核磁気共鳴法による粗メチルナフタレン中の 1-及び2-メチルナフタレンの同時定量

概要

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A method for the determination of isomers in methylnaphthalenes by NMR spectroscopy was investigated, and the application of this method to the analysis of imported methylnaphthalenes used as industrial raw materials also examined. The NMR measurements were made with a Hitachi R-20 spectrometer (60 MHz). The probe temperature during measurement was 34℃. In the NMR spectra of 1- and 2-methylnaphthalene and methyl benzoate (intenal standard) dissolved in CCl_4, the methyl proton signals appeared at 2.48, 2.30 and 3.83 ppm, respectively. The integral intensities of these characteristic peaks were used directly for the detemination of the isomers. The synthetic standard mixtures of two isomers were examined under following conditions: isomer ratio; (lO〜90)% (1.0g of the mixture and O.5g of methyl benzoate in 1 ml of CCl_4), RF; 4×1O microvolt, Sweep width; 2.4 Hz/s. The standard deviattions of 1-and 2-methylnaphthalene were O.44% and 0.54%. From the results of GC and GC-MS analysis of imported methylnaphthalenes, it was found that the impurities which accompanied with methylnaphtalenes were mainly naphthalene, ethylnaphthalene, biphenyl and indole.The effect of these impurities on the integral intensity measurements could not be observed. This method is rapid and does not require stndard methylnaphthalenes.
社団法人日本分析化学会の論文
1975-07-10