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Method for refining isosorbide by distillation and melt crystallization coupling technology

A technology of isosorbide and melt crystallization, applied in the chemical field, can solve the problems of high production cost, poisonous, harmful to the health of production operators, etc., and achieve the effect of saving energy consumption

Inactive Publication Date: 2010-03-10
NANJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The distillation operation of the present invention is simple and does not require inert gas protection; the use of molten crystallization overcomes the high energy consumption and high production cost of secondary distillation, and the use of organic solvents for solvent crystallization, most of which are poisonous, making it harmful to the health of production operators and A large amount of organic waste is produced, causing environmental pollution and other disadvantages; and the coupling method of distillation and crystallization saves a lot of energy consumption, so that the separation operation can be carried out continuously, which can meet the requirements of large-scale industrial production

Method used

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  • Method for refining isosorbide by distillation and melt crystallization coupling technology

Examples

Experimental program
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Effect test

Embodiment 1

[0019] 1Kg of sorbitol dehydration product was introduced into the distillation tank, and the content of isosorbide was detected to be 63%. The mixed solution was heated to 155° C., vacuumed, and the vacuum degree was controlled at 320 Pa to carry out vacuum distillation. The distilled low-boiling point fractions were collected and kept at 70°C, and then introduced into the crystallizer that had been filmed, and the crystal layer was grown for 0.8 hours, and then the temperature was lowered at a rate of 0.02°C / min to continue the growth of the crystal layer for 3 hours, and the uncrystallized The liquid is discharged out of the crystallizer; the temperature of the crystallizer is raised at a rate of 0.01°C / min to make the crystal layer sweat, and the sweating end point temperature is 45°C, and the molten liquid is drained; the temperature is raised to melt the crystal layer and collected for sampling analysis . Obtain 446g of pure isosorbide with a purity of 99.92%.

Embodiment 2

[0021] 1Kg of sorbitol dehydration product was introduced into a distillation tank, and the content of isosorbide was detected to be 65%. The mixed solution was heated to 170° C., vacuumed, and the vacuum degree was controlled at 320 Pa for vacuum distillation. The distilled low-boiling point fractions were collected and kept at 60°C, and then introduced into the crystallizer that had been filmed, and the crystal layer was grown for 0.8 hours, and then the temperature was lowered at a rate of 0.02°C / min to allow the crystal layer to continue to grow for 3 hours, and the uncrystallized The liquid is discharged out of the crystallizer; the temperature of the crystallizer is raised at a rate of 0.03°C / min to make the crystal layer sweat, and the sweating end point temperature is 55°C, and the molten liquid is drained; the temperature is raised to melt the crystal layer and then collected for sampling analysis . Obtain 486g of pure isosorbide with a purity of 99.84%.

Embodiment 3

[0023]1Kg of sorbitol dehydration product was introduced into a distillation tank, and the content of isosorbide was detected to be 63%. The mixed solution was heated to 185° C., vacuumed, and the vacuum degree was controlled at 320 Pa for vacuum distillation. The distilled low-boiling point fractions were collected and kept at 65°C, and then introduced into the crystallizer that had been filmed, and the crystal layer was grown for 1 hour, and then the temperature was lowered at a rate of 0.03°C / min to allow the crystal layer to continue to grow for 3.5 hours, and the uncrystallized The liquid is discharged out of the crystallizer; the temperature of the crystallizer is raised at a rate of 0.05°C / min to make the crystal layer sweat, and the sweating end point temperature is 55°C, and the molten liquid is exhausted; the temperature is raised to melt the crystal layer and then collected for sampling analysis . Obtain 522g of pure isosorbide with a purity of 99.63%.

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Abstract

The invention discloses a method for refining isosorbide by a distillation and melt crystallization coupling technology. The method comprises the following steps: dehydrated mixed liquor of sorbitol is introduced to a distillation retort for reducing pressure and distilling; low-boiling isosorbide vaporization flows out from the upper part and enters a heat exchanger, high-boiling sorbitol, 1.4-dehydrated sorbitol and other dehydrated products remain at the bottom of a kettle, and are discharged from the bottom of the kettle. Vapor from the upper part enters the heat exchanger by introductionfor heat exchanging and condenses into liquid state after heat is exchanged by the heat exchanger; low-boiling distillate after heat exchanging is directly introduced into a crystallizer for reducingtemperature and crystallizing. The processes of temperature reducing and crystallization are melt crystallization, comprising four steps: hanging membrane, crystallizing, sweating and melting. In theinvention, the distillation and melt crystallization technologies are coupled and adopted to refine the isosorbide, in the melt crystallization process, 3-8 crystallizers are used for cycle use in turn, and the distillation and crystallization can be carried out continuously. The method of the invention has simple operation, less pollution to environment and low power consumption and the like; andthe ultimate purity of isosorbide can reach over 99.5%.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, and in particular relates to a method for refining isosorbide by adopting a distillation-melt crystallization coupling process. Background technique [0002] Isosorbide is added to PET as a polymer additive to increase the glass transition temperature H of the polymer g It has become a research hotspot in recent years, and people have set off a new upsurge in the preparation and purification of isosorbide. As an oral diuretic, isosorbide has an important application in medicine, and is also an excellent antihypertensive drug for the treatment of intracranial hypertrophy. In addition, isosorbide can also be used as a pharmaceutical intermediate, which is widely used in the preparation of special effects for the treatment of coronary heart disease The drug Nitroisosorbide (Nitoride) and other finished medicines and synthetic organic pesticides. Because isosorbide has special chiral char...

Claims

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Application Information

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IPC IPC(8): C07D493/04
Inventor 黄和余定华谢毓胜
Owner NANJING UNIV OF TECH
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