CN107226903B - A kind of the difunctional of synthesis of chiral glycol, bimetallic catalyst and its application - Google Patents

Abstract

The present invention relates to the catalyst fields for polycarbonate synthesis, in particular to difunctional, the bimetallic catalyst of synthesis isotaxy polycarbonate are reacted in a kind of the difunctional of synthesis of chiral glycol, bimetallic catalyst and its application by catalytic activation carbon dioxide with meso epoxyalkane.The catalyst is for synthesizing isotaxy polycarbonate, which is that two metal centers are connected double tetradentate schiff base complexs by biphenyl backbone, and quaternary ammonium salt or quaternary phosphonium salt groups there are two containing in molecule.Selective catalysis carbon dioxide reacts difunctional, the bimetallic catalyst of preparation stereoregularity polycarbonate with meso epoxyalkane under the present invention reaction condition lower and relatively mild in catalyst concn, the polycarbonate of synthesis passes through simple hydrolysis, it is easy to obtain the diol compound of high chiral content.

Description

A kind of bifunctional, bimetallic catalyst and application thereof for synthesizing chiral diol

technical field

The invention relates to the field of catalysts for synthesizing polycarbonates, in particular to a bifunctional and bimetallic catalyst for synthesizing chiral diols and its application, which can be used to synthesize isotactic structures by catalytically activating carbon dioxide and meso-alkylene oxides. Bifunctional, bimetallic catalysts for polycarbonates.

Background technique

The excessive emission of carbon dioxide in human daily life and industrial production makes carbon dioxide the main gas that causes the greenhouse effect. However, on the other hand, carbon dioxide is still one of the most important carbon sources on the earth, and is the most important part of the carbon cycle in nature. The chemical fixation of carbon dioxide is an important research field of green chemistry. Among them, the asymmetric alternating copolymerization of carbon dioxide and alkylene oxide to form polycarbonate is one of its most important applications. Under the action of catalyst, carbon dioxide can be copolymerized with alkylene oxide to prepare biodegradable polycarbonate. The high polymer has excellent oxygen and water barrier properties, and can be used as engineering plastics, biodegradable non-polluting materials, disposable medicine and food packaging materials, adhesives and composite materials, etc.

There are many patent reports on the preparation of polycarbonate by copolymerization of carbon dioxide and alkylene oxide at home and abroad, such as: U.S. Patents US 3585168, US 3900424 and US 3953383, using a two-component catalyst based on alkyl zinc to obtain polycarbonate with a molecular weight higher than 20,000 Polycarbonate, polyurethane and polyether. Japan has disclosed patent patents JP 02142824 and JP02575199, using porphyrin complexes to catalyze carbon dioxide and alkylene oxide to synthesize polycarbonate, the catalytic efficiency is as high as 10 ³ to 10 ⁴ grams of polymer per mole of catalyst, but the molecular weight of the polymer is only about 5000, and The response time needs more than 10 days. Japan's Nozaki (J.Am.Chem.Soc.,1999,121,11008-11009) and Coates (Chem.Commum,2000,2007-2008) applied chiral bimetallic zinc complexes to catalyze epoxycyclohexane or Identical polycarbonate was prepared by alternating copolymerization of epoxycyclopentane and carbon dioxide. However, this method has low catalytic activity and the obtained polycarbonate is in an amorphous state, which makes the injection molding process of the polymer difficult. The patent reported by Lu Xiaobing's research group (CN 102229745A, J.Am.Chem.Soc., 2012,134,5682-5688) uses an asymmetric Salen complex to catalyze the alternating copolymerization of epoxycyclohexane and carbon dioxide, and prepares a crystalline High performance polycarbonate, but requires a lower reaction temperature.

Most of the above methods for preparing polycarbonate have low catalyst activity, long reaction time, and high pressure, which requires an organic solvent, accompanied by the production of cyclic carbonate by-products or low carbonate units in the polymerization product, and the catalyst and reaction in the reaction system. The molar ratio of the substrate is high, and the separation of the product and the catalyst is difficult.

Contents of the invention

The technical problem to be solved by the present invention is to provide a bifunctional, bimetallic catalyst that selectively catalyzes the reaction of carbon dioxide and meso-alkylene oxide to prepare stereoregular polycarbonate under low catalyst concentration and relatively mild reaction conditions For its application, the synthesized polycarbonate is easily hydrolyzed to obtain diol compounds with high chiral content.

Technical scheme of the present invention is:

A bifunctional, bimetallic catalyst for the synthesis of chiral diols for the synthesis of isotactic polycarbonates, the catalyst being a bistetradentate Schiff base complex with two metal centers linked by a biphenyl skeleton, and The molecule contains two quaternary ammonium salts or quaternary phosphonium salt groups, and its structural formula is as follows:

In the formula, M is Fe ³⁺ , Co ³⁺ , Ni ³⁺ , Cr ³⁺ , Mn ³⁺ , Al ³⁺ or Ru ³⁺ ;

R ¹ is H, CH ₃ , CH ₂ CH ₃ , CH(CH ₃ ) ₂ , C(CH ₃ ) ₃ , OCH ₃ , OCH ₂ CH ₃ , adamantyl F, Cl, Br, I or NO2 _;

R ² is H, CH ₃ , CH ₂ CH ₃ or Ph;

R ³ is C ₁ -C ₆ alkyl or phenyl;

Y is F ^– , Cl ^– , Br ^– , I ^– , NO ₃ ^– , CH ₃ COO ^– , CCl ₃ COO ^– , CF ₃ COO ^– , ClO ₄ ^– , BF ₄ ^– , BPh ₄ ^– , N ₃ ^– , Toluate, p-toluenesulfonate, o-nitrophenolate, p-nitrophenolate, m-nitrophenolate, 2,4-dinitrophenolate, 3,5-dinitrophenolate phenoxy, 2,4,6-trinitrophenoloxy, 3,5-dichlorophenoloxy, 3,5-difluorophenoloxy, 3,5-di-trifluoromethylphenoloxy or pentafluorophenol Oxygen anions;

Z is N or P;

n=0～10;

^R4 is one;

R ⁵ is H, CH ₃ , CH ₂ CH ₃ , CH(CH ₃ ) ₂ , C(CH ₃ ) ₃ , OCH ₃ , OCH ₂ CH ₃ , F, Cl, Br, I or NO ₂ ;

R ⁶ is H, CH ₃ , CH ₂ CH ₃ , CH(CH ₃ ) ₂ , C(CH ₃ ) ₃ , OCH ₃ , OCH ₂ CH ₃ , Cl, Br, I or NO ₂ ;

X is F ^- , Cl ^- , Br ^- , I ^- , NO ₃ ^- , CH ₃ COO ^- , CCl ₃ COO ^- , CF ₃ COO ^- , ClO ₄ ^- , BF ₄ ^- , BPh ₄ ^- , N ₃ ^- , p Methylbenzoate, p-toluenesulfonate, o-nitrophenolate, p-nitrophenolate, m-nitrophenolate, 2,4-dinitrophenolate, 3,5-dinitrophenolate, 2 , 4,6-trinitrophenoloxy, 3,5-dichlorophenoloxy, 3,5-difluorophenoloxy, 3,5-di-trifluoromethylphenoloxy, or pentafluorophenoloxy anion.

The application of a bifunctional and bimetallic catalyst for the synthesis of chiral diols as claimed in claim 1, at first, in an autoclave, add catalyst and solvent in the following order at ambient temperature; then, to the sealed autoclave Pump in alkylene oxide respectively, feed carbon dioxide gas, and rise to the set temperature; then, after maintaining the set temperature, pressure and reaction time in the autoclave, stop stirring, release unreacted carbon dioxide, and use chloroform/ The methanol precipitate was washed clean, dried to constant weight under vacuum, and polycarbonate was synthesized;

Among them, the reaction conditions are as follows: the reaction temperature is -20 to 120°C, the _CO2 pressure is 0.1 to 6.0 MPa, the molar ratio of the catalyst to the alkylene oxide is 1:1000 to 1:200000, the reaction is 1 to 48 hours, and the reaction solvent is toluene or ethylene glycol dimethyl ether.

The application of the bifunctional and bimetallic catalysts for the synthesis of chiral diols, in the described reaction conditions, as the reactant meso-alkylene oxide, its structural formula is:

one.

According to the application of the bifunctional and bimetallic catalyst for synthesizing chiral diol, the polycarbonate synthesized by the bifunctional and bimetallic catalyst has an isotropic degree of 95-99%.

The present invention has the following advantages and beneficial effects:

1. The present invention still has high catalytic activity at low catalyst concentration.

2. The reaction conditions of the present invention are relatively mild, and the process is simple and convenient.

3. The catalyst of the present invention has high activity and high selectivity of polymerization products.

4. The alternating structure in the polycarbonate product of the present invention is higher than 98%, and the molecular weight distribution is relatively narrow.

5. The polycarbonate obtained in the present invention has an isotacticity higher than 99%, and some polymers are semi-crystalline materials.

6. After the high isotacticity polymer obtained in the present invention is hydrolyzed by aqueous sodium hydroxide solution, the enantiomeric excess values of the obtained diols are all >99%.

Description of drawings

Fig. 1 is the ¹ H NMR spectrum of the polycyclopentenyl carbonate of the present invention.

Fig. 2 is the ¹ H NMR spectrum of the polycarbonate of cis-2,3 butylene oxide of the present invention.

Fig. 3 is the ¹ H NMR spectrum of the polycarbonate of 3,4-epoxytetrahydrofuran of the present invention.

Fig. 4 is the ¹ H NMR spectrum of the polycarbonate of 2,3-epoxy-1,2,3,4-tetralin of the present invention.

Fig. 5 is the ¹ H NMR spectrum of the polycarbonate of 4,4-dimethyl-3,5,8-trioxa-bicyclo[5.1.0]octane of the present invention.

Fig. 6 is the ¹³ C NMR spectrum of the polycyclopentenyl carbonate of the present invention.

Fig. 7 is the ¹³ C NMR spectrum of the polycarbonate of cis-2,3 butylene oxide of the present invention.

Fig. 8 is a ¹³ C NMR spectrum of the polycarbonate of 3,4-epoxytetrahydrofuran of the present invention.

Fig. 9 is a ¹³ C NMR spectrum of polycarbonate of 2,3-epoxy-1,2,3,4-tetralin.

Fig. 10 is a ¹³ C NMR spectrum of polycarbonate of 4,4-dimethyl-3,5,8-trioxa-bicyclo[5.1.0]octane.

Fig. 11 is an NMR spectrum of a chiral diol in an embodiment of the present invention.

Fig. 12 is the NMR spectrum of chiral diol in another embodiment of the present invention.

Detailed ways

In the specific implementation process, the bifunctional and bimetallic catalyst for synthesizing chiral diol of the present invention is used for synthesizing isotactic polycarbonate. The catalyst is a double tetradentate mat that connects two metal centers through a biphenyl skeleton. Phosphate base complexes, and contain two quaternary ammonium salts or quaternary phosphonium salt groups in the molecule, and its structural formula is as follows:

In the formula, M is Fe ³⁺ , Co ³⁺ , Ni ³⁺ , Cr ³⁺ , Mn ³⁺ , Al ³⁺ or Ru ³⁺ ;

R ¹ is H, CH ₃ , CH ₂ CH ₃ , CH(CH ₃ ) ₂ , C(CH ₃ ) ₃ , OCH ₃ , OCH ₂ CH ₃ , adamantyl F, Cl, Br, I or NO2 _;

R ² is H, CH ₃ , CH ₂ CH ₃ or Ph;

R ³ is C ₁ -C ₆ alkyl or phenyl;

Y is F ^– , Cl ^– , Br ^– , I ^– , NO ₃ ^– , CH ₃ COO ^– , CCl ₃ COO ^– , CF ₃ COO ^– , ClO ₄ ^– , BF ₄ ^– , BPh ₄ ^– , N ₃ ^– , Toluate, p-toluenesulfonate, o-nitrophenolate, p-nitrophenolate, m-nitrophenolate, 2,4-dinitrophenolate, 3,5-dinitrophenolate phenoxy, 2,4,6-trinitrophenoloxy, 3,5-dichlorophenoloxy, 3,5-difluorophenoloxy, 3,5-di-trifluoromethylphenoloxy or pentafluorophenol Oxygen anions;

Z is N or P;

n=0～10;

^R4 is one;

R ⁵ is H, CH ₃ , CH ₂ CH ₃ , CH(CH ₃ ) ₂ , C(CH ₃ ) ₃ , OCH ₃ , OCH ₂ CH ₃ , F, Cl, Br, I or NO ₂ ;

R ⁶ is H, CH ₃ , CH ₂ CH ₃ , CH(CH ₃ ) ₂ , C(CH ₃ ) ₃ , OCH ₃ , OCH ₂ CH ₃ , Cl, Br, I or NO ₂ ;

X is F ^- , Cl ^- , Br ^- , I ^- , NO ₃ ^- , CH ₃ COO ^- , CCl ₃ COO ^- , CF ₃ COO ^- , ClO ₄ ^- , BF ₄ ^- , BPh ₄ ^- , N ₃ ^- , p Methylbenzoate, p-toluenesulfonate, o-nitrophenolate, p-nitrophenolate, m-nitrophenolate, 2,4-dinitrophenolate, 3,5-dinitrophenolate, 2 , 4,6-trinitrophenoloxy, 3,5-dichlorophenoloxy, 3,5-difluorophenoloxy, 3,5-di-trifluoromethylphenoloxy, or pentafluorophenoloxy anion.

The specific embodiments of the present invention are described in detail below in conjunction with the technical solutions, see Table 1.

In a 100mL stainless steel autoclave, add in the following order at ambient temperature: a certain amount of catalyst (any metal complex mentioned above) and solvent (used to dissolve the generated polymer, which is toluene or ethylene glycol dimethyl ether) ). Then pump 20mL of alkylene oxide into the sealed autoclave respectively, introduce carbon dioxide gas, and quickly raise it to the set temperature, and keep the carbon dioxide pressure in the reaction system constant through the regulating valve. Then keep the autoclave at an appropriate temperature and pressure and after a regular reaction time, stop stirring and slowly release unreacted carbon dioxide. The polymer product was precipitated and washed three times with chloroform/methanol, dried under vacuum to constant weight, and the molecular weight and distribution of the polymer were determined by gel permeation chromatography. Use Varian INOVA-400MHz to measure its ¹ HNMR, and calculate the carbonate unit content of the polymer product. Measure its ¹³ CNMR with 500MHz NMR, and calculate the tacticity of polycarbonate. For the use of chiral catalyst, the polymer product is hydrolyzed into chiral diol with NaOH dilute solution, and its enantioselectivity is determined by chiral chromatography.

Table 1. Alternating copolymerization of carbon dioxide and alkylene oxide catalyzed by trivalent metal complexes

As shown in FIG. 1 , it can be seen from the ¹ H NMR spectrum of the polycyclopentenyl carbonate of the embodiment of the present invention, these data indicate that the structure of the polymer product prepared in this embodiment is correct.

As shown in Figure 2, it can be seen from the ¹ H NMR spectrogram of the polycarbonate of cis-2,3 epoxybutylene in the embodiment of the present invention that these data illustrate that the structure of the polymer product prepared in this embodiment is correct .

As shown in FIG. 3 , it can be seen from the ¹ H NMR spectrum of the polycarbonate of 3,4-epoxytetrahydrofuran in the embodiment of the present invention, these data indicate that the structure of the polymerization product prepared in this embodiment is correct.

As shown in Figure 4, from the ¹ H NMR spectrogram of the polycarbonate of 2,3-epoxy-1,2,3,4-tetralin of the embodiment of the present invention, it can be seen that these data illustrate the present embodiment The structure of the obtained polymer product is correct.

As shown in Figure 5, it can be seen from the ¹ H NMR spectrum of the polycarbonate of 4,4-dimethyl-3,5,8-trioxa-bicyclo[5.1.0]octane of the embodiment of the present invention These data show that the structure of the polymer product obtained in this embodiment is correct.

As shown in FIG. 6 , it can be seen from the ¹³ C NMR spectrum of the polycyclopentenyl carbonate of the embodiment of the present invention, these data indicate that the structure of the polymerization product prepared in this embodiment is correct.

As shown in Figure 7, it can be seen from the ¹³ C NMR spectrogram of the polycarbonate of cis-2,3 epoxybutylene in the embodiment of the present invention that these data show that the structure of the polymer product prepared in this embodiment is correct .

As shown in Figure 8, it can be seen from the ¹³ C NMR spectrogram of the polycarbonate of cis-2,3 epoxybutylene in the embodiment of the present invention, these data show that the structure of the polymerization product prepared in this embodiment is correct .

As shown in Figure 9, it can be seen from the ¹³ C NMR spectrogram of the polycarbonate of 2,3-epoxy-1,2,3,4-tetrahydronaphthalene in the embodiment of the present invention that these data illustrate the present embodiment The structure of the obtained polymer product is correct.

As shown in Figure 10, it can be seen from the ¹³ C NMR spectrum of the polycarbonate of 4,4-dimethyl-3,5,8-trioxa-bicyclo[5.1.0]octane of the embodiment of the present invention These data show that the structure of the polymer product obtained in this embodiment is correct.

The chiral diol that adopts bifunctional of the present invention, bimetallic catalyst synthesized is as follows:

As shown in FIG. 11 , it can be seen from the NMR spectrum of a chiral diol in an example of the present invention, these data indicate that the structure of the chiral diol prepared in this example is correct.

As shown in FIG. 12 , it can be seen from the NMR spectrum of the chiral diol in another embodiment of the present invention, these data indicate that the structure of the chiral diol prepared in this embodiment is correct.

Claims (4)

1. a kind of difunctional, the bimetallic catalyst of synthesis of chiral glycol, which is characterized in that for synthesizing isotactic poly carbonic acid Ester, the catalyst are to connect two metal centers by biphenyl backbone to obtain double tetradentate schiff base complexs, and molecule In contain there are two quaternary ammonium salt or quaternary phosphine salt groups, structural formula it is as follows:

In formula, M Fe³⁺、Co³⁺、Ni³⁺、Cr³⁺、Mn³⁺、Al³⁺Or Ru³⁺；

R¹For OCH₃、OCH₂CH₃, adamantylOr F；

R²For Ph；

R³For C₁~C₆Alkyl or phenyl；

Y is F^–、Cl^–、Br^–、I^–、NO₃ ^–、CH₃COO^–、CCl₃COO^–、CF₃COO^–、ClO₄ ^–、BF₄ ^–、BPh₄ ^–、N₃ ^–, p-methylbenzoic acid Root, p-methyl benzenesulfonic acid root, o-nitrophenol oxygen, p- nitrophenol oxygen, m- nitrophenol oxygen, 2,4- dinitrophenol oxygen, 3,5- dinitrophenol oxygen, 2,4,6- trinitrophenol oxygen, 3,5- chlorophenesic acid oxygen, 3,5- difluorophenol oxygen, bis--trifluoro of 3,5- Methylphenol oxygen or pentafluranol negative oxygen ion；

Z is N or P；

N=0~10；

R⁴ForOne of；

R⁵For H, CH₃、CH₂CH₃、CH(CH₃)₂、C(CH₃)₃、OCH₃、OCH₂CH₃, F, Cl, Br, I or NO₂；

R⁶For H, CH₃、CH₂CH₃、CH(CH₃)₂、C(CH₃)₃、OCH₃、OCH₂CH₃, Cl, Br, I or NO₂；

X is F^-、Cl^-、Br^-、I^-、NO₃ ^-、CH₃COO^-、CCl₃COO^-、CF₃COO^-、ClO₄ ^-、BF₄ ^-、BPh₄ ^-、N₃ ^-, p-methylbenzoic acid Root, p-methyl benzenesulfonic acid root, o-nitrophenol oxygen, p-nitrophenol oxygen, metanitrophenol oxygen, 2,4- dinitrophenol oxygen, 3,5- Dinitrophenol oxygen, 2,4,6- trinitrophenol oxygen, 3,5- chlorophenesic acid oxygen, 3,5- difluorophenol oxygen, 3,5- di-trifluoromethyl Phenol oxygen or pentafluranol negative oxygen ion.

2. a kind of difunctional, bimetallic catalyst application of synthesis of chiral glycol described in claim 1, which is characterized in that Firstly, catalysts and solvents are added in the following order in autoclave, under environment temperature；Then, to the autoclave sealed It is pumped into epoxyalkane respectively, is passed through carbon dioxide gas, and rise to set temperature；Then, by autoclave keep setting temperature, Pressure and after the reaction time stops stirring, discharges unreacted carbon dioxide, and polymerization product is dry with chloroform/methanol washing of precipitate Only, it is dried under vacuum to constant weight, polycarbonate synthesis；

Wherein, reaction condition is as follows: reaction temperature is -20~120 DEG C, CO₂Pressure is 0.1~6.0MPa, catalyst and alkylene oxide The molar ratio of hydrocarbon is 1:1000 to 1:200000, is reacted 1~48 hour, and reaction dissolvent is toluene or glycol dimethyl ether.

3. difunctional, bimetallic catalyst the application of synthesis of chiral glycol according to claim 2, which is characterized in that In the reaction condition, as its structural formula of reactant meso epoxyalkane are as follows:

One of.

4. difunctional, bimetallic catalyst the application of synthesis of chiral glycol according to claim 2 or 3, feature exist In using this difunctional, polycarbonate synthesized by bimetallic catalyst complete unison for 95~99%.