Boosting Activity and Selectivity of UiO-66 through Acidity/Alkalinity Functionalization in Dimethyl Carbonate Catalysis.

The acid-base properties of supports have an enormous impact on catalytic reactions to regulate the selectivity and activity of supported catalysts. Herein, a train of Pd-X-UiO-66 (X = NO2 , NH2 , and CH3 ) catalysts with different acidity/alkalinity functional groups and encapsulated Pd(II) species is first developed, whose activities in dimethyl carbonate (DMC) catalysis are then investigated in details. Thereinto, the Pd-NO2 -UiO-66 catalyst with acidity functionalization exhibits the best catalytic behavior: the DMC selectivity stemmed from methyl nitrite (MN) is up to 68%, the conversion of CO is 73.4%. The obtained experimental results demonstrate that the NO2 group not only affected the interaction between X-UiO-66 and Pd(II) active sites but also play an indispensable role in the adsorption and activation of MN and CO, which remarkably promote the formation of the COOCH3 * intermediate and DMC product.

[Investigation on current status of infections of soil-borne nematodes in Yunxiao County].

OBJECTIVE: To understand the endemic situation of soil-borne nematodes and their distribution characteristics, so as to provide the evidence for formulating prevention strategy. METHODS: According to The Survey Program of Important Human Parasitic Diseases in Fujian Province, the survey spots were determined by the stratified cluster randomly sampling method. The eggs of Ascaris lurmbricoides, hookworm and Trichuris trichiura in feces were detected by Kato-Katz technique; the eggs of Enterobius vermnicularis were checked by rectal swabs using transparent adhesive tape. A questionnaire survey was performed for recording the gender, age, education levels and related epidemiological factors. RESULTS: Altogether 2002 residents in 21 villages of 4 towns were investigated. There were 169 residents infected with soil-borne nematodes (8.44%). The infection rates of hookworm, Trichuris trichiura and Ascaris lumbricoides were 4.35%, 1.70% and 0.15% respectively. The infection rate of Enterobius vermicularis was 13.48% (43/319) in children. The infection rates of soil-borne nematodes were higher in children aged below 7 years and residents aged above 45 years, and the infection rate was higher in the women than in the men. The infection rates 'vere negative correlated with the education levels. CONCLUSION: The prevalence of soil-borne nematodes has a reduction trend in Yunxiao County. However, the infection rate of hookworm is still high in areas of mainly planting economic crops. The infection rate of Enterobius vermicularis is still high in children, and we should pay more attention to it.

Highly efficient iridium catalyst for asymmetric transfer hydrogenation of aromatic ketones under base-free conditions.

[reaction: see text] Catalytic systems generated in situ from the chiral PNNP ligands with iridium or rhodium hydride complexes exhibited excellent catalytic activity and good enantioselectivity in the asymmetric transfer hydrogenation of aromatic ketones without added base. The best result was obtained in the IrH(CO)(PPh(3))(3)-ligand 2 catalytic system with up to 99% yield and 97% ee.