Method for catalyzing and synthesizing nitrobenzene by loading silicon dioxide with heteropoly acid ammonium

A technology for supporting heteropolyacids and silica, which is applied in chemical instruments and methods, catalysts for physical/chemical processes, preparation of nitro compounds, etc., can solve the problems of tediousness, lack of catalyst reuse data, etc., and achieve good selectivity. , Solve the effect of corrosion equipment and environmental protection, easy separation and recovery

Inactive Publication Date: 2009-09-23
LIAOCHENG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The selectivity of substituted benzene in this method is 100%, which eliminates the unsafe factors in the nitration process of benzene, and the nitration conversion rate of benzene is above 70%. However, the catalyst preparation process of this method includes molecular sieve modification, drying and roasting, etc. Cumbersome and does not provide catalyst reuse data

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Make 100ml of ethyl silicate into a solution by volume ratio of ethyl silicate: ethanol: water = 1:2:2, heat at 70-80°C for 40min; dissolve 3.3g of ammonium molybdate and 0.18g of ammonium dihydrogen phosphate In deionized water, add nitric acid to adjust the pH to 1, heat at 70-80°C for 5 hours, add the pre-heated ethyl silicate alcohol aqueous solution, continue heating at 70-80°C until gel appears, and age for 12 hours , and dried at 110° C. to obtain sample No. 1 of ammonium phosphomolybdate catalyst with a loading capacity (in terms of the mass ratio of metal oxide and silicon dioxide) of 10% on silicon dioxide.

Embodiment 2

[0028] Make 100ml of ethyl silicate into a solution by volume ratio of ethyl silicate: ethanol: water = 1:2:2, heat at 70-80°C for 40min; dissolve 3.1g of ammonium tungstate and 0.11g of ammonium dihydrogen phosphate In deionized water, add nitric acid to adjust the pH to 1, heat at 70-80°C for 5 hours, add the pre-heated ethyl silicate alcohol aqueous solution, continue heating at 70-80°C until gel appears, and age for 20 hours , and dried at 110°C to obtain sample No. 2 of ammonium phosphotungstate catalyst with a loading capacity of 10% silica.

Embodiment 3

[0030]Prepare 100ml of ethyl silicate as a solution by volume ratio of ethyl silicate: ethanol: water = 1:2:2, heat at 70-80°C for 40min; mix 1.75g ​​of ammonium metavanadate with 1.7g of ammonium dihydrogen phosphate Dissolve in deionized water, add nitric acid to adjust the pH to 1, heat at 70-80°C for 5 hours, add the above-mentioned ethyl silicate alcohol aqueous solution, continue heating at 70-80°C until gel appears, and after aging for 30 hours, Dry at 110° C. to obtain sample No. 3 of ammonium phosphovanadate catalyst with a loading capacity of 10% silica.

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Abstract

The invention discloses a method for catalyzing and synthesizing nitrobenzene by loading silicon dioxide with heteropoly acid ammonium, which belongs to the technical field of organic synthesis. In the method, nitric acid with 65 percent of mass fraction concentration is used as a nitrating agent and a reaction is carried out under the conditions of normal pressure and temperature between 60 DEG C and 110 DEG C. The method uses the silicon dioxide loaded with the heteropoly acid ammonium as a catalyst and ensures that a mixed liquor of benzene and the nitric acid is stirred in a kettle type reactor to carry out a benzene nitration reaction, wherein the reaction time is between 1 hour and 7 hours. The method has 100 percent of nitration selectivity, eliminates the unsafe factor that the benzene nitration process generates explosive substances such as multiple nitrobenzene, oxide compounds, and the like and has the characteristics of high yield, reutilization of the catalyst and environmental protection.

Description

technical field [0001] The invention relates to a method for preparing mononitrobenzene, in particular to a method for catalytically synthesizing mononitrobenzene supported by ammonium heteropolyacid on silica, which belongs to the technical field of organic synthesis. Background technique [0002] Nitrobenzene and other benzene-type aromatic hydrocarbon nitro compounds are important chemical raw materials and important organic solvents, which can be used as intermediates for dyes, agricultural chemicals and medicines, especially for the production of aniline dyes, and the recently developed Two very important intermediates p-aminodiphenylamine and p-aminophenol. [0003] The traditional industrial production method of nitrobenzene is the nitric acid-sulfuric acid mixed acid method proposed in 1934. The disadvantages are obvious. One is that a large amount of sulfuric acid is required, a large amount of waste sulfuric acid and waste water are produced, the equipment is corro...

Claims

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Application Information

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IPC IPC(8): C07C205/06C07C201/08B01J27/24
CPCY02P20/582
Inventor 龚树文尹汉东刘丽君崔庆新李考真
Owner LIAOCHENG UNIV
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