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Catalyst for synthesizing 2, 5-dimethylpyrazine as well as preparation method and application of catalyst

A technology of dimethylpyrazine and catalyst, which is applied in the field of catalyst for synthesizing 2,5-dimethylpyrazine and its preparation, can solve the problems of poor catalyst life, high reaction temperature, many reaction steps and the like, and achieves good dehydration Effect, uniform mixing, good selectivity

Pending Publication Date: 2021-07-02
JINAN ENLIGHTEN BIOTECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method has many reaction steps and requires the use of nitrite and mercuric oxide, which is costly, not environmentally friendly, and not suitable for large-scale industrial production
[0006] 2. With acrolein and ammonia as raw materials, 2,5-dimethylpyrazine can be obtained by heating reaction in glycerol in the presence of ammonium salt, but acrolein is highly toxic, and the reaction process is prone to explosion, which poses a great safety hazard
[0008] 4. Use ethylenediamine as raw material, copper oxide / copper chromate as catalyst, use fixed bed reactor, and synthesize 2,5-dimethylpyrazine by gas-solid phase catalysis at 380°C, but the reaction temperature is high and the life of the catalyst Difference
Chinese patent CN103949266A adopts copper oxide, zinc oxide and chromium oxide / silver oxide mixed oxide as catalyst, and the cost of using silver catalyst is high, and the use of heavy metal chromium is environmentally unfriendly; Chinese patent CN106582672A uses silica-loaded Cr, Cu and Zn oxides Catalyst, there is also the problem that the use of heavy metal chromium is not friendly to the environment

Method used

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  • Catalyst for synthesizing 2, 5-dimethylpyrazine as well as preparation method and application of catalyst

Examples

Experimental program
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preparation example Construction

[0031] A second aspect of the present invention provides the preparation method of the above-mentioned catalyst, the preparation method comprising:

[0032] S1. Dissolving the copper salt and the zinc salt in water, completely dissolving into a copper-zinc salt solution;

[0033] S2. Add the precipitating agent to the solution prepared in step S1. After the precipitation is completed, add the ZSM-5 molecular sieve to the solution under stirring conditions, and continue to age again; the ZSM-5 molecular sieve and the copper zinc oxide precursor are in the solution Direct mixing, compared with solid mechanical mixing, there is no dust pollution, and the mixing is more uniform.

[0034] S3. The precipitate obtained in step S2 is purified and then roasted.

[0035] Wherein, in the step S1, the copper salt is a soluble copper salt, including but not limited to copper chloride, copper sulfate and copper nitrate, preferably copper nitrate Cu(NO 3 ) 2 ·3H 2 O;

[0036] Described ...

Embodiment 1

[0050] The catalyst used in the direct synthesis of 2,5-dimethylpyrazine from isopropanolamine in this example is prepared by mixing ZSM-5 molecular sieve and copper salt and zinc salt in aqueous solution.

[0051] The mass percentage of ZSM-5 molecular sieve in the catalyst is 1%, the mass percentage of CuO is 55%, and the mass percentage of ZnO is 44%. The preparation method of the catalyst comprises the following steps:

[0052] Step 1, 82.7gCu(NO 3 ) 2 ·3H 2 O and 79.5gZn(NO 3 ) 2 ·6H 2 O was dissolved in hot distilled water, stirred and completely dissolved into a copper-zinc salt solution;

[0053] Step 2. Dissolve 129g of anhydrous sodium carbonate in hot distilled aqueous solution as a precipitant, add the precipitant dropwise to the solution of step 1, control the precipitation temperature to 60°C, pH value to 8, and control the precipitation time After the precipitation is completed, add 0.5 g of ZSM-5 molecular sieve with a silicon-aluminum ratio of 26:1 into ...

Embodiment 2

[0057] The catalyst used in the direct synthesis of 2,5-dimethylpyrazine from isopropanolamine in this example is prepared by mixing ZSM-5 molecular sieve and copper salt and zinc salt in aqueous solution.

[0058] The mass percentage of ZSM-5 molecular sieve in the catalyst is 5%, the mass percentage of CuO is 55%, and the mass percentage of ZnO is 40%. The preparation method of the catalyst comprises the following steps:

[0059] Step 1, 83.5gCu(NO 3 ) 2 ·3H 2 O and 73.1gZn(NO 3 ) 2 ·6H 2 O was dissolved in hot distilled water, stirred and completely dissolved into a copper-zinc salt solution;

[0060] Step 2. Dissolve 89g of anhydrous sodium carbonate in hot distilled aqueous solution as a precipitant, add the precipitant dropwise to the solution of step 1, control the precipitation temperature to 60°C, pH value to 8, and control the precipitation time After the precipitation is completed, add 2.5 g of ZSM-5 molecular sieve with a silicon-aluminum ratio of 26:1 into t...

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Abstract

The invention provides a catalyst for synthesizing 2, 5-dimethylpyrazine as well as a preparation method and application thereof, and belongs to the technical field of catalyst preparation. The catalyst is prepared by mixing a ZSM-5 molecular sieve, a copper salt and a zinc salt in an aqueous solution. The catalyst for synthesizing the 2, 5-dimethylpyrazine by taking the isopropanolamine as the raw material through the gas-solid phase reaction is successfully prepared, the catalyst is used for continuous gas-solid phase reaction, the conversion rate is high, the selectivity is good, the service life is long, the catalyst is environmentally friendly, the cost is low, and therefore the catalyst has good practical application value.

Description

technical field [0001] The invention belongs to the technical field of catalyst preparation, and in particular relates to a catalyst for synthesizing 2,5-dimethylpyrazine, a preparation method and application thereof. Background technique [0002] The information disclosed in this background section is only intended to increase the understanding of the general background of the present invention, and is not necessarily taken as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to those skilled in the art. [0003] 2,5-Dimethylpyrazine is a colorless to amber liquid with a roasted, nutty raw potato, musty, and chocolate odour. 2,5-Dimethylpyrazine is easily soluble in water and ethanol. It is a spice allowed in my country's GB-2760-86. It is often used as a natural seasoning and spice for potatoes, beer, cocoa, coffee, and meat. And seasoning such as nuts. [0004] The inventors have found that the current method for syn...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J29/42B01J37/04C07D241/12
CPCB01J29/42B01J37/04C07D241/12B01J2229/18
Inventor 冯先涛种道皇李新孙斌
Owner JINAN ENLIGHTEN BIOTECH CO LTD