Graphene-loaded tin-tungsten bimetallic catalyst as well as preparation method and application thereof

Abstract

The invention discloses a graphene-loaded tin-tungsten bimetallic catalyst as well as a preparation method and application thereof. The preparation method of the catalyst comprises the following steps: adding graphite oxide prepared by virtue of a Hummers process into a polar solvent, carrying out ultrasonic stripping to obtain graphene oxide, then adding sodium tungstate dihydrate, tin salt and hydrochloric acid solution, continuously carrying out ultrasonic stripping, then carrying out ageing at a certain temperature, then transferring reaction liquid into a high pressure reactor, carrying out heating reaction, and finally washing and carrying out vacuum drying, thus obtaining the catalyst. When the prepared graphene-loaded tin-tungsten bimetallic catalyst is adopted for carrying out catalytic oxidation on alcohol to generate aldehyde or ketone, time required for reaction is short, conversion rate is 95% or abvoe, selectivity is 95% or above, and recycling and reproduction propertiesof the catalyst are excellent, so that the catalyst disclosed by the invention is well suitable for industrial production and has a good application value.

Description

technical field [0001] The invention belongs to the fields of new material manufacturing and fine chemical industry, and specifically relates to a preparation method of a graphene-supported tin-tungsten bimetallic catalyst and its application in catalytic oxidation to prepare aldehydes or ketones. Background technique [0002] Aldehydes or ketones are a very important class of fine chemical intermediates, widely used in the fields of medicine, pesticides and cosmetics. The catalytic oxidation of carbonyl compounds such as alcohols to aldehydes or ketones by designing some efficient catalysts is currently a research hotspot for chemists. Alcohol-to-aldehyde catalytic systems mainly include metal-free catalysis and metal catalysis. [0003] Non-metallic catalytic systems mainly include: 1) α-H secondary hydroxylamine derived N-O radical catalytic oxidation system; 2) TEMPO combined with NaClO catalytic oxidation system. The metal-free catalytic oxidation of alcohol is widely...

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Problems solved by technology

2) Ru-based catalysts, such catalysts overcome the limitation that they are only effective on secondary alcohols, and have good applicability to primary alcohols and aliphatic alcohols, but the synthesis of Ru-based catalysts is relatively difficult, and the ligand stability is not good. High, thus affecting the catalytic recyclability

3) Transition metal Cu-based catalysts, as a relatively cheap transition metal, Cu is very competitive in cost, such as the catalyst Cu 2 (OH)PO 4 and Cu 4 O(PO 4 ) 2 , the catalyst at O 2 Or in the air, the corresponding aldehydes and ketones of benzyl alcohol and cyclohexanol oxygen can be converted, but it is worth noting that the recovery of the catalyst is relatively difficult (J Catal[J],2003,218:460-464.)

[0006] Generally speaking, the catalysts used in the above catalytic systems are more precious metals, the cost is higher, and the preparation of the catalysts is more troublesome. In addition, the oxidants are mainly stoichiometric metal oxidants and organic homogeneous oxidants, and the subsequent treatment of the products is troublesome. The difficulty of catalyst separation in the catalytic system, the selectivity or conversion rate of the product is not high, etc.

[0007] The Chinese patent application whose publication number is CN 106861696 A discloses a graphene-loaded iron-aluminum composite magnetic catalyst. When the catalyst is used for the oxidation of alcohol, it is convenient to separate from the product. When it is applied to the catalytic oxidation of benzyl alcohol to prepare benzaldehyde, it has Higher selectivity, however, when the applicant finds that this catalyst is used for other alcohols (for example benzyl alcohol and secondary alcohol with substituents), the reaction effect is not ideal enough, and the yield and selectivity are not high enough