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Catalyst for gas-phase synthesis of oxalate and its preparing process

A gas-phase synthesis, catalyst technology, applied in chemical instruments and methods, physical/chemical process catalysts, metal/metal oxide/metal hydroxide catalysts, etc., can solve problems such as low space-time yield, and achieve stable and high reaction. Reactivity and selectivity, easily controlled effects

Inactive Publication Date: 2002-11-27
EAST CHINA UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Subsequently, many patents have successively reported that Mo, Ni, Ti, Fe, Ga, Cu, Na 2 O, and SiO 2 Catalysts composed of additives such as carbon monoxide and nitrite are used in the gas phase synthesis of dimethyl oxalate, diethyl oxalate and diisopropyl oxalate, but the space-time yield is still low

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Weigh 10gα-Al 2 o 3 , by 1wt%Pd+0.3wt%Ce / α-Al 2 o 3 content preparation catalyst, the steps are as follows: select Ce(NO 3 ) 3 According to the amount of Ce loading, the impregnating solution is formulated. In order to prevent metal ions from hydrolyzing to form hydroxides or oxides, a small amount of nitric acid is added to the impregnating solution to make the pH of the impregnating solution = 5, and then the specific surface area is 3m 2 / g carrier α-Al 2 o 3 Soak in the impregnating solution for 12 hours, dry it in a water bath to become a solid after being fully absorbed, then dry the solid at 120°C for 12 hours, and bake it at 300-650°C for 6 hours, then put the solid in the PdCl 2 It is formulated to be soaked in the impregnation solution for 12 hours, and dried at 120°C for 12 hours to make Pd-Ce / α-Al 2 o 3 catalyst.

Embodiment 2

[0030] Weigh 10gα-Al 2 o 3 , by 1wt%Pd+0.1wt%Ce / α-Al 2 o 3 content preparation catalyst, the steps are as follows: select Ce(NO 3 ) 3 According to the amount of Ce loading, the impregnating solution is formulated. In order to prevent metal ions from hydrolyzing to form hydroxide or oxide precipitation, a small amount of nitric acid is added to the impregnating solution to make the pH of the impregnating solution = 7, and then the specific surface area is 30m 2 / g carrier α-Al 2 o 3 Soak in the impregnating solution for 12 hours, dry it in a water bath to become a solid after being fully absorbed, then dry the solid at 120°C for 12 hours, and bake it at 300-650°C for 6 hours, then put the solid in the Pd(NO 3 ) 2 It is formulated to be soaked in the impregnation solution for 12 hours, and dried at 120°C for 12 hours to make Pd-Ce / α-Al 2 o 3 catalyst.

Embodiment 3

[0031] Embodiment 3, the test of catalyst activity:

[0032] The catalyst is placed in a quartz glass reactor with an inner diameter of 20mm. The reactor is equipped with a thermocouple sleeve. The catalyst loading is 2ml. The raw material gas passes through the catalyst bed from top to bottom, and the product dimethyl oxalate is drawn out from the bottom of the reactor. . Before the catalyst participates in the reaction, it needs to undergo hydrogen reduction treatment. The reduction temperature is 350°C, the reduction time is 3 hours, and the hydrogen flow rate is 50ml / min. The optimal flow ratio of reaction gas carbon monoxide and nitrite is 1.3, the reaction is carried out under normal pressure, the reaction temperature is 140°C, the single-pass conversion rate of carbon monoxide reaches 78%, and the space-time yield of dimethyl oxalate is 821g / L.h, Dimethyl oxalate and formaldehyde were not detected in the product.

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Abstract

A catalyst for gas-phase synthesis of dimethyl (or diethyl) oxalate from CO and nitrite is prepared from alpha-Al2O3 as carrier and Ce and Pd as active components through the dipping method. Its advantages are high reaction activity and selectivity, long service life and easy control of reaction.

Description

technical field [0001] The invention relates to a catalyst and a preparation method thereof, in particular to a catalyst for gas-phase synthesis of oxalate and a preparation method thereof. Background technique [0002] Oxalate is an important chemical raw material, which can be used to prepare oxalic acid, ethylene glycol, oxamide and intermediates of some drugs and dyes. [0003] At present, dialkyl oxalate is produced domestically by esterification and dehydration of oxalic acid and alkyl alcohol with toluene. One of its main raw materials, oxalic acid, is produced by the sodium formate method, by mixing carbon monoxide and sodium hydroxide at 160°C, 16-20kgf / cm 2 Under pressure, synthesize sodium formate, then concentrate and dehydrogenate at 400 to generate sodium oxalate, then react with lead sulfate to generate lead oxalate, further acidify with sulfuric acid to obtain crude oxalic acid, and finally coagulate and settle with barium carbonate and 1% polyacrylamide to ...

Claims

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Application Information

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IPC IPC(8): B01J23/44C07C69/12
Inventor 赵红钢肖文德朱毓群赵秀阁赵铁均
Owner EAST CHINA UNIV OF SCI & TECH
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