background and overview[1]
1-benzothiophene-3(2h)-one is an organic intermediate that can be prepared by reacting 2-carboxymethylthiobenzoic acid as a starting material. it can be used to prepare fluorescent red 5b. fluorescent red 5b is a bluish red oil-soluble solvent pigment with good heat resistance, light resistance, high tinting power and bright color; it can be used for coloring a variety of resins.
preparation[1]
synthesis of 1-benzothiophene-3(2h)-one: weigh 38kg of 2-carboxymethylthiobenzoic acid and 33kg of sodium hydroxide according to the proportion, and mix the above raw materials evenly in a closed-loop kettle. , heated to 180°c, and then performed a ring-closing reaction. the reaction time of the ring-closing reaction was 9 hours. after the ring-closing reaction is completed, add 75kg of water to dilute. the diluted solution is subjected to solid-liquid separation, insoluble matter is removed and the filtrate is collected to prepare an aqueous solution of 1-benzothiophene-3(2h)-one.
apply[1]
1-benzothiophene-3(2h)-one can be used to prepare fluorescent red solvent pigments: transfer the 1-benzothiophene-3(2h)-one aqueous solution to the oxidation kettle, and add 1-benzothiophene-3(2h)-one to the oxidation kettle. air was introduced into the aqueous solution of 3(2h)-ketone, heated to 90°c, and then an oxidation reaction was performed. the reaction time of the oxidation reaction was 14 hours. after the oxidation reaction is completed, the temperature is lowered to 35°c, and a filter cake is obtained after solid-liquid separation. the filter cake is washed with water until neutral, and dried to obtain a fluorescent red solvent pigment.
main reference materials
[1]cn201910806039.5 fluorescent red solvent pigment and preparation method thereof
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