CN1189246C - High activity catalyzer utilized to synthesize cyclic carbonate - Google Patents

Abstract

The highly active catalyst for the synthesis of cyclic carbonates relates to cycloaddition reaction catalysts, in particular to a highly active catalyst for the synthesis of cyclic carbonates by reacting alkylene oxides with carbon dioxide; the main catalyst is a tetradentate Schiff base Metal complex (R ₁ )(R ₂ )SalenMX; the cocatalyst is the quaternary ammonium salt of R ¹ R ² ₃ NX ¹ or the quaternary phosphonium salt of R ¹ R ² ₃ PX ¹ ; the cocatalyst and the main catalyst four The molar ratio of the tooth Schiff alkali metal complex is 0.2:1 to 5:1; the two-component catalyst can catalyze the reaction of epoxy compound and carbon dioxide under very mild conditions to synthesize cyclic carbonate with high efficiency, and no poly By-products such as carbonates and polyethers.

Description

Highly active catalysts for the synthesis of cyclic carbonates

technical field

The invention relates to a cycloaddition reaction catalyst, in particular to a high-activity catalyst for synthesizing cyclic carbonate by reacting alkylene oxide with carbon dioxide.

Background technique

In US 43 14945, McMullen described the synthesis of cyclic carbonates by the reaction of alkylene oxides with carbon dioxide catalyzed by tetrahydrocarbyl quaternary ammonium salts.

Sachs and Harvey described in US 4786741 and US 4841072, respectively, quaternary phosphonium salt catalysts for catalyzing the cycloaddition reaction of carbon dioxide and oxirane under a pressure of 2.5-20 MPa. In US 4931571, Weinstein described using a quaternary arsine halide as a catalyst to catalyze the reaction of carbon dioxide and ethylene oxide in the range of 90-200 ° C to synthesize ethylene carbonate.

Kisch (Chem. Ber., 1986, 119, 1090-1094; 1990, 123, 277-283) reported a bifunctional catalyst composed of ZnCl2 and a high concentration of quaternary ammonium salt or quaternary phosphonium salt.

In CN 1343668, Deng Youquan described the use of an ionic liquid in a liquid state at room temperature consisting of a nitrogen-containing heterocyclic compound halogenated alkylpyridine or a halogenated 1,3-dialkylimidazole and a non-metallic halide as a catalyst, and the alkali metal halide compound or tetrabutylammonium bromide as the co-catalyst of the reaction, at 100-140°C and the initial pressure of carbon dioxide is 1.5-4.5MPa, and the amount of catalyst is 0.2-2.5mol% of the amount of epoxy compound, after 4-8 hours The reaction converts the epoxide to the corresponding cyclic carbonate.

Utilizing the catalysts described above often requires the presence of high temperature, high pressure and high concentration catalyst to effectively catalyze the reaction of alkylene oxide and carbon dioxide to synthesize the corresponding cyclic carbonate.

During the reaction of alkylene oxide and carbon dioxide to form cyclic carbonate, it is often accompanied by the formation of by-products such as polycarbonate and polyether, especially under low temperature and low pressure conditions.

Contents of the invention

The object of the present invention is to provide a high activity catalyst for synthesizing cyclic carbonate with high activity and high selectivity for cycloaddition reaction under low temperature, low pressure and isothermal conditions.

The technical solution of the present invention is that the highly active catalyst for synthesizing cyclic carbonate consists of a main catalyst and a cocatalyst. The main catalyst is a tetradentate Schiff base metal complex (R ₁ )(R ₂ )SalenMX, whose structural formula is:

Wherein, M is Al(III) or Cr(III).

R ₁ and R ₂ are -H, 1-6 carbon alkyl, alkoxy, -Cl, -Br or -NO ₂ groups; R ₃ and R ₄ are -(CH ₂ ) ₄ -, H, CH ₃ Or Ph, -(CH) ₄ -; X is Cl ^- , Br ^- , I ^- , CH ₃ O ^- , CH ₃ CH ₂ O ^- , NO ₃ ^- , CH ₃ COO ^- , ClO ₄ ^- , BF ₄ ^- or BPh ₄ ^- Negative ion.

The cocatalyst is a quaternary ammonium salt with the chemical formula R ¹ R ² ₃ NX ¹ or a quaternary phosphonium salt with the chemical formula R ¹ R ² ₃ PX ¹ , wherein R ¹ and R ² are hydrocarbon groups, and X ¹ is a monovalent anion.

The molar ratio of the cocatalyst to the main catalyst tetradentate Schiff base metal complex is 0.2:1 to 5:1.

The co-catalyst is a quaternary ammonium salt with the chemical formula R ¹ R ² ₃ NX ¹ , where R ¹ is an alkyl group with 1-16 carbons, R ² is an alkyl group with 1-6 carbons, and X ¹ is Cl ^- , Br ^- , I ^- , NO ₃ ^- , CH ₃ COO ^- , ClO ₄ ^- , BF ₄ ^- or BPh ₄ ^- negative ions.

The cocatalyst is a quaternary phosphonium salt with the chemical formula R ¹ R ² ₃ PX ¹ , where R ¹ is 1-16 carbon alkyl, R ² is 1-6 carbon alkyl or phenyl, X ¹ is Cl ^- , Br ^- , I ^- , NO ₃ ^- , CH ₃ COO ^- , ClO ₄ ^- , BF ₄ ^- or BPh ₄ ^- negative ions.

The molar ratio of the cocatalyst to the main catalyst tetradentate Schiff base metal complex is 0.2:1 to 5:1.

In the main catalyst, the coordination with the metal ion is a tetradentate Schiff base ligand obtained by reacting salicylaldehyde homologs with diamine compounds.

The substituents contained in the salicylaldehyde homologs are t-butyl, -OCH ₃ , -Cl, -Br or -NO ₂ groups.

The diamine compound is ethylenediamine, 1,2-propylenediamine, o-phenylenediamine, cyclohexanediamine or 1,2-diphenylethylenediamine.

Metal ions that form complexes with tetradentate Schiff base ligands are Al(III) or Cr(III).

The axial ligand X is Cl ^- , Br ^- , I ^- , CH ₃ O ^- , CH ₃ CH ₂ O ^- , NO ₃ ^- , CH ₃ COO ^- , ClO ₄ ^- , BF ₄ ^- or BPh ₄ ^- anion.

These metal complexes are easy to synthesize, and the yield is very high, synthetic can refer to (S.J.Dzugan, V.L.Goedken, Inorg.Chem.1986,25,2858 and D.A.Atwood, J.A.Jegier, D.Rutherford, Inorg.Chem.1996,35 , 63, and L.E.Martinez, E.N.Jacobsen, et al., J.Am.Chem.Soc., 1995, 117, 5897) and other documents.

Quaternary ammonium salts are tetrahydrocarbyl ammonium halides.

Tetraalkylammonium halides are tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium iodide, tetrapropylammonium iodide, tetraethylammonium bromide, tetraethylammonium chloride.

Quaternary phosphonium salts are tetrahydrocarbylphosphonium halides.

Tetrahydrocarbylphosphonium halides are butyltriphenylphosphonium bromide, butyltriphenylphosphonium iodide, butyltriphenylphosphonium chloride, ethyltriphenylphosphonium bromide, methyltriphenylphosphonium iodide.

The molar ratio of cocatalyst to tetradentate Schiff base metal complex is 0.2:1 to 5:1.

In the reaction of carbon dioxide and alkylene oxide to synthesize cyclic carbonate, the temperature is 15-120°C, the constant pressure of carbon dioxide is controlled at 0.1-6MPa, and the molar ratio of tetradentate Schiff alkali metal complex to alkylene oxide is 1:200 The molar ratio of cocatalyst to tetradentate Schiff base metal complex is 0.2:1 to 5:1 to 1:10000.

Detailed ways

Below in conjunction with embodiment the present invention will be further described,

Example 1

In a stainless steel autoclave with an effective volume of 200ml, add in the following order at ambient temperature: 0.5×10 ^-3 moles of tetra-n-butylammonium iodide, 0.5×10 ^-3 moles of SalenAlCl (R ₁ =R ₂ =R ₃ = R ₄ =H), and then add 0.25 mol propylene oxide with a syringe under the protection of carbon dioxide.

The temperature was controlled at 25°C while carbon dioxide was added to the autoclave so as to maintain a constant pressure of 0.7 MPa.

After reacting under magnetic stirring for 10 hours, stop passing carbon dioxide, and slowly let off unreacted carbon dioxide and alkylene oxide in the autoclave.

24.4 g of propylene carbonate was distilled under reduced pressure, the purity of which was higher than 99.5%, and the residue was analyzed by FTIR and ¹ H, ¹³ C-NMR without any by-products such as polycarbonate and polyether. Considering the loss during distillation, the conversion rate of propylene oxide should be higher than 98%.

Example 2

In the same apparatus as used in Example 1, under the same conditions, only ethylene oxide was used instead of propylene oxide. After 7 hours of reaction at 25° C., 21 g of ethylene carbonate was obtained, and the conversion of ethylene oxide was higher than 95%.

Example 3

In the same apparatus as used in Example 1, under the same conditions, except that n-butyltriphenylphosphonium bromide was used instead of tetra-n-butylammonium iodide. After reacting at 25° C. for 12 hours, 25.2 g of propylene carbonate was obtained, and the conversion rate of propylene oxide was 99%.

Example 4

In _{the same} equipment as used in Example ₁ , under the same conditions _, except that SalenAlCl (R ₁ = R ₂ =R ₃ =R ₄ =H). After reacting at 25° C. for 11 hours, 25 g of propylene carbonate was obtained, and the conversion rate of propylene oxide was 98%.

Example 5

In a stainless steel autoclave with an effective volume of 200ml, add in the following order at ambient temperature: 0.5×10 ^-3 moles of tetra-n-butylammonium bromide, 0.5×10 ^-3 moles of SalenAlCl (R ₁ =R ₂ =R ₃ = R ₄ =H), and then add 0.25 mol propylene oxide with a syringe under the protection of carbon dioxide.

At this time, the temperature was raised to 45°C while carbon dioxide was added to the autoclave so as to maintain a constant pressure of 0.8 MPa. After reacting for 6 hours under magnetic stirring, 25.3 g of propylene carbonate was obtained, and the conversion rate of propylene oxide was 99%.

Example 6

In a stainless steel autoclave with an effective volume of 200ml, add in the following order at ambient temperature: 0.25×10 ^-3 moles of tetra-n-butylammonium iodide, 0.25×10 ^-3 moles of SalenAlCl (R ₁ =R ₂ =R ₃ = R ₄ =H), and then add 0.25 mol propylene oxide with a syringe under the protection of carbon dioxide.

At this time, the temperature of the oil bath was raised to 110°C, and at the same time, carbon dioxide was added to the autoclave so as to maintain a constant pressure of 2.0 MPa. After reacting for 1 hour under magnetic stirring, 25.2 g of propylene carbonate was obtained, and the conversion rate of propylene oxide was 98%.

Example 7

In the same apparatus as used in Example 6, under the same conditions, only epichlorohydrin was used instead of propylene oxide. After reacting at 110° C. and 2.0 MPa carbon dioxide constant pressure for 3 hours, 33 g of chloropropylene carbonate was obtained, and the conversion rate of epichlorohydrin was 97%.

Example 8

In the same apparatus as used in Example 6, under the same conditions, except that (t-Bu) ₂ SalenCrCl (R ₁ =R ₂ =t-Bu, R ₃ =R ₄ =H) was used instead of SalenAlCl. After reacting at 110° C. for 1 hour, 24.6 g of propylene carbonate was obtained, and the conversion rate of propylene oxide was 96%.

Example 9

In the same equipment as used in Example 6, under the same conditions, except that (t-Bu) ₂ SalenCrCl (R ₁ = R ₂ = t-Bu, R ₃ and R ₄ are -(CH ₂ ) ₄ - ) instead of SalenAlCl. After reacting at 110° C. for 1 hour, 25.3 g of propylene carbonate was obtained, and the conversion rate of propylene oxide was 99%.

Example 10

In the same apparatus as used in Example 6, under the same conditions, except that (t-Bu) ₂ SalenCrCl (R ₁ =R ₂ =t-Bu, R ₃ =R ₄ =Ph) was used instead of SalenAlCl. After reacting at 110° C. for 1 hour, 25 g of propylene carbonate was obtained, and the conversion rate of propylene oxide was 98%.

Claims (7)

1. be used for the highly active catalyst of synthetic cyclic carbonate, it is characterized in that, be made up of procatalyst and cocatalyst, The main catalyst is a tetradentate Schiff base metal complex (R ₁ )(R ₂ )SalenMX, whose structural formula is: Wherein, M is Al(III) or Cr(III), R ₁ and R ₂ are -H, 1-6 carbon alkyl, alkoxy, -Cl, -Br or -NO ₂ groups; R ₃ and R ₄ are -(CH ₂ ) ₄ -, -H,- CH ₃ or -Ph, -(CH) ₄ -; X is Cl ^- , Br ^- , I ^- , CH ₃ O ^- , CH ₃ CH ₂ O ^- , NO ₃ ^- , CH ₃ COO ^- , ClO ₄ ^- , BF ₄ ^- or BPh ₄ ^- negative ion, The promoter is a quaternary ammonium salt with a chemical formula of R ¹ R ² ₃ NX ¹ or a quaternary phosphonium salt with a chemical formula of R ¹ R ² ₃ PX ¹ , wherein R ¹ and R ² are hydrocarbon groups, and X ¹ is a monovalent anion, The molar ratio of the cocatalyst to the main catalyst tetradentate Schiff base metal complex is 0.2:1 to 5:1. 2. the highly active catalyst for synthesizing cyclic carbonate according to claim 1, is characterized in that, cocatalyst is the quaternary ammonium salt of chemical formula R ¹ R ² ₃ NX ¹ , and R in the formula ¹ is 1-16 carbon alkyl, R ² is 1-6 carbon alkyl, X ¹ is Cl ^- , Br ^- , I ^- , NO ₃ ^- , CH ₃ COO ^- , ClO ₄ ^- , BF ₄ ^- or BPh ₄ ^- anion. 3. the highly active catalyst for synthesizing cyclic carbonate according to claim 1, is characterized in that, cocatalyst is the quaternary phosphonium salt that chemical formula is R ¹ R ² ₃ PX ¹ , and R in the formula ¹ is 1-16 Carbon alkyl, R ² is 1-6 carbon alkyl or phenyl, X ¹ is Cl ^- , Br ^- , I ^- , NO ₃ ^- , CH ₃ COO ^- , ClO ₄ ^- , BF ₄ ^- or BPh ₄ ^- anion . 4. The highly active catalyst for synthesizing cyclic carbonates according to claim 1, characterized in that its axial ligand is CH ₃ O ^- or CH ₃ CH ₂ O ^- . 5. according to claim 1 and 2 described highly active catalysts for synthesizing cyclic carbonate, it is characterized in that, promoter quaternary ammonium salt is tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutyl ammonium Ammonium iodide, tetrapropylammonium iodide, tetraethylammonium bromide, or tetraethylammonium chloride. 6. according to claim 1 and 3 described highly active catalysts for synthesizing cyclic carbonate, it is characterized in that, cocatalyst quaternary phosphonium salt is butyltriphenylphosphonium bromide, butyltriphenylphosphonium iodide , butyltriphenylphosphonium chloride, ethyltriphenylphosphonium bromide or methyltriphenylphosphonium iodide. 7. the application of highly active catalyst as claimed in claim 1 in the synthetic cyclic carbonate, is characterized in that, in carbon dioxide and alkylene oxide synthesis cyclic carbonate reaction, temperature is 15-120 ℃, feeds carbon dioxide constant The pressure is controlled at 0.1-6MPa, the molar ratio of the tetradentate Schiff alkali metal complex to the alkylene oxide is 1:200 to 1:10000, and the molar ratio of the cocatalyst to the tetradentate Schiff alkali metal complex is 0.2:1 to 5:1.