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Method for preparing o-nitrophenol through phenol nitration selectivity

An o-nitrophenol, selective technology, applied in the field of o-nitrophenol preparation, can solve the problem that the o-nitrophenol content is difficult to exceed 95%, o-nitroanisole is difficult to recycle, and production wastewater treatment is difficult problems such as short preparation period, low cost and high conversion rate of phenol

Inactive Publication Date: 2013-02-27
LIAOCHENG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

At present, the production process of o-nitrophenol is relatively mature, but there are some defects in various processes
[0003] The traditional method is to use nitric acid as a nitrating agent to nitrate phenol, but the selectivity of o-nitrophenol in this method is poor, and the product is a mixture of o-nitrophenol and p-nitrophenol, which is then distilled, cooled, and crystallized to obtain o-nitrophenol. Nitrophenol, because concentrated nitric acid has oxidative properties in this method, phenol is oxidized to quinone compounds, resulting in a low yield of o-nitrophenol
In addition, o-nitrochlorobenzene is used as a raw material, hydrolyzed with sodium hydroxide solution, acidified with sulfuric acid, cooled, crystallized, and separated to obtain o-nitrophenol. This method uses lye and acid treatment, causing environmental pollution
It is also possible to produce o-nitrophenol with o-nitroanisole, but in this method, the o-nitrophenol content is difficult to exceed 95%, the o-nitroanisole is difficult to recycle, the production wastewater treatment is difficult, and the energy consumption is high. advanced defects

Method used

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  • Method for preparing o-nitrophenol through phenol nitration selectivity

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Embodiment 1: prepare o-nitrophenol:

[0030] (1) Preparation of catalyst: 1gH 4 PMo 11 VO 40 Dissolve in 9g of deionized water to make 10% H 4 PMo 11 VO 40 Aqueous solution, heated at 50°C for 30min, dissolved 0.091g of cesium carbonate in an appropriate amount of deionized water, and kept at 50°C for 5h to obtain cesium heteropolyacid CsH 3 PMo 11 VO 40 suspension; take 37g (about 39ml) of ethyl silicate, make a solution according to the volume ratio of ethyl silicate: ethanol: water = 1:2:2, heat at 60°C for 30min; Cesium CsH 3 PMo 11 VO 40 The suspension was stirred and added dropwise to the alcohol aqueous solution of ethyl silicate, and continued to heat at 60°C until the gel appeared. After aging for 24 hours, it was dried at 120°C. After drying, 10% cesium heteropolyacid supported on silica was obtained. C 3 PMo 11 VO 40 catalyst.

[0031] (2) Add 0.2mol of phenol to 50ml of 1,2-dichloroethane, add 0.5g of the above catalyst, stir and drop 0.2mol ...

Embodiment 2

[0032] Embodiment 2: prepare o-nitrophenol:

[0033] (1) Preparation of catalyst: 1gH 5 PMo 10 V 2 o 40 Dissolve in 9g of deionized water to make 10% H 4 PMo 10 VO 40 Aqueous solution, heated at 50°C for 30min, dissolved 0.094g of cesium carbonate in an appropriate amount of deionized water, and kept at 40°C for 6h to obtain cesium heteropolyacid CsH 4 PMo 10 V 2 o 40 suspension; take 37g (about 39ml) of ethyl silicate, make a solution by volume ratio of ethyl silicate: ethanol: water = 1:2:2, heat at 80°C for 30min; Cesium CsH 4 PMo 10 V 2 o 40 The suspension was stirred and added dropwise to the alcohol aqueous solution of ethyl silicate, and continued to heat at 80°C until the gel appeared. After aging for 36 hours, it was dried at 110°C. After drying, 10% cesium heteropolyacid supported on silica was obtained. C 4 PMo 10 V 2 o 40 catalyst.

[0034](2) Add 0.2mol of phenol to 50ml of 1,2-dichloroethane, add 1.0g of the above catalyst, stir and drop 0.25mo...

Embodiment 3

[0035] Embodiment 3: prepare o-nitrophenol:

[0036] (1) Preparation of catalyst: 1gH 6 PMo 9 V 3 o 40 Dissolve in 9g of deionized water to make 10% H 6 PMo 9 V 3 o 40 Aqueous solution, heated at 50°C for 30min, dissolved 0.096g of cesium carbonate in an appropriate amount of deionized water, and kept at 60°C for 4h to obtain cesium heteropolyacid CsH 5 PMo 9 V 3 o 40 suspension; take 37g (about 39ml) of ethyl silicate, and make a solution according to the volume ratio of ethyl silicate: ethanol: water = 1:2:2, heat at 70°C for 30min; Cesium CsH 5 PMo 9 V 3 o 40 The suspension was stirred and added dropwise to the alcohol aqueous solution of ethyl silicate, and continued to heat at 70°C until the gel appeared. After aging for 24 hours, it was dried at 100°C. After drying, 10% cesium heteropolyacid supported on silica was obtained. C 5 PMo 9 V 3 o 40 catalyst.

[0037] (2) Add 0.2 mol of phenol to 50 ml of 1,2-dichloroethane, add 1.5 g of the above catalyst,...

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Abstract

The invention discloses a method for preparing o-nitrophenol, which comprises the following steps: nitrating phenol in mild conditions with silica loaded heteropoly acid cesium as a catalyst and low-concentration nitric acid as a nitrating agent; and successively performing extraction, distillation, steam distillation and recrystallization to obtain the o-nitrophenol. The silica loaded heteropoly acid cesium is formed by loading 1% to 40% (wt%) of heteropoly acid cesium to silica. The method for preparing o-nitrophenol has the advantages of high phenol conversion rate, high o-phenol nitration selectivity, easiness in preparation of the catalyst, high catalytic activity, easy separation of the catalyst after the action, reusability and broad application prospects.

Description

technical field [0001] The invention relates to a method for preparing o-nitrophenol, more specifically, the invention relates to a method for preparing o-nitrophenol with high selectivity. Background technique [0002] O-nitrophenol can be used as an intermediate in medicine, dyes, rubber additives and photosensitive materials, and can also be used as a monochromatic pH value indicator, so the preparation of o-nitrophenol is very important. At present, the production process of o-nitrophenol is relatively mature, but there are some defects in various processes. [0003] The traditional method is to use nitric acid as a nitrating agent to nitrate phenol, but the selectivity of o-nitrophenol in this method is poor, and the product is a mixture of o-nitrophenol and p-nitrophenol, which is then distilled, cooled, and crystallized to obtain o-nitrophenol. Nitrophenol, this method is because concentrated nitric acid has oxidation property, and phenol is oxidized to quinone compo...

Claims

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Application Information

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IPC IPC(8): C07C205/22C07C201/08B01J27/199
Inventor 刘丽君龚树文李永新崔庆新尹汉东
Owner LIAOCHENG UNIV
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