Influence of zinc state on the catalyst properties of Zn/HZSM-5 zeolite in 1-hexene aromatization and cyclohexane dehydrogenation

Rational design of Zn-containing HZSM-5 zeolite(Zn/HZSM-5)with high reactivity and excellent aromatization performance for olefin aromatization is crucially desired.We develop a new and uncomplicated method to synthesize Zn/HZSM-5(IMX/Z5)with superior aromatization performance in the paper.Compared to incipient wetness impregnation(IMP/Z5)and mechanical mixing(MIX/Z5),the asprepared IMX/Z5 presents a higher amount of surface ZnOH^(+)species(2.87%)while keeping identical bulk zinc content.As a result,more surface ZnOH^(+)favor both the aromatization of 1-hexene and cyclohexane dehydrogenation.For the two olefin aromatization pathways(hydrogen transfer and dehydrogenation),it is the first time found both the hydrogen transfer ability and the dehydrogenation ability increase linearly with the amount of surface ZnOH^(+)species while keeping identical bulk zinc content.We believe that the linear relationships are essential to design next generation olefin aromatization catalysts.

Mechanism transformation of cyclohexene-thiophene competitive adsorption in FAU zeolite

Competition of hydrocarbon compounds with sulfides in gasoline has caused a not very high selectivity of sulfides in adsorption desulfurization so far,resulting in a reduction of catalyst lifetime as well as more sulfur oxide emissions.Tostudy the whole competitive process changing with the increase of the loading,the dynamic competition adsorption mechanism of cyclohexene and thiophene in siliceous faujasite(FAU)zeolite was analyzed by the Monte Carlo simulation.The results showed that with the increase of the loading,thiophene and cyclohexene had different performances before and after the inflection point of 40 molecule/UC.The adsorbates were distributed ideally at optimal sites during the stage that occurred before the inflection point,which is called the“optimal-displacement adsorption”stage.When approaching the inflection point,the competition became apparent and the displacement appeared accordingly,some thiophene molecules at S sites(refers to the sites inside the supercages)were displaced by cyclohexene.After the inflection point,the concentration of adsorbates at W sites(refers to the 12-membered ring connecting the supercages)was significantly reduced,whereas the adsorbates at S sites got more concentrated.The stage some cyclohexene molecules displaced by thiophene and inserted into the center of the supercage can be named as the“insertion-displacement adsorption”stage,and both the adsorption behavior and the competitive relationship became localized when the adsorption amount became saturated.This shift in the competitive adsorption mechanism was due to the sharp increase of interaction energy between the adsorbates.Besides,the increase in temperature and ratio of Si/Al will allow the adsorbates,especially thiophene molecules to occupy more adsorption sites,and it is beneficial to improve the desulfurization selectivity.

Benzo[a]pyrene stimulates miR-650 expression to promote the pathogenesis of fatty liver disease and hepatocellular carcinoma via SOCS3/JAK/STAT3 cascades

Modern diets,which often feature high levels of fat and charcoal-grilled meat,contribute to the pathogenesis of obesity and non-alcoholic fatty liver disease(NAFLD),resulting in liver cancer progression.Benzo(a)pyrene(B[a]P)is a common environ-mental and foodborne pollutant found in smoke and fire-grilled foods,which can have an adverse effect on human health.Hepatocellular carcinoma(HCC)is the fifth leading cause of cancer and the second leading cause of cancer-related deaths worldwide.The epidemiological studies suggest that both environmental risk factors and chronic liver injury including NAFL are important for HCC development,but the precise mechanisms linking eating habits to hepato-carcinogenesis remain unclear.In the present study,we demonstrated that various miRNAs in B[a]P-exposed tumor cells contribute to tumor metastasis,among which miR-650 could be the most potent inducer.Furthermore,we found that the suppressor of cytokine signaling 3(SOCS3)is directly regulated by miR-650 and its suppression regulates the activation of the Janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3)cascade.Our findings reveal a possible adverse outcome pathway of SOCS3/JAK/STAT3 regulation in B[a]P-induced HCC progress.These results provide a better understanding of the adverse effects of chronic exposure to B[a]P on human health.