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Gold-based catalyst for preparing carboxylic ester by oxidative esterification and application thereof

A technology of oxidative esterification and catalyst, which is applied in the direction of metal/metal oxide/metal hydroxide catalyst, physical/chemical process catalyst, carboxylate preparation, etc. It can solve the problems of unclear catalytic mechanism and achieve significant industrialization prospects , high selectivity, and mild reaction conditions

Active Publication Date: 2021-01-26
XIAMEN UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Asahi Kasei's Au catalyst has passed pilot production, but the catalytic mechanism of this system is not yet clear, and it is still necessary to study how to fine-tune the active components of the catalyst and optimize the performance of the catalyst, but in general, Au-catalyzed MAL oxidative esterification to MMA is very marketable prospect

Method used

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  • Gold-based catalyst for preparing carboxylic ester by oxidative esterification and application thereof
  • Gold-based catalyst for preparing carboxylic ester by oxidative esterification and application thereof
  • Gold-based catalyst for preparing carboxylic ester by oxidative esterification and application thereof

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preparation example Construction

[0035] A kind of preparation method of the gold-based catalyst that the present invention is used for oxidative esterification to prepare carboxylic acid ester comprises the following steps:

[0036] S1: Preparation of gold colloid: dissolve the protective agent and gold source in a solvent, stir evenly to obtain the first solution;

[0037] Add a reducing agent to the first solution under stirring, and continue stirring to obtain gold colloids;

[0038] S2: adding carrier and additive salt solution to the gold colloid and stirring, separating after stirring, and washing several times to obtain a solid catalyst, drying and roasting the solid catalyst to obtain the gold-based catalyst.

[0039] In the present invention, in step S1, the protective agent is one or more of PVP, CTAB, PVA and SDS; the gold source is chloroauric acid, sodium chloroaurate, gold chloride, gold nitrate, potassium dicyanoalloy One or more in; Solvent is one or more in water, ethanol, ethylene glycol; R...

Embodiment 1

[0044] Weigh an appropriate amount of PVP and dissolve it in deionized water, configure a 1wt.% PVP aqueous solution, stir for 10 minutes, and dissolve a certain amount of HAuCl 4 The aqueous solution was added to the PVP aqueous solution to obtain the first solution, so that Au / PVP (mass ratio) = 1:1. After continuous stirring for 5min, add the configured 0.5mol / L NaBH 4 aqueous solution, making Au / NaBH 4 (Molar ratio) = 1:4, the mixed solution will quickly turn wine red to obtain gold colloid. Continue to stir for 30 min, then add the corresponding carrier AlOOH, wherein the content of chlorine in the carrier is less than or equal to 1wt.%, and the stirring time is 12h, so that the Au loading is 1wt.%. After stirring and adsorption, filter and wash with deionized water for several times until there is no residual Cl ion in the solution, put the obtained solid catalyst in a vacuum drying oven at 60°C for 8 hours, and finally put the dried solid catalyst in a muffle In an a...

Embodiment 2

[0055]The gold-based catalyst obtained in Example 1 is applied to the one-step oxidative esterification of MAL to prepare MMA reaction, the conditions are: 0.5g catalyst is added in the reaction solution composed of MAL and MeOH, wherein MeOH / MAL (alcohol-aldehyde molar ratio) Set different ratios, the flow rate of oxygen is 20mL / min, and the reaction time is 2h. The results obtained are shown in Table 2. It can be seen from the table that the catalyst still has good catalytic activity at low aldehyde content, alcohol: aldehyde = 20:1 (molar ratio). As the aldol-aldehyde ratio increases, the activity of the catalyst is excellent, which can increase the cost. The consumption of raw material methanol improves the conversion rate of MAL and the selectivity of MMA.

[0056] The reaction result of table 2 different aldol mol ratios

[0057]

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Abstract

The invention relates to a gold-based catalyst for preparing carboxylic ester by oxidative esterification, and a preparation method and application thereof. The catalyst comprises an active componentgold and / or an auxiliary agent loaded on a carrier, the carrier comprises hydroxide of aluminum, and the hydroxide of aluminum accounts for more than 60% of the total mass of the carrier; the active component is gold, and the content of the active component is 0.2-8 wt.%; the content of the auxiliary agent is 0-20 wt.%. The preparation method comprises the following steps: firstly preparing gold colloid, then adding the carrier and the auxiliary agent into the gold colloid, and preparing the catalyst through drying and low-temperature roasting. The gold and the carrier in the catalyst have strong interaction, the catalyst has high MAL conversion rate and high MMA selectivity when being used for one-step esterification and oxidation reaction of MAL and methanol, and the catalyst has good stability and high economic value.

Description

technical field [0001] The invention relates to the technical field of catalysts, in particular to a gold-based catalyst used for oxidative esterification to prepare carboxylic acid esters, its preparation method and its application. Background technique [0002] Methyl methacrylate (MMA) is an important organic chemical raw material, widely used in chemical industry, aviation, building materials, machinery and electronics and other fields. MMA production process can be divided into three process routes of C2, C3 and C4 according to the number of carbon atoms in the raw material. The C2 route is mainly from ethylene through the propionaldehyde method (BASF process) and the methyl propionate method (Alpha process); the C3 route is mainly the acetone cyanohydrin method (ACH) and its improved process; the C4 route is mainly the isobutylene oxidative esterification method . The current MMA production process is still dominated by the ACH method, accounting for more than 60% of...

Claims

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Application Information

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IPC IPC(8): B01J23/66B01J23/89C07C69/54C07C67/39
CPCB01J23/66B01J23/8906C07C67/39C07C69/54
Inventor 陈秉辉牟哲盈郑进保刘明久王杰兴
Owner XIAMEN UNIV