Method of synthesizing 2-nitroresorcinol by utilizing silica gel as assistant dehydrant

A technique for nitroresorcinol and resorcinol, which is applied in the field of synthesis of 2-nitroresorcinol, can solve the problems of harsh reaction conditions, increased cost, low yield and the like, and achieves mild reaction conditions, The effect of improving productivity and reducing production costs

Inactive Publication Date: 2014-07-09
ZHEJIANG UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But, the drawback that these technical schemes exist is that if adopt nitric acid, sulfuric acid as nitrating agent, productive rate is lower than 20%; Adopt acetic anhydride or acetic acid to make cost increase as dehydrating agent, and productive rate is lower than 30%; Use oleum When the mixture with nitric acid is used as a nitrating agent, the reaction conditions are harsh, and the yield will still be lower than 30%.

Method used

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  • Method of synthesizing 2-nitroresorcinol by utilizing silica gel as assistant dehydrant

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Mix 1.5ml of 98% concentrated sulfuric acid with 3.0ml of 65% concentrated nitric acid, and cool the reactant to below 5°C in an ice-water bath.

[0023] Mix 5.0g resorcinol and 0.25g silica gel and put it into a 250ml three-neck round bottom flask, then slowly add 8ml98% concentrated sulfuric acid dropwise, turn on the mixer, and continue to dropwise add 17ml98% concentrated sulfuric acid while stirring. Then slowly heat to 30°C under full stirring, and keep it warm for 15 minutes, then use an ice-water bath to cool the reactant to below 5°C, then add the sulfur-nitrate mixed acid cooled in the first step, while maintaining the temperature at 5°C; After that, keep warm at 5°C for 2h, then add 20g of crushed ice and 0.1g of urea into the reactor, and continue stirring until completely dissolved. The resulting mixture was subjected to steam distillation, and the fractions on the wall of the condensation tube and in the receiving bottle were collected, cooled with ice wat...

Embodiment 2

[0025] Mix 2.5ml of 98% concentrated sulfuric acid with 5.0ml of 65% concentrated nitric acid, and cool the reactant to below 5°C in an ice-water bath.

[0026] Mix 5.0g resorcinol and 0.5g silica gel and put it into a 250ml three-neck round bottom flask, then slowly add 8ml98% concentrated sulfuric acid dropwise, turn on the mixer, and continue to dropwise add 17ml98% concentrated sulfuric acid while stirring. Then slowly heat to 60°C under full stirring, and keep it warm for 60 minutes, then use an ice-water bath to cool the reactant to below 5°C, then add the sulfur-nitrate mixed acid cooled in the first step, while maintaining the temperature at 5°C; After that, keep warm at 5°C for 3h, then add 20g of crushed ice and 0.1g of urea into the reactor, and continue stirring until completely dissolved. The resulting mixture was subjected to steam distillation, and the fractions on the wall of the condensation tube and in the receiving bottle were collected, cooled with ice wate...

Embodiment 3

[0028] Mix 3.5ml of 98% concentrated sulfuric acid with 4.0ml of 65% concentrated nitric acid, and cool the reactant to below 5°C in an ice-water bath.

[0029] Mix 5.0g resorcinol and 1.0g silica gel and put it into a 250ml three-neck round bottom flask, then slowly add 8ml98% concentrated sulfuric acid dropwise, turn on the mixer, and continue to dropwise add 17ml98% concentrated sulfuric acid while stirring. Then slowly heat to 65°C under full stirring, and keep it warm for 45 minutes, then cool the reactant to below 5°C with an ice-water bath, then add the sulfur-nitrate mixed acid cooled in the first step, while maintaining the temperature at 5°C; After that, keep warm at 5°C for 3.5h, then add 20g of crushed ice and 0.1g of urea into the reactor, and continue stirring until completely dissolved. The resulting mixture was subjected to steam distillation, and the fractions on the wall of the condensation tube and in the receiving bottle were collected, cooled with ice wate...

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Abstract

The invention relates to a synthesis method of 2-nitroresorcinol, and particularly relates to a method of synthesizing 2-nitroresorcinol by utilizing silica gel as an assistant dehydrant. The method includes: mixing concentrated sulfuric acid and concentrated nitric acid to obtain sulfuric-nitric mixed acid; mixing resorcinol and the silica gel, adding the mixture of the resorcinol and the silica gel into a reactor, slowly adding dropwise concentrated sulfuric acid, cooling with an ice-water bath, adding dropwise the sulfuric-nitric mixed acid, adding crushed ice and urea, subjecting the mixture to steam distillation, collecting fractions, refluxing and dissolving the solid obtained by suction filtration with the ratio of the resorcinol to the ethanol having a concentration of 50% being 1:4, taking out after the solid is fully dissolved, cooling with ice water, and subjecting the precipitate to suction filtration, washing and drying to obtain a finished product. In the method, the silica gel is adopted as the dehydrant and has excellent performances, and therefore the yield of the product is increased and can be higher than 44%, so that obvious economic benefit is generated. By adoption of the silica gel for dehydration, reaction conditions are mild and the production cost is reduced.

Description

technical field [0001] The invention relates to a synthesis method of 2-nitroresorcinol, specifically, adopting silica gel as a dehydrating aid to promote sulfonation of resorcinol and mixed acid nitration reaction to prepare 2-nitroresorcinol. Background technique [0002] 2-Nitroresorcinol is not only an important industrial raw material, but also one of the key synthetic intermediates because the nitro group can be easily reduced to an amino group, and has a wide range of applications. The main applications are: 2-nitroresorcinol shows yellow in acid and red in alkali, pH=5.4~7.4, pKIn=6.4±0.1, pT=6.2, because its pK is close to that of strong acid to strong The isoelectric point of the alkali (pI=7.0), so it can be used as an acid-base indicator; 2-nitroresorcinol and its salts are used as a coupling agent for the synthesis of oxidative hair dyes and for polyesters, silk wool Acidic azo dyes for textiles and blended textiles; used as a stabilizer for color photo develop...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C205/22C07C201/12C07C309/42C07C303/22C07C303/06
Inventor 姜华昌曾翎
Owner ZHEJIANG UNIVERSITY OF SCIENCE AND TECHNOLOGY
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