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Method for the manufacture of 4-nitro-n-(c1-8 alkyl)phthalimide

A technology of methyl phthalimide and phthalimide, applied in the field of preparing 4-nitro-N-(C1-8 alkyl) phthalimide, Can solve the problem of polymer discoloration, poor yield, etc.

Pending Publication Date: 2021-09-14
SHPP GLOBAL TECH BV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Polymer discoloration can result due to adverse effects on subsequent nitro displacement reactions, i.e. formation of desired bisimides in poor yields or formation of highly colored bisimides which when converted to polymers can cause polymer discoloration , the presence of such dinitro derivatives is generally considered undesirable

Method used

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  • Method for the manufacture of 4-nitro-n-(c1-8 alkyl)phthalimide
  • Method for the manufacture of 4-nitro-n-(c1-8 alkyl)phthalimide
  • Method for the manufacture of 4-nitro-n-(c1-8 alkyl)phthalimide

Examples

Experimental program
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Effect test

Embodiment 1

[0043] Add 80 grams of 99% sulfuric acid to the vessel and slowly add 20 grams of PI with stirring at 30 to 40°C. A separate container was charged with 100 grams of 99% nitric acid and 100 grams of 99% sulfuric acid. The material was delivered to a coiled tubular microreactor made of a strong sulfuric and nitric acid resistant fluorinated polymer with an inner diameter of 1 mm and a total volume of 10 mL. The feed rate of the PI / sulfuric acid mixture was 2.1 mL / min and the flow rate of the acid solution was 0.4 mL / min. The residence time in the reactor was 4 minutes. The molar ratio of nitric acid and PI was 1.2:1. The reactor is enclosed in a heatable chamber (eg, a suitably designed oven), wherein the temperature of the chamber and reactor is controlled to within 1°C. In this example, the temperature was controlled to 70°C. The outlet of the reactor is equipped with a back pressure control valve. Control back pressure at 10 to 20 bar. The effluent is directed to a vess...

Embodiment 2 and 3

[0046] The reactor described in Example 1 was fed with PI diluted in 99% sulfuric acid at 20 wt% solids at 1.23 mL / min and 99 wt% nitric acid at 0.44 mL / min. The residence time in the reactor was 6 minutes, the molar ratio of nitric acid to PI was 2:1, and the oven temperature was 60°C or 80°C. The degree of conversion was 76% at 60°C and 89% at 80°C. In Example 2 (at 60°C) the recovered solids contained 1.85 wt% DNPI, and in Example 3 (at 80°C) the recovered solids contained 1.96 wt% DNPI.

Embodiment 4 and 5

[0048] The reactor described in Example 1 was fed PI diluted in 99% sulfuric acid at 15 wt% solids and a 50 / 50 (wt / wt) mixture of 99 wt% nitric acid and 99% sulfuric acid was fed. The residence time in the reactor was 6 minutes and the molar ratio of nitric acid to PI was 1.4:1 (Example 4) or 2.2:1 (Example 5), and the oven temperature was 80°C. The degree of conversion was 88% at a molar ratio of 1.4:1 and 100% at a molar ratio of 2.2:1. In Example 4, the recovered solids contained 1.68 wt% DNPI, and in Example 5, the recovered solids contained 0.53 wt% DNPI

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Abstract

A method for the manufacture of 4-nitro-N-(C1-8 alkyl)phthalimide includes providing a first stream having a solution of a N-(C1-8 alkyl)phthalimide and sulfuric acid; and a second stream including nitric acid and sulfuric acid to a micro-reactor under conditions effective to provide a product stream including 4-nitro-N-(C1-8 alkyl)phthalimide. A method for the manufacture of 4-nitro-N-(C1-8 alkyl)phthalimide can include providing a first stream having a molten N-(C1-8 alkyl)phthalimide; and a second stream consisting of nitric acid; to a micro-reactor under conditions effective to provide a product stream including 4-nitro-N-(C1-8 alkyl)phthalimide Advantageously, 4-nitro-N-(C1-8 alkyl)phthalimide obtained by the process can have reduced levels of di-nitro byproducts.

Description

[0001] Citations to Related Applications [0002] This application claims priority to and the benefit of European Application No. 18215782.6, filed on December 21, 2018, the contents of which are hereby incorporated by reference in their entirety. Background technique [0003] N-substituted nitrophthalimides are useful starting reactants for the preparation of various organic dianhydrides, diimides and polyimides. One method of preparing N-substituted nitrophthalimides is by reacting nitrophthalic anhydride and an organic isocyanate in the presence of an alkali metal carbonate catalyst. See, eg, US Patent No. 3,868,389. In another method, a solution of N-alkylphthalimide in a solvent comprising 98-103 wt% concentrated sulfuric acid is combined with 98-100 wt% concentrated nitric acid at a temperature in the range of 35-80° C. Batch mode contact followed by isolation of the reaction product by extraction with dichloromethane. See, eg, US Patent No. 3,933,852. Another method...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D209/48
CPCC07D209/48
Inventor 托马斯·林克·古根海姆加内桑·巴拉克里什南萨蒂什·钱德拉·潘迪普兰希尔·拉赫特西瓦库马尔·斯里拉马吉里
Owner SHPP GLOBAL TECH BV
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