CN108129506B - Preparation method of Zr (IV) compound and application of Zr (IV) compound in reduction of carbon dioxide into methanol - Google Patents

Abstract

A Zr (IV) compound and its application in reducing carbon dioxide to methanol comprises the following steps: 1) in a glove box, the Zr (IV) compound Cl is weighed₃THF₂ZrBH₄In a Schlenk flask, add tetrahydrofuran; 2) the Schlenk flask was taken out of the glove box, connected to a vacuum line and degassed, connected to a balloon filled with carbon dioxide, and reacted at room temperature for 12 hours; 3) after the reaction was complete, hydrolysis gave methanol in 72.5% yield. The invention prepares Zr (IV) compound Cl₃THF₂The method of ZrBH is simple, the cost of raw materials is low, and the industrial amplification production is easy to realize. The Zr (IV) compound can reduce carbon dioxide into methanol at normal temperature and normal pressure, and NaCl and boric acid generated in the reaction process can be continuously recycled, so that industrial circulation is realized, and the aim of sustainable production is fulfilled.

Description

Preparation method of Zr (IV) compound and application of Zr (IV) compound in reduction of carbon dioxide into methanol

Technical Field

The invention relates to a method for efficiently reducing carbon dioxide into methanol, in particular to a preparation method and application of a Zr (IV) compound with high reducibility.

Background

Carbon dioxide is a widely available renewable resource, and the production of carbon dioxide includes combustion, biological respiration, industrial fuel combustion, and the release of carbon dioxide from some depths below the ground. Carbon dioxide is one of the main components of greenhouse gases, and the release of large amounts of carbon dioxide causes a number of devastating problems, such as glaciers melting, sea level elevation, etc. The world also pays more and more attention to the harm caused by excess carbon dioxide, and more scientists participate in the development, transformation and application of carbon dioxide in order to control the carbon dioxide within a proper range.

Methanol is not only an important chemical raw material, but also an excellent energy source and automobile fuel. Methanol reacts with isobutylene to produce methyl tertiary butyl ether, which is a high octane unleaded gasoline additive and can also be used as a solvent. Besides, the method can also prepare olefin and propylene, thereby solving the problem of resource shortage. The importance of methanol is far more important, and the methanol also comprises a series of important chemical intermediates such as formaldehyde, formic acid, methyl formate and the like. Therefore, the carbon dioxide which is a renewable large amount of C1 resource is reasonably applied and converted into the methanol, and the methanol-carbon dioxide is a subject which benefits the society and benefits the autumn and the thousands of generations.

The current method for industrially producing methanol utilizes H₂And CO in a high-pressure reaction kettle, the method has the following disadvantages: (1) high pressure conditions, high equipment requirements and expensive equipment maintenance. (2) H₂And CO are both flammable and explosive gases, extremely dangerous. (3) CO is toxic. (4) The by-products are numerous.

Therefore, how to prepare the methanol more efficiently and in an environment-friendly way becomes a key and hard item of the majority of researchers.

Disclosure of Invention

The present invention is directed to solve the above problems of the prior art, and an object of the present invention is to provide a method for preparing a zr (iv) compound capable of reducing carbon dioxide to methanol at normal temperature and pressure without using a catalyst, and an application of the zr (iv) compound in reducing carbon dioxide to methanol. The method has the advantages of simple operation, low requirement on equipment, wide raw material source, low cost, low toxicity, no other by-products, simple treatment, mild synthesis conditions, high yield, good selectivity and easy industrial amplification, and realizes more efficient and environment-friendly preparation of methanol.

In order to achieve the purpose, the invention adopts the technical scheme that:

a preparation method of a Zr (IV) compound comprises the following steps:

1) in a glove box, sodium borohydride and zirconium tetrachloride were weighed into a Schlenk flask, Tetrahydrofuran (THF) was added and stirred. The dosage ratio of sodium borohydride, zirconium tetrachloride and tetrahydrofuran is 75.7 mg: 466.1 mg: 20 mL;

2) stirring until white precipitate is generated, taking out the Schlenk bottle from the glove box, connecting a vacuum line, and then filtering (filter residue is sodium chloride);

3) concentrating the filtrate to 5mL at low temperature, adding 10mL of n-hexane, standing overnight to obtain colorless blocky crystal Cl₃THF₂ZrBH₄。

II, Cl prepared by the method₃THF₂ZrBH₄Preparation of [ Cl ] by reduction of carbon dioxide₃THF₂ZrO_0.5]₂The method comprises the following steps:

1) weighing Cl prepared by the method in a glove box₃THF₂ZrBH₄In a Schlenk flask, tetrahydrofuran was added. ZrBH₄Cl₃THF₂And tetrahydrofuran in an amount of 100 mg: 10 mL;

2) taking out the Schlenk bottle from the glove box, connecting a vacuum line and degassing, connecting a balloon filled with carbon dioxide to the Schlenk bottle, and reacting at room temperature for 12 hours;

3) after the reaction is finished, the solvent in the Schlenk bottle is pumped out at low temperature to obtain colorless blocky crystals [ Cl₃THF₂ZrO_0.5]₂。

Thirdly, using the Cl prepared in the first step₃THF₂ZrBH₄A process for the preparation of methanol by reduction of carbon dioxide comprising the steps of:

1) weighing the compound Cl prepared by the method in the step one in a glove box₃THF₂ZrBH₄In a Schlenk flask, add tetrahydrofuran; cl₃THF₂ZrBH₄And tetrahydrofuran at a dose ratio of 357 mg: 5 mL;

2) the Schlenk flask was taken out of the glove box, connected to a vacuum line and degassed, connected to a balloon filled with carbon dioxide, and reacted at room temperature for 12 hours;

3) after the reaction is finished, hydrolyzing to obtain methanol and boric acid; the methanol yield was 72.5%.

The invention has the advantages that:

the invention prepares Zr (IV) compound Cl₃THF₂ZrBH₄The method is simple, the raw material cost is low, and the industrial amplification production is easy to realize. The Zr (IV) compound can reduce carbon dioxide into methanol at normal temperature and normal pressure. NaCl and boric acid generated in the reaction process can be continuously recycled, so that industrial circulation is realized, and the aim of sustainable production is fulfilled.

Drawings

FIG. 1 is an X-ray powder diffraction pattern of sodium chloride.

FIG. 2 is Cl₃THF₂ZrBH₄The model of a ball stick of (1).

FIG. 3 is Cl₃THF₂ZrBH₄X-ray powder diffraction pattern of (a).

FIG. 4 is Cl₃THF₂ZrBH₄Is/are as follows¹¹BNMR image.

FIG. 5 is [ Cl ]₃THF₂ZrO_0.5]₂The model of a ball stick of (1).

FIG. 6 is [ Cl ]₃THF₂ZrO_0.5]₂X-ray powder diffraction pattern of (a).

FIG. 7 shows the results obtained by hydrolysis after completion of the reaction¹HNMR map.

FIG. 8 is a graph obtained by hydrolysis after completion of the reaction¹³A CNMR map.

FIG. 9 is a diagram showing a result obtained by hydrolysis after completion of the reaction¹¹BNMR image.

FIG. 10 is a complete reaction sequence of the present invention.

Detailed Description

In order to more particularly describe the invention, it is now illustrated for purposes of explanation, and the exemplary embodiments are intended to provide specific reference thereto, without intending to be limited thereto.

Example 1: zr (IV) compound Cl₃THF₂ZrBH₄Preparing;

1) in a glove box, sodium borohydride and zirconium tetrachloride were weighed into a Schlenk flask, Tetrahydrofuran (THF) was added and stirred. The dosage ratio of sodium borohydride, zirconium tetrachloride and tetrahydrofuran is 75.7 mg: 466.1 mg: 20 mL;

2) stirring until a white precipitate is generated, taking out a Schlenk bottle from a glove box, connecting a vacuum line, and then filtering (filter residue is sodium chloride);

3) the filtrate was concentrated to 5mL at low temperature and added10mL of n-hexane, standing overnight to obtain colorless blocky crystal Cl₃THF₂ZrBH₄。

FIG. 1 is an X-ray powder diffraction pattern of sodium chloride, in which line a is a simulated pattern of NaCl crystals and line b is an X-ray powder diffraction pattern of a white precipitate, and the two curves agree well, indicating that the resulting white powder is NaCl.

FIG. 2 is Cl₃THF₂ZrBH₄The diagram shows that the molecular formula of the obtained crystal is Cl₃THF₂ZrBH₄。

FIG. 3 is Cl₃THF₂ZrBH₄X-ray powder diffraction pattern of (1), wherein the line a is Cl₃THF₂ZrBH₄The simulated diagram of the crystal, the line b is the X-ray powder diffraction diagram of the obtained crystal, and the two curves are well matched, which indicates that the obtained crystal is pure phase.

FIG. 4 is Cl₃THF₂ZrBH₄Is/are as follows¹¹BNMR image shows that the structure contains boron hydrogen radical ions, which is consistent with the single crystal test structure.

Example 2: cl prepared in example 1 was used₃THF₂ZrBH₄Preparation of [ Cl ] by reduction of carbon dioxide₃THF₂ZrO_0.5]₂；

1) In a glove box, the Cl prepared in example 1 was weighed₃THF₂ZrBH₄In a Schlenk flask, tetrahydrofuran was added. ZrBH₄Cl₃THF₂And tetrahydrofuran in an amount of 100 mg: 10 mL.

2) The Schlenk flask was taken out of the glove box, connected to a vacuum line and degassed, and connected to a balloon filled with carbon dioxide and reacted at room temperature for 12 hours.

3) After the reaction is finished, the solvent in the Schlenk bottle is pumped out at low temperature to obtain colorless blocky crystals [ Cl₃THF₂ZrO_0.5]₂。

FIG. 5 is [ Cl ]₃THF₂ZrO_0.5]₂Shows the molecular formula of the obtained crystal as [ Cl ]₃THF₂ZrO_0.5]₂。

FIG. 6 is [ Cl ]₃THF₂ZrO_0.5]₂In the X-ray powder diffraction pattern of (1), line a is [ Cl ]₃THF₂ZrO_0.5]₂The simulated diagram of the crystal, the line b is the X-ray powder diffraction diagram of the obtained crystal, and the two curves are well matched, which indicates that the obtained crystal is pure phase.

Example 3: cl prepared using example 1₃THF₂ZrBH₄A process for the preparation of methanol by reduction of carbon dioxide;

1) in a glove box, the Cl prepared in example 1 is weighed₃THF₂ZrBH₄In a Schlenk flask, add tetrahydrofuran; cl₃THF₂ZrBH₄And tetrahydrofuran at a dose ratio of 357 mg: 5 mL.

2) The Schlenk flask was taken out of the glove box, connected to a vacuum line and degassed, connected to a balloon filled with carbon dioxide, and reacted at room temperature for 12 hours;

3) after the reaction is finished, hydrolyzing to obtain methanol and boric acid; the methanol yield was 72.5%.

FIG. 7 shows the results obtained by hydrolysis after completion of the reaction¹HNMR chart, 1.72 and 3.58ppm are nuclear magnetism characteristic peak of deuterated THF; 6.53ppm is the nuclear magnetic characteristic peak of the internal standard 1,1,2, 2-tetrachloroethane; 3.58ppm is the nuclear magnetic characteristic peak of methanol. This indicated no additional by-products after hydrolysis, a yield of 72.5% (1,1,2, 2-tetrachloroethane as internal nuclear magnetic standard) and a selectivity of 100%.

FIG. 8 is a graph obtained by hydrolysis after completion of the reaction¹³CNMR chart, 25.31 and 67.58ppm are nuclear magnetic characteristic peak of deuterated THF; 75.78ppm is the nuclear magnetism characteristic peak of the internal standard '1, 1,2, 2-tetrachloroethane'; 49.62ppm is the nuclear magnetic characteristic peak of methanol. Indicating no other by-products after hydrolysis with 100% selectivity.

FIG. 9 is a diagram showing a result obtained by hydrolysis after completion of the reaction¹¹BNMR chart, 20.11ppm is the nuclear magnetic characteristic peak of the product 2,4, 6-trimethoxyboroxine and the product boric acid after the hydrolysis of trimethyl lipid, no other by-products and the selectivity is 100%.

FIG. 10 is a complete reaction sequence of the present invention, in which the whole is explained in detailFirstly, zirconium tetrachloride and sodium borohydride react in tetrahydrofuran solution to generate Zr (IV) compound Cl₃THF₂ZrBH₄And sodium chloride precipitation; then Cl₃THF₂ZrBH₄Reaction with carbon dioxide to give [ Cl₃THF₂ZrO_0.5]₂2,4, 6-trimethoxyboroxine and trimethacrylate borate; finally hydrolyzing the 2,4, 6-trimethoxyboroxine and trimethyl borate to obtain the methanol.

The above description is intended to be illustrative of a preferred embodiment and not to limit the scope of the invention, and any substantially equivalent substitutions, process optimizations, modifications, and combinations of conditions are intended to be within the scope of the claims. A few terms are necessary in the description and illustration, nor are they intended to be limiting of the invention.

Claims (3)

1. A method for preparing a Zr (IV) compound, which is characterized by comprising the following steps:

1) in a glove box, weighing sodium borohydride and zirconium tetrachloride in a Schlenk bottle, adding tetrahydrofuran and stirring; the dosage ratio of sodium borohydride, zirconium tetrachloride and tetrahydrofuran is 75.7 mg: 466.1 mg: 20 mL;

2) stirring until white precipitate is generated, taking out the Schlenk bottle from the glove box, connecting a vacuum line and filtering, wherein filter residue is sodium chloride;

3) concentrating the filtrate to 5mL at low temperature, adding 10mL of n-hexane, standing overnight to obtain colorless blocky crystal Cl₃THF₂ZrBH₄。

2. A compound Cl prepared using the method of claim 1₃THF₂ZrBH₄Preparation of [ Cl ] by reduction of carbon dioxide₃THF₂ZrO_0.5]₂The method is characterized by comprising the following steps:

1) weighing the compound Cl prepared by the method of claim 1 in a glove box₃THF₂ZrBH₄In a Schlenk flask, add tetrahydrofuran; cl₃THF₂ZrBH₄And use of tetrahydrofuranThe dosage ratio is 100 mg: 10 mL;

2) the Schlenk flask was taken out of the glove box, connected to a vacuum line and degassed, connected to a balloon filled with carbon dioxide, and reacted at room temperature for 12 hours;

3) after the reaction is finished, the solvent in the Schlenk bottle is pumped out at low temperature to obtain colorless blocky crystals [ Cl₃THF₂ZrO_0.5]₂。

3. A compound Cl prepared using the method of claim 1₃THF₂ZrBH₄A process for the preparation of methanol by reduction of carbon dioxide comprising the steps of:

1) in a glove box, compound Cl prepared by the method of claim 1 is weighed₃THF₂ZrBH₄In a Schlenk flask, add tetrahydrofuran; cl₃THF₂ZrBH₄And tetrahydrofuran at a dose ratio of 357 mg: 5 mL;

2) the Schlenk flask was taken out of the glove box, connected to a vacuum line and degassed, connected to a balloon filled with carbon dioxide, and reacted at room temperature for 12 hours;

3) after the reaction is finished, hydrolyzing to obtain methanol and boric acid; the methanol yield was 72.5%.

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