Synthesis process of isatoic anhydride

A synthesis process, the technology of isatoic anhydride, applied in the field of synthesis of isatoic anhydride, can solve the problems of low yield and purity of isatoic anhydride, increase of production cost, etc.

Active Publication Date: 2015-03-11
甘肃西部鑫宇化学有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In the process of synthesizing phthalimide from phthalic anhydride, the yield of phthalimide is only 92% to 93%, while phthalimide is in the process of synthesizing isatoic anhydride, indigo The yield of isatoic anhydride is 91%~92%, and the pur

Method used

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  • Synthesis process of isatoic anhydride
  • Synthesis process of isatoic anhydride
  • Synthesis process of isatoic anhydride

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] 1) Take 100g of phthalic anhydride and put it in a 2000mL flask, heat and stir to melt for 5-10min;

[0033] 2) Add 21.5g of urea after it is completely melted, and cool down to 10°C after fully reacting;

[0034] 3) Add 500mL of water and 84g of liquid caustic soda with a concentration of 32wt%, continue stirring and dissolving, and cool down to 1°C. When the system becomes clear, the phthalimide is completely dissolved;

[0035] 4) Add sodium hypochlorite solution in the flask, the system changes from clarification to turbidity and becomes clear again, and KI test paper shows obvious color, stops adding sodium hypochlorite, added concentration and is 10wt% sodium hypochlorite solution 424.7g;

[0036] 5) Slowly add 77.2g of hydrochloric acid with a concentration of 31wt% dropwise, adjust the pH=6.4, and crystals are precipitated;

[0037] 6) Suction filtration, and the obtained crystals are dried in an oven.

Embodiment 2

[0039] 1) Take 100g of phthalic anhydride and put it in a 2000mL flask, heat and stir to melt for 5-10min;

[0040] 2) Add 21.5g of urea after it is completely melted, and cool down to 15°C after fully reacting;

[0041] 3) Add 500mL of water and continue stirring to dissolve and cool down. When the temperature drops to about 10°C, add 85g of liquid caustic soda with a concentration of 32wt%, and continue to cool down and dissolve to 1°C. When the system becomes clear, the phthalimide is completely dissolved;

[0042]4) Sodium hypochlorite is added in the flask, and the system changes from clarification to turbidity to clarification again, and the KI test paper shows obvious color, stops adding sodium hypochlorite, and adds concentration and is 427.4g of sodium hypochlorite of 13wt%;

[0043] 5) Slowly add 77g of hydrochloric acid with a concentration of 31wt% dropwise, adjust the pH=6.4, and crystals are precipitated;

[0044] 6) Suction filtration, and the obtained crystals...

Embodiment 3

[0046] 1) Take 100g of phthalic anhydride and put it in a 2000mL flask, heat and stir to melt for 5-10min;

[0047] 2) Add 21.5g of urea after it is completely melted, and cool down to 20°C after fully reacting;

[0048] 3) Add 400mL of water and 85g of liquid caustic soda with a concentration of 32wt%, continue to stir and dissolve, and cool down to 1°C. When the system becomes clear, the phthalimide is completely dissolved;

[0049] 4) Sodium hypochlorite is added in the flask, and the system changes from clarification to turbidity to clarification again, and the KI test paper shows obvious color, stops adding sodium hypochlorite, and the addition concentration is 12wt% sodium hypochlorite 439.3g;

[0050] 5) Slowly add 78g of hydrochloric acid with a concentration of 31wt% dropwise, adjust the pH=6.4, and crystals are precipitated;

[0051] 6) Suction filtration, and the obtained crystals are dried in an oven.

[0052] Table 1 The yield data table of embodiment 1~embodime...

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Abstract

The invention provides a synthesis process of isatoic anhydride. The synthesis process comprises the following steps: a) heating phthalic anhydride until phthalic anhydride is molten and mixing the molten phthalic anhydride with urea, and cooling to 10-20 DEG C after a reaction; b) mixing reaction products obtained after cooling with liquid alkali, cooling to minus 5- 0 DEG C to carry out a first reaction, mixing reaction products with pypocholoride, mixing reaction products with hydrochloric acid after a second reaction, and carrying out a third reaction to obtain isatoic anhydride. During the synthesis process of isatoic anhydride, reaction temperature is controlled strictly. Thus, generation of by-products is avoided, and yield of isatoic anhydride is raised. Meanwhile, by one kettle way for synthesis of isatoic anhydride, industrial operations are minimized, the discharging link is reduced, and yield is raised. It shows through experimental results that yield of isatoic anhydride reaches more than 94% and purity reaches more than 99%.

Description

technical field [0001] The invention relates to the technical field of fine chemical production technology, in particular to a synthesis technology of isatoic anhydride. Background technique [0002] Isatoic anhydride (C 8 h 5 NO 3 ) is an important chemical intermediate, which can react with both electrophile and nucleophile. Isatoic anhydride and its homologues and derivatives are widely used in the synthesis of agricultural chemicals, dyes, pigments, fragrances, flavors, medicines, ultraviolet absorbers, foaming agents, flame retardants, preservatives, bleaching agents, fungicides and Sanitary disinfectants and other fine chemical products. [0003] The traditional synthesis process of isatoic anhydride is to use phthalic anhydride and urea raw materials, and the phthalimide prepared by the reaction of phthalic anhydride and urea is discharged and then dried, and then the dry phthalimide is used as raw material, and its dissolved Afterwards, it is oxidized with sodiu...

Claims

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Application Information

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IPC IPC(8): C07D265/26
CPCC07D265/26
Inventor 王龙何普泉赵国霞雷士超
Owner 甘肃西部鑫宇化学有限公司
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