Yinhui Yang,Zhengfeng Chang,Xiaohong Yang,Meiling Qi,Jinliang Wang
Herein we report a propeller-like hexaphenylbenzene-based hydrocarbon material (denoted as BT) as the stationary phase for capillary gas chromatography (GC). The statically-coated BT capillary column showed a high column efficiency of 4340 plates m −1 and weak polarity. Owing to its unique conformation, π-electron toroidal delocalization and intrinsic microporosity , the BT stationary phase exhibited interesting selectivity for aromatic compounds over alkanes. Compared with the graphene (G) column, the BT column showed much prolonged retention and high selectivity for aromatic isomers, especially methylnaphthalenes , dimethylnaphthalenes and phenanthrene/anthracene, mainly because of its propeller-like conformation with rich intercalation effects. Moreover, it exhibited good column repeatability (intra-day, inter-day) and reproducibility (between-column) with RSD values on the retention times less than 0.08% for intra-day, 0.32% for inter-day and 3.8% for between-column, respectively. Also, it showed good potential for determination of minor isomer impurities in real samples. To the best of our knowledge, this work presents the first example of employing an neat aromatic hydrocarbon material as the GC stationary phase with high selectivity for analytes of a wide ranging polarity.
Qiuxiang Yao,Lei He,Duo Ma,Yong Zhang,Dan Zhang,Ming Sun
The naphthalene derivatives in coal tar naphthalene and anthracene oil fractions mostly contain short-chain alkyl groups. The enrichment of PAHs (polycyclic aromatic hydrocarbons, mainly including naphthalene, anthracene, and pyrene) by the dealkylation of PAHs-rich fraction in coal tar was assumed to obtain high-purity PAHs by distillation. Based on this strategy, using 2-methylnaphthalene as the model compound, and the influences of catalysts with different supports (SiO 2 , Al 2 O 3 , ZSM-5, Beta, and HY) and different active metal components (Ni, Co, Mo, and W) prepared by the equivalent-volume impregnation method on the hydro-dealkylation performance of 2-methylnaphthalene under different technological conditions (temperature, H 2 initial pressure and reaction time) were systematically investigated in a pressurized batch reactor. The experimental results show that the conversion rate of 2-methylnaphthalene is 81.23 % and the selectivity of naphthalene is 64.22 % under conditions of 480 °C, 2 MPa, 4 h, and 6 W-HY. Loading 0.8 wt% La on the 6 W-HY catalyst can improve the dispersion of active metal component W on the support, but it does not change the skeleton structure of the support. In addition, one-dimensional diffusion is the most probable reaction mechanism for 2-methylnaphthalene, and the evolution profiles of naphthalene can be reflected by the reaction mechanism with a reaction order of n = 4 using the model fitting method.
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