Lacunary silicotungstic heteropoly salts as high-performance catalysts in oxidation of cyclopentene

The development of polyoxometalates for olefin oxidation is critical to achieving the green chemical process of the C5 fraction further processing.Di-lacunary silicotungstic anions were easily obtained by continuously adjusting the p H instead of the traditional step-by-step method,which exhibited excellent performance in the catalytic oxidation of cyclopentene(CPE)to aldehydes or alcohols.The 93.69%CPE conversion and 97.15%total product selectivity(41.38%for glutaraldehyde(GA)and 55.77%for 1,2-cyclopentanediol(1,2-diol)were achieved by using H_(2)O_(2)as the oxidant and acetonitrile as the solvent.Through complementary characterization,it was found that the optimized di-lacunary silicotungstic polyoxometalate retained a complete Keggin structure,and exhibited better catalytic activity and stability than the mono-lacunary or saturated silicodecatungstate because it exposed more catalytic active centers.Furthermore,in situ FT-IR spectra was utilized to monitor the reaction process,revealing the formation of the active species W(O_(2))on the di-lacunary silicotungstic polyoxometalate and the intermediate epoxycyclopentane during the catalytic oxidation of cyclopentene.

Selective oxidation of cyclopentene with H2O2 by using H3PW12O40 and TBAB as a phase transfer catalyst

The selective oxidation of cyclopentene by aqueous H2O2 using H3PW12O40 and tetrabutyl ammonium bromide(TBAB) as a phase transfer catalyst has been investigated. The results show that the presence of TBAB significantly improved the oxidation selectivity of cyclopentene. The effects of the reaction conditions on the conversion of cyclopentene were investigated in detail. The optimal reaction conditions are as follows: the H3PW12O40 to TBAB molar ratio, 1:1–1:3;H3PW12O40 to cyclopentene molar ratio,0.54:100–0.64:100;and molar ratio of H2O2 to cyclopentene, 1.6:1. The conversion reached to 59.8% in 4h at 35.0 ℃, while the selectivity of glutaraldehyde was 38.0% and the selectivity of 1,2-cyclopentanediol was 55.6%. In addition, a route for oxidation of cyclopentene by aqueous H2O2 using a heteropoly acid and quaternary ammonium salt as a phase transfer catalyst was proposed.

Convenient one-pot synthesis of functionalized cyclopentene via Sm/TMSCl/t-BuOH system mediated hydrodimerization cyclization of gem-diactivated alkene

Functionalized cyclopentenes could be prepared through Sm/TMSCl/t-BuOH mediated hy-drodimerization cyclization of gem-diactivated alkene in one-pot at mom temperature. The trans- or trans, transform isomer is in the majority and the major product was isolated from its stereoisomers through the fractional crystallization method.

Possible mechanism of 15D-PGJ2 in promoting periodontal tissue regeneration in patients with mandibular defects

Objective:To explore the main physiological mechanism of 15d-PGJ2 promoting periodontal tissue regeneration in patients with jaw defects caused by periodontal disease.Methods:From February 2016 to July 2019,a controlled study was conducted on 73 healthy residents(healthy group)and 73 patients(case group)with periodontal disease combined with jaw defects in Changsha medical university.T test was used to compare the growth factors of gingival crevicular fluid between the two groups.Peripheral blood cells;Cement-specific protein;Peripheral blood enzyme;Statistical differences in bone metabolites.The t test method compared the content of each index before and after treatment(15d-PGJ2 was treated at a dose of 200 mu/kg for 14 days).The method of factor analysis explores the internal correlation of each index.Result:RANKL,ICAM-1,TGF-β1,Th17,Treg,PDLSCs,SOST,CAP,HMGB1,CTSK,5-LOX,COX-2,NTX were higher in the case group than in the healthy group.In the case group,RANKL,ICAM-1,TGF-β1,Th17,Treg,PDLSCs,SOST,CAP,HMGB1,CTSK,5-LOX,COX-2,NTX were lower than those in the healthy group.The differences between the groups were statistically significant(P<0.05).Compared with before treatment,IL-1β,IL-17,Bfgf,YKL-40,BMP-2,ICTP,PICP,CTX were significantly decreased after treatment.RANKL,ICAM-1,TGF-β1,Th17,Treg,PDLSCs,SOST,CAP,HMGB1,CTSK,5-LOX,COX-2,NTX were significantly increased.The differences were statistically significant(P<0.05).Factor analysis shows that four common factors can be extracted from 21 indicators,and the cumulative contribution rate is 96.993%.Conclusions:The treatment of 15d-PGJ2 in patients with periodontal disease with maxillary defects can significantly affect the expression of multiple characteristic indicators,which may involve four mechanisms:dysregulation of cell differentiation or migration,local inflammation or immune imbalance,destruction of alveolar bone microstructure,load or stimulation,and remodeling.The specific pathway related to this is still to be further explored.