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Preparation method of 4-bromo phthalic anhydride

A technology of bromophthalic anhydride and phthalic anhydride, applied in the field of preparation of 4-bromophthalic anhydride, can solve the problems of difficulty in improving product yield and purity, complicated operation and high cost, and achieve high product yield, high purity, and production energy consumption reduced effect

Active Publication Date: 2016-03-16
WEIFANG YUCHENG CHEM
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Problems solved by technology

In recent years, with the increase in the amount of polyamide and dyes, the amount of 4-bromophthalic anhydride has also increased. However, the current production process of 4-bromophthalic anhydride is complicated in operation and high in cost; it is difficult to improve the product yield and purity. And other issues

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  • Preparation method of 4-bromo phthalic anhydride

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Embodiment 1

[0022] Embodiment 1, this embodiment provides a kind of preparation method of 4-bromophthalic anhydride. First, dissolve 5.6g of sodium hydroxide in 22.4g of water, add 10g of phthalic anhydride and stir thoroughly, then add 0.1g of tetrabutylammonium bromide catalyst and continue to stir evenly. Then use three-stage program temperature control and add reactants three times to react. The temperature control temperature of the first stage is 40°C, the mass of bromine added is 5g, and the reaction time is 1.5 hours; the temperature control temperature of the second stage is 60°C. , the mass of bromine added is 5g times, and the reaction time is 4.5 hours; the third stage temperature control temperature is 75°C, the mass of additional sodium hydroxide is 1g, the mass of bromine added is 4g, and the reaction time is 4.5 hours; the reaction ends Finally, 5 g of 20% oleum solution was added to the reaction solution, and the temperature was raised to 90° C. for acidification. After a...

Embodiment 2

[0023] Example 2, this example provides a preparation method of 4-bromophthalic anhydride, first dissolve 5g of sodium hydroxide in 30g of water, add 10g of phthalic anhydride and stir thoroughly, then add 0.5g of tetraethylammonium bromide catalyst and continue stirring uniform. Then use three-stage program temperature control and add reactants three times to react. The temperature control temperature of the first stage is 50°C, the mass of bromine added is 6g, and the reaction time is 2.5 hours; the temperature control temperature of the second stage is 70°C. , the mass of bromine added is 6g, and the reaction time is 6 hours; the third stage temperature control temperature is 85°C, after adding 2g of sodium hydroxide, bromine is added to continue the reaction, the mass of bromine added is 6g, and the reaction time is 5.5 hours Add 20% oleum 8g to the reaction product after the three-stage temperature control program reaction finishes, heat up to 100°C for acidification, coo...

Embodiment 3

[0024] Embodiment 3, this embodiment provides a kind of preparation method of 4-bromophthalic anhydride. First, dissolve 5.3g of solid sodium hydroxide in 26.5g of deionized water, add 10g of phthalic anhydride and stir thoroughly, then add 0.3g of benzyltriethylammonium chloride catalyst and continue to stir evenly. Then adopt the method of three-stage temperature control and add the reactant three times to carry out the reaction. The first stage temperature control temperature is 48 ℃, the quality of bromine added is 5.6g of the mass of phthalic anhydride, and the reaction time is 2 hours; The temperature is 64°C, the mass of bromine added is 5.4g, and the reaction time is 5.1 hours; the third stage temperature control temperature is 82°C, after adding 1.4g of sodium hydroxide, bromine is added to continue the reaction, and the mass of bromine added is 5g, the third reaction time is 5 hours; after the reaction, add 6g of 20% oleum to the product, and heat up to 95°C for acid...

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Abstract

The invention belongs to the field of chemical engineering, and relates to a preparation method of 4-bromo phthalic anhydride. The preparation method includes the following steps that sodium hydroxide is dissolved in water, phthalic anhydride and a phase transfer catalyst are added and evenly mixed, a reaction is performed in the mode that programmed temperature control is performed in three stages and reactants are added in three times, 20% fuming sulphuric acid is added for acidification, a sodium bisulfite aqueous solution is added after cooling for removing excessive bromine, an organic solvent is added for extraction, the organic solvent is removed through distillation, then temperature is increased to obtain a crude 4-bromo phthalic anhydride product, rectification dehydration is performed under the vacuum condition, fraction is collected, and the finished 4-bromo phthalic anhydride product is obtained. Compared with a multi-step reaction in the prior art, the process steps are simplified, the product yield is high, the production energy consumption is reduced, the three-waste emission is greatly reduced, the energy consumption and wastewater treatment cost for extraction of 4-bromophthalic acid crystals are reduced, production cost is reduced, and environmental protection pressure is relieved.

Description

technical field [0001] The invention belongs to the field of chemical industry and relates to fine chemical organic synthesis, in particular to a preparation method of 4-bromophthalic anhydride. Background technique [0002] 4-Bromophthalic anhydride is a very important chemical intermediate widely used in the production of dyes and polymers. In recent years, with the increase in the amount of polyamide and dyes, the amount of 4-bromophthalic anhydride has also increased. However, the current production process of 4-bromophthalic anhydride has complicated operations and high costs; it is difficult to improve the product yield and purity. And other issues. Therefore, developing a method for preparing 4-bromophthalic anhydride with simplified steps, low production cost, high product yield, good product quality, and less three-waste pollution has attracted people's attention day by day. Contents of the invention [0003] The invention aims at the deficiencies of the prior a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D307/89
CPCC07D307/89
Inventor 吴多坤张国强秦善宝王同同
Owner WEIFANG YUCHENG CHEM
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