KR20140105183A - Method for preparation of anhydrosugar alcohols by using a screw-type continuous reactor - Google Patents

Abstract

The present invention relates to a method of preparing anhydrosugar alcohol using a screw-type continuous reactor, and more specifically, to a method of preparing anhydrosugar alcohol in which a screw-type continuous reactor containing one or more partition walls is used to carry out a reaction when performing a step of dehydrating hydrogenated sugar to be converted into anhydrosugar alcohol, thereby having many advantages of increasing conversion rate, work stability and quality uniformity of a reaction result solution, decreasing the size of a reactor in comparison to a batch operation, being easy to work, easily setting the step by step temperatures in comparison to a continuous operation using multiple reactors, reducing relevant costs due to easy installation, allowing maintenance work to carry out, etc.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing alcohol-free alcohol using a screw-type continuous reactor,

The present invention relates to a process for preparing an alcohol-free alcohol using a screw-type continuous reactor, and more particularly, to a process for converting a hydrogenated sugar into a dihydric alcohol by dehydration, , It is possible to improve the conversion rate and improve the stability of the operation and the uniformity of the quality of the reaction resultant liquid, and to reduce the size of the reactor for the batch operation, The present invention relates to a method for producing alcohol-free alcohol having various advantages such as easy setting of the stepwise temperature compared to the continuous operation using a plurality of reactors, simplification of facilities, reduction of related costs and maintenance, and the like.

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 largest industrial application range at present.

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 and low limit of conversion, distillation and purification yield, it is possible to improve the alcohol-free alcohol conversion rate in a more inexpensive and simple manner , The development of a technique capable of improving the stability of the operation and the uniformity of the quality of the resultant liquid has been demanded.

Particularly, a method of converting a hydrogenated sugar into an alcohol-free alcohol through a batch reaction has been mainly used. However, this method is inconvenient to work and has a problem that the reactor size becomes too large for industrial scale production. As an alternative, there is a method in which a plurality of reactors are used to operate continuously, but this method has a problem that it is difficult to set the temperature stepwise and the equipment becomes complicated. Therefore, it is possible to reduce the reactor size compared to the batch operation, to work conveniently, to set continuous temperature by continuous operation using plural reactors, to easily set the temperature, to reduce the related costs, Is being developed.

SUMMARY OF THE INVENTION The present invention has been made to overcome the problems of the prior art described above, and it is an object of the present invention to provide a process for producing an alcohol-free alcohol, It is possible to increase the uniformity of the quality of the liquid, to reduce the reactor size compared to the batch operation, to facilitate the operation, to set the stepwise temperature for the continuous operation using the plurality of reactors, to simplify the facility, The present invention also provides a method for producing alcohol-free alcohol having various advantages such as easy maintenance, and the like.

In order to solve the above-mentioned technical problems, the present invention provides a method for preparing an alcohol-free alcohol, comprising the steps of dehydrating a hydrogenated sugar to convert it into a dihydric alcohol, wherein the dehydration reaction is performed in two or more zones, Characterized in that the process is carried out in a continuous single reactor comprising at least one partition wall which is divided into a plurality of zones and which maintains a fluid connection between the zones and an inner screw passing through the zones.

According to another aspect of the present invention there is provided a reactor for a liquid material comprising: at least one feedstock in fluid communication with the outside of the reactor; At least one outlet in fluid communication with the outside of the reactor; One or more exhaust lines in fluid communication with the outside of the reactor; One or more partitions dividing the interior of the reactor into two or more zones and maintaining a fluid connection between the zones; And an inner screw passing through the zones.

According to another aspect of the present invention, there is provided a method of treating a liquid substance, which comprises reacting a liquid substance in the single continuous reactor.

In accordance with the present invention, conversion of hydrogenated sugar to anhydrosugar alcohol can improve the conversion of alcohol-free alcohol to other conventional conversion processes, improve the stability of operation and uniformity of quality of reaction solution, Can be reduced and the operation is convenient. It is easy to set the stepwise temperature for continuous operation using a plurality of reactors, the facilities are simplified because the stirrer is not necessary, the related costs can be reduced, and maintenance can be easily achieved. have.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic view showing one embodiment of a screw-type continuous reactor usable in the method for producing an alcohol-free alcohol of the present invention. FIG.
2 is a schematic view showing another embodiment of a screw-type continuous reactor usable in the method for producing an alcohol-free alcohol of the present invention.

Hereinafter, the present invention will be described in detail.

The method for producing an alcohol-free alcohol of the present invention is characterized in that the dehydrogenation reaction of the hydrogenated sugar is carried out by using at least one partition wall dividing the inside of the reactor into two or more zones and maintaining the fluid connection between the zones, ≪ / RTI > in a continuous, single reactor comprising a < RTI ID = 0.0 >

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 (or sugar alcohol) in one or more steps in any manner.

In the present invention, hexitol is preferably used as the hydrogenating sugar, more preferably hydrogenated sugar selected from sorbitol, mannitol, editol, and mixtures thereof.

Therefore, in the present invention, dianhydrohexitol, which is a dehydrate of hexitol, is obtained as the above-mentioned alcohol without sugar, more preferably isosorbide (1,4-3,6-dianhydrosorbitol), iso Anhydrous alcohol selected from mannide (1,4-3,6-dianhydro mannitol), isodide (1,4-3,6-dianhydride) and mixtures thereof is obtained. Of these, isosorbide is particularly high in industrial and medicinal applications.

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.

It is preferable that an acid catalyst is used to convert the hydrogenated sugar to dehydrated and converted to anhydrated alcohol.

According to one embodiment of the present invention, a single acid catalyst such as sulfuric acid, nitric acid, hydrochloric acid, p-toluenesulfonic acid, or phosphoric acid may be used as the acid catalyst, more preferably sulfuric acid may be used.

According to another embodiment of the present invention, a mixed acid of a first acid and a second acid can be used as the acid catalyst, more preferably, sulfuric acid as a first acid, p-toluenesulfonic acid as a second acid, At least one sulfur-containing acid material selected from the group consisting of phosphoric acid, ethanesulfonic acid, benzenesulfonic acid, naphthalenesulfonic acid and aluminum sulfate can be used.

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 excessively smaller than this range, the conversion time to the alcohol without sugar alcohol may become too long, whereas if the amount of the acid catalyst is excessively larger than this range, the production of the saccharide polymer increases, have.

According to one embodiment of the present invention, the step of converting the hydrogenated sugar into anhydrosugar alcohol is carried out in the presence of an acid catalyst as described above at a temperature of 105-200 占 폚 (more preferably 110-150 占 폚) and 1 to 100 mmHg (More preferably, 1 to 50 mmHg) for 1 to 10 hours (more preferably, 2 to 5 hours), but the present invention is not limited thereto.

In the case of using an acid catalyst in the dehydrogenation reaction of the hydrogenated sugar, it is preferable that the reaction liquid is neutralized. 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.

According to one preferred embodiment of the process for preparing anhydrosugar alcohol of the present invention, the liquid resulting from the conversion of the hydrogenated sugar to the anhydride alcohol can be pretreated prior to introduction into the distillation stage. This pretreatment is intended to remove moisture and low boiling matter remaining in the liquid resulting from the conversion step, and the resulting liquid is subjected to a conversion step at a temperature of 90 ° C. to 110 ° C. and a pressure of 10 mmHg to 100 mmHg for 1 hour or more , 1 to 4 hours), but is not limited thereto.

In the present invention, the dehydrogenation reaction of the hydrogenated saccharide as described above is carried out by using at least one partition wall which divides the inside of the reactor into two or more zones and maintains the fluid connection between the zones and an inner screw ≪ / RTI >

The inside of the reactor is divided into two or more, more preferably three or more zones by the partition walls. However, the partition does not completely divide the zones, but fluid connection is maintained between adjacent zones. That is, at least one of the ends of the barrier rib is spaced apart from the inner surface of the reactor, preferably, the upper end of the barrier rib is spaced apart from the reactor upper end inner surface, and the remaining ends (lower end and left and right ends) of the barrier are all in contact with the reactor inner surface.

There is no particular limitation on the material of the partition wall, and it may be the same material as the inner surface of the reactor or may be different. The partition wall may be formed integrally with the reactor, or may be additionally installed inside the reactor as required.

In the present invention, by dividing the inside of the reactor into two or more zones connected in fluid by using the above-described partition, a sufficient reaction time can be given to the reaction liquid, and a uniform quality conversion liquid can be obtained.

The continuous single reactor of the present invention comprises an inner screw passing through the zones divided by the partition walls. The reaction liquid is transferred while stirring while the inner screw rotates. Therefore, the present invention does not require an agitator, which simplifies the facilities, reduces the related costs, and has the advantage of easy maintenance. As the material of the screw, a material which is not corrosive to an acid substance such as sulfuric acid can be used. There is no particular limitation on the shape of the screw, and a form that can be used for transferring the alcohol-free alcohol conversion reaction solution suffices.

In the method for producing anhydrous alcohol using the continuous single reactor of the present invention, preferably, the temperature of the zones divided by the partition walls can be controlled independently. The temperature of each zone may, for example, be adjusted using a jacket, but is not so limited. The continuous single reactor of the present invention may preferably have at least one exhaust line in fluid communication with the outside of the reactor, and the degree of vacuum in the reactor through the exhaust line during the alcohol-free alcohol conversion reaction , 50 torr or less), so that water generated during the reaction can be easily removed.

According to one preferred embodiment of the invention, the continuous single reactor interior is divided into three zones by two partitions, which are penetrated by one inner screw. The tops of the bulkheads are spaced apart from the top of the reactor interior so that each zone is fluidly connected. On the basis of the flow direction of the reaction liquid, hydrogenated saccharide (for example, sorbitol) is added to the reactor together with the catalyst in the first zone (first zone) and mixed. The hydrogenated saccharide and the catalyst may be introduced through separate lines or may be mixed and fed through one line. The temperature condition of the first zone may be generally 110 to 130 ° C, and the residence time of the reaction solution in the first zone may be generally 5 to 30 minutes, but is not limited thereto. Subsequently, the reaction liquid is transferred from the first zone to the second zone (second zone) based on the direction of the reaction liquid flow by the inner screw, wherein the conversion reaction is carried out in earnest. At the upper part of the reactor region corresponding to the second zone, there is an exhaust line through which a degree of vacuum (for example, 50 torr or less) is applied to the inside of the reactor to remove moisture generated during the reaction. The temperature condition of the second zone may be higher than that of the first zone and may be usually 120 to 150 ° C. The residence time of the reaction solution in the second zone may be normally 60 to 120 minutes, but is not limited thereto. Subsequently, the reaction liquid is transferred from the second zone to the third zone (third zone) based on the reaction liquid flow direction by the inner screw, wherein the conversion reaction is further performed. At the upper part of the reactor zone corresponding to the third zone, there is an exhaust line through which a degree of vacuum (for example, 50 torr or less) is applied to the interior of the reactor to remove water generated during the reaction. The temperature condition of the third zone may be higher than that of the second zone, usually 130 to 180 ° C, and the residence time of the reaction solution in the third zone may be 60 to 360 minutes, but is not limited thereto. The reaction solution passed through the third zone exits the outlet. At this time, a neutralizing agent (for example, liquid sodium hydroxide) is continuously introduced at the outlet end of the outlet to neutralize the reaction solution.

In the present invention, preferably, the hydrogenated saccharide is continuously introduced into a continuous single reactor while the dehydrogenation reaction of the hydrogenated sugar is performed, and the produced anhydrous alcohol can be continuously discharged out of the reactor. That is, while the dehydrogenation reaction of the hydrogenated sugar is carried out, a continuous flow of the reaction mixture can be formed in the continuous single reactor. The flow rate of the reaction mixture which forms a continuous flow within a continuous single reactor can be appropriately selected depending on the specification of the specific reactor and other operating conditions and the like.

The continuous flow that can be formed within the continuous single reactor during the dehydration reaction is preferably a steady state flow. Here, the steady flow means that there is no substantial change in the reaction system as seen by the external observer, that is, the rate of material input into the continuous single reactor and the rate of material discharge out of the reactor are substantially the same, Quot; same " as used herein means, for example, that the material feed rate in a continuous single reactor is 0.95 to 1.05 times, more preferably 0.99 to 1.01 times, most preferably both of the discharge rates.

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.

According to one preferred embodiment of the present invention, the dehydration reaction of the neutralized hydrogenated sugar results in the liquid being subjected to the distillation step after the step of removing moisture therefrom. The process of removing moisture from the liquid as a result of the dehydration reaction may be performed using a degasser or a flash box or may be performed by a method of removing water in a vacuum in a storage tank, And is not particularly limited.

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 performed using activated carbon, and the ion exchange resin treatment may be performed using a cationic exchange resin, an anionic ion exchange resin, or both sequentially.

According to another aspect of the present invention, there is provided a reactor for a liquid material, comprising: at least one raw material inlet portion in fluid communication with an outside of a reactor; At least one outlet in fluid communication with the outside of the reactor; One or more exhaust lines in fluid communication with the outside of the reactor; One or more partitions dividing the interior of the reactor into two or more zones and maintaining a fluid connection between the zones; And an inner screw passing through the zones. Specific examples of the continuous single reactor for liquid material of the present invention and their use examples are as described above, but are not limited thereto.

In addition, the continuous single reactor for the liquid material according to the present invention is preferably used for converting the hydrogenated sugar into anhydrosugar alcohol, but can also be applied to the reaction of other liquid substances. Therefore, according to another aspect of the present invention, there is provided a method for treating a liquid substance, which comprises reacting a liquid substance in the single continuous reactor.

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 ]

Example  One

A dehydration reaction of the hydrogenated sugar was carried out in a single screw-type continuous reactor as shown in Fig. A sorbitol solution (D-sorbitol, manufactured by Samyang Genex Co., Ltd.) having a moisture content of 1% or less was added to the feed inlet of the reactor at a rate of 515 mL / hr. At this time, sulfuric acid (Duksan Chemical Co.) was added together at a rate of 8 g / hr. The degree of vacuum in the reactor was adjusted to 50 mmHg or less to remove water generated during the conversion reaction. The temperature of each zone of the reactor was adjusted using a jacket. The temperature of the mixing portion was maintained at 120 ° C, the temperature of the first reaction portion was maintained at 140 ° C, and the temperature of the second reaction portion was maintained at 150 ° C. The rpm of the screw was adjusted to 40 to stir and transport the reaction solution. The reaction time was 3 hours and 30 minutes in total. The resultant liquid was transferred to a storage tank. At this time, 50% liquid sodium hydroxide (Seonjeon-gun, Co., Ltd.) was continuously fed at the rate of 15 g / hr at the downstream of the outlet to terminate the reaction. The conversion of the conversion solution without a sugar-free alcohol was 77.8%.

Gas chromatograph (GC) was used for the analysis.

- Conversion rate: [produced moleless alcohol mole / injected hexitol (sorbitol) mole] x 100

Comparative Example  One

3090 g of a sorbitol solution having a moisture content of 1% or less was placed in a 6 L reactor (without a partition wall) equipped with a stirrer and a jacket, and 30.9 g and 15.5 g of sulfuric acid and methane sulfonic acid were added, respectively. Lt; / RTI > During the reaction, water generated during the reaction was removed while maintaining the vacuum degree of the reactor below 50 mmHg. After completion of the reaction for 6 hours, 70 g of 50% sodium hydroxide solution was added to terminate the reaction. The conversion of the free alcohol to the free alcohol was 74.5%.

Comparative Example  2

Using a two-stage reactor equipped with a stirrer and two jacketed 2L reactors connected in series, the dehydration reaction of the hydrogenated sugar was carried out using the same raw materials as in Example 1 Respectively.

Sorbitol, sulfuric acid, methane sulfonic acid and sodium hydroxide were added at the same rate as in Example 1, and the rate of the conversion liquid discharged from the second reactor was the same. The temperatures of the primary and secondary reactors were controlled using a jacket. The internal temperature of the primary reactor was maintained at 130 캜, and the internal temperature of the secondary reactor was maintained at 140 캜. The dihydrate alcohol conversion of the conversion solution completed up to the second reaction was 72%.

As described above, in the case of Example 1 in which dehydration reaction of hydrogenated sugar was performed in a single screw-type continuous reactor according to the present invention, Comparative Example 1 operated in batch mode or two reactors connected in series, Was higher than that of Comparative Example 2, which was operated at a low temperature. In addition, the reaction time could be significantly shortened as compared with Comparative Example 1 which was operated in a batch manner.

1: mixing part (first zone)
2: first reaction part (second zone)
3: Second reaction part (third zone)
4: Internal Screw
5-1, 5-2:
6-1: Sorbitol injection line
6-2: Acid injection line
7-1, 7-2: Vacuum line
8: reaction result liquid discharge line

Claims (19)

Dehydrating the hydrogenated sugar to convert it into an anhydrosugar alcohol,
Wherein the dehydration reaction is carried out in a continuous single reactor comprising at least one partition wall which divides the interior of the reactor into two or more zones and maintains a fluid connection between the zones and an inner screw passing through the zones ≪ / RTI > The method of claim 1, wherein the upper end of the partition wall is spaced apart from the reactor upper end inner surface, and all the other ends of the partition walls are in contact with the reactor inner surface. The method of claim 1, wherein the temperature of the zones divided by the partition walls is independently controlled. The process according to claim 1, wherein the interior of the continuous single reactor is divided into three zones by two partition walls. The method of claim 4, wherein the temperature of the first zone is 110-130 ° C, the temperature of the second zone is higher than the temperature of the first zone within the range of 120-150 ° C, the temperature of the third zone is 130 Wherein the dehydration reaction is carried out under a condition higher than the temperature of the second zone within the range of < RTI ID = 0.0 > ~ 180 C. < / RTI > 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. 7. The process according to claim 6, wherein the acid catalyst is a single acid selected from sulfuric acid, nitric acid, hydrochloric acid, p-toluenesulfonic acid and phosphoric acid. 7. The process of claim 6, wherein the acid catalyst is a mixed acid of a first acid and a second acid, wherein the first acid is sulfuric acid and the second acid is selected from the group consisting of p-toluenesulfonic acid, methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, Sulfonic acid, and aluminum sulfate. ≪ RTI ID = 0.0 > 15. < / RTI > The process according to claim 1, wherein the hydrogenated saccharide is continuously introduced into a continuous single reactor while the dehydrogenation reaction of the hydrogenated sugar is carried out, and the produced anhydrous alcohol is continuously discharged outside the reactor. Way. 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 an alcohol-free alcohol according to claim 10, further comprising the step of removing moisture from the liquid resulting from the dehydration reaction of the neutralized hydrogenated sugar and then distilling it. 12. The process according to claim 11, wherein the distillation is carried out using a thin film still. 12. The method of claim 11, further comprising purifying the resulting liquid after distillation by at least one process selected from crystallization, decolorization and ion-exchange resin treatment. 14. The process for producing an alcohol-free alcohol according to claim 13, wherein the crystallization is carried out by a crystallization method using a solvent or a melt crystallization method. 14. The process for producing an alcohol-free alcohol according to claim 13, wherein the decolorizing treatment is carried out using activated carbon. 14. The method of claim 13, wherein the ion exchange resin treatment is carried out using a cation exchange resin, an anionic ion exchange resin, or both sequentially. A reactor for a liquid material,
At least one feedstock in fluid connection with the outside of the reactor;
At least one outlet in fluid communication with the outside of the reactor;
One or more exhaust lines in fluid communication with the outside of the reactor;
One or more partitions dividing the interior of the reactor into two or more zones and maintaining a fluid connection between the zones; And
An inner screw passing through the zones;
≪ / RTI > 18. The continuous single reactor of claim 17, wherein the temperature of the zones divided by the partition walls is independently adjustable. A method for treating a liquid substance, comprising reacting a liquid substance in a continuous single reactor according to claim 17 or 18.

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