Method for synthesizing isatoic anhydride

A technology of isatoic anhydride and phthalimide, applied in the direction of organic chemistry, can solve the problems of reduced yield, difficult treatment, difficult waste water, etc., and achieve the effect of mild reaction conditions and reduced generation and emission

Active Publication Date: 2011-02-16
HEFEI XINGYU CHEM
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Problems solved by technology

[0007] (3) Phthalic anhydride and azide react under the action of concentrated sulfuric acid, and the reaction process exotherms violently, and simultaneously generates a mixture of isatoic anhydride and benzimidazolone, which is also difficult to handle;
Although the yield of this method is high, it has high requirements on reaction temperature, time, and pH. If it deviates from the optimum conditions, the yield will be significantly reduced, and a large amount of waste water pollution that is difficult to handle will be generated in the reaction.
[0009] The traditional production process of synthesizing isatoic anhydride has many disadvantages in production, such as raw materials such as highly toxic and dangerous phosgene, chromium trioxide, etc., or problems such as relatively high reaction conditions or the production of a large amount of industrial wastewater and large pollution.

Method used

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  • Method for synthesizing isatoic anhydride
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Examples

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Embodiment 1

[0021] Add 150 milliliters of ethylene dichloride to a 250 milliliter four-neck flask equipped with a stirrer, a temperature device, a reflux device, a chlorine passage device and a hydrogen chloride tail gas absorption device. After starting the stirring, add 25.0 grams of phthalimide (content 99%, 0.168mol), heat to 60-65°C and stir to dissolve; cool down to 40-45°C, and then pass 12.1 grams of chlorine gas (content 99%, 0.169 mol), stirred for 1.5 hours, slowly added 6.9 grams of solid alkali sodium hydroxide (content 98%, 0.169mol) into the bottle and controlled the temperature at 40-45°C, continued to stir for 1 hour after adding, filtered the sodium chloride while it was hot Salt, the filtrate is isatoic anhydride solution. The solution was cooled to 15-20° C., isatoic anhydride was precipitated in the solution, and solid isatoic anhydride was filtered to obtain 25.6 grams of solid isatoic anhydride after drying. The measured content was 99.2%, and the calculated isatoic...

Embodiment 2

[0023] Add 120 milliliters of chloroform in a 250 milliliter four-neck flask equipped with a stirrer, a temperature device, a reflux device, a chlorine passage device and a hydrogen chloride tail gas absorption device. After starting the stirring, add 25.0 grams of phthalimide (content 99%, 0.168mol), heat to reflux state, stir and dissolve; cool down to 40-45°C, and then pass 12.6 grams of chlorine gas (content 99%, 0.176 mol), stirred for 2 hours, slowly added 7.2 grams of solid alkali sodium hydroxide (content 98%, 0.176mol) into the bottle and controlled the temperature below 45°C, continued to stir for 1 hour after adding, filtered the sodium chloride salt while it was hot , The filtrate is isatoic anhydride solution. Cool the solution to 15-20°C to precipitate isatoic anhydride, filter and dry 25.5 grams, and the measured content is 99.0%. The product yield of isatoic anhydride calculated by analysis is 92.4%. The sodium chloride recovered by filtration can meet the fi...

Embodiment 3

[0025] Add 150 milliliters of dichloromethane to a 250 milliliter four-neck flask equipped with a stirrer, a temperature device, a reflux device, a chlorine passage device and a hydrogen chloride tail gas absorption device. After starting the stirring, add 25.0 grams of phthalimide (content 99%, 0.168mol), heat to 60-65°C and stir to dissolve; cool down to 40-45°C, and then pass 12.1 grams of chlorine gas (content 99%, 0.169 mol), stirred for 2 hours, slowly added 7 grams of solid alkali sodium hydroxide (content 98%, 0.172mol) into the bottle and controlled the temperature at 40-45°C, continued to stir for 1 hour after adding, filtered the sodium chloride while it was hot Salt, the filtrate is isatoic anhydride solution. The solution was cooled to 15-20° C., isatoic anhydride was precipitated in the solution, and solid isatoic anhydride was obtained by filtration, 25.4 grams after drying, the measured content was 99.1%, and the calculated isatoic anhydride product yield was 9...

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Abstract

The invention discloses a method for synthesizing isatoic anhydride, which comprises the following steps: (1) adding phthalimide to a reaction solvent; (2) controlling the temperature to be within the range of 40-45 DEG C, introducing chlorine gas, and reacting for 1.5-2 hours; (3) controlling the temperature to be below 45 DEG C, adding solid caustic soda, and then continuing to react for 0.5-1.5 hours; and (4) filtering and collecting salts to obtain an isatoic anhydride filtrate, cooling, crystallizing, filtering, and drying to obtain solid isatoic anhydride. The method for synthesizing the isatoic anhydride avoids the use of a large amount of virulent and dangerous chemical substances and has moderate anhydrous reaction conditions, and hydrogen chloride and sodium chloride as reaction byproducts can be treated to produce high-quality hydrochloric acid and industrial sodium chloride byproducts, thereby reducing the generation and the discharge of harmful impurities and a large amount of waste water difficult to treat. The yield can be up to 92% or above. Thus, the invention is suitable for industrial application.

Description

technical field [0001] The invention relates to a method for synthesizing isatoic anhydride, belonging to the field of fine chemicals. Background technique [0002] Isatoic anhydride, also known as Etoic anhydride, English name Isatoic anhydride, is a very useful chemical intermediate, which can react with both electrophilic reagents and nucleophilic reagents. It 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 sanitation Disinfectants and other fine chemical products. Its chemical structure is as follows: [0003] [0004] There are many existing synthesis methods of isatoic anhydride: [0005] (1) Use anthranilic acid as a raw material to react with phosgene or ethyl chloroformate, etc., and isatoic anhydride can also be obtained by reacting methyl anthranilate with phosg...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D265/26
Inventor 何普泉丁云好姚海波周林王龙王兰兰
Owner HEFEI XINGYU CHEM
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