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CN-122011358-A - Polynuclear phosphaborane catalyst and preparation method and application thereof

CN122011358ACN 122011358 ACN122011358 ACN 122011358ACN-122011358-A

Abstract

The invention discloses a polynuclear phosphaborane catalyst, a preparation method and application thereof, belonging to the fields of chemical synthesis and chemical catalysis. The catalyst is constructed by combining a borane component and an organic phosphazene base ligand, has strong basicity of the organic phosphazene base and Lewis acidic sites of multicenter borane, and can efficiently activate monomers and stabilize active species by acid-base synergy. The preparation method takes hexachlorocyclotriphosphazene or octachlorocyclotetraphosphazene as a raw material, obtains a precursor through olefin group substitution, and then reacts with a hydroboration reagent to obtain the hexachlorocyclotriphosphazene or octachlorocyclotetraphosphazene. The catalyst can efficiently catalyze epoxide homopolymerization and epoxide and anhydride copolymerization, and can prepare low-molecular-weight polyether and polyester with controllable structure in a high selectivity manner, and the product has narrow molecular weight distribution and wide application prospect.

Inventors

  • LI ZHIBO
  • LIU SHAOFENG
  • Yuan Chenyao
  • WANG ZEHAO
  • ZHANG JINBO

Assignees

  • 青岛科技大学

Dates

Publication Date
20260512
Application Date
20260127

Claims (10)

  1. 1. The polynuclear phosphaborane catalyst is characterized by having the following structural general formula: The skeleton of the cyclotriphosphazene is [ P 3 N 3 ] Wherein X represents a-R 1 -(CH 2 ) n -BY 2 group; The skeleton of the cyclotetraphosphazene is [ P 4 N 4 ] Wherein X represents a-R 1 -(CH 2 ) n -BY 2 group; Wherein BY 2 is each independently selected from a 9-borabicyclo [3.3.1] nonane derivative group, a cyclopentylborane derivative group, a cyclohexylborane derivative group, a dicyclohexylborane derivative group, a diphenylborane derivative group, or a 3-methylcyclopentaylborane derivative group; The derivative group is a monovalent organic boron group formed by replacing 1B-H bond on boron atom by the listed parent borane, the bonding mode is bonding connection with methylene (-CH 2 -) through boron atom, R 1 is independently selected from N, O, -NH or-CH 2 , and n is a positive integer of 1-3; The catalyst has organic phosphazene alkali skeleton and multicenter borane Lewis acidic site, and the organic phosphazene alkali skeleton and the multicenter borane Lewis acidic site form synergistic catalytic acid-alkali pair.
  2. 2. The polynuclear phosphazene catalyst according to claim 1, wherein the degree of substitution of Cl atoms of the cyclotriphosphazene skeleton is 100%, and the degree of substitution of Cl atoms of the cyclotetraphosphazene skeleton is 100%; The number of Lewis acid sites of the multicenter borane is regulated by the substitution degree on the phosphazene framework, the number of acid sites=the number of substituted Cl atoms or 2 times of the number of substituted Cl atoms, the hexachlorocyclotriphosphazene framework is introduced with 12 acid sites at most, and the octachlorocyclotetraphosphazene framework is introduced with 16 acid sites at most.
  3. 3. A method for preparing the polynuclear phosphazene catalyst according to claim 1 or 2, which is characterized by comprising the steps of carrying out a hydroboration reaction on an olefin-containing substituted phosphazene precursor compound and a hydroboration reagent HBY 2 in an organic solvent, wherein the olefin-containing substituted phosphazene precursor compound is allyl, butenyl or pentenyl, the reaction temperature is 25-60 ℃, the reaction time is 12-48 h, the mole ratio of the olefin-containing substituted phosphazene precursor compound to the hydroboration reagent is 1 (1-16), and purifying after the reaction is finished to obtain the polynuclear phosphazene catalyst.
  4. 4. A method for preparing a polynuclear phosphaborane catalyst according to claim 3, wherein the organic solvent is at least one selected from benzene, toluene, xylene, and tetrahydrofuran; The hydroboration agent HBY 2 is at least one selected from 9-borabicyclo [3.3.1] nonane, cyclopentylborane, cyclohexaylborane, dicyclohexylborane, diphenylborane, and 3-methylcyclopentaylborane.
  5. 5. The method for preparing polynuclear phosphazene catalyst according to claim 3, wherein the preparation method of the phosphazene precursor compound containing olefin group substitution comprises the steps of reacting hexachlorocyclotriphosphazene or octachlorocyclotetraphosphazene serving as a raw material with olefine amine, olefine lithium, olefine Grignard reagent or olefine alcohol in an organic solvent in the presence of an acid binding agent; the reaction temperature is 0-150 ℃, the reaction time is 1-72 h, and the molar ratio of the raw materials, the reaction reagent and the acid binding agent is 1 (1-16): 1-16.
  6. 6. The method for preparing polynuclear phosphaborane catalyst according to claim 5, wherein the acid binding agent is at least one selected from triethylamine, sodium carbonate, sodium bicarbonate, sodium hydroxide and potassium hydroxide; The organic solvent is selected from at least one of benzene, toluene, xylene and tetrahydrofuran; the olefinic lithium or olefinic grignard reagent comprises at least one of allyllithium, allylmagnesium bromide, 2-methylallylmagnesium bromide, 4-pentenylmagnesium bromide.
  7. 7. A preparation method of a polymer is characterized in that the polynuclear phosphaborane catalyst according to claim 1 or 2 is adopted, the polymer is polyether, the reaction is carried out in the presence of a chain transfer agent, the reaction temperature is-20-80 ℃, and the reaction time is 0.1-72 h; The polymer is polyester, the reaction is carried out in the presence of a chain transfer agent and an organic solvent, the reaction temperature is 80-150 ℃, and the reaction time is 0.1-72 h.
  8. 8. The method of claim 7, wherein when the polymer is a polyether, the reactive monomer is at least one epoxide monomer selected from at least one of propylene oxide, ethylene oxide, butylene oxide, hexane oxide, and octane oxide.
  9. 9. The method according to claim 7, wherein when the polymer is a polyester, the reaction monomer is a combination of at least two monomers and the reaction is performed in an organic solvent, the monomers are at least two selected from the group consisting of cyclohexane oxide, propylene oxide, ethylene oxide, butylene oxide, hexane oxide, octane oxide, glutaric anhydride, phthalic anhydride, isophthalic anhydride, succinic anhydride, and the organic solvent is at least one selected from the group consisting of benzene, toluene, methylene chloride, and tetrahydrofuran.
  10. 10. The method for preparing a polymer according to claim 7, wherein the chain transfer agent is 1, 4-terephthalyl alcohol (BDM), ethylene glycol, 1, 3-propanediol or 1, 4-butanediol; When the polymerized monomer is propylene oxide, the number average molecular weight of polyether is 1.4-60.0 kg/mol and the molecular weight distribution is 1.03-2.16 by adjusting the mole ratio of the chain transfer agent to the monomer to be 0.01-1:20; When the molar ratio of the propylene oxide to the phthalic anhydride is 2:1, the polyester can be prepared, the number average molecular weight is 25.4-47.5 kg/mol, and the molecular weight distribution is 1.06-1.14.

Description

Polynuclear phosphaborane catalyst and preparation method and application thereof Technical Field The invention relates to the fields of chemical synthesis and chemical catalysis, in particular to a polynuclear phosphaborane catalyst, a preparation method and application thereof. Background In the fields of chemical synthesis and chemical catalysis, ring Opening Polymerization (ROP) and Ring Opening Copolymerization (ROCOP) are core technical paths for preparing high-performance high-molecular materials such as polyether and polyester, and the materials are widely applied to a plurality of fields such as packaging, medicines, engineering materials and the like. The polymerization efficiency, product structure controllability and reaction condition mildness of cyclic monomers (such as epoxide, anhydride and the like) directly depend on the performance of the catalyst, so the development of a high-efficiency and high-selectivity catalytic system is a research core and key requirement in the field. The phosphazene compound (also called phosphazene) has excellent alkalinity and structure adjustability because of containing characteristic phosphazene (P=N) double bonds, has wide application in anion polymerization catalysis, and can be suitable for polymerization reactions of various monomers such as epoxy compounds, cyclosiloxanes, lactams and the like. The structure of the organic phosphazene base is a core factor for determining the catalytic performance, and the alkali strength and the steric hindrance effect directly influence the monomer activation efficiency, the active species stability and the product selectivity. In the prior art, catalysts such as cyclotriphosphazene alkali CTPB, phosphazene salt P 5 Cl and the like have been proved to form loose ion pairs with borane Lewis acid, and have certain catalytic activity in the copolymerization reaction of epoxide and carbon dioxide, but the catalytic system still has obvious technical defects: 1. Traditional phosphazene catalysts depend on a single active site to play a role, and lack of cooperative optimization of monomer activation, active species stabilization and chain growth regulation leads to limited polymerization reaction efficiency, and particularly, in multi-monomer copolymerization, the reaction rate and the product selectivity are difficult to be compatible. 2. The polymer prepared by the existing catalyst has the problems of wide molecular weight distribution, nonuniform end group structure, difficult precise regulation and control of low molecular weight products and the like, and can not meet the requirement of high-end materials on the refinement of the polymer structure. 3. Most of the catalytic systems need high temperature, high pressure and other auxiliary conditions to achieve effective catalytic activity, so that not only is the process complexity and the production cost increased, but also the product pollution or side reaction is possibly increased. 4. The traditional phosphazene-borane composite catalyst is designed aiming at specific monomer combination, has poor suitability for different types of cyclic monomers (such as epoxide and anhydride), and is difficult to realize the efficient catalytic preparation of one catalyst for various polymers (polyether, polyester and the like). Disclosure of Invention Based on the prior research and the existing problems, the invention provides a polynuclear phosphazene catalyst, a preparation method and application thereof after further research and analysis, and the polynuclear phosphazene catalyst system has the advantages of high activity and easy synthesis, can be efficiently and selectively applied to the field of catalytic polymerization, and greatly expands the types and application fields of organic phosphazenes and organic boron catalysts. In order to achieve the above purpose, the present invention provides the following technical solutions: A polynuclear phosphaborane catalyst having the following structural formula: the skeleton of the cyclotriphosphazene is [ P 3N3 ] Wherein X represents a-R 1-(CH2)n-BY2 group; The skeleton of the cyclotetraphosphazene is [ P 4N4 ] Wherein X represents a-R 1-(CH2)n-BY2 group; Wherein BY 2 is each independently selected from a 9-borabicyclo [3.3.1] nonane derivative group, a cyclopentylborane derivative group, a cyclohexylborane derivative group, a dicyclohexylborane derivative group, a diphenylborane derivative group, or a 3-methylcyclopentaylborane derivative group; The derivative group is a monovalent organic boron group formed by replacing 1B-H bond on boron atom by the listed parent borane (precursor is borane-tetrahydrofuran complex, borane-dimethyl sulfide complex or free borane hydride), the bonding mode is bonded with methylene (-CH 2 -) through boron atom, R 1 is independently selected from N, O, -NH or-CH 2, n is a positive integer of 1-3 (n=1 corresponds to allyl derivative chain, n=2 corresponds to butenyl derivative chain, n=3 corres