A kind of preparation method of molybdenum catalyst and its application

Abstract

The invention discloses a preparation method and application of a molybdenum catalyst. The method firstly reacts pentaerythritol and ethylene oxide to prepare macromolecular alcohol; and then reacts the macromolecular alcohol and ammonium dimolybdate in the presence of a solvent to prepare Molybdenum catalyst solution. The molybdenum catalyst can be used in the epoxidation reaction of styrene. Under the reaction conditions, the catalyst is in a homogeneous state. After the reaction is completed, the catalyst can be precipitated from the epoxidation reaction liquid by cooling down, and the catalyst can be obtained by simple separation. The method can effectively improve the conversion rate of styrene and peroxide, effectively reduce the content of by-products, improve the selectivity of the product ethylene oxide, the catalyst is easy to recover, and the molybdenum catalyst can be recycled and applied, which is a green synthesis method. craft.

Description

technical field

[0001] The invention relates to the field of catalysts, in particular to a preparation method of a molybdenum catalyst and its application in epoxidation reaction.

[0002] technical background

[0003] Ethylene oxide, also known as styrene oxide, is an important organic synthesis intermediate and epoxy resin diluent.

[0004] At present, the main process of ethylene oxide is the halohydrin method, but this method has serious environmental pollution. In order to find an environment-friendly preparation method, the direct oxidation method has attracted more and more attention. The direct oxidation method mainly uses crop oxidants such as hydrogen peroxide and TBHP, but needs to add relatively expensive metal catalysts in the reaction, and the catalysts currently used are mainly molybdenum catalysts and homogeneous catalytic systems, and the selectivity of peroxides in the system is low. The unconverted peroxide increases the difficulty of post-treatment, and t...

Examples

Embodiment 1

[0041] The preparation method of platinum catalyst in the present invention is as follows:

[0042] First, 100 g of pentaerythritol and 0.36 g of formic acid were added to the reaction kettle, and after nitrogen replacement, heated to 100° C., 258 g of ethylene oxide was added to the kettle within 1 h, and then the reaction was continued for 5 h, and the ethylene oxide was removed under reduced pressure. The macromolecule alcohol was obtained, and Mn=481 by GPC analysis.

[0043] Take 100 g of macromolecular alcohol obtained above, 50 g of ammonium dimolybdate, and 30 g of ethylbenzene into another reaction kettle, and react at 100 ° C for 60 h. After the reaction is completed, the temperature is lowered to room temperature, and possible residual solid substances are removed by filtration to obtain a molybdenum catalyst. , No. Mo-1.

[0044] The preparations of other catalysts are the same as the above-mentioned methods, and the specific feeding amounts and conditions are con...

Embodiment 2-5

[0051] For the four catalysts prepared in Example 1, the epoxidation reactions were evaluated respectively:

[0052] Take the evaluation of catalyst Mo-1 as an example to introduce the evaluation method:

[0053] 565.8g of styrene, 5.6g of hydroquinone, and 0.2g of catalyst Mo-1 were added to the epoxidation reaction kettle. After nitrogen replacement was completed, the temperature was raised to 110°C, and 295.8g of tert-butyl was added to the system within 1 hour. base hydrogen peroxide (concentration is 55%), the reaction was continued for 1 h after the addition, and then the temperature was lowered to 30°C. After analysis, the conversion rate of tert-butyl hydroperoxide was 99.2%, and the selectivity of ethylene oxide was 98.3%.

[0054] The evaluation of other catalysts is the same as the above method, and the specific feeding amount and conditions are controlled in the following table.

Embodiment 8-11

[0062] After evaluating the reaction and cooling down as above, solids were all precipitated, and solid substances were obtained by simple sedimentation and decantation. After unified and simple drying treatment (100 ° C drying for 4 h), solid substances 0.16g, 0.24g, and 0.54g were obtained in Examples 2-5, respectively. , 0.88g. These four solids are numbered Mo-1', Mo-2', Mo-3', Mo-4', respectively.

technical field

[0001] The invention relates to the field of catalysts, in particular to a preparation method of a molybdenum catalyst and its application in epoxidation reaction.

[0002] technical background

[0003] Ethylene oxide, also known as styrene oxide, is an important organic synthesis intermediate and epoxy resin diluent.

[0004] At present, the main process of ethylene oxide is the halohydrin method, but this method has serious environmental pollution. In order to find an environment-friendly preparation method, the direct oxidation method has attracted more and more attention. The direct oxidation method mainly uses crop oxidants such as hydrogen peroxide and TBHP, but needs to add relatively expensive metal catalysts in the reaction, and the catalysts currently used are mainly molybdenum catalysts and homogeneous catalytic systems, and the selectivity of peroxides in the system is low. The unconverted peroxide increases the difficulty of post-treatment, and t...

Examples

Embodiment 1

[0041] The preparation method of platinum catalyst in the present invention is as follows:

[0042] First, 100 g of pentaerythritol and 0.36 g of formic acid were added to the reaction kettle, and after nitrogen replacement, heated to 100° C., 258 g of ethylene oxide was added to the kettle within 1 h, and then the reaction was continued for 5 h, and the ethylene oxide was removed under reduced pressure. The macromolecule alcohol was obtained, and Mn=481 by GPC analysis.

[0043] Take 100 g of macromolecular alcohol obtained above, 50 g of ammonium dimolybdate, and 30 g of ethylbenzene into another reaction kettle, and react at 100 ° C for 60 h. After the reaction is completed, the temperature is lowered to room temperature, and possible residual solid substances are removed by filtration to obtain a molybdenum catalyst. , No. Mo-1.

[0044] The preparations of other catalysts are the same as the above-mentioned methods, and the specific feeding amounts and conditions are con...

Embodiment 2-5

[0051] For the four catalysts prepared in Example 1, the epoxidation reactions were evaluated respectively:

[0052] Take the evaluation of catalyst Mo-1 as an example to introduce the evaluation method:

[0053] 565.8g of styrene, 5.6g of hydroquinone, and 0.2g of catalyst Mo-1 were added to the epoxidation reaction kettle. After nitrogen replacement was completed, the temperature was raised to 110°C, and 295.8g of tert-butyl was added to the system within 1 hour. base hydrogen peroxide (concentration is 55%), the reaction was continued for 1 h after the addition, and then the temperature was lowered to 30°C. After analysis, the conversion rate of tert-butyl hydroperoxide was 99.2%, and the selectivity of ethylene oxide was 98.3%.

[0054] The evaluation of other catalysts is the same as the above method, and the specific feeding amount and conditions are controlled in the following table.

Embodiment 8-11

[0062] After evaluating the reaction and cooling down as above, solids were all precipitated, and solid substances were obtained by simple sedimentation and decantation. After unified and simple drying treatment (100 ° C drying for 4 h), solid substances 0.16g, 0.24g, and 0.54g were obtained in Examples 2-5, respectively. , 0.88g. These four solids are numbered Mo-1', Mo-2', Mo-3', Mo-4', respectively.

Images