赤外線分光分析による薄荷異性体の研究

薄荷の研究第2報

抄録

An attempt has been made to determine the infra-red absorption character of menthol-isomers.
Three isomers, i.e. d-isomenthol, d-isomenthol and d-neoisomenthol were synthesized in pure state from natural l-menthol, and their infra-red absorption spectrum were studies.
(1) l-Menthol was purified from commercial l-menthol by recrystallzation.
(2) d-Neomenthol was preparated by READ's method. (Table 1)
(3) d-Isomenthol was synthesized from l-menthone and d-isomenthone mixture inverted from l-menthone. (Table 2)
(4) d-Neoisomenthol was obtained from the mixture of four menthol-isomers by means of the difference of esterification velocity. (Table 3)
Their infra-red absorption spectra gave the singular absorption curves (Fig. 2.)
Following key bands were found applicable to analyse the isomers of menthol, 10.88 μ for l-menthol, 12.26μ and 14.70μ for d-isomenthol, 13.02μ for d--isomenthol, and 12.58μ and 14.45μ for d-neoisomenthol.