Diamine-based metal catalyst as well as preparation method and application thereof

A catalyst and metal-based technology, which is applied in the field of diamine-based metal catalysts and their preparation, can solve the problems of high production cost, biotoxicity, and complex structure, and achieve small steric hindrance, low biotoxicity, and good biocompatibility Effect

Active Publication Date: 2022-04-15
WANHUA CHEM GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] For the cyclodepolymerization and polymerization process involved in the existing catalytic PLA synthesis reaction, especially the lactide synthesis and ring-opening polymerization, the catalyst needs to support the participation of ligands, and improve the reaction by changing the steric hindrance and electrical properties of the central metal. The problem of activity and controllability, as well as the complex structure of conventional ligands, high production costs, and the current industrial catalysts contain certain biological toxicity problems, it is necessary to develop a new catalyst for the preparation of polylactic acid

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Condensation reaction and lactide synthesis reaction are as follows: 300g L-lactic acid aqueous solution (87wt%) is added in 1L prepolymerization reactor and system temperature is raised to 150 ℃, pressure 50hpa, dehydration 30min, detection water content is less than 1%; Then, Add 0.286g prepared catalyst Ca[N(CH 3 ) 2 ][NHOCH 3 ], the temperature of the reaction system was raised to 170°C, the system pressure was 30hpa, and the reaction was carried out for 60 minutes. The molecular weight distribution of the lactic acid oligomers obtained by the prepolymerization reaction was around 1500, and the distribution coefficient was 1.23-1.31; finally, the prepolymerization reaction solution was taken out and placed in In the depolymerization reactor, the temperature was raised to 180° C., the system pressure was 25 hpa, and the reaction was carried out for 30 minutes to obtain crude lactide with an optical purity of 99.5%. .

[0034] 0.19gCa[N(CH 3 ) 2 ][CH 3 NOCH 3 ]...

Embodiment 2

[0036] Condensation reaction and lactide synthesis reaction are as follows: 300g L-lactic acid aqueous solution (87wt%) is added in 1L prepolymerization reactor and system temperature is raised to 150 ℃, pressure 50hpa, dehydration 30min, detection water content is less than 1%; Then, Add 3.2g prepared catalyst Sn[N(CH 3 ) 2 ][NHOCH 3 ], keep the temperature constant, the system pressure is 50hpa, react for 3h, the molecular weight distribution of the lactic acid oligomers obtained by the prepolymerization reaction is about 1500, and the distribution coefficient is 1.4; finally, the prepolymerization reaction solution is taken out and placed in the depolymerization reactor , the temperature was raised to 170° C., the system pressure was 10 hpa, and the reaction was carried out for 30 minutes to obtain crude lactide with an optical purity of 99.5%.

[0037] 0.35g Sn[N(CH 3 ) 2 ][CH 3 NOCH 3 ] Catalyst, be dissolved in 5mL dichloromethane solvent, then add 34mL toluene sol...

Embodiment 3

[0039] Condensation reaction and lactide synthesis reaction are as follows: 300g L-lactic acid aqueous solution (87wt%) is added in 1L prepolymerization reactor and system temperature is raised to 150 ℃, pressure 50hpa, dehydration 30min, detection water content is less than 1%; Then, Add 1.73g prepared catalyst Mg[N(CH 3 ) 2 ][NHOCH 3 ], the temperature of the reaction system was raised to 160°C, the system pressure was 30hpa, and the reaction was carried out for 0.5h. The molecular weight distribution of the lactic acid oligomers obtained by the prepolymerization reaction was around 1000, and the distribution coefficient was 1.04; finally, the prepolymerization reaction liquid was taken out and placed in a solution In the polymerization reactor, the temperature was raised to 200° C., the system pressure was 10 hpa, and the reaction was carried out for 30 minutes to obtain crude lactide with an optical purity of 99.7%.

[0040] 0.56g Mg[N(CH 3 ) 2 ][CH 3 NOCH 3 ] Cataly...

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Abstract

The invention discloses a diamine metal catalyst and a preparation method thereof, the structural formula of the catalyst is M [N (CH3) 2] [CH3NOCH3], and M is one or more of Zn, Ca, Mg and Sn. The catalyst is used for catalyzing polycondensation of lactic acid monomers, synthesis of lactide and ring-opening polymerization of lactide to prepare polylactic acid. The problems that an existing metal catalyst for catalyzing condensation polymerization and cyclic ester ring opening needs complex ligands, synthesis steps are many, and meanwhile the coordination activity of metal in the reaction process is limited due to the influence of ligand steric hindrance are solved, the used amine donor is small in steric hindrance, and reaction of the metal and a target group in the reaction process is facilitated.

Description

technical field [0001] The invention relates to a diamine-based metal catalyst and a preparation method thereof, as well as its use in polycondensation of lactic acid monomers, synthesis of cyclic esters, and ring-opening of cyclic esters to prepare polylactic acid. Background technique [0002] Polylactic acid, also known as polylactide, is a polymer with excellent performance, biocompatibility and biodegradability, mainly used in degradable packaging materials, drug microsphere carriers, anti-mucosal films, biological catheters, orthopedics Fixtures, orthopedic surgical devices, artificial bones, etc. [0003] Polylactic acid can be synthesized in two ways, one is the direct polycondensation of lactic acid monomers, which is generally difficult to prepare polymers with high relative molecular weight; the other is a two-step method, that is, dehydration and polycondensation of lactic acid to obtain lactic acid oligomerization Then through the cyclization reaction of the ol...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G63/08C08G63/83C08G63/85
Inventor 范天熙何岩刘英俊胡江林陈建旭李洪昌李川董清锋
Owner WANHUA CHEM GRP CO LTD
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