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Method for storing and transporting cyclic diesters

A cyclic diester, diester technology, applied in the field of storage and/or transportation of intramolecular cyclic esters, can solve problems such as decomposition product pollution, dilactide has no use value, etc., and achieve the effect of preventing crystallization

Active Publication Date: 2014-11-05
UHDE INVENTA FISCHER
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, it should be taken into account during storage that under standard storage conditions (e.g. in a normal atmosphere containing water and oxygen) decomposition and ring-opening reactions of dilactide occur, resulting in dilactide being produced contamination by decomposition products, and since high purity standards must be maintained, contaminated dilactide is no longer suitable for ring-opening polymerization to produce polylactide
[0003] It is known from the literature that storage of dilactide in the molten state is of no use (NL 2000454); however, for other substances (e.g. ε-caprolactam) this storage form is the preferred storage form (DE 101 00 752)

Method used

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  • Method for storing and transporting cyclic diesters
  • Method for storing and transporting cyclic diesters
  • Method for storing and transporting cyclic diesters

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] The flask containing Fraction B was sealed with a septum made of PTFE-coated butyl rubber and a standard sealing disc and flange cap, and preheated to 110 °C Place in a furnace for 24 hours. The COOH concentrations before and after that were 2 mmol / kg, respectively. Before the test, the content of meso-dilactide was 4.1%, after the test it was 3.9%, and the difference to 100% was L-dilactide.

Embodiment 2

[0043] The procedure of Example 1 was repeated, but this time the flask was not sealed. After 24 hours in the furnace, the COOH concentration rose from 2 mmol / kg to 69 mmol / kg. Before the test, the content of meso-dilactide was 4.1%, and after the test was 3.5%.

[0044] Examples 1 and 2 show that degradation of the liquid during storage can be prevented by merely excluding water and oxygen.

Embodiment 3

[0046] Repeat the steps of Example 1. This time, the flasks of fractions A, B and C were each placed in an oven heated to 110°C for three days. Therefore, the contents of the flask were always liquid. The carboxyl-terminal content was determined by means of titration, and the proportion of meso-dilactide was determined by HPLC.

[0047] The results are shown in the table below:

[0048] COOH before after

[0049] Fraction A 217mmol / kg 298mmol / kg

[0050] Fraction B 18mmol / kg 18mmol / kg

[0051] Fraction C 25mmol / kg 31mmol / kg

[0052] Content of meso-dilactide Before After *

[0053] Fraction A 78.5% 75.9%

[0054] Fraction B 5.9% 4.9%

[0055] Fraction C 95.2% 94.1%

[0056] * The difference to 100% is L-dilactide.

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Abstract

Procedure for storing and / or transporting a cyclic diester compound (I), comprises transferring the compound (I) in the liquid aggregate state directly into an inertized storage vessel; and temporarily storing and / or transporting at 40-150[deg] C and at 0.1-10 bar in the storage vessel. The water content of the compound (I) amounts to maximum 100 ppm. Procedure for storing and / or transporting a cyclic diester compound of formula (I), comprises transferring the compound (I) in the liquid aggregate state directly into an inertized storage vessel; and temporarily storing and / or transporting at 40-150[deg] C and at 0.1-10 bar in the storage vessel. The water content of the compound (I) amounts to maximum 100 ppm. R : H or 1-6C aliphatic residue. [Image]

Description

technical field [0001] The present invention relates to a method for storing and / or transporting intramolecular cyclic esters (lactones), in particular lactide. Background technique [0002] In the production of biodegradable polyesters such as polylactide, the intermediate product dilactide is produced as standard. Dilactide can exist as L,L-dilactide, D,D-dilactide, meso dilactide, or a mixture of two or three of said isomers. The properties of polymers produced by ring-opening polymerization depend largely on the purity or mixing ratio of the isomers. In order to be able to flexibly serve the market with polylactide (PLA) types with different properties and for application purposes, it is advantageous to store the isomers in transit or to transport them between plants (the isomers are further separated from each other in molten form). However, it should be taken into account during storage that under standard storage conditions (e.g. in a normal atmosphere containing w...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D319/12
CPCC07D319/12
Inventor 赖纳哈根尤多米尔鲍尔
Owner UHDE INVENTA FISCHER
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