- Synthesis method of 4-halogenated phthalic anhydride and derivative thereof
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The invention relates to a synthetic method of 4-halogenated phthalic anhydride and a derivative of the 4-halogenated phthalic anhydride, and solves the technical problems of low product purity, poorproduct performance, complex synthetic process and low utilization ratio of monohalide isomers and polyhalides in the existing production process. The method specifically comprises the following steps: dissolving phthalic anhydride in an organic solvent, and introducing a halogenating reagent under the action of iron powder and a Lewis acid catalyst to prepare a halogenated phthalic anhydride mixture; rectifying and purifying the polyhalogenated phthalic anhydride mixture to obtain a 4-halogenated phthalic anhydride pure product; and continuing subjecting residual halogenated phthalic anhydride mixture to halogenation reaction under the action of fuming sulfuric acid and the catalyst to prepare tetrahalogenated phthalic anhydride, and to realize comprehensive utilization of the raw materials. The method is widely applied to the technical field of flame retardant synthesis.
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Paragraph 0024; 0028-0029; 0033-0034; 0038-0039; 0043-0044;
(2020/12/30)
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- Method for preparing tetrabromophthalic anhydride
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The invention belongs to the field of chemical engineering, relates to fine chemical engineering organic synthesis, and particularly relates to a method for preparing tetrabromophthalic anhydride. The method comprises the following steps: adding fuming sulfuric acid into a reaction kettle, dissolving phthalic anhydride in the reaction kettle, adding a weak Lewis acid catalyst to stir, reacting by a mode of heating in three parts and adding reactants in three times, adding filter cake which is obtained in suction filtration into a sodium hydroxide aqueous solution, adding activated carbon to stir, and filtering; and adding filtrate into a hydrochloric acid aqueous solution to acidify, cooling, extracting with an organic solvent, distilling the organic solvent under a vacuum condition, and dehydrating at high temperature. Compared with multi-step reaction in the prior art, the process product has the advantages of white appearance color, low content of sulfate radical and high purity of a pure product; and the product has high purity, low impurity content and high yield.
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Paragraph 0021; 0026
(2016/12/16)
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- Intermediates to tetrabromophthalic anhydride and process therefor
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Tetrabromophthalic anhydride and the corresponding free acid are propared by oxidizing in the liquid phase a compound of the formula STR1 each of A and A' is independently selected from oxygen, OH or acetoxy; each of R and R' is independently selected from H, OH, alkyl, alkylidene or oxygen; x is 0 or 1; y is 3-x; and Ry and R'y may together form a closed alicyclic or heterocyclic ring structure. Mixtures of two or more compounds of formula (I), optionally in the presence of an oxidation catalyst, can also be employed as the starting material.
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- Divinyl compounds and chromogenic recording-material prepared by using thereof
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Disclosed herein are novel divinyl compounds represented by the formula (I): STR1 and a recording-material prepared by utilizing the divinyl compounds. The present divinyl compound is in itself almost colorless, extremely stable in the atmosphere and develops rapidly blakish color by a developer. The color image given by the present divinyl compound is excellect in light-resistance and moisture-resistance and the letters developed can be read by an optical letter-reading apparatus or a barcord reading apparatus.
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- Halogenated polyol-ester neutralization agent
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Haze-free reactive flame retardant halo polyols are made by reacting (a) a halogen containing cyclic acid anhydride (e.g. tetrabromophthalic anhydride), (b) an aliphatic polyol, e.g. diethylene glycol, and (c) an epoxide, e.g. propylene oxide, and including potassium salt of fatty acids (e.g. potassium acetate) in the reaction mixture in an amount at least sufficient to neutralize residual sulfuric acid that is usually present in the halogen containing cyclic acid anhydride.
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- Flame retardant for polymeric compositions
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An additive flame retardant bisimide containing halogen atoms and ammonium acid tetrahalophthalate, e.g. N,N'-bis(2-ethylene tetrabromophthalimide) ammonium acid tetrabromophthalate. These compounds are useful in a variety of polymeric compositions and demonstrate increased thermal stability. They also foam on decomposition with the evolution of gas thus readily lending themselves to the preparation of flame retardant coatings.
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