simple method of adding a polyol as a diluent during the dehydration reaction without changing or adding an existing facility when manufacturing anhydrosugar alcohol. Can be. In addition, since the flowability of the conversion liquid after the reaction is improved by the added polyol, it is expected to have a positive effect on the improvement of the working efficiency and the yield in the subsequent distillation process.

Hereinafter, the present invention will be described in detail.

The method for producing anhydrosugar alcohols of the present invention is characterized in that it comprises a step of dehydrating hydrogenated sugars to anhydrosugar alcohols in the presence of a polyol as a reaction diluent.

The hydrogenated sugar is generally referred to as sugar alcohol and means a compound obtained by adding hydrogen to the reducing end group of the saccharide. Hydrogenated sugars are classified into tetritol, pentitol, hexitol and heptitol (C 4, 5, 6 and 7, respectively) depending on the number of carbon atoms. Among them, hexitol having 6 carbon atoms includes sorbitol, mannitol, iditol, galactitol and the like, and sorbitol and mannitol are particularly useful substances.

As used herein, the expression ' anhydrous alcohol ' refers to any material obtained by removing one or more water molecules from the original internal structure of the hydrogenated sugar in one or more steps in any manner.

In the present invention, hexitol is preferably used as the hydrogenated sugar, more preferably hydrogenated sugar selected from sorbitol, mannitol, editol, and mixtures thereof, and more preferably hydrogenated sugar from starch Lt; RTI ID = 0.0 > sorbitol < / RTI >

The hydrogenated sugar is converted to a dihydric alcohol by dehydration reaction. There is no particular limitation on the method of dehydrogenating the hydrogenated sugar, and known methods known in the art can be used as it is or modified appropriately.

In the present invention, the polyol used as the reaction diluent in the dehydration reaction refers to an organic compound including two or more hydroxyl groups (-OH) in the molecular structure. Preferred polyols usable in the present invention include those selected from ethylene glycol, polyethylene glycol, polypropylene glycol, glycerol and mixtures thereof, and more preferably polyethylene glycol may be used. When a polymerizable polyol such as polyethylene glycol or polypropylene glycol is used, the molecular weight thereof is preferably 100 to 500, but is not necessarily limited thereto.

In the present invention, the amount of polyol used as the reaction diluent is preferably 1 to 20 parts by weight, more preferably 2 to 10 parts by weight per 100 parts by weight of hydrogenated sugar (eg, hexitol). If the amount of polyol used is less than 1 part by weight per 100 parts by weight of hydrogenation, the effect of improving the conversion rate is insignificant. If it exceeds 20 parts by weight, the efficiency of the conversion reaction process and subsequent distillation process may be reduced.

The acid catalyst is preferably used for dehydrating the hydrogenated sugar and converting it into anhydrosugar alcohol. More preferably, a mixed acid of the first acid and the second acid can be used. As the acid catalyst, sulfuric acid, hydrochloric acid, phosphoric acid and the like can be used in the case of a single acid catalyst, and sulfuric acid as a primary acid and p-toluenesulfonic acid, methanesulfonic acid, ethanesulfonic acid, benzene At least one sulfur-containing acid salt selected from the group consisting of sulfonic acid, naphthalenesulfonic acid and aluminum sulfate can be used.

When a mixed acid is used, the ratio of the first acid to the second acid is preferably 1: 9 to 7: 3 by weight. If the ratio is less than 1: 9 (that is, if the amount of the primary acid is relatively excessively small), the rate of formation of an alcohol free alcohol may be lowered, and if it exceeds 7: 3 If too much, the production of saccharide polymers may be increased.

The amount of the acid catalyst to be used is preferably 0.5 to 10 parts by weight per 100 parts by weight of hydrogenated sugar (e.g., hexitol). If the amount of the acid catalyst is less than 0.5 parts by weight per 100 parts by weight of hydrogenation, the conversion time to the alcohol without sugar alcohol may be too long. If the amount is more than 10 parts by weight, the production of the saccharide polymer may be increased and the conversion may be lowered.

According to one embodiment of the present invention, the step of converting the hydrogenated sugars to anhydrosugar alcohols is carried out at temperature conditions of 105 to 200 ° C. (more preferably 110 to 150 ° C.) and 1 in the presence of an acid catalyst and a polyol diluent as described above. It may be carried out for 1 to 10 hours (more preferably 2 to 5 hours) at a pressure condition of (to more preferably 1 to 50mmHg) to 100mmHg, but is not necessarily limited thereto.

The dehydration reaction of the hydrogenated sugar preferably results in neutralization of the liquid. Neutralization can be performed by lowering the temperature of the reaction liquid after completion of the dehydration reaction (for example, 100 ° C or less) and adding a known alkali such as sodium hydroxide. The pH of the solution is preferably 6 to 8 as a result of the neutralization reaction.

In the present invention, dianhydrohexitol, which is a dehydrate of hexitol, is preferably obtained as the resultant product of the dehydration reaction, more preferably isosorbide (1,4-diol, Sorbitol), isomannide (1,4-3,6-dianhydromonitol), isoidide (1,4-3,6-dianhydride), and mixtures thereof. Among these, isosorbide is particularly high in industrial and medical applications.

The liquid resulting from the dehydration reaction of the neutralized hydrogenated sugar obtained as described above can then be produced as a high purity anhydrous alcohol product through pretreatment, distillation, and subsequent purification if necessary.

There is no particular limitation on the distillation of the liquid as a result of the dehydration reaction of the hydrogenated sugar, and known methods and apparatuses known in the art can be used as is or modified appropriately. For example, a general condenser type distiller or distillation tower still can be used, or a thin film still can be used.

The subsequent purification step of the distillation result liquid may include at least one selected from crystallization, decoloring treatment and ion-exchange resin treatment, but is not limited thereto, and there is no particular limitation in the order. These subsequent purification steps can also be carried out without any particular limitation, and the known methods and apparatuses known in the art can be used as they are or modified appropriately for the treatment process.

According to an embodiment of the present invention, the distillation may be carried out using a thin film still, and the crystallization may be performed by a crystallization method using a solvent (for example, an acetone solvent) or by a melt crystallization method ≪ / RTI > The decolorizing treatment may be carried out using activated carbon, and the ion exchange resin treatment may be carried out using sequential use of a strong cation exchange resin, a strong anionic ion exchange resin, or both.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the following examples are intended to assist the understanding of the present invention, and the scope of the present invention is not limited thereto.

[ Example  And Comparative Example ]

<Measurement of Conversion Rate>

The conversion of anhydrous alcohol was measured by gas chromatography (GC) equipped with a flame ionization detector. Helium was used as the transfer gas. Analytical samples were prepared as follows.

10 mL of acetonitrile was added to 0.1 g of the conversion reaction solution, 1 mL of 1-trimethylsilylimidazole was added thereto, and the mixture was stirred for 30 minutes in a water bath at 80 ° C.

Conversion rate calculation: Alcohol mole / mole of produced hepatol mole x 100 (%) =

Example 1

3000 g of sorbitol powder (D-sorbitol, Samyang Genex Co., Ltd.) were put into a four-necked glass reactor, a stirrer, a cooler, a flask for collecting distillate and a thermometer were connected, and the temperature was raised to melt sorbitol. 30 g sulfuric acid as a catalyst and 150 g polyethylene glycol (PEG) as a diluent (average molecular weight: 400) were added to a melt at 110 ° C., and then heated to maintain an internal temperature of 130 to 135 ° C. under a reduced pressure of 45 mmHg or less. The dehydration reaction proceeded by depressurizing for 3 hours. Then, to neutralize the reaction solution, after the temperature of the reaction solution was lowered to 120 ° C. or lower, 50 g of 50% sodium hydroxide solution was added. The water produced by the neutralization reaction was again removed under reduced pressure. Gas chromatography analysis showed that the conversion was 74.1%.

Example 2

The same procedure as in Example 1 was carried out except that 30 g of sulfuric acid as a catalyst and 150 g of ethylene glycol as a diluent were used. The conversion rate was 73.8%.

Comparative Example

The same procedure as in Example 1 was carried out except that 30 g of sulfuric acid was used as a catalyst and no polyethylene glycol as a diluent was added. The conversion rate was 72.2%.

As can be seen from the results of the above examples and comparative examples, according to the present invention, an improved anhydrosugar alcohol conversion was obtained by a simple method of adding a polyol as a diluent during the dehydration of hydrogenated sugars.

Claims (13)

Dehydrating the hydrogenated sugar to convert it into an anhydrosugar alcohol,
Wherein said dehydration reaction is carried out in the presence of a polyol as a reaction diluent. The method of claim 1, wherein the polyol is selected from ethylene glycol, polyethylene glycol, polypropylene glycol, glycerol, and mixtures thereof. The method of claim 1, wherein the polyol is used in an amount of 1 to 20 parts by weight per 100 parts by weight per hydrogenation. The process for producing an alcohol-free alcohol according to claim 1, wherein an acid catalyst is used in the step of dehydrating the hydrogenated sugar to convert it to an alcohol-free alcohol. 5. The acidic catalyst of claim 4, wherein the acid catalyst is a mixed acid of the first acid and the second acid, wherein the first acid is sulfuric acid, and the second acid is p-toluene sulfonic acid, methane sulfonic acid, ethane sulfonic acid, benzene sulfonic acid, naphthalene At least one sulfur-containing acid salt selected from the group consisting of sulfonic acid and aluminum sulfate. The process for producing an alcohol-free alcohol according to claim 1, wherein the dehydration reaction of the hydrogenated sugar is carried out at a temperature of 105 to 200 DEG C and a pressure of 1 to 100 mmHg for 1 to 10 hours. The process for producing an alcohol-free alcohol according to claim 1, wherein the dehydration reaction of the hydrogenated sugar is neutralized. The method for producing anhydrosugar alcohol according to claim 7, further comprising distilling a dehydration resultant solution of the neutralized hydrogenated sugar. The method of claim 8, wherein the distillation is carried out using a thin film distillator. The method for producing anhydrosugar alcohol according to claim 8, further comprising purifying the resultant liquid after distillation by one or more processes selected from crystallization, decolorization treatment and ion exchange resin treatment. The method for producing anhydrosugar alcohol according to claim 10, wherein the crystallization is carried out by a crystallization method using a solvent or a melt crystallization method. The process for producing anhydrosugar alcohols according to claim 10, wherein the decolorizing treatment is performed using activated carbon. The method for producing anhydrosugar alcohols according to claim 10, wherein the ion exchange resin treatment is performed using sequentially a strong cationic exchange resin, a strong anionic ion exchange resin, or both.