TWI827008B - Novel heterogeneous catalysts for synthesizing cyclic carbonates and their preparation - Google Patents

Abstract

Novel heterogeneous catalysts for synthesizing cyclic carbonates and their preparation are disclosed. Typically, the heterogeneous catalysts are silica-based type heterogeneous catalysts or polyurethane type heterogeneous catalysts. Both of them contain at least one complex group formed from alkaline earth metal halides and bis[tris(hydroxylmethyl)methylamino] alkanes.

Description

A kind of heterogeneous catalyst for synthesizing cyclic carbonate and preparation method thereof

The invention relates to a heterogeneous catalyst for synthesizing cyclic carbonate and its preparation method. Specifically, the heterogeneous catalyst is a silicon-based carrier-type heterogeneous catalyst or a polyurethane-type heterogeneous catalyst. The structure of the silicon-based carrier-type heterogeneous catalyst or the polyurethane-type heterogeneous catalyst includes at least one compound composed of an alkaline earth metal halide and a bis[tris(hydroxyl) Methyl) methylamino] complex group composed of alkanes.

The conventional technology for synthesizing cyclic carbonates is to proceed under high pressure and high temperature (>100 degrees Celsius) reaction conditions, while using transition metals as catalysts to prepare cyclic carbonates. It is well known that reaction conditions of high pressure and high temperature can cause potential risks of major industrial safety incidents. Second, the disadvantages of transition metal catalysts include high toxicity, environmental unfriendliness, and the inability to be reused. All the above have limited the development of current cyclic carbonate-related industries.

In summary, providing a safe and environmentally friendly catalyst system for today's cyclic carbonate-related industries is a topic that urgently needs research breakthroughs.

In view of the above background of the invention, in order to meet the industrial requirements, the first object of the present invention is to provide a heterogeneous catalyst for synthesizing cyclic carbonate. The heterogeneous catalyst It can catalyze the reaction of compounds with epoxy groups and carbon dioxide to form cyclic carbonates under mild reaction conditions. It also has the technical efficacy of high conversion rate and high recycling times.

The above-mentioned heterogeneous catalyst can effectively catalyze the reaction of compounds with epoxy groups and carbon dioxide under normal pressure or low pressure carbon dioxide environment, converting the epoxy groups to obtain cyclic carbonates. Compared with the conventional preparation method of cyclic carbonate with high pressure and high toxicity, it is obvious that the heterogeneous catalyst for preparing cyclic carbonate provided by the present invention has the advantages of safety, environmental friendliness and is conducive to the green process of catalyst recovery. developing.

In particular, the heterogeneous catalyst used for synthesizing cyclic carbonates of the present invention is a silicon-based carrier heterogeneous catalyst or a polyurethane heterogeneous catalyst. The structure of the silicon-based carrier heterogeneous catalyst or polyurethane heterogeneous catalyst includes at least one alkaline earth catalyst. A complex group composed of metal halide and bis[tris(hydroxymethyl)methylamino]alkanes.

Specifically, the silicon-based carrier heterogeneous catalyst has a structure shown in formula (1).

M represented by the above formula (1) is magnesium or calcium; X is chlorine, bromine or iodine; a is an integer of 6 to 14 and b is an integer of 2 to 4.

Specifically, the polyurethane heterogeneous catalyst of the present invention has the following formula: structure.

M represented by the above formula (2) is magnesium or calcium;

The second object of the present invention is to provide a method for preparing a silicon-based carrier-type heterogeneous catalyst. The steps include: reacting silicon dioxide and an aminosilane compound at a temperature of 50-150 degrees to generate a silicon-based carrier with an amine group; A silicon-based carrier with an amine group and a diisocyanate form an intermediate product with a urea functional group and an isocyanate terminal; and the intermediate product is added with a complex composed of an alkaline earth metal halide and bis[tris(hydroxymethyl)methylamino]alkanes. material, thereby obtaining the silicon-based carrier-type heterogeneous catalyst. The structure of the silicon-based carrier-type heterogeneous catalyst has urea and carbamate functional groups.

Specifically, the above-mentioned silicon-based supported heterogeneous catalyst is used to convert compounds with epoxy groups into cyclic carbonates.

Specifically, the above-mentioned silicon-based carrier-type heterogeneous catalyst has a structure shown in the above-mentioned formula (1).

Formula 1).

M represented by the above formula (1) is magnesium or calcium; X is chlorine, bromine or iodine; a is an integer of 6 to 14 and b is an integer of 2 to 4.

The third object of the present invention is to provide a method for preparing a polyurethane heterogeneous catalyst. The steps include: performing a coordination reaction between an alkaline earth metal halide and a bis[tris(hydroxymethyl)methylamino]alkane compound to obtain a complex. , react the complex and diisocyanate at a temperature of 50-150 degrees to obtain a diisocyanate with the complex group, and perform a polymerization reaction to generate the above-mentioned diisocyanate with the complex group. The polyurethane heterogeneous catalyst is a polyurethane cross-linked polymer.

Specifically, the above-mentioned polyurethane heterogeneous catalyst is used to convert compounds with epoxy groups into cyclic carbonates.

Specifically, the above-mentioned polyurethane heterogeneous catalyst has a structure represented by the above-mentioned formula (2).

Formula (2).

M represented by the above formula (2) is magnesium or calcium;

The fourth object of the present invention is to provide a method for synthesizing cyclic carbonate. The steps include: providing a mixture, the mixture includes a compound with an epoxy group and a silicon-based support type heterogeneous compound as shown in the above formula (1). Catalyst or polyurethane heterogeneous catalyst as shown in the above formula (2); react with the mixture at a carbon dioxide pressure of 1 to 5 atm and a temperature of 20 to 100°C, thereby converting the compound with an epoxy group into a ring carbonate.

Specifically, the compound with an epoxy group includes epichlorohydrin, 1,2-epoxybutane, phenyl oxirane, 1,7-octadiene diepoxide, tert-butyl glycidyl ether , phenyl glycidyl ether or bisphenol A diglycidyl ether.

In summary, the present invention reveals the technical characteristics of heterogeneous catalysts for the synthesis of cyclic carbonates. The heterogeneous catalyst used for synthesizing cyclic carbonate is a silicon-based carrier type heterogeneous catalyst with a structure shown in the above formula (1) or a polyurethane type heterogeneous catalyst shown in the above formula (2), and its preparation method And used to catalyze the conversion of compounds with epoxy groups and carbon dioxide into cyclic carbonates. Innovatively, the heterogeneous catalyst used for synthesizing cyclic carbonates of the present invention has the technical efficacy of both high conversion rate and high recovery times, and provides a technical solution with higher economic value for the recovery and reuse of carbon dioxide, so it can be widely used. In chemical and environmental related industries.

[Figure 1] is a synthesis route diagram of the silicon-based carrier heterogeneous catalyst of the present invention.

[Figure 2] is a synthesis route diagram of the polyurethane heterogeneous catalyst of the present invention.

[Figure 3] shows the FT-IR spectra of the silicon-based carrier type heterogeneous catalyst and the polyurethane type heterogeneous catalyst of the present invention.

[Figure 4] is the XPS pattern of the silicon-based carrier heterogeneous catalyst of the present invention.

[Figure 5] is the XPS pattern of the polyurethane heterogeneous catalyst of the present invention.

[Figure 6] shows the reaction formula for synthesizing cyclic carbonate of the present invention and its representative compounds.

[Figure 7] is a bar graph showing the relationship between the number of recovery times and the conversion rate of the silicon-based carrier type heterogeneous catalyst and the polyurethane type heterogeneous catalyst of the present invention.

According to a first embodiment of the present invention, the present invention provides a heterogeneous catalyst for synthesizing cyclic carbonate. Specifically, the heterogeneous catalyst for synthesizing cyclic carbonate is a silicon-based carrier heterogeneous catalyst or a polyurethane heterogeneous catalyst, and the structure of the silicon-based carrier heterogeneous catalyst or polyurethane heterogeneous catalyst includes at least one halogenated alkaline earth metal. A complex group composed of two [tri(hydroxymethyl)methylamino]alkanes.

In a specific embodiment, the alkaline earth metal content of the silicon-based carrier heterogeneous catalyst is about 2~10wt.%, preferably 2~5wt.%; the halogen content is about 3~20wt.%, preferably 3~ 10wt.% and the silicon content is about 10~50wt.%, preferably 10~40wt.%; and has a structure as shown in formula (1).

Formula 1).

M represented by the above formula (1) is magnesium or calcium; X is chlorine, bromine or iodine; a is an integer of 6 to 14 and b is an integer of 2 to 4.

In a representative embodiment, the silicon-based carrier heterogeneous catalyst has a structure shown in formula (3).

In a specific embodiment, the alkaline earth metal content of the polyurethane heterogeneous catalyst is about 5~30wt.%, preferably 10~20wt.%; the halogen content is about 5~20wt.%, preferably 5~10wt. .%; and has the structure shown in formula (2).

M shown in the above formula (2) is magnesium or calcium; X is chlorine, bromine or iodine; y is 2~4 is an integer, z is an integer from 2 to 6 and n is an integer from 30 to 1000.

In a specific embodiment, the polyurethane heterogeneous catalyst is cross-linked polyurethane.

In a representative embodiment, the polyurethane heterogeneous catalyst has a structure shown in formula (4).

In a specific embodiment, the alkaline earth metal halide is selected from one of the following groups or a combination thereof: magnesium chloride, magnesium bromide, magnesium iodide, calcium chloride, calcium bromide and calcium iodide.

In a specific embodiment, the bis[tris(hydroxymethyl)methylamino]alkanes include 1,2-bis[tris(hydroxymethyl)methylamino]ethane, 1,3-bis[tris(hydroxymethyl) )methylamino]propane or 1,4-bis[tris(hydroxymethyl)methylamino]butane.

According to a second embodiment of the present invention, the present invention provides a method for preparing a silicon-based carrier-type heterogeneous catalyst. The steps include: reacting silicon dioxide and an aminosilane compound at a temperature of 50-150 degrees to generate a silicon group with an amine group. Carrier; the silicon-based carrier with an amine group and the diisocyanate form an intermediate product with a urea functional group and an isocyanate terminal; and the intermediate product is composed of an alkaline earth metal halide and a bis[tris(hydroxymethyl)methylamino]alkane. complex, thereby obtaining the silicon-based carrier-type heterogeneous catalyst. The structure of the silicon-based carrier-type heterogeneous catalyst has urea and carbamate functional groups.

In a specific embodiment, the above-mentioned silicon-based supported heterogeneous catalyst is used to react a compound with an epoxy group and carbon dioxide to form a cyclic carbonate.

In a specific embodiment, the above-mentioned silicon-based carrier-type heterogeneous catalyst has a structure shown in the above-mentioned formula (1).

In a specific embodiment, the aminosilane compound includes 3-aminopropyltriethoxysilane.

In a specific embodiment, the diisocyanate includes hexamethylene diisocyanate, diphenylmethane 4,4'-diisocyanate or 1,8-diisocyanatooctane.

In a representative embodiment, please refer to Figure 1, 3-aminopropyltriethoxysilane is added to silica gel to make the silica have (-NH ₂ ) amine groups, and then hexamethylene diamine is added. Diisocyanates such as isocyanate, diphenylmethane 4,4'-diisocyanate or 1,8-diisocyanatooctane react to form an intermediate product with a urea functional group and an isocyanate terminal, and then add calcium iodide and 1,3 -The complex of bis[tris(hydroxymethyl)methylamino]propane finally obtains a silicon-based carrier-type heterogeneous catalyst with both urea and polyurethane functional groups.

According to a third embodiment of the present invention, the present invention provides a method for preparing a polyurethane heterogeneous catalyst. The steps include: performing a coordination reaction between an alkaline earth metal halide and a bis[tris(hydroxymethyl)methylamino]alkane compound to obtain A complex compound, reacting the complex compound with diisocyanate at a temperature of 50-150 degrees to obtain a diisocyanate having the complex compound group, and performing a polymerization reaction to make the above-mentioned diisocyanate having the complex compound group Isocyanate generates the polyurethane heterogeneous catalyst, and the polyurethane heterogeneous catalyst is a polyurethane cross-linked polymer.

In a specific embodiment, the above-mentioned polyurethane heterogeneous catalyst is used to react a compound with an epoxy group and carbon dioxide to form a cyclic carbonate.

In a specific embodiment, the above-mentioned polyurethane heterogeneous catalyst has a structure shown in the above formula (2).

In a specific embodiment, the diisocyanate includes hexamethylene diisocyanate, diphenylmethane 4,4'-diisocyanate or 1,8-diisocyanatooctane.

In a representative embodiment, please refer to Figure 2. A coordination reaction is carried out between environmentally friendly alkaline earth metal calcium iodide and 1,3-bis[tris(hydroxymethyl)methylamino]propane in dimethylformamide. , and then after adding hexamethylene diisocyanate for reaction, the polymerization reaction is performed by heating in a high vacuum environment to obtain a cross-linked polymer solid. This cross-linked polymer solid is the polyurethane heterogeneous catalyst of the present invention.

According to a fourth embodiment of the present invention, the present invention provides a method for synthesizing cyclic carbonate. The steps include: providing a mixture containing a compound having an epoxy group and silicon represented by the above formula (1). A carrier-type heterogeneous catalyst or a polyurethane-type heterogeneous catalyst as shown in the above formula (2); react with the mixture at a carbon dioxide pressure of 1 to 5 atm and a temperature of 20 to 100°C, thereby making the epoxy group The compound is converted to form a cyclic carbonate.

In a specific embodiment, the compound with an epoxy group includes epichlorohydrin, 1,2-epoxybutane, phenyloxirane, 1,7-octadiene diepoxide, tert-butyl Glycidyl ether, phenyl glycidyl ether or bisphenol A diglycidyl ether.

In a specific embodiment, the above method further includes performing a filtration step, thereby recycling and using the silicon-based carrier type heterogeneous catalyst or polyurethane type heterogeneous catalyst, and the recycled silicon-based carrier type heterogeneous catalyst or polyurethane type heterogeneous catalyst has Greater than 70% cyclic carbonate conversion.

In a representative embodiment, phenyl glycidyl ether and the above-mentioned silicon are used respectively. A carrier-based heterogeneous catalyst or a polyurethane heterogeneous catalyst (20 mol%) is reacted in carbon dioxide (1 atm) and a temperature of 60°C. The reaction solvent is DMSO, and the reaction is monitored using H-NMR and FT-IR. When the reaction is completed, The above-mentioned silicon-based carrier type heterogeneous catalyst or polyurethane type heterogeneous catalyst, product and solvent are separated by air extraction and filtration. The filtered silicon-based carrier-type heterogeneous catalyst or polyurethane-type heterogeneous catalyst can be recycled after being washed with methylene chloride, using high vacuum, and dried at 60°C.

The following examples serve as detailed descriptions of the invention.

Structural analysis of the heterogeneous catalyst of the present invention

The silicon-based carrier type heterogeneous catalyst and the polyurethane type heterogeneous catalyst of the present invention use Fourier transform infrared spectroscopy (FT-IR) to determine the specific functional groups (urea, urethane) of the catalyst. The FTIR spectrum is shown in Figure 3.

The silicon-based carrier-type heterogeneous catalysis and the polyurethane-type heterogeneous catalyst of the present invention use X-ray photoelectron spectroscopy (XPS) to determine the elements and contents on the heterogeneous catalyst. The XPS patterns are shown in Figures 4 and 5 respectively.

In a representative example, the composition weight percentage of the silicon-based carrier heterogeneous catalyst is shown in Table 1.

In a representative example, the composition weight percentage of the polyurethane heterogeneous catalyst is shown in Table 2.

In one example, the code names of the silicon-based carrier type heterogeneous catalyst and the polyurethane type heterogeneous catalyst of the present invention are SG-A-PU and PU respectively, using phenyl glycidyl ether and the above-mentioned silicon-based carrier type heterogeneous catalyst or polyurethane type heterogeneous catalyst respectively. The catalyst (20 mol%) reacted in carbon dioxide (1 atm) and a temperature of 60°C. The reaction solvent was DMSO, and the reaction was monitored by H-NMR and FT-IR. The experimental results are shown in Table 3, in which CaI ₂ and CaI ₂ -BTP are used as experimental controls, thereby confirming the catalytic effect of the silicon-based carrier heterogeneous catalyst or polyurethane heterogeneous catalyst of the present invention.

In one example, the present invention uses carbon dioxide to react and convert to form cyclic carbon The starting materials, products and reaction formula of the acid ester are shown in Figure 6. The starter having an epoxy group includes epichlorohydrin, 1,2-epoxybutane, tert-butyl glycidyl ether, phenyl glycidyl ether, phenyl ethylene oxide and 1,7-octanedi Alkene diepoxide; the cyclic carbonate products generated by conversion are 4-ethyl-1,3-dioxolane-2-one, 4-(tert-butoxymethyl)-1,3-dioxo Pentan-2-one, 4-(phenoxymethyl)-1,3-dioxolane-2-one, 4-phenyl-1,3-dioxolane-2-one 4,4 '-(Butane-1,4-diyl)bis(1,3-dioxolane-2-one) and 4,4'-(((propane-2,2-diylbis(4,1 -phenylene))bis(oxy))bis(methylene))bis(1,3-dioxolane-2-one).

In one example, the usage times and conversion rates of the recycled silicon-based carrier heterogeneous catalysts or polyurethane heterogeneous catalysts are shown in Figure 7. Obviously, the silicon-based carrier heterogeneous catalysts or polyurethane heterogeneous catalysts of the present invention are recycled and reused 8 times. The conversion rate is still greater than 80%, which proves the technical efficacy of the present invention.

Although the present invention has been described above with specific experimental examples, this does not limit the scope of the present invention. As long as it does not deviate from the gist of the present invention, those skilled in the art will understand that various modifications or changes can be made without departing from the intention and scope of the present invention. In addition, the abstract section and title are only used to assist in searching patent documents and are not intended to limit the scope of the invention.

Claims (10)

A silicon-based carrier-type heterogeneous catalyst for synthesizing cyclic carbonates. The silicon-based carrier-type heterogeneous catalyst has a magnesium or calcium content of about 2 to 10 wt.%, a chlorine, bromine or iodine content of about 3 to 20 wt.% and silicon. The content is about 10~50wt.%, and has a structure shown in formula (1):

Where M is magnesium or calcium; X is chlorine, bromine or iodine; a is an integer from 6 to 14 and b is an integer from 2 to 4. A polyurethane-type heterogeneous catalyst for synthesizing cyclic carbonate. The polyurethane-type heterogeneous catalyst has a magnesium or calcium content of about 5 to 30 wt.%, a chlorine, bromine or iodine content of about 5 to 20 wt.%, and has the formula (2) The structure shown:

Where M is magnesium or calcium, X is chlorine, bromine or iodine; y is an integer from 2 to 4, z is an integer from 2 to 6 and n is an integer from 30 to 1000. A method for preparing a silicon-based carrier-type heterogeneous catalyst, the steps of which include: reacting silicon dioxide and an aminosilane compound at a temperature of 50-150 degrees to generate a silicon-based carrier with an amine group; the silicon-based carrier with an amine group and Diisocyanate forms an intermediate product with a urea functional group and an isocyanate terminal; and a complex composed of an alkaline earth metal halide and a bis[tris(hydroxymethyl)methylamino]alkane is added to the intermediate product, thereby obtaining the described A silicon-based carrier-type heterogeneous catalyst, the structure of the silicon-based carrier-type heterogeneous catalyst has urea and carbamate functional groups. As for the preparation method of the silicon-based carrier heterogeneous catalyst described in claim 3, the aminosilane compound includes 3-aminopropyltriethoxysilane. The preparation method of the silicon-based carrier type heterogeneous catalyst as described in claim 3, the diisocyanate includes hexamethylene diisocyanate, diphenylmethane 4,4'-diisocyanate or 1,8-diisocyanatooctane . A method for preparing a polyurethane-type heterogeneous catalyst. The steps include: carrying out a coordination reaction between an alkaline earth metal halide and a bis[tris(hydroxymethyl)methylamino]alkane compound to obtain a complex, at a temperature of 50-150 degrees The complex is reacted with a diisocyanate to obtain a diisocyanate having the complex group, and a polymerization reaction is performed to generate the polyurethane heterogeneous catalyst from the above-mentioned diisocyanate having the complex group, and the polyurethane Type heterogeneous catalyst is polyurethane cross-linked polymer. The preparation method of polyurethane heterogeneous catalyst as described in claim 6, the diisocyanate Acid esters include hexamethylene diisocyanate, diphenylmethane 4,4'-diisocyanate or 1,8-diisocyanatooctane. A method for synthesizing cyclic carbonate, the steps of which include: providing a mixture, the mixture includes a compound with an epoxy group and a silicon-based support type heterogeneous catalyst as described in claim 1 or a polyurethane type as described in claim 2 Heterogeneous catalyst; react with the mixture at a carbon dioxide pressure of 1 to 5 atm and a temperature of 20 to 100°C, thereby converting the compound with an epoxy group into a cyclic carbonate. The method for synthesizing cyclic carbonate as described in claim 8, wherein the compound with an epoxy group includes epichlorohydrin, 1,2-epoxybutane, phenylethylene oxide, and 1,7-octanedi Alkene diepoxide, tert-butyl glycidyl ether, phenyl glycidyl ether or bisphenol A diglycidyl ether. The method for synthesizing cyclic carbonate as described in claim 8, further comprising performing a filtration step to recover and use the silicon-based carrier type heterogeneous catalyst as described in claim 1 or the polyurethane as described in claim 2 type heterogeneous catalyst, and the recycled silicon-based carrier type heterogeneous catalyst described in claim 1 or the polyurethane type heterogeneous catalyst described in claim 2 has a cyclic carbonate conversion rate greater than 70%.

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