2.1 Materials
All chemicals (AR grade) were purchased commercially and used as
received. H2SO4 (A.R, 98 wt%) was
bought from Sinopharm Chemical Reagent Co., Ltd.
Choline chlorides
and carbon tetrachloride (≥99.5%) were purchased from Shanghai Titan
Scientific Co., Ltd. Phenol (≥99.0%) and
benzoic acid
(99.5%) were purchased from Shanghai Aladdin Biochemical Technology
Co., Ltd.
P-toluenesulfonic acid
(99.0%) and
hydroxylamine hydrochloride
(98.5%) were purchased from Shanghai MackLin Biochemical Technology
Co., Ltd. Isobutane/2-butene mixture (86.9/13.1 wt%)was obtained from
Shanghai Weichuang Standard Gas Analysis Technology Co., Ltd. Nitrogen
(99.99%) gas was purchased from Air Liquide (Shanghai) Gas Co., Ltd.