关键词:

活性白土, 松节油, 对伞花烃, 反应过程

Abstract:

p-Cymene was prepared by the liquid phase method with turpentine as raw material and activated bentonite as catalyst.The reaction process and mechanism were investigated by Fourier infrared spectrophotometry (FT-IR)and gas chromatography-mass spectrometry (GC-MS).44 peaks were separated and 41 compounds were identified by GC-MS.The main products were p-cymene and p-menthene, with the relative contents of 56.57% and 10.46%, respectively.Complete conversion of pinene and 62.78% yield for p-cymene were obtained.Some nonvolatile products and polymeric species, such as cembrene were first identified in the products.As a result of FT-IR, the absorbance peak of the endo-double bond of α-pinene at 3022 cm^-1, 1655 cm^-1 and ＝CH₂ of β-pinene at 3067 cm^-1 almost disappeared, while the peak of the stretching in aromatic rings at 1611 cm^-1, 1498 cm^-1, 1458 cm^-1 and that at 815 cm^-1 from p-substituent of benzene ring increased.It also meant that pinene was converted completely, mainly to p-cymene.The analysis results showed that the isomerization and intermolecular hydrogen transfer disproportionation of bicyclic terpene pinene were the main reactions.Simultaneously, some accompanying side reactions, such as further ring-opening isomerization,aquated rearrangment and polymerization reaction occurred, while isomerization and dehydrogenation as well as aquated rearrangement of sesquiterpene were observed.

Key words:

活性白土, 松节油, 对伞花烃, 反应过程