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Method for preparing isatin

A technology of isatin and hydroxylamine sulfate, applied in organic chemistry and other directions, can solve the problems of low melting point, low product purity of isatin, and low product purity, and achieve the effect of improving internal quality

Active Publication Date: 2008-04-09
XIANGSHUI HENRYDA TECH CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] But the purity of the isatin product prepared by this method is lower (94%), because product purity is lower and causes fusing point low (200 ℃), can not satisfy user's requirement

Method used

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  • Method for preparing isatin
  • Method for preparing isatin

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Embodiment 1

[0021] A kind of method for preparing isatin according to the present embodiment comprises following five steps:

[0022] (1) Put 100ml of water, 20g of sodium nitrite, and 15g of soda ash into a 250ml four-necked flask equipped with heating, stirring, thermometer and dropping funnel. Stir, control the temperature below 15°C, and feed in 25 grams (about 9.2 L) of sulfur dioxide for about 6 hours. After the aeration was completed, the temperature was raised to boiling for about 1 hour, and cooled to 40° C. to obtain 100 grams of hydroxylammonium sulfate.

[0023] (2) Put 100 grams of hydroxylamine sulfate into a four-necked flask, add 54.6 grams each of aniline and hydrochloric acid, heat up to 50 ° C, and after about 20 minutes, add 43.6 grams of 100% chloral, and then use 1 hour to raise the temperature Boiling (98°C), heat preservation for 5 minutes, rapid cooling to 30°C, standing for 1 hour and then filtering; washing with cooling water until neutral, drying to obtain 64....

Embodiment 2

[0029] A method for preparing isatin according to this embodiment includes five steps, the operation of the first four steps is the same as above, and in the fifth step, the filter cake obtained by the first four steps is added to ethanol, heated, and the insoluble matter Remove by filtration, collect the filtrate, wait for cooling, and the isatin product is precipitated.

[0030] It has been determined that the content of isatin is 99.6%; the initial melting point is 201°C.

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Abstract

The invention relates to a preparative method for isatin, including the procedures as follows: compounding hydroxylamine sulphate; utilizing the hydroxylamine sulphate to synthesize oximido antifebrin; carrying out cyclization reaction and deamination reaction for the oximido antifebrin to product the coarse product of the isatin; and refining the coarse product of the isatin to obtain the isatin product, wherein, sodium nitrite, carbonate and supercarbonate of alkali metal and sulfur dioxide are adopted as the raw materials to synthesize the ydroxylamine sulphate. Te alkali metal is kalium or natrium. The isatin product produced by the method disclosed in the present invention has the advantages of high purity and good quality.

Description

technical field [0001] The invention relates to a preparation method of isatin. Background technique [0002] Isatin or indolinone is an important intermediate of fine chemical industry, especially fuel and medicine. It belongs to heterocyclic compounds and is a class of intermediates with a wide range of uses. Its structural formula is as follows: [0003] [0004] The synthetic process of isatin is longer and has higher technical content. The traditional preparation method is to use hydroxylamine to synthesize oxime-acetanilide with aniline and chloral, followed by cyclization and deamination in sulfuric acid medium to generate isatin product. Wherein the preparation method of hydroxylamine is generated by reacting sodium nitrite, sodium binitrite and water. The reaction equation of this preparation method is as follows: [0005] (1) [0006] NaNO 2 +NH 4 HSO 3 +SO 2 →(NH 2 OH)2H 2 SO 4 [0007] [0008] However, the purity of the isatin product prepared...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D209/38
Inventor 潘培华张正富蒋利荣
Owner XIANGSHUI HENRYDA TECH CHEM
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