Propylene gas-phase epoxidation catalyst used at low temperature and preparation method of catalyst

Abstract

The invention discloses a catalyst CuOX-MoO3-Bi2SiO5 / SiO2 for preparing propylene epoxide by propylene gas-phase epoxidation at the low temperature and a preparation method of the catalyst. The catalyst is applied to a reaction of preparing propylene epoxide from molecular oxygen (O2) or air as an oxidizing agent by the propylene gas-phase epoxidation, the reaction conditions are mild, inhibitorsare not required, and the catalyst keeps higher catalytic activity at the temperature of 300-380 DEG C. The catalyst adopts Bi2SiO5 / SiO2 as a supporter, MoO3 as an active component and Cu as a modification aid, and is prepared from the components in percentage by mass as follows: 75.0%-95.0% of the supporter Bi2SiO5 / SiO2, 4.2%-21.0% of MoO3 and 0.8%-4.0% of CuOX. A mole ratio of Si to Bi in the supporter Bi2SiO5 / SiO2 is 50, the supporter Bi2SiO5 / SiO2 is synthesized with a hydrothermal method, the active component MoO3 and the aid Cu impregnate Mo and Fe precursor to the supporter with an ultrasonic assisted co-impregnation method, and the catalyst is prepared accordingly.

Description

technical field [0001] The invention belongs to the field of petrochemical catalyst preparation methods, and more specifically relates to a catalyst for preparing propylene oxide and a preparation method thereof, especially a catalyst for preparing propylene oxide by gas-phase epoxidation of propylene and a preparation method thereof. Background technique [0002] Propylene oxide, referred to as PO, is an important chemical raw material, a very important organic compound raw material, and the third largest propylene derivative after polypropylene and acrylonitrile. At present, the main methods of producing PO in industry are chlorohydrin method and co-oxidation method. Moreover, the chlorohydrin method is still the main production method of PO, which has the advantages of low investment, good selectivity, high efficiency, and large operating flexibility. However, the hypochlorous acid produced during the production process of this process severely corrodes equipment and prod...

AI Technical Summary

Problems solved by technology

With TS-1 molecular sieve as catalyst, the reaction conditions are mild and the PO yield is high, but due to TS-1 and H 2 o 2 The cost is higher, and H 2 o 2 There are potential safety hazards in storage and transportation, which limits its industrialization process to a certain extent.

M. Haruta et al. (Journal of Catalysis, 1998, 178(2): 566-575) synthesized Au / TiO by deposition-precipitation method for the first time 2 Catalyst, in H 2 with O 2 Under coexistence conditions, a PO selectivity as high as 93% was obtained, but the conversion of propylene was less than 2.5%

Authorized patent CN104128176 B discloses a catalyst TiO for the production of propylene oxide by gas-phase epoxidation of propylene with high activity 2 -MoO 3 -Bi 2 SiO 5 / SiO 2 , the prepared catalyst has high catalytic activity, but there is a problem that the reaction temperature is too high, and the activity drops sharply when the reaction temperature is lowered. The higher reaction temperature requires higher energy consumption, which increases the production cost virtually, and is not conducive to Large-scale industrialization, in order to better promote the industrialization of the propylene gas-phase epoxidation process, it is still necessary to develop a low-cost, high-activity propylene gas-phase epoxidation catalyst at a lower reaction temperature