著者

関口 慶二

出版者

公益社団法人 日本薬学会

雑誌

YAKUGAKU ZASSHI (ISSN:00316903)

巻号頁・発行日

vol.81, no.5, pp.669-674, 1961-05-25 (Released:2010-02-19)

参考文献数

9

被引用文献数

8

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Thermal analysis was carried out on 26 kinds of binary systems, having caffeine as one component and various carboxylic acids as the other. Molecular compounds were formed by caffeine with o-, m-, and p-hydroxybenzoic acid, gallic acid, m-me-thoxybenzoic acid, m-nitrobenzoic acid, o-, m-, and p-aminobenzoic acid, phenylacetic acid, malonic acid, oxalic acid dihydrate, and maleie acid. Caffeine did not form a molecular compound with benzoic and phthalic acids. Comparison of the result of thermal analysis and the report of Higuchi and others regarding caffeine complex in aqueous solution suggested that there is some difference in the behavior of caffeine between anhydrous state and in aqueous solution.

著者

関口 慶二

出版者

公益社団法人 日本薬学会

雑誌

YAKUGAKU ZASSHI (ISSN:00316903)

巻号頁・発行日

vol.81, no.5, pp.664-669, 1961-05-25 (Released:2010-02-19)

参考文献数

9

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Solubilizing action of the sodium salt of benzoic acid, o-, m-, and p-hydroxy-, methoxy-, amino-, nitro-, and chloro-benzoic acid, and nicotinic acid on caffeine was determined and the effect of the kind and position on the solubilization was examined. The solubilizing action was found to be in the descending order, in molar equivalent of the salt, of salicylate≅m-chloro-, p-chloro-, m-hydroxy-≅p-hydroxy-≅m-methoxy-≅p-methoxy-, m-nitro-, p-nitro-, o-amino-, and p-amino-benzoate, benzoate, m-aminobenzoate, nicotinate, and o-chloro-, o-methoxy-, and o-nitro-benzoate. The solubilizing action of these benzoates is assumed to be not due to formation of a complex of established composition but due to the formation of a hydrogen bond between caffeine and benzoate, with the water molecule of the solvent acting as the hydrogen-bond donor.