Enhanced Lewis acid-base pair catalytic system and application thereof

Abstract

The invention relates to an enhanced Lewis acid-base pair catalytic system and application thereof. The catalytic system comprises Lewis base, cyclic anhydride and Lewis acid, wherein the molar ratio of the lewis base to the cyclic anhydride to the lewis acid is 1: (0.1-10): (0.25-10). The preparation method comprises the following steps: sequentially adding cyclic anhydride, Lewis base, epoxide and Lewis acid into a reaction kettle, then adding a carbon-single monomer, and carrying out bulk polymerization reaction at 25-150 DEG C under a closed condition for 0.1-36 hours to obtain an epoxy copolymer; according to the invention, the reaction activity and selectivity of Lewis acid-base to a catalytic system can be enhanced, high activity is still maintained under low catalyst concentration, and the highest conversion frequency (TOF) is 78000h <-1 >.

Description

Technical Field

[0001] The invention relates to the field of catalysts, and in particular to an enhanced Lewis acid-base catalytic system and application thereof in the copolymerization of epoxides and carbon-one monomers. Background Art

[0002] Carbon monomers including carbon dioxide (CO2), carbon oxysulfide (COS), and carbon disulfide (CS2) are considered to be abundant, cheap and easily available resources. In the field of polymer material synthesis, the preparation of polymers by ring-opening copolymerization of carbon monomers and epoxides is considered to be a very atom-economical strategy. The prepared polycarbonate is an attractive degradable material. Due to the introduction of sulfur, polythiocarbonate polymers can exhibit excellent optical properties. Studies in recent years have shown that in the field of Lewis acid-base catalysis of epoxide and carbon monomer copolymerization, there are generally problems such as high catalyst concentration, low reaction activity, and poor controllability, which affect the production of products. Therefore, the development of simple, highly active and highly selective catalytic systems is the current research focus.

[0003] In 2017, a literature reported that an acid-base pair system with guanamine, amidine, quaternary ammonium salt and quaternary phosphonium salt as Lewis base and triethylboron as Lewis acid was used to catalyze the ring-opening copolymerization of epoxide and carbon oxysulfide to prepare polythiocarbonate (Angew. Chem. Int. Ed. 2017, 56, 5774–5779). The polymer prepared under the condition of 0.2 mol% Lewis base had a clear structure. However, the Lewis acid-base catalytic system showed low reactivity (turnover frequency (TOF) = 119 h -1 ), and the poor controllability of the reaction system will produce undesirable cyclic compounds with a polymer selectivity of 94%.

[0004] Subsequently, the literature developed an acid-base catalytic system with tertiary amine or diamine as Lewis base and triethylborane as Lewis acid (Polymer Chemistry, 2021, 12, 5283-5288; Macromolecules 2021, 54, 2178-2186). In the copolymerization of epoxide and COS, the reaction activity was greatly improved under the condition of low Lewis base (0.05 mol%), and its TOF = 69800h -1 However, the catalytic system still cannot avoid the production of by-product cyclic compounds and its polymer selectivity is less than 100%. In the copolymerization of epoxide and CO2, the catalytic activity of the catalytic system is low (TOF = 67h -1 ), the catalyst concentration was high, the amount of Lewis base used was 0.2 mol%, and the product selectivity was not ideal (polymer selectivity was 94%).

[0005] In order to solve the problem of low reactivity of epoxide and CO2 copolymerization, a hindered Lewis acid-base pair has been developed recently, including tertiary phosphine as Lewis base and tributyl boron as Lewis acid (Macromolecules 2023, 56, 4901-4909). When the Lewis base was used at 0.3 mol%, the activity of the reaction system was improved, showing moderate reactivity (TOF = 447 h -1 ); however, cyclic carbonates are still inevitably produced (polymer selectivity is 96%). It should be pointed out that when the amount of Lewis base used is reduced to 0.03 mol%, the activity and selectivity of the reaction system are significantly reduced, and the catalytic system shows poor tolerance at 120°C, and the obtained products are almost entirely cyclic carbonates.

[0006] Therefore, there is an urgent need to develop an organic catalytic system with high activity, high temperature resistance and low catalyst loading. Summary of the invention

[0007] The purpose of the present invention is to provide an enhanced Lewis acid-base catalytic system and its application in view of the limitations of the current technology. The catalytic system adds a cyclic anhydride to the Lewis acid-base system, and the cyclic anhydride can interact with the Lewis base in situ to generate a quaternary onium carboxylate intermediate (no need for synthetic preparation, just sequential addition), and this intermediate can further interact with an alkyl boron Lewis acid to generate IV-1 and IV-2 structure compounds. The present invention can enhance the reaction activity and selectivity of the Lewis acid-base catalytic system and still maintain high activity at low catalyst concentrations, with a TOF of 78000h -1 The catalyst raw materials can be obtained from commercial channels, have low cost, do not contain metals and are environmentally friendly.

[0008] The technical solution of the present invention is:

[0009] An enhanced Lewis acid-base catalytic system, the catalytic system comprising a Lewis base, a cyclic anhydride and a Lewis acid;

[0010] The molar ratio of Lewis base: cyclic anhydride: Lewis acid is 1:0.1-10:0.25-10, preferably 1:0.1-4:0.5-4;

[0011] The general structural formula of the Lewis base is shown in (I-1) or (I-2):

[0012]

[0013] In formula (I-1), A is selected from the element P or N; R1, R2, and R3 are independently selected from one or more of hydrogen, C1-C16 saturated or unsaturated alkyl and branched isomers thereof, C1-C16 cycloalkyloxy, di-C1-C16 alkylamino, C1-C16 cycloalkylamino, C1-C16 alkoxy, C1-C16 cycloalkyloxy, 0-5 substituted aromatic groups, and halogen;

[0014] In formula (I-2), A is selected from the element P or N; R1, R2, R3, and R4 are independently selected from one or more of hydrogen, C1-C16 saturated or unsaturated alkyl and branched isomers thereof, C1-C16 cycloalkyloxy, di-C1-C16 alkylamino, C1-C16 cycloalkylamino, C1-C16 alkoxy, C1-C16 cycloalkyloxy, 0-5 substituted aromatic groups, and halogen; n is selected from any integer between 1 and 16;

[0015] The general structural formula of the cyclic anhydride is shown in (II):

[0016]

[0017] In formula (II), R1 and R2 are independently selected from one or more of hydrogen, C1-C16 saturated or unsaturated alkyl and branched isomers thereof, C1-C16 cycloalkyloxy, di-C1-C16 alkylamino, C1-C16 cycloalkylamino, C1-C16 alkoxy, C1-C16 cycloalkyloxy, 0-5 substituted aryl, and halogen;

[0018] The general structural formula of the Lewis acid is shown in (III):

[0019]

[0020] In formula (III), R1, R2, and R3 are independently selected from one or more of hydrogen, C1-C16 saturated or unsaturated alkyl and branched isomers thereof, C1-C16 cycloalkyloxy, di-C1-C16 alkylamino, C1-C16 cycloalkylamino, C1-C16 alkoxy, C1-C16 cycloalkyloxy, 0-5 substituted aromatic groups, and halogen.

[0021] Preferably, the Lewis base is selected from a nucleophilic organic base, which is one or more of an aminophosphine, a tertiary phosphine, a tertiary amine, a guanamine, an amidine, an imidazole, and a pyridine.

[0022] More preferably, the Lewis base is tris(dimethylamino)phosphine (a-1), tris(diethylamino)phosphine (a-2), tris(dipropylamino)phosphine (a-3), tris(dibutylamino)phosphine (a-4), tripyrrolidinephosphine (a-5), tris(piperidin-1-yl)phosphine (a-6), 2,8,9-trimethyl-2,5,8,9-tetraaza-1-phosphabicyclo[3.3.3]undecane (a-7), [2,5,8,9-tetraaza-1-phosphabicyclo[3.3.3]undecane-2,8,9-tri(1-methylethyl)] (a-8), 2,8,9-triisobutyl-2,5,8 ,9-tetraaza-1-phospho[3.3.3]undecane (a-9), triethylamine (b-1), tripropylamine (b-2), tributylamine (b-3), N,N-dimethylcyclohexylamine (b-4), N,N-diethylcyclohexylamine (b-5), trimethylphosphine (c-1), triethylphosphine (c-2), tripropylphosphine (c-3), tributylphosphine (c-4), tri-tert-butylphosphine (c-5), triisopropylphosphine (c-6), tricyclohexylphosphine (c-7), triphenylphosphine (c-8), N,N,N',N'-tetramethylmethanediamine (d-1), N,N,N',N'-tetraethylmethanediamine (d-2 )、N,N,N',N'-tetramethylethylenediamine (d-3), N,N,N',N'-tetraethylethylenediamine (d-4), N,N,N',N'-tetraethyl-1,3-propylenediamine (d-5), 1,4-diazabicyclo[2.2.2]octane (d-6), 1,2-bis(di-tert-butylphosphino)ethane (e-1), 1,2-bis(di-tert-butylphosphino)butane (e-2), 1,2-bis(di-tert-butylphosphino)benzene (e-3), 1,2-bis(dicyclohexylphosphino)ethane (e-4), 1,2-bis(dicyclohexylphosphino)butane (e-5), 1,2-bis(diphenylphosphino)ethane (e- 6), 1,2-bis(diphenylphosphino)propane (e-7), 1,8-diazabicyclo[5.4.0]undec-7-ene (f-1), 1,5-diazabicyclo[4.3.0]non-5-ene (f-2), 1,5,7-triazabicyclo[4.4.0]decene-5-ene (f-3), 7-methyl-1,5,7-triazabicyclo[4.4.0]decene-5-ene (f-4), tetramethylguanidine (f-5), 2-tert-butyl-1,1,3,3-tetramethylguanidine (f-6), pyridine (f-7), 4-dimethylaminopyridine (f-8), imidazole (f-9) One or more. The specific structural formulas are as follows:

[0023]

[0024]

[0025] Preferably, the Lewis acid is one or more of trialkyl boron, dialkyl alkoxy boron, trialkoxy boron, and trisubstituted aryl boron.

[0026] More preferably, the Lewis acid is one or more of triethylboron (a-1), tripropylboron (a-2), tributylboron (a-3), tri-sec-butylboron (a-4), triisopropylboron (a-5), diethylmethoxyboron (a-6), trimethoxyboron (a-7), triphenylboron (a-8), tris(pentafluorophenyl)boron (a-9), and 9-borabicyclo[3.3.1]nonane (a-10). The specific structural formulas are shown below:

[0027]

[0028] Optimized, the cyclic anhydride includes but is not limited to maleic anhydride (a-1), glutaric anhydride (a-2), succinic anhydride (a-3), diglycolic anhydride (a-4), hexahydrophthalic anhydride (a-5), tetrahydrophthalic anhydride (a-6), phthalic anhydride (a-7), 4-methylphthalic anhydride (a-8), 4-chlorophthalic anhydride (a-9), 4-methoxyphthalic anhydride (a-10), 4-nitrophthalic anhydride (a-11), 4-hydroxyphthalic anhydride (a-12), 4-carboxyphthalic anhydride (a-13 ), naphthalene dianhydride (a-10), pyromellitic dianhydride (b-1), bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (b-2), 2,3,6,7-naphthalenetetracarboxylic dianhydride (b-3), naphtho[1,2-c:5,6-c']difuran-1,3,6,8-tetraone (b-4), 2,3,6,7-anthracenetetracarboxylic dianhydride (b-5), benzo[1,2,3-de:4,5,6-d'e']diisobenzopyran-1,3,7,9-tetraone (b-6) or more. The specific structural formulas are as follows:

[0029]

[0030] The application of the enhanced Lewis acid-base catalytic system comprises the following steps:

[0031] Cyclic anhydride, Lewis base, epoxide and Lewis acid are sequentially added into a reaction kettle, and then a carbon one monomer is added, and a bulk polymerization reaction is carried out at 25°C to 150°C under closed conditions for 0.1h to 36h to obtain an epoxy copolymer;

[0032] Wherein, the molar ratio of the Lewis base to the epoxide is 1:300 to 20000;

[0033] The structural formula of the carbon-monomer is shown in (VI):

[0034]

[0035] Wherein, R1 and R2 are independently selected from oxygen or sulfur;

[0036] More preferably, the carbon monomer includes one or more of carbon dioxide, carbon oxysulfide, and carbon disulfide.

[0037] When the carbon monomer is carbon dioxide or carbon oxysulfide, the pressure of the carbon dioxide and carbon oxysulfide is 0.5MPa to 3.0MPa;

[0038] When the carbon monomonomer is carbon disulfide, the molar ratio of the carbon disulfide to the epoxide is 0.5-4:1; the carbon disulfide is added before sealing.

[0039] The copolymerization reaction temperature is preferably 60°C to 120°C; the reaction time is preferably 0.1h to 10h.

[0040] The general structural formula of the epoxide is shown in (V):

[0041]

[0042] Wherein, R1 and R2 are independently selected from one or more of hydrogen, C1-C16 saturated or unsaturated alkyl and branched isomers thereof, C1-C16 cycloalkyloxy, di-C1-C16 alkylamino, C1-C16 cycloalkylamino, C1-C16 alkoxy, C1-C16 cycloalkyloxy, 0-5 substituted aromatic groups, halogen or ester groups.

[0043] Further preferably, the epoxide includes but is not limited to one or more of ethylene oxide, propylene oxide, butylene oxide, hexyl oxide, styrene oxide, epichlorohydrin, allyl glycidyl ether, phenyl glycidyl ester, cyclohexene oxide, vinyl cyclohexene oxide, cyclopentane oxide, and limonene oxide.

[0044] The invention provides a catalytic system for enhancing Lewis acid-base pairs, which realizes epoxide copolymerization with high reactivity and maintains catalytic activity under high reaction temperature and high monomer dosage.

[0045] The essential features of the present invention are:

[0046] In current technology, the structure of Lewis acid-base pairs is as follows:

[0047]

[0048] The coordination bond structure formed by Lewis base and Lewis acid is used to realize the copolymerization reaction of epoxide and carbon-one monomer, wherein the Lewis base part has nucleophilicity and can attack the activated epoxide to form an active growth center for polymerization.

[0049] In the present invention, the third component cyclic anhydride is added to the Lewis base and the Lewis acid, and a novel enhanced Lewis acid-base pair can be generated in situ without any synthetic route, and its structural formula is as follows:

[0050]

[0051] The method utilizes Lewis base to attack cyclic anhydride to form quaternary onium carboxylate zwitterion, which has both nucleophilic and electrophilic dual functions, and further forms a coordination bond structure with triethylboron. The addition of cyclic anhydride can transform Lewis base into electrophilic functional group, and quaternary onium cation can activate epoxide synchronously with triethylboron to improve the initiation and growth rate, and the nucleophilicity of carboxylate group can ensure the formation of growth active center for the initiation of epoxide.

[0052] The beneficial effects of the present invention are:

[0053] (1) The present invention discloses a novel non-metal enhanced Lewis acid-base pair, which is in situ generated by sequentially adding a Lewis base, a cyclic anhydride and a Lewis acid, and is used to catalyze the copolymerization of epoxide and a carbon-monomer to prepare polycarbonates and polythiocarbonates without metal residue, with controllable molecular weight and narrow molecular weight distribution.

[0054] (2) The catalytic activity of the catalytic system disclosed in the present invention is extremely high. In the application of epoxide and CO2 copolymerization, its conversion frequency TOF can reach up to 3600h -1 , which is more than 7 times more active than the current tertiary amine / triethyl boron or tertiary phosphine / tributyl boron catalytic system. In the application of epoxide and COS copolymerization, its conversion frequency TOF can reach up to 78,000h -1 , higher than the tertiary amine / triethyl boron catalytic system (TOF = 69800h -1 ).

[0055] (3) The catalytic system disclosed in the present invention has excellent product selectivity, can avoid the production of undesirable by-product cyclic small molecules. It also has good high temperature tolerance. The reaction system still shows good controllability at 120°C, and the product is mainly polycarbonate. The tertiary phosphine / tributyl boron catalytic system has poor controllability at 120°C, and the products obtained are almost all cyclic carbonates.

[0056] (4) The catalytic system disclosed in the present invention has good universality. The Lewis bases including aminophosphine, tertiary amine, tertiary phosphine, guanamine, amidine, imidazole, pyridine and alkyl boron as well as cyclic anhydrides of different structures can generate enhanced Lewis acid-base pairs and show excellent activity and selectivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 The crude PO / CO2 copolymer prepared in Example 1 1 H NMR spectrum.

[0058] Figure 2 The purified PO / CO2 copolymer prepared in Example 1 1 H NMR spectrum.

[0059] Figure 3 The purified PO / CO2 copolymer prepared in Example 1 13 C NMR spectrum.

[0060] Figure 4 This is the GPC spectrum of the purified PO / CO2 copolymer prepared in Example 1.

[0061] Figure 5 This is the MALDI-TOF MS spectrum of the purified PO / CO2 copolymer prepared in Example 18.

[0062] Figure 6 This is the TGA chart of the purified product of PO / CO2 copolymer prepared in Example 18. DETAILED DESCRIPTION

[0063] The mechanism of the present invention is:

[0064] In the present invention, the third component cyclic anhydride is added to the Lewis base and the Lewis acid, and a novel enhanced Lewis acid-base pair can be generated in situ without any synthetic route, and the general structural formula thereof is shown in (IV-1) or (IV-2):

[0065]

[0066] The method utilizes Lewis base to attack cyclic anhydride to form quaternary onium carboxylate zwitterion, which has both nucleophilic and electrophilic dual functions, and further forms a coordination bond structure with triethylboron. The addition of cyclic anhydride can transform Lewis base into electrophilic functional group, and quaternary onium cation can activate epoxide synchronously with triethylboron to improve the initiation and growth rate, and the nucleophilicity of carboxylate group can ensure the formation of growth active center for the initiation of epoxide.

[0067] Bifunctional catalysts have been developed. It should be noted that the bifunctional catalysts currently developed need to go through multiple synthesis steps and purification steps before they can be used. Unlike the coordination bond effect of the present invention, the bifunctional catalysts are linked by covalent bonds and strongly rely on the influence of the units linked by covalent bonds. The present invention only needs to change the type of cyclic anhydride to change the nucleophilicity and electrophilicity of the catalytic system, which is simpler and more efficient.

[0068] In order to describe the present invention more specifically, the specific implementation scheme is combined with corresponding diagrams to explain the technical solution of the present invention in detail below, but the implementation mode of the present invention is not limited thereto.

[0069] Example 1 Preparation of polycarbonate by PO / CO2 copolymerization

[0070] Before the polymerization reaction, dry the 25mL reactor at 110°C for about 4 hours, cool it to room temperature in a small vacuum chamber in the glove box, and transfer it to a glove box under an argon atmosphere. Add a certain amount of 4-methoxyphthalic anhydride, tri(dibutylamino)phosphine, propylene oxide and triethylboron (the molar ratio of propylene oxide, tri(dibutylamino)phosphine, 4-methoxyphthalic anhydride and triethylboron is 500 / 1 / 1 / 2) to the reactor in sequence, seal the reactor, take out the reactor and fill it with 2.0MPa carbon dioxide, and place it in a 60°C oil bath to react for 2.0h. After the reaction is completed, cool it to room temperature to release the unreacted CO2 gas, take a small amount of the crude polymerization product and add 1 drop of glacial acetic acid to quench the reaction, and add deuterated chloroform to 1 H NMR test determines the composition of the crude product and the composition of the polymer chain segments. The remaining crude polymer product is dissolved in an appropriate amount of dichloromethane, and the polymer is precipitated in a methanol solution acidified with hydrochloric acid. The washing is repeated three times to obtain a pure polymer, which is dried to constant weight under vacuum conditions. The PO conversion rate is calculated by weighing, the content of each chain segment in the polymer is determined by nuclear magnetic resonance, and the molecular weight and molecular weight distribution of the polymer are determined by gel permeation chromatography. The test results are shown in Table 1.

[0071] The polycarbonate obtained in Example 1 was characterized by NMR. The test results are as follows Figure 1 , 2 As shown in Figures 3 and 4, the results show that the polymer has excellent product selectivity (99%), the polycarbonate has a clear alternating structure, excellent structural selectivity (carbonate content CU = 97%), and good regioselectivity (head-to-tail structure HT = 88%). At the same time, it can be observed that cyclic anhydrides exist in the polymer chain segments, which proves the enhanced formation of Lewis acid-base pairs.

[0072] Example 2 Preparation of polycarbonate by PO / CO2 copolymerization

[0073] The polymerization operation and result analysis were the same as those in Example 1, except that the reaction temperature was adjusted to 80° C. and the reaction time was 0.67 h. The test results are shown in Table 1.

[0074] Example 3 Preparation of polycarbonate by PO / CO2 copolymerization

[0075] The polymerization operation and result analysis were the same as those in Example 1, except that the reaction temperature was adjusted to 100° C. and the reaction time was 0.25 h. The test results are shown in Table 1.

[0076] Example 4 Preparation of polycarbonate by PO / CO2 copolymerization

[0077] The polymerization operation and result analysis were the same as those in Example 1, except that the reaction temperature was adjusted to 120° C. and the reaction time was 0.1 h. The test results are shown in Table 1.

[0078] Example 5 Preparation of polycarbonate by PO / CO2 copolymerization

[0079] The polymerization operation and result analysis were the same as those in Example 2, except that the molar ratio was adjusted to 2000 / 1 / 1 / 2 and the reaction time was 5 h. The test results are shown in Table 1.

[0080] Example 6 Preparation of polycarbonate by PO / CO2 copolymerization

[0081] The polymerization operation and result analysis were the same as those in Example 2, except that the molar ratio was adjusted to 4000 / 1 / 1 / 2 and the reaction time was 10 h. The test results are shown in Table 1.

[0082] Example 7 Preparation of polycarbonate by PO / CO2 copolymerization

[0083] The polymerization operation and result analysis were the same as those in Example 2, except that the molar ratio was adjusted to 8000 / 1 / 1 / 2 and the reaction time was 10 h. The test results are shown in Table 1.

[0084] As shown in Table 1, the enhanced Lewis acid-base catalytic system still exhibits high reactivity under high temperature and high monomer dosage conditions. Although it will lead to a decrease in the selectivity of the polymerization product, it still shows that the polymerization system has good high temperature resistance and high monomer dosage tolerance.

[0085] Table 1 Polymerization results of PO / CO2 copolymerization under different reaction conditions

[0086]

[0087] 1 The data are calculated based on the isolated product; 2 are obtained based on the H NMR spectrum test of the crude product; 3 are obtained by gel permeation chromatography test.

[0088] Examples 8 to 14 use different types of cyclic anhydrides and tri(dibutylamino)phosphine / triethylboron to form an enhanced Lewis acid-base catalyst system to catalyze the copolymerization of PO and CO2. The relevant data are summarized in Table 2. It can be found that a variety of cyclic anhydrides and tri(diethylamino)phosphine / triethylboron successfully form an efficient catalyst system, and the obtained polymer selectivity can reach 99%.

[0089] Example 8 Preparation of polycarbonate by PO / CO2 copolymerization

[0090] The polymerization operation and result analysis were the same as those in Example 1, except that 4-methoxyphthalic anhydride was replaced with succinic anhydride (SA) in equal moles. The test results are shown in Table 2.

[0091] Example 9 Preparation of polycarbonate by PO / CO2 copolymerization

[0092] The polymerization operation and result analysis were the same as those in Example 1, except that 4-methoxyphthalic anhydride was replaced with hexahydrophthalic anhydride (CHA) in equal moles. The test results are shown in Table 2.

[0093] Example 10 Preparation of polycarbonate by PO / CO2 copolymerization

[0094] The polymerization operation and result analysis were the same as those in Example 1, except that 4-methoxyphthalic anhydride was replaced with tetrahydrophthalic anhydride (THPA) in equal moles. The test results are shown in Table 2.

[0095] Example 11 Preparation of polycarbonate by PO / CO2 copolymerization

[0096] The polymerization operation and result analysis were the same as those in Example 1, except that 4-methoxyphthalic anhydride was replaced with nadic anhydride (NA) in equal moles. The test results are shown in Table 2.

[0097] Example 12 Preparation of polycarbonate by PO / CO2 copolymerization

[0098] The polymerization operation and result analysis were the same as those in Example 1, except that 4-methoxyphthalic anhydride was replaced with 4-methylphthalic anhydride (4-MePA) in equal moles. The test results are shown in Table 2.

[0099] Example 13 Preparation of polycarbonate by PO / CO2 copolymerization

[0100] The polymerization operation and result analysis were the same as those in Example 1, except that 4-methoxyphthalic anhydride was replaced with phthalic anhydride (PA) in equal moles. The test results are shown in Table 2.

[0101] Example 14 Preparation of polycarbonate by PO / CO2 copolymerization

[0102] The polymerization operation and result analysis were the same as those in Example 1, except that 4-methoxyphthalic anhydride was replaced with 4-chlorophthalic anhydride (4-ClPA) in equal moles. The test results are shown in Table 2.

[0103] Table 2 Polymerization results of PO / CO2 copolymerization with different types of anhydride catalyst systems

[0104]

[0105] 1 The data are calculated based on the isolated product; 2 are obtained based on the H NMR spectrum test of the crude product; 3 are obtained by gel permeation chromatography test.

[0106] Examples 15 to 20 use different types of Lewis bases, phthalic anhydride and triethylboron to form an enhanced Lewis acid-base catalytic system to catalyze the copolymerization of PO and CO2. The relevant data are summarized in Table 3. The various enhanced Lewis acid-base catalytic systems have good universality.

[0107] Example 15 Preparation of polycarbonate by PO / CO2 copolymerization

[0108] The polymerization operation and result analysis were the same as those in Example 5, except that tri(dibutylamino)phosphine was replaced by 1.0 equivalent of triethylamine (Et3N), and 4-methoxyphthalic anhydride was replaced by an equal molar amount of phthalic anhydride; the test results are shown in Table 3.

[0109] Example 16 Preparation of polycarbonate by PO / CO2 copolymerization

[0110] The polymerization operation and result analysis were the same as those in Example 5, except that tri(dibutylamino)phosphine was replaced by 0.5 equivalent of N,N,N',N'-tetraethylethylenediamine (TEED), and 4-methoxyphthalic anhydride was replaced by an equal molar amount of phthalic anhydride; the test results are shown in Table 3.

[0111] Example 17 Preparation of polycarbonate by PO / CO2 copolymerization

[0112] The polymerization operation and result analysis were the same as those in Example 5, except that tri(dibutylamino)phosphine was replaced by 1.0 equivalent of tricyclohexylphosphine (Cy3P), and 4-methoxyphthalic anhydride was replaced by an equal molar amount of phthalic anhydride; the test results are shown in Table 3.

[0113] Example 18 Preparation of polycarbonate by PO / CO2 copolymerization

[0114] The polymerization operation and result analysis were the same as those in Example 5, except that tri(dibutylamino)phosphine was replaced by 1.0 equivalent of tri(dimethylamino)phosphine ((Me2N)3P), and 4-methoxyphthalic anhydride was replaced by an equal molar amount of phthalic anhydride; the test results are shown in Table 3.

[0115] Example 19 Preparation of polycarbonate by PO / CO2 copolymerization

[0116] The polymerization operation and result analysis were the same as those in Example 5, except that tri(dibutylamino)phosphine was replaced by 1.0 equivalent of tri(diethylamino)phosphine ((Et2N)3P), and 4-methoxyphthalic anhydride was replaced by an equal molar amount of phthalic anhydride; the test results are shown in Table 3.

[0117] The matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF MS) results of the purified product are as follows: Figure 5As shown, it can be observed that there are mainly two structures in the polymer: (Et2N)3P-(PO)1-(PO-alt-CO2) n -H and (Et2N)3P-PA-(PA-alt-PO)1-(PO)1-(PO-alt-CO2) n -H, on the one hand, proved the good controllability of the reaction system, PO and CO2 were inserted alternately, and on the other hand, it proved the enhanced Lewis acid-base pair formation again. In terms of polymer material application, the polymer prepared by enhancing the Lewis acid-base pair can enhance the thermal stability of the polymer material, which is better than the current catalytic system. The TGA test results are as follows Figure 6 shown.

[0118] Example 20 Preparation of polycarbonate by PO / CO2 copolymerization

[0119] The polymerization operation and result analysis were the same as those in Example 5, except that tri(dibutylamino)phosphine was replaced by 1.0 equivalent of tripyrrolidinephosphine (Py3P), and 4-methoxyphthalic anhydride was replaced by an equal molar amount of phthalic anhydride; the test results are shown in Table 3.

[0120] Table 3 Polymerization results of PO / CO2 copolymerization in different types of Lewis base catalytic systems

[0121]

[0122] 1 The data are calculated based on the isolated product; 2 are obtained based on the H NMR spectrum test of the crude product; 3 are obtained by gel permeation chromatography test.

[0123] Example 21 Preparation of polythiocarbonate by PO / COS copolymerization

[0124] Before the polymerization reaction, dry the 25mL reactor at 110°C for about 4 hours, cool it to room temperature in a small vacuum chamber in the glove box, and transfer it to a glove box under an argon atmosphere. Add a certain amount of 4-methoxyphthalic anhydride, tri(dibutylamino)phosphine, propylene oxide, and triethylboron (the molar ratio of propylene oxide, tri(dibutylamino)phosphine, phthalic anhydride, and triethylboron is 1000 / 1 / 1 / 1) to the reactor in sequence, seal the reactor, take out the reactor, fill it with 2.0MPa carbon oxysulfide, and place it in an 80°C oil bath to react for 1.0 min. After the reaction is completed, cool it to room temperature to release the unreacted COS gas, take a small amount of the crude polymerization product, add 1 drop of glacial acetic acid to quench the reaction, and add deuterated chloroform to 1H NMR test determines the composition of the crude product and the composition of the polymer chain segments. The remaining crude polymer product is dissolved in an appropriate amount of dichloromethane, and the polymer is precipitated in a methanol solution acidified with hydrochloric acid. The washing is repeated three times to obtain a pure polymer, which is dried to constant weight under vacuum conditions. The PO conversion rate is calculated by weighing, the content of each chain segment in the polymer is determined by nuclear magnetic resonance, and the molecular weight and molecular weight distribution of the polymer are determined by gel permeation chromatography. The test results are shown in Table 1.

[0125] Example 22 Preparation of polythiocarbonate by PO / COS copolymerization

[0126] The polymerization operation and result analysis were the same as those in Example 19, except that the molar ratio was adjusted to 2000 / 1 / 1 / 1 and the reaction time was 2.0 min.

[0127] Example 23 Preparation of polythiocarbonate by PO / COS copolymerization

[0128] The polymerization operation and result analysis were the same as those in Example 19, except that the molar ratio was adjusted to 5000 / 1 / 1 / 1 and the reaction time was 2.0 min.

[0129] Table 4 Polymerization results of PO / COS copolymerization under different monomer ratios

[0130]

[0131] 1 The data are calculated based on the isolated product; 2 are obtained based on the H NMR spectrum test of the crude product; 3 are obtained by gel permeation chromatography test.

[0132] Matters not covered by the present invention are known technologies.

Claims

1. An enhanced Lewis acid-base catalytic system, characterized in that: The catalytic system includes a Lewis base, a cyclic acid anhydride and a Lewis acid; Wherein, the molar ratio of Lewis base: cyclic anhydride: Lewis acid is 1:0.1-10:0.25-10; The general structural formula of the Lewis base is shown in (I-1) or (I-2): In formula (I-1), A is selected from the element P or N; R1, R2, and R3 are independently selected from one or more of hydrogen, C1-C16 saturated or unsaturated alkyl and branched isomers thereof, C1-C16 cycloalkyloxy, di-C1-C16 alkylamino, C1-C16 cycloalkylamino, C1-C16 alkoxy, C1-C16 cycloalkyloxy, 0-5 substituted aromatic groups, and halogen; In formula (I-2), A is selected from the element P or N; R1, R2, R3, and R4 are independently selected from one or more of hydrogen, C1-C16 saturated or unsaturated alkyl and branched isomers thereof, C1-C16 cycloalkyloxy, di-C1-C16 alkylamino, C1-C16 cycloalkylamino, C1-C16 alkoxy, C1-C16 cycloalkyloxy, 0-5 substituted aromatic groups, and halogen; n is selected from any integer between 1 and 16; The general structural formula of the cyclic anhydride is shown in (II): In formula (II), R1 and R2 are independently selected from one or more of hydrogen, C1-C16 saturated or unsaturated alkyl and branched isomers thereof, C1-C16 cycloalkyloxy, di-C1-C16 alkylamino, C1-C16 cycloalkylamino, C1-C16 alkoxy, C1-C16 cycloalkyloxy, 0-5 substituted aryl, and halogen; The general structural formula of the Lewis acid is shown in (III): In formula (III), R1, R2, and R3 are independently selected from one or more of hydrogen, C1-C16 saturated or unsaturated alkyl and branched isomers thereof, C1-C16 cycloalkyloxy, di-C1-C16 alkylamino, C1-C16 cycloalkylamino, C1-C16 alkoxy, C1-C16 cycloalkyloxy, 0-5 substituted aromatic groups, and halogen.

2. The enhanced Lewis acid-base catalytic system according to claim 1, characterized in that the molar ratio of Lewis base: cyclic anhydride: Lewis acid is 1:0.1-4:0.5-4; The Lewis base is one or more of aminophosphine, tertiary phosphine, tertiary amine, guanamine, amidine, imidazole, and pyridine; The Lewis acid is one or more of trialkyl boron, dialkyl alkoxy boron, trialkoxy boron, and trisubstituted aryl boron.

3. The enhanced Lewis acid-base catalytic system according to claim 1, characterized in that: The Lewis base is tris(dimethylamino)phosphine (a-1), tris(diethylamino)phosphine (a-2), tris(dipropylamino)phosphine (a-3), tris(dibutylamino)phosphine (a-4), tripyrrolidinephosphine (a-5), tris(piperidin-1-yl)phosphine (a-6), 2,8,9-trimethyl-2,5,8,9-tetraaza-1-phosphabicyclo[3.3.3]undecane (a-7), [2,5,8,9-tetraaza-1-phosphabicyclo[3.3.3]undecane-2,8,9-tri(1-methylethyl)] (a-8), 2,8,9-triisobutyl-2,5,8,9-tetraaza Hetero-1-phospho[3.3.3]undecane (a-9), triethylamine (b-1), tripropylamine (b-2), tributylamine (b-3), N,N-dimethylcyclohexylamine (b-4), N,N-diethylcyclohexylamine (b-5), trimethylphosphine (c-1), triethylphosphine (c-2), tripropylphosphine (c-3), tributylphosphine (c-4), tri-tert-butylphosphine (c-5), triisopropylphosphine (c-6), tricyclohexylphosphine (c-7), triphenylphosphine (c-8), N,N,N',N'-tetramethylmethanediamine (d-1), N,N,N',N'-tetraethylmethanediamine (d-2), N , N,N',N'-tetramethylethylenediamine (d-3), N,N,N',N'-tetraethylethylenediamine (d-4), N,N,N',N'-tetraethyl-1,3-propylenediamine (d-5), 1,4-diazabicyclo[2.2.2]octane (d-6), 1,2-bis(di-tert-butylphosphino)ethane (e-1), 1,2-bis(di-tert-butylphosphino)butane (e-2), 1,2-bis(di-tert-butylphosphino)benzene (e-3), 1,2-bis(dicyclohexylphosphino)ethane (e-4), 1,2-bis(dicyclohexylphosphino)butane (e-5), 1,2-bis(diphenylphosphino)ethane (e-6) , 1,2-bis(diphenylphosphino)propane (e-7), 1,8-diazabicyclo[5.4.0]undec-7-ene (f-1), 1,5-diazabicyclo[4.3.0]non-5-ene (f-2), 1,5,7-triazabicyclo[4.4.0]decene-5-ene (f-3), 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (f-4), tetramethylguanidine (f-5), 2-tert-butyl-1,1,3,3-tetramethylguanidine (f-6), pyridine (f-7), 4-dimethylaminopyridine (f-8), imidazole (f-9) or one or more thereof; The Lewis acid is one or more of triethylboron (a-1), tripropylboron (a-2), tributylboron (a-3), tri-sec-butylboron (a-4), triisopropylboron (a-5), diethylmethoxyboron (a-6), trimethoxyboron (a-7), triphenylboron (a-8), tris(pentafluorophenyl)boron (a-9), and 9-borabicyclo[3.3.1]nonane (a-10); The cyclic anhydride is maleic anhydride (a-1), glutaric anhydride (a-2), succinic anhydride (a-3), diglycolic anhydride (a-4), hexahydrophthalic anhydride (a-5), tetrahydrophthalic anhydride (a-6), phthalic anhydride (a-7), 4-methylphthalic anhydride (a-8), 4-chlorophthalic anhydride (a-9), 4-methoxyphthalic anhydride (a-10), 4-nitrophthalic anhydride (a-11), 4-hydroxyphthalic anhydride (a-12), 4-carboxyphthalic anhydride (a-13), deicing One or more of succinic anhydride (a-10), pyromellitic anhydride (b-1), bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic anhydride (b-2), 2,3,6,7-naphthalenetetracarboxylic anhydride (b-3), naphtho[1,2-c:5,6-c']difuran-1,3,6,8-tetraone (b-4), 2,3,6,7-anthracenetetracarboxylic anhydride (b-5), and benzo[1,2,3-de:4,5,6-d'e']diisobenzopyran-1,3,7,9-tetraone (b-6).

4. The use of the enhanced Lewis acid-base catalytic system as claimed in claim 1, characterized in that: The steps include: Cyclic anhydride, Lewis base, epoxide and Lewis acid are sequentially added into a reaction kettle, and then a carbon one monomer is added, and a bulk polymerization reaction is carried out at 25°C to 150°C under closed conditions for 0.1h to 36h to obtain an epoxy copolymer; Wherein, the molar ratio of the Lewis base to the epoxide is 1:300 to 20000; The structural formula of the carbon-monomer is shown in (VI): Wherein, R1 and R2 are independently selected from oxygen or sulfur.

5. The use of the enhanced Lewis acid-base catalytic system as claimed in claim 4, characterized in that: The carbon monomer includes one or more of carbon dioxide, carbon oxysulfide, and carbon disulfide; When the carbon monomer is carbon dioxide or carbon oxysulfide, the pressure of the carbon dioxide and carbon oxysulfide is 0.5MPa to 3.0MPa; When the carbon monomonomer is carbon disulfide, the molar ratio of the carbon disulfide to the epoxide is 0.5-4:1; the carbon disulfide is added before sealing.

6. The use of the enhanced Lewis acid-base catalytic system as claimed in claim 4, characterized in that: The copolymerization reaction temperature is 60°C to 120°C; the reaction time is 0.1h to 10h.

7. The use of the enhanced Lewis acid-base catalytic system as claimed in claim 4, characterized in that: The general structural formula of the epoxide is shown in (V): Wherein, R1 and R2 are independently selected from one or more of hydrogen, C1-C16 saturated or unsaturated alkyl and branched isomers thereof, C1-C16 cycloalkyloxy, di-C1-C16 alkylamino, C1-C16 cycloalkylamino, C1-C16 alkoxy, C1-C16 cycloalkyloxy, 0-5 substituted aromatic groups, halogen or ester groups.

8. The use of the enhanced Lewis acid-base catalytic system as claimed in claim 4, characterized in that: The epoxide is one or more of ethylene oxide, propylene oxide, butylene oxide, hexyl oxide, styrene oxide, epichlorohydrin, allyl glycidyl ether, phenyl glycidyl ester, cyclohexene oxide, vinyl cyclohexene oxide, cyclopentane oxide, and limonene oxide.

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