Efficient Method for Producing and Purifying Anhydrous Sugar Alcohol

Patent metadata

Field	Value
Publication number	US-2017349603-A1
Application number	US-201515538301-A
Country	US
Kind code	A1
Filing date	Dec 23, 2015
Priority date	Dec 23, 2014
Publication date	Dec 7, 2017
Grant date	—

Abstract

The present invention relates to a method of producing and purifying a high-purity anhydrosugar alcohol in high yield by a simple process and apparatus, the method includes the steps of: allowing a sugar alcohol to react in the presence of an acid catalyst in a reactor, and, at the same time, evaporating a product of the reaction; cooling the evaporated product to remove water and obtain a crude anhydrosugar alcohol; and introducing the crude anhydrosugar alcohol into a melt crystallization process to obtain a high-purity anhydrosugar alcohol.

First claim

1 . A method of preparing and purifying anhydrosugar alcohol, the method comprising:
reacting a sugar alcohol in a presence of an acid catalyst in a reactor, and at the same time, evaporating a reaction product; cooling an evaporated product, thereby obtaining a crude anhydrosugar alcohol; and introducing the crude anhydrosugar alcohol into a melt crystallization process, thereby obtaining a high-purity anhydrosugar alcohol.

2 . A method of preparing and purifying anhydrosugar alcohol, the method comprising:
reacting a sugar alcohol in a presence of an acid catalyst in a reactor, and at the same time, evaporating a reaction product; cooling an evaporated product, thereby obtaining a crude anhydrosugar alcohol; adsorbing the crude anhydrosugar alcohol; and introducing an adsorbed crude anhydrosugar alcohol into a melt crystallization process, thereby obtaining a high-purity anhydrosugar alcohol.

3 . The method of claim 1 , wherein the acid catalyst has a boiling point of 160° C. or higher at 10 mmHg and pKa range of −3.0 to 3.0, and reacts at a homogeneous phase.

4 . The method of claim 3 , wherein the acid catalyst is naphthalenesulfonic acid.

5 . The method of claim 1 , wherein a temperature of the reactor is 150° C. to 220° C. and a pressure of the reactor is 1 to 50 torr.

6 . The method of claim 1 , wherein the anhydrosugar alcohol is isosorbide, and the sugar alcohol is sorbitol.

7 . The method of claim 1 , wherein the reactor comprises:
(a) a reactor unit including a dispenser disposed at an upper portion thereof for reacting a raw material with flowing down along an inner wall side of the reactor, (b) a raw material supply unit disposed at one side of the upper portion of the reactor unit; (c) a means for separating/recovering unreacted raw material and by-product, disposed in the reactor unit spaced apart from a bottom of the reactor unit by a predetermined distance; (d) a condenser disposed at the inner center of the reactor unit to pass through the means for separating/recovering; (e) a means disposed at one side of the reactor unit to reduce an internal pressure of the reactor unit; and (f) a product outlet disposed at a bottom center of the reactor unit to discharge a product flowing down from the condenser.

8 . The method of claim 1 , wherein the melt crystallization process comprises:
contacting the crude anhydrosugar alcohol into surface maintained at a temperature lower than a freezing point of pure anhydrosugar alcohol, thereby forming crystals; and increasing a temperature of the surface on which the crystals are formed, to a temperature between the freezing point of pure anhydrosugar alcohol and the temperature at which the crystals of the crude anhydrosugar alcohol are formed.

9 . The method of claim 8 , wherein in a temperature-increasing step, impurities trapped in the crystals are removed by diffusion to the surface of the crystals, and
wherein the melt crystallization process further comprises, after the temperature-increasing step, a step of increasing the temperature of the surface to at least the freezing point of pure anhydrosugar alcohol to thereby melting the anhydrosugar alcohol formed on the surface.

10 . The method of claim 8 , wherein the temperature of the surface on which the crystals are formed is −40° C. to 63° C.

11 . The method of claim 1 , wherein the melt crystallization is falling film melt crystallization, static melt crystallization or a combination thereof.

12 . The method of claim 11 , wherein the falling film melt crystallization comprises forming crystals by flowing the crude anhydrosugar alcohol to a surface which is maintained at a temperature lower than a freezing point of pure anhydrosugar alcohol, and
wherein the static melt crystallization comprises contacting an object whose surface temperature is maintained at a temperature lower than the freezing point of pure anhydrosugar alcohol with the crude anhydrosugar alcohol in a vessel storing the crude anhydrosugar alcohol, thereby forming crystals on the surface of the object.

13 . The method of claim 1 , wherein a residue in the melt crystallization is recycled to the reactor or the melt crystallization.

14 . The method of claim 1 , wherein a reaction residue (DD residue) discharged from a bottom of the reactor is recycled to the reactor.

15 . The method of claim 14 , wherein the reaction residue discharged from the bottom of the reactor is recycled after passing through an impurity removing means.

16 . The method of claim 15 , wherein the impurity removing means is a filter.

17 . The method of claim 15 , wherein the reaction residue comprises unreacted sugar alcohol, intermediates, a sugar alcohol polymer, a sugar alcohol oligomer, carbonized materials, or a mixture thereof, and the impurity comprises a sugar alcohol polymer, a sugar alcohol oligomer, carbonized materials, or a mixture thereof.

18 . The method of claim 14 , wherein high temperature and high pressure vapor is added to a recycled feed to induce an additional conversion of unreacted materials and intermediates.

19 . The method of claim 18 , wherein the recycled feed is maintained at a pressure of at least saturated water vapor pressure.

20 . The method of claim 18 , wherein a temperature of the recycled feed is higher than that of the reactor.

21 . The method of claim 18 , wherein the temperature of the recycled feed is 150 to 300° C.

22 . The method of claim 18 , wherein a back pressure regulator is installed in front of or behind the recycled feed.

23 . The method of claim 2 , wherein the evaporated product is cooled to a temperature between room temperature and 60° C. to obtain a crude anhydrosugar alcohol containing water of 1-30 wt %.

24 . The method of claim 2 , wherein a flash evaporation process is additionally carried out after the adsorption process to remove water.

25 . The method of claim 2 , wherein the adsorption process is performed by activated carbon, ion exchange resin or a combination thereof.

Assignees

• Sk Innovation Co Ltd

Inventors

• Son Sung Real
• Song In Hyoup
• Yim Yoon Jae
• Hong Suk Joon
• Choi Young Bo

Classifications

• Y02P20/582

  Recycling of unreacted starting or intermediate materials · CPC title

• B01D3/002

  by continuous methods · CPC title

• B01D3/10

  Vacuum distillation (B01D3/12 takes precedence) · CPC title

• C07D493/04 Primary

  Ortho-condensed systems · CPC title

• C07B2200/13

  Crystalline forms, e.g. polymorphs · CPC title