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Silver catalyst for olefin epoxidation and preparation method thereof

A silver catalyst, epoxidation technology, used in physical/chemical process catalysts, metal/metal oxide/metal hydroxide catalysts, chemical instruments and methods, etc.

Active Publication Date: 2015-07-08
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The reactivity of such silver catalysts needs to be improved. Therefore, studies on the crystal planes of silver nanocrystals with different shapes and their catalytic ethylene epoxidation have been carried out at home and abroad. The morphology of these silver nanocrystals is, for example, silver nanopolyhedron, silver nanocrystal Cubes, silver nanorods, silver nanosheets, silver nanotriangular prisms and silver nanobicones, etc.; the above silver nanocrystals expose different crystal faces

Method used

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  • Silver catalyst for olefin epoxidation and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1 and comparative example 3

[0030] Preparation of Catalysts C and D: Add 25ml of ethylene glycol into a three-necked flask with magnetic stirring at 140°C, heat at this temperature for 1 hour, add 5ml of HCl solution with a concentration of 25μM, and inject it with a double-channel microinjection after 10 minutes The pump adds 94mM AgNO at a rate of 45ml / h 3 Solution and 147mM polyvinylpyrrolidone (PVP, molecular weight Mw ≈ 55000), reacted for about 8 hours, then the solution was centrifuged at 4000 rpm for 20 minutes, and the resulting precipitate was washed 3-5 times with ethanol and water and put into vacuum drying Dry in an oven at room temperature; prepare silver nanocubes whose size is concentrated at 70-80 nm and which preferentially expose silver {100} crystal planes. Then put the silver nanocube and carrier a (or carrier b) into ethanol, stir and mix, dry at 70°C for 3 hours, and then heat-treat at 250°C to obtain supported silver catalysts C and D.

Embodiment 2

[0032]Preparation of Catalyst E: the same steps as in Example 1, except that the concentration of HCl was changed from 25 μM to 12 μM. The silver nanocubes whose size is concentrated in 180-200nm and preferentially expose the silver {100} crystal faces are prepared. Catalyst E was obtained by loading it on carrier a.

Embodiment 3

[0034] The preparation of catalyst F: the same step as in Example 1, except that AgNO 3 And PVP solution concentration changed from 94mM and 147mM to 235mM and 367.5mM. Silver nanorods with a diameter of 80-100 nm, a length of 3-5 μm, and preferentially exposed silver {100} and silver {111} crystal planes were prepared. Catalyst F is obtained by loading it on carrier a.

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Abstract

The present invention provides a silver catalyst for olefin epoxidation. The silver catalyst comprises nano silver and an alpha-alumina carrier. The nano silver contains silver {100} crystal face; the alpha-alumina carrier has specific surface area of about 0.8-3 m<2> / g, water absorption of 50-80% and hole size of 0.5-1.0 ml / g. The silver catalyst obtained in the invention used in the ethylene epoxidation production of epoxy ethane catalyst realizes better ethylene oxide selectivity and catalytic activity than the prior art.

Description

technical field [0001] The invention relates to the field of catalysts, in particular to a silver catalyst for olefin epoxidation and a preparation method thereof. Background technique [0002] In 2011, my country's equivalent ethylene oxide production capacity was 3.6 million tons, of which 1.4 million tons were commercial ethylene oxide. At present, ethylene oxide in my country is mainly used to produce ethylene glycol, accounting for 75% of the total consumption of EO, while the other 25% is used to produce non-ionic surfactants, polyether / polyethylene glycol, ethanolamine, choline and pharmaceutical intermediates body etc. As the core part of the ethylene oxide production plant, the silver catalyst determines the production cost. With the increase of crude oil price and ethylene price, in order to reduce the production cost, the new EO / EG unit adopts high-selectivity silver catalyst, so it is necessary to seek better technology to produce catalyst with better performanc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/50B01J23/68C07D303/04C07D301/10
Inventor 孙欣欣李金兵林伟任冬梅王辉李贤丰汤之强林强崔宝林
Owner CHINA PETROLEUM & CHEM CORP