Composite catalyst for synthesizing p-dimethoxybenzeneand preparation method and industrial application thereof

Abstract

The invention discloses a composite catalyst for synthesizing p-dimethoxybenzen and a preparation method and industrial application thereof, and belongs to the technical field of chemical catalysts. The composite catalyst for synthesizing p-dimethoxybenzen comprises a main catalyst and an antioxidant, the main catalyst comprises an active component and an auxiliary agent; the active component is alkali metal or alkaline earth metal halide, and the auxiliary agent is metal nitrate, wherein the main catalyst comprises the following components in percentage by mole: 30%-90% of the active component and 10%-70% of the auxiliary agent. The composite catalyst for synthesizing the p-dimethoxybenzen is simple in preparation process and low in cost. The catalyst for synthesizing p-dimethoxybenzen can be used for producing p-dimethoxybenzen by using hydroquinone as a raw material and dimethyl carbonate as a methylation reagent, has high catalytic activity and high product yield, and can be in large-scale industrial application.

Description

technical field

[0001] The invention belongs to the technical field of chemical catalysts, and relates to a composite catalyst for synthesizing p-xylylene dimethyl ether, a preparation method and industrial application thereof. Background technique

[0002] P-phenylenedimethyl ether is a high value-added fine chemical product, which is widely used in medicine and pesticides. It can be used in the production of drug methoxyamine hydrochloride, dye black salt ANS, etc., as a fixative, in daily chemicals, in the preparation of food and tobacco flavors; as an additive, it can also be used as an anti-wind erosion agent for plastics and coatings.

[0003] At present, the main production method in the industry is to react hydroquinone with alkali to obtain sodium phenate, and then substitute it with dimethyl sulfate to obtain the product. The reaction conditions of this route are relatively mild, but the raw material dimethyl sulfate is a highly toxic substance, which has great po...

Examples

preparation example Construction

[0026] Correspondingly, the present invention further provides a preparation method for synthesizing p-xylylene dimethyl ether catalyst with hydroquinone and dimethyl carbonate as raw material, comprising the following steps:

[0027] 1) According to the composition ratio of the main catalyst, weigh a certain amount of active components alkali metal or alkaline earth metal halide and auxiliary metal nitrate, the amount of each component makes the final active component molar percentage account for the amount of the main catalyst is 30% ~90%, the molar percentage of the auxiliary agent accounts for 10%~70% of the amount of the main catalyst, and the main catalyst mass percentage is 5%~30% antioxidant.

[0028] 2) At room temperature, mechanically mix the above three components, the stirring speed is 10-60r / min, and the stirring time is 0.5-2.0h.

[0029] The present invention also provides the application of a composite catalyst in the synthesis of p-xylylene dimethyl ether wit...

Embodiment 1

[0032] According to mole percentage, weigh 50% NaCl and 50% Ca(NO 3 ) 2 For the preparation of the main catalyst, weigh the main catalyst mass fraction to be 5% antioxidant 264, and add the corresponding three components into the solid mixing device. At room temperature, the stirring speed is 50r / min, and the stirring time is 0.5h. The mixed composite catalyst used for synthesizing p-phenylene dimethyl ether is packed into barrels for subsequent use.

[0033] at 2.5m 3 In the reaction kettle, hydroquinone and dimethyl carbonate are carried out on the composite catalyst for methylation reaction according to the molar ratio of 1:2.0. 1 wt.% of hydroquinone, the stirring rate is 80r / min, the reaction temperature is 200°C, the reaction pressure is 4MPa, and the reaction time is 6h. After the reaction, the mixed liquid was frozen and cooled for crystallization and purification, and the yield of p-xylylene dimethyl ether was 81%, and the purity was greater than 99.5%.

Embodiment 2

[0035] According to mole percentage, weigh 50% NaBr and 50% Cu(NO 3 ) 2 For preparing the main catalyst, weigh the main catalyst mass fraction as 10% Antioxidant 330, and add the corresponding three components into the solid mixing device. At room temperature, the stirring speed is 50r / min, and the stirring time is 0.5h. The mixed composite catalyst used for synthesizing p-phenylene dimethyl ether is packed into barrels for subsequent use.

[0036] at 2.5m 3 In the reaction kettle, hydroquinone and dimethyl carbonate are carried out on the composite catalyst according to the molar ratio of 1:2.5, and the methylation reaction is carried out. 1.5wt.% of hydroquinone, the stirring rate is 100r / min, the reaction temperature is 210°C, the reaction pressure is 5MPa, and the reaction time is 6h. After the reaction, the mixed liquid was frozen and cooled for crystallization and purification, and the yield of p-xylylene dimethyl ether was 87%, and the purity was greater than 99.5%....

technical field

[0001] The invention belongs to the technical field of chemical catalysts, and relates to a composite catalyst for synthesizing p-xylylene dimethyl ether, a preparation method and industrial application thereof. Background technique

[0002] P-phenylenedimethyl ether is a high value-added fine chemical product, which is widely used in medicine and pesticides. It can be used in the production of drug methoxyamine hydrochloride, dye black salt ANS, etc., as a fixative, in daily chemicals, in the preparation of food and tobacco flavors; as an additive, it can also be used as an anti-wind erosion agent for plastics and coatings.

[0003] At present, the main production method in the industry is to react hydroquinone with alkali to obtain sodium phenate, and then substitute it with dimethyl sulfate to obtain the product. The reaction conditions of this route are relatively mild, but the raw material dimethyl sulfate is a highly toxic substance, which has great po...

Examples

preparation example Construction

[0026] Correspondingly, the present invention further provides a preparation method for synthesizing p-xylylene dimethyl ether catalyst with hydroquinone and dimethyl carbonate as raw material, comprising the following steps:

[0027] 1) According to the composition ratio of the main catalyst, weigh a certain amount of active components alkali metal or alkaline earth metal halide and auxiliary metal nitrate, the amount of each component makes the final active component molar percentage account for the amount of the main catalyst is 30% ~90%, the molar percentage of the auxiliary agent accounts for 10%~70% of the amount of the main catalyst, and the main catalyst mass percentage is 5%~30% antioxidant.

[0028] 2) At room temperature, mechanically mix the above three components, the stirring speed is 10-60r / min, and the stirring time is 0.5-2.0h.

[0029] The present invention also provides the application of a composite catalyst in the synthesis of p-xylylene dimethyl ether wit...

Embodiment 1

[0032] According to mole percentage, weigh 50% NaCl and 50% Ca(NO 3 ) 2 For the preparation of the main catalyst, weigh the main catalyst mass fraction to be 5% antioxidant 264, and add the corresponding three components into the solid mixing device. At room temperature, the stirring speed is 50r / min, and the stirring time is 0.5h. The mixed composite catalyst used for synthesizing p-phenylene dimethyl ether is packed into barrels for subsequent use.

[0033] at 2.5m 3 In the reaction kettle, hydroquinone and dimethyl carbonate are carried out on the composite catalyst for methylation reaction according to the molar ratio of 1:2.0. 1 wt.% of hydroquinone, the stirring rate is 80r / min, the reaction temperature is 200°C, the reaction pressure is 4MPa, and the reaction time is 6h. After the reaction, the mixed liquid was frozen and cooled for crystallization and purification, and the yield of p-xylylene dimethyl ether was 81%, and the purity was greater than 99.5%.

Embodiment 2

[0035] According to mole percentage, weigh 50% NaBr and 50% Cu(NO 3 ) 2 For preparing the main catalyst, weigh the main catalyst mass fraction as 10% Antioxidant 330, and add the corresponding three components into the solid mixing device. At room temperature, the stirring speed is 50r / min, and the stirring time is 0.5h. The mixed composite catalyst used for synthesizing p-phenylene dimethyl ether is packed into barrels for subsequent use.

[0036] at 2.5m 3 In the reaction kettle, hydroquinone and dimethyl carbonate are carried out on the composite catalyst according to the molar ratio of 1:2.5, and the methylation reaction is carried out. 1.5wt.% of hydroquinone, the stirring rate is 100r / min, the reaction temperature is 210°C, the reaction pressure is 5MPa, and the reaction time is 6h. After the reaction, the mixed liquid was frozen and cooled for crystallization and purification, and the yield of p-xylylene dimethyl ether was 87%, and the purity was greater than 99.5%....