Method for preparing solid p-disodium hydroxybenzoate
AssigneeNippon Petrochemicals Company, Limited
InventorsFumio Tanimoto, Hisao Kitano
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Abstract
The present invention provides a method for preparing solid p-disodium hydroxybenzoate which is characterized by comprising the steps of reacting phenol, carbon tetrachloride in an amount of 0.9 to 1.2 moles per mole of phenol and sodium hydroxide in an amount of 7 to 20 moles per mole of phenol prior to the reaction in an aqueous liquid containing 10 to 40% by weight of p-disodium hydroxybenzoate and/or sodium chloride in the presence of a transition metal powder in an amount of 0.01 to 1.00% by weight based on the weight of a reaction system at a reaction temperature of 50.degree. to 150.degree. C.; cooling the resulting reaction mixture to a level of -20.degree. to +20.degree. C.; and separating said p-disodium hydroxybenzoate therefrom.
Claims11
A method for preparing solid p-disodium hydroxybenzoate benzoate which is characterized by comprising the steps of reacting phenol, carbon tetrachloride in an amount of 0.9 to 1.2 moles per mole of phenol and sodium hydroxide in an amount of 7 to 20 moles per mole of phenol prior to the reaction in an aqueous liquid containing 10 to 40% by weight of p-disodium hydroxybenzoate and/or sodium chloride in the presence of a transition metal powder in an amount of 0.01 to 1.00% by weight based on the weight of a reaction system at a reaction temperature of 50.degree. to 150.degree. C.;
- cooling the resulting reaction mixture to a level of -20.degree. to +20.degree. C.;
- and separating said solid p-disodium hydroxybenzoate therefrom.
A method for preparing solid p-disodium hydroxybenzoate according to claim 10 in which the amount of non-ionic surface active agent is 0.5 to 3% by weight.
Dependencies are inferred from the claim text.