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Low-molecular-weight high trans-1,4-polyisoprene and preparation method thereof

A polyisoprene, low molecular weight technology, applied in the field of conjugated diene catalytic polymerization, can solve the problems of reducing the double bond electron cloud density of the molecular chain, difficult to control the cyclization side reaction, and reducing the cyclization side reaction, etc. Good controllable polymerization effect, low polymerization side reaction, high double bond retention rate

Active Publication Date: 2020-06-19
QINGDAO INST OF BIOENERGY & BIOPROCESS TECH CHINESE ACADEMY OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The present invention aims to solve the technical problem that the cyclization side reaction is difficult to control in the process of existing cationic polymerization of isoprene, resulting in the loss of double bonds, starting from the suppression of the cyclization side reaction, to study less but cheap protonic acid (containing different The substituent's bis-sulfonimide protonic acid) is used as a catalyst, and an ionic liquid is used as a solvent to reduce the side reaction of cyclization by reducing the electron cloud density of the double bond of the molecular chain, thereby providing a low-molecular-weight, high-trans-1 , 4-polyisoprene and preparation method thereof

Method used

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  • Low-molecular-weight high trans-1,4-polyisoprene and preparation method thereof
  • Low-molecular-weight high trans-1,4-polyisoprene and preparation method thereof
  • Low-molecular-weight high trans-1,4-polyisoprene and preparation method thereof

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specific Embodiment approach 1

[0032] Specific embodiment 1: The specific steps of a method for preparing a low molecular weight, high trans-1,4-polyisoprene of this embodiment are as follows:

[0033] Under argon atmosphere, add catalyst (2.8mg, 10μmol, 1equiv.), ionic liquid ([C 4 MPyr][NTf 2 ], 0.5mL) and isoprene monomer (20mmol, 2mL, 2000equiv.), polymerize at 25°C for 24h while stirring, quench the reaction with 10mL of methanol, filter, wash the product twice with methanol, and vacuum Dry to obtain low molecular weight, high trans-1,4-polyisoprene;

[0034] The structural formula of the catalyst (2.8 mg, 10 μmol, 1 equiv.) in this embodiment is

[0035] Results: The yield was 95%, the double bond retention (DB) was 88%, and the number average molecular weight (M n ) Is 874g / mol, molecular weight distribution (PDI) is 2.1; selectivity: trans-1,4 structure accounts for 96%, 3,4- structure accounts for 4%.

[0036] figure 1 The low molecular weight, high trans-1,4-polyisoprene obtained in this embodiment 1 HNM...

specific Embodiment approach 2

[0040] Embodiment 2: The difference between this embodiment and Embodiment 1 is that the polymerization reaction time is 28 hours, and the other steps and parameters are the same as Embodiment 1.

[0041] Result: Yield> 99%, double bond retention rate (DB) is 83%, M n It is 985g / mol, PDI is 2.2; Selectivity: trans-1,4 structure accounts for 97%, 3,4- structure accounts for 3%.

specific Embodiment approach 3

[0042] Specific embodiment three: The specific steps of the preparation method of a low molecular weight, high trans-1,4-polyisoprene of this embodiment are as follows:

[0043] Under argon atmosphere, add catalyst (2.8mg, 10μmol, 1equiv.), ionic liquid ([C 4 MPyr][NTf 2 ], 1.25mL) and isoprene monomer (50mmol, 5mL, 5000equiv.), polymerize at 25℃ for 28h while stirring, quench the reaction with 10mL of methanol, filter, wash the product twice with methanol, and vacuum Dry to obtain low molecular weight, high trans-1,4-polyisoprene;

[0044] The structural formula of the catalyst (2.8 mg, 10 μmol, 1 equiv.) in this embodiment is

[0045] Result: Yield> 99%, double bond retention rate (DB) is 87%, M n It is 998g / mol, PDI is 2.4; selectivity: trans-1,4 structure accounts for 96%, 3,4- structure accounts for 4%.

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Abstract

The invention relates to low-molecular-weight high trans-1,4-polyisoprene and a preparation method thereof, belonging to the field of catalytic polymerization of conjugated diene. The invention aims to solve the technical problem of double bond deficiency caused by difficult control of cyclization side reactions in conventional cationic polymerization process of isoprene. According to the low-molecular-weight high trans-1,4-polyisoprene and the preparation method thereof provided in the invention, inhibition of the cyclization side reactions is taken as a start point, protonic acid (disulfimide protonic acid containing different substituent groups) which is rarely researched but has low price is used as a catalyst, ionic liquid is used as a solvent, and the cyclization side reactions are reduced by reducing electron cloud density of molecular chain double bonds. The microstructure composition of the low-molecular-weight high trans-1,4-polyisoprene disclosed by the invention is composedof, in percentage by mass, 90 to 98% of trans-1,4-polyisoprene and 2 to 10% of 3,4-polyisoprene. The number-average molecular weight of the low-molecular-weight high trans-1,4-polyisoprene is 500 g / mol to 3000 g / mol, molecular weight distribution is 1.2-3.0, and a double bond retention rate DB is 82%-94%.

Description

Technical field [0001] The invention belongs to the field of conjugated diene catalytic polymerization, and specifically relates to a low molecular weight, high trans-1,4-polyisoprene and a preparation method thereof. Background technique [0002] As an important material intermediate, Trans-1,4-polyisoprene is widely used in the preparation of tires, films and adhesives. Acid-catalyzed cationic polymerization of isoprene has been extensively studied for the production of high trans-1,4 low molecular weight polymers. However, it is difficult to effectively control the side reactions of cyclization or branching during the polymerization process, which results in the loss of double bonds in the polymer chain. [0003] For a long time, the Lewis catalyst system has received much attention. For example BF 3 Derivatives, AlCl 3 ,SnCl 4 ,TiCl 4 ,AlEt 2 Cl 2 ,[Ph 3 C][SbCl 6 ],[C 7 H 7 ][SbCl 6 ] And other combinations of Lewis acids and cocatalysts have been extensively studied; while ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F136/08C08F4/00C08F2/06
CPCC08F136/08C08F4/00C08F2/06Y02P20/54
Inventor 王庆刚王亮朱广乾
Owner QINGDAO INST OF BIOENERGY & BIOPROCESS TECH CHINESE ACADEMY OF SCI
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