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Preparation method of 3-methyl-2-butenal

A kind of butenal and methyl technology, which is applied in the field of preparation of 3-methyl-2-butenal, can solve the problems of increasing operating costs, unfavorable continuous and stable operation of devices, and clogging of a catalyst bed of a feed pipeline by carbon formation.

Pending Publication Date: 2022-04-22
WANHUA CHEM GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This solution only solves the problem of improving the single-pass conversion rate and selectivity of the reaction, but there is a problem that the feed pipeline and the catalyst bed are easily blocked by carbon formation during the process of mixing the raw materials (including recycled materials) with air after gasification, As a result, the reaction system needs to repeatedly burn (remove) charcoal and activate, which increases operating costs
In the above patent scheme, although the reactor can run continuously for 1167 days without replacing the catalyst, it needs to be interrupted for several hours every week during the operation to burn off the coke and other organic products on the catalyst, which is not conducive to the continuous and stable operation of the device

Method used

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  • Preparation method of 3-methyl-2-butenal
  • Preparation method of 3-methyl-2-butenal
  • Preparation method of 3-methyl-2-butenal

Examples

Experimental program
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Effect test

preparation example Construction

[0042] (2) Preparation of catalyst:

[0043] ①Add 8g AgNO to 10ml of deionized water 3 , 0.60g Cu(NO 3 ) 2 , 0.015g CsNO 3 and 0.02gMg(NO 3 ) 2 , stir until completely dissolved;

[0044] ②In a round bottom flask, add 5g of α-Al 2 o 3 For the carrier, soak it in the solution of step ① for 1 hour, take out the carrier, drain it, remove the excess solution, and then dry it at 5KPa(A) and 80°C;

[0045] ③Put the carrier impregnation obtained in step ② into a round-bottomed flask, then add 10wt% oxalic acid solution to soak for 2 hours, drain the carrier after taking it out, remove the excess solution, and then put it under the conditions of 5KPa(A) and 150°C down to dry;

[0046] ④Put the impregnated carrier obtained in step ③ into a muffle furnace for roasting, first roast at 260°C for 0.5h, then raise the temperature to 400°C within 0.5h, continue roasting for 5h, and finally use hydrogen reduction for 5h to obtain an oxidation reaction catalyst , denoted as catalyst A;...

Embodiment 1

[0056] (1) Preparation of 3-methyl-2-butenal

[0057] Fresh 3-methyl-3-butenol was gasified at 150°C, and fed into a fixed-bed reactor with an inner diameter of 1 cm filled with 2 ml of catalyst A at a rate of 0.12 mol / h; meanwhile, according to The oxygen-alcohol ratio is 0.5, and the water-alcohol ratio is 1.2 to prepare a mixed gas of air and water vapor (oxygen content is 6.16mol%), and the mixed gas is preheated and fed together with unsaturated alcohol vapor into the fixed-bed reactor ; Control the reaction temperature to 390°C and the reaction volume space velocity to 29756h -1 . After the reaction was completed, gas chromatography analysis of the reaction product showed that the reaction conversion rate was 74.5%, and the total selectivity of 3-methyl-3-butenal and 3-methyl-2-butenal was 96.8%.

[0058] (2) reclaim 3-methyl-3-butenol

[0059] After the gas-phase oxidation products are rearranged according to the above method, the reaction liquid is sent to the dehyd...

Embodiment 2

[0061] The fresh 3-methyl-3-butenol and the 3-methyl-3-butenol (conjugated compound content 0.5wt%) reclaimed by the previous examples are mixed in a mass ratio of 3:1, and then mixed with O 2 The oxygen-containing gas with a concentration of 3mol% is pretreated according to the volume ratio of oxygen-containing gas:unsaturated alcohol=100:1 at a pressure of 1 bar (A) and a temperature of 70°C for a treatment time of 10 minutes; The concentration of the conjugated compound was reduced to 500 ppm.

[0062] The obtained unsaturated alcohol is gasified at 150°C, and fed at a rate of 0.12mol / h to a fixed-bed reactor filled with 2ml of Catalyst A with an inner diameter of 1cm; The ratio is 1.2 to prepare the mixed gas of air and water vapor (oxygen content is 6.16mol%), and after the mixed gas is preheated, it is fed into the fixed-bed reactor together with unsaturated alcohol vapor; the reaction temperature is controlled at 390 ° C, and the reaction Volumetric airspeed 29756h -1...

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Abstract

The invention discloses a preparation method of 3-methyl-2-butenal, which comprises the following steps: mixing air of which the O2 concentration is controlled below the limit oxygen concentration of unsaturated alcohol with unsaturated alcohol steam, introducing the mixture into a fixed bed reactor filled with an oxidation catalyst, and carrying out gas-phase catalytic oxidation to prepare 3-methyl-2-butenal, the unsaturated alcohol is 3-methyl-2-butenol, 3-methyl-3-butenol or a mixture of the 3-methyl-2-butenol and the 3-methyl-3-butenol. The method provided by the invention can greatly prolong the stable operation period of a reaction device, is beneficial to reducing the process operation cost, and has a good industrial prospect.

Description

technical field [0001] The invention relates to a preparation method, in particular to a preparation method of 3-methyl-2-butenal. Background technique [0002] 3-Methyl-2-butenal (prenyl aldehyde) is an extremely important chemical raw material, and its manufacturing technology is the core technical difficulty of the citral industry chain. Citral is the main raw material for the production of nutritional chemicals such as vitamin A, vitamin E, menthol, geraniol, and flavors and fragrances. At present, about 90% of the world's production capacity is concentrated in BASF (70kt / a) and Japan's Kuraray (10kt / a). a) Two, China's annual import volume is nearly 10,000 tons. [0003] BASF patent US6013843A adopts a silver-loaded catalyst to prepare unsaturated aliphatic aldehydes in a shell-and-tube reactor, with a conversion rate of 52-55% and a selectivity of 90-92%. This solution only solves the problem of improving the single-pass conversion rate and selectivity of the reactio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C47/21C07C45/29C07C45/83B01J23/89
CPCC07C45/29C07C45/83B01J23/8946C07C47/21Y02P20/584
Inventor 刘英俊朱小瑞庞计昌张红涛沈元伟张永振张礼昌黎源
Owner WANHUA CHEM GRP CO LTD
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