Synthetic method of fire-retardant N,N'-ethylene bis-tetrabromo phthalimide and screw thrust tubular reactor

Abstract

The present invention discloses the synthesis process of fire retardant Nú¼Níõ-ethylene bis-tetrabromo phthalimide and its screw thrust tubular reactor. Inside the screw thrust tubular reactor, phthalic anhydride and ethylene diamine are first condensated under no water condition to synthesize Nú¼Níõ-ethylene bis-phthalimide, and bromine is then dropped to produce bromination in fuming sulfuric acid as solvent and in the presence of multiple phase catalyst so as to produce Nú¼Níõ-ethylene bis-tetrabromo phthalimide. The process may include post-treatment steps of water washing, sand grinding, pressure filtering, stoving, etc. to obtain the target product fine white Nú¼Níõ-ethylene bis-tetrabromo phthalimide powder. It has no color change in high temperature roasting, and may be used in product with high color requirement.

Description

technical field [0001] The invention belongs to a production method of a flame retardant, in particular to an industrial synthesis method of a flame retardant N, N'-ethylene bistetrabromophthalimide. Background technique [0002] N,N'-Ethylene bis-tetrabromophthalimide, molecular formula structure: [0003] [0004] The pure product is white powder, melting point is 450°C, decomposition temperature is above 450°C, density is 2660 kg / m3, solubility (g / 100g, temperature 25°C), in acetone, benzene, o-dichlorobenzene and dimethyl Formamide is less than 0.5, 0.015 in cottonseed oil, and 0.002 in water. It is an efficient additive flame retardant. [0005] Looking at the production and research and development status at home and abroad, the synthesis route of N,N′-ethylene bis-tetrabromophthalimide flame retardant from phthalic anhydride is as follows: [0006] ①First bromination and then organic solvent condensation process [0007] Typical synthesis method of tetrabromopht...

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Problems solved by technology

[0008] There are several problems in the above-mentioned method: the first, use organic solvent in the condensation reaction, cost height, pollute greatly; Second, the reaction time is long, generally more than 20 hours; It turns gray when roasted at high temperature, so it cannot be used for products with high color requirements

The brominated product has not undergone bromine removal, crushing and other treatment processes, the acid value of the product is high, the bromine content exceeds the theoretical value, and the fineness does not meet the requirements

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