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A method for the production of 4 - hydroxy - 3,5 - dimethoxy - benzoesaeure from 3,4,5 - trimethoxy - benzoesaeure
A method for the production of 4 - hydroxy - 3,5 - dimethoxy - benzoesaeure from 3,4,5 - trimethoxy - benzoesaeure
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机译:一种由3,4,5-三甲氧基-苯甲酰脲生产4-羟基-3,5-二甲氧基-苯甲酰脲的方法
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摘要
P the invention relates to a method of manufacture of the hydroxy - 4, dimethoxy - 3,5 benzoic acid from the acid trimethoxy - 3,4,5 benzoic acid / p & & p & the demethylation of the acid trimethoxy - 3,4,5 benzoic acid in the presence of an excess of alkali metal hydroxide in a quantity of ethylene - glycol just sufficient to obtain a heterogeneous medium which is sufficiently fluid during the operation, while distilling off the monomethyl ether of ethylene - glycol and water formed during their formation and the acid hydroxyl - 4 dimethoxy - 3,5 benzoic acid obtained is separated by acidification by means of a strong acid and crystallization. / p & & p & application to the manufacture of the hydroxy - 4 dimethoxy - 3,5 benzoic acid / p
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