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Method for preparing thiolactide

A technology of thiolactide and cyclic thiolactide, which is applied in the field of preparation of thiolactide, can solve the problems of time-consuming, unsuitable for large-scale production, and many waste by-products, so as to save resources and costs, and is an important application value, avoidance of process effects

Pending Publication Date: 2022-07-29
CHANGCHUN INST OF APPLIED CHEMISTRY - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this method needs to add an equimolar equivalent (or excess) of dehydrating agent, which produces more waste by-products, which greatly increases the difficulty of separation and purification of the target product, and is not suitable for large-scale production.
Document Makromol.Chem., 1970,140,21 reported that in the process of directly heating thioglycolic acid to prepare polythioester, the by-product thioglycolide was separated, but the method took a long time (5 days) and the thioglycolate The yield of glycolide is low (about 20%), and the separation and purification process is complicated
So far, there is no report on the preparation method of thiolactide suitable for large-scale production

Method used

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  • Method for preparing thiolactide

Examples

Experimental program
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Effect test

Embodiment 1

[0045] Weigh 92g of thioglycolic acid into a 2L round-bottom flask, add 1L of toluene to dissolve, then slowly add 7.5g (4.0ml) of trifluoromethanesulfonic acid, and react at 120°C with water for 6h. The reaction is stopped, and the toluene is spin-dried to obtain a mixture of cyclic thioglycolide and thioglycolic acid oligomer, and the steamed toluene can be recovered and reused.

[0046] The above mixture was transferred to a vacuum sublimation device, and sublimed under reduced pressure at 120° C. and a vacuum degree of about 100 Pa, and the product was collected, which was directly cyclic thioglycolide. Add 3g sodium thiophenate and 30g polyethylene glycol monomethyl ether to the remaining product, continue to sublime under reduced pressure, and collect the sublimation product, which is the thioglycolide after depolymerization, and the cosolvent polyethylene glycol monomethyl ether. Can be recycled and reused. A total of 56g was obtained by two sublimations (the yield was...

Embodiment 2

[0048] Weigh 92g of thioglycolic acid into a 2L round-bottom flask, add 1L of toluene to dissolve, then add 17g of tetrabutyl titanate, and react at 120°C with water for 8h. The reaction is stopped, and the toluene is spin-dried to obtain a mixture of cyclic thioglycolide and thioglycolic acid oligomer, and the steamed toluene can be recovered and reused.

[0049] The above mixture was transferred to a vacuum sublimation device, and sublimed under reduced pressure at 120° C. and a vacuum degree of about 100 Pa, and the product was collected, which was directly cyclic thioglycolide. Add 2.5g sodium thiophenate and 30g polyethylene glycol monomethyl ether to the remaining product, continue to sublime under reduced pressure, collect the sublimation product, namely the thioglycolide after depolymerization, and the cosolvent polyethylene glycol monomethyl ether. Ether can be recycled and reused. A total of 48 g were obtained by two sublimations (yield about 65%, purity 94%), 1 H ...

Embodiment 3

[0051] Weigh 92g of thioglycolic acid into a 2L round-bottom flask, add 1L of toluene to dissolve, then add 16.7g of pentafluoroaniline trifluoromethanesulfonate, and react at 80°C for 8h. The reaction is stopped, and the toluene is spin-dried to obtain a mixture of cyclic thioglycolide and thioglycolic acid oligomer, and the steamed toluene can be recovered and reused.

[0052] The above mixture was transferred to a vacuum sublimation device, and sublimed under reduced pressure at 120° C. and a vacuum degree of about 100 Pa, and the product was collected, which was directly cyclic thioglycolide. Add 3.2g of sodium thiophenate and 30g of polyethylene glycol monomethyl ether to the remaining product, continue to sublime under reduced pressure, and collect the sublimation product, which is the thioglycolide after depolymerization, and the cosolvent polyethylene glycol monomethyl ether. Ether can be recycled and reused. A total of 53g was obtained by two sublimations (yield abou...

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Abstract

The invention relates to a method for preparing thiolactide, and belongs to the technical field of organic synthesis. The problems that in an existing thiolactide preparation technology, an equivalent or even excessive dehydration reagent needs to be added, consequently, a large amount of waste is caused, and a target product is difficult to separate and purify are solved. According to the method, alpha-mercapto acid is used as a raw material, and under the heating condition and the action of a catalyst, the alpha-mercapto acid is directly dehydrated to generate cyclic thiolactide and a mercapto acid oligomer. And the high-purity cyclic thiolactide can be prepared by direct sublimation or distillation and re-sublimation or distillation after depolymerization. The preparation method disclosed by the invention is simple, high in product yield, reusable in solvent and few in waste products, is an efficient and high-purity thiolactide preparation method, and is suitable for industrial production.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, in particular to a method for preparing thiolactide. Background technique [0002] The large-scale use and disposal of plastics have caused serious waste of resources and huge economic losses. How to deal with plastic wastes economically and environmentally has become a global pressing issue. Closed-loop recycled plastic is a polymer material synthesized by designing specific monomers. After use, it can be directly converted from the polymer material to the original monomer to realize resource recycling and use at the same level. Compared with traditional biodegradable plastics, closed-loop recycling of plastics has more advantages in resource conservation and low-carbon emissions, and is an effective way to fundamentally solve the problem of plastic waste disposal. [0003] Compared with lactide monomers such as glycolide and lactide, thiolactide is thermodynamically more conducive to...

Claims

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Application Information

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IPC IPC(8): C07D339/08
CPCC07D339/08Y02P20/55
Inventor 陶友华陈金龙
Owner CHANGCHUN INST OF APPLIED CHEMISTRY - CHINESE ACAD OF SCI
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