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Double-layer catalyst and preparation thereof, and application of catalyst in preparation of pyromellitic dianhydride

A double-layer catalyst and catalyst technology, applied in the direction of physical/chemical process catalysts, organic chemistry, chemical instruments and methods, etc., can solve the problems of many impurities, unsatisfactory, heavy color, etc., and achieve easy reaction conditions, low requirements, and high color. shallow effect

Active Publication Date: 2012-09-12
SHIJIAZHUANG HAOPU CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the production of homoanhydride mostly uses durene as raw material, and is prepared by fixed-bed gas-phase catalytic oxidation process. Usually, a single-layer catalyst is used, and it is difficult to effectively control the reaction depth with a single-layer catalyst.
When the concentration of durene in the feed gas is high, the selectivity of conversion to homoanhydride is poor
Therefore, the production process mostly adopts high air velocity (greater than 5000hr -1 ), high reaction temperature (440-460°C), the resulting product has many impurities, heavy color and low purity due to many side reactions
These are far from ideal in industrial production

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] Catalyst E 8 preparation of

[0040] Heat 500ml of deionized water to 60-80°C to dissolve 96.9g of oxalic acid, add 44.858g of ammonium metavanadate to dissolve, then add 0.592g of sodium carbonate, 1.38g of ammonium dihydrogen phosphate, and 0.353g of ammonium molybdate (molybdenum is used as other elements) All dissolved, and finally 67.805 g of anatase titanium dioxide and 6 g of whiskers were added to prepare a slurry. At 200-300°C, spray the slurry onto a 600g ring carrier (6mm×6mm×3mm in size). The roasting furnace is evenly heated to 520°C in no less than 3 hours, the sprayed annular carrier is put into the roasting furnace for 5 hours, and the catalyst E is obtained after natural cooling. 8 , The load of the active ingredient is greater than 10g / 100g carrier.

[0041] Catalyst E 12 preparation of

[0042] Heat 500ml of deionized water at 60-80°C to dissolve 96.9g of oxalic acid, first add 44.858g of ammonium metavanadate to dissolve, then add 0.592g of sodi...

Embodiment 2

[0049] Catalyst E prepared in embodiment 1 is loaded into the small test reaction tube of internal diameter 26mm 12 , Catalyst G 13 , Catalyst E 12 Installed at the outlet of the reaction gas, the filling height is 130mm; Catalyst G 13 It is installed at the inlet end of the raw material mixture, and the filling height is 75mm. The operating conditions are: feed gas concentration 17.5g / Nm 3 , the reaction temperature is 410-425°C, and the space velocity is 4500hr -1 . The crude average anhydride product is lighter in color. Crude anhydride weight yield 103.5%, illustrate that the selectivity of this catalyst is better. The content of homoanhydride was analyzed by gas chromatography to be 97.64%, indicating that the purity of homoanhydride is relatively high.

Embodiment 3

[0051] Catalyst E prepared by embodiment 1 8 and Catalyst G 4 Single-tube tests are performed in stacks. The single tube reactor has a length of 3.6m and an inner diameter of 29mm. Catalyst E 8 Installed at the outlet of reaction gas, bed height 1300mm, catalyst G 4 Installed at the inlet and outlet of raw gas, the bed height is 750mm. Add an inert isolation layer of 20cm between the two catalysts (the specification is 6mm×6mm×3mm ceramic ring). The concentration of raw material mixture is 17.5-19.8g / Nm 3 , the reaction temperature is 410-420°C, and the space velocity is 4300-4500hr -1 . After 896 hours of continuous operation, the color of the crude homoanhydride product is relatively light, and the yield of crude anhydride is 95.6-98.7%, which shows that the catalyst has good selectivity. After a single-tube test, it can enter industrial trial production. The content of homoanhydride is 97.5-99.9% through gas chromatography analysis, indicating that the purity of hom...

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Abstract

The invention belongs to preparation and application of a catalyst, and particularly relates to a double-layer catalyst and preparation thereof, and application of the catalyst in preparation of pyromellitic dianhydride. The preparation method comprises the following steps: respectively weighing effective quantities of active components (V2O5, TiO2, P2O5, Na2O, MoO3 and Sb2O3), compounds of other metals and whiskers, preparing solutions, preparing spraying slurry, spraying the slurry on a support, roasting, cooling and carrying out other technical steps to obtain catalysts E and G; respectively putting the catalysts G and E at a raw material gas mixture inlet end and a reaction gas outlet end; and preparing the pyromellitic dianhydride under the conditions of low air speed, low temperature and the like. The invention solves the problems of high operating condition requirements, massive product impurities, heavy color, low purity and the like, and has the advantages of low operating condition requirements, high product purity, fewer impurities and the like.

Description

technical field [0001] The invention belongs to the preparation and application of a catalyst, in particular to a double-layer catalyst, its preparation and the application of the catalyst in the preparation of homoanhydride. Background technique [0002] Pyromellitic dianhydride (referred to as homoanhydride) can be used to prepare high-temperature-resistant insulating materials, plasticizers, epoxy resin curing agents, matting agents for powder coatings, etc., and is an important chemical raw material. [0003] At present, homoanhydride is mostly produced by using durene as raw material through fixed-bed gas-phase catalytic oxidation process. Usually, a single-layer catalyst is used, and it is difficult to effectively control the reaction depth by using a single-layer catalyst. When the concentration of durene in the feed gas is high, the selectivity of converting to homoanhydride is poor. Therefore, the production process mostly adopts high air velocity (greater than 500...

Claims

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Application Information

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IPC IPC(8): B01J27/228B01J27/24C07D493/04
Inventor 张科张民强冯中山
Owner SHIJIAZHUANG HAOPU CHEM
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