مشخصات پژوهش

عنوان	Thiamine-modified octamolybdate catalyzes solvent-free stereoselective olefin epoxidation with TBHP
نوع پژوهش	مقاله چاپ‌شده در مجلات علمی
کلیدواژه‌ها	Vitamin B1 Thiamine Polyoxomolybdate Heterogeneous catalysis Epoxidation Stilbene
چکیده	Simple stirring of an acidic aqueous solution (pH=3) containing sodium molybdate and thiamine hydrochloride (VB1) at room temperature resulted in an octamolybdate-containing VB1 (MoB1) material as an efficient and cost-effective epoxidation catalyst using tert‑butyl hydroperoxide (TBHP) under solvent-free condition. The stereospecific stilbene oxidation (>99 %) observed in the presence of MoB1 can be originated from the steric hindrance of some groups on the thiamine molecule and π–π stacking interactions of its pyrimidine and/or thiazole rings with phenyl rings of stilbenes. Further olefins such as cyclooctene, indene, 1-octene, and styrenes are efficiently oxidized using MoB1/TBHP catalytic system. The catalyst is composed of two thiaminium dications (C12H18N4OS)2+ and one Mo8O26 4 – tetraanion based on different characterization techniques and chemical compositional analyses. Field Emission Scanning Electron Microscope (FE-SEM) images shows a sheet-like nanostructure for MoB1 comprising layers with thicknesses ranging from 50 to 500 nm. It exhibits a heterogeneous nature in catalysis evidenced by hot filtration test and ICP-OES analysis. X-ray photoelectron spectroscopy (XPS) indicates minor contributions of Mo in the oxidation states +V and +IV in addition to MoVI attributed to partial electron transfer from VB1 to Mo8O26 4 – . The scavenging experiments support the presence of radical species during catalysis, while, they do not damage the structural integrity of the MoB1 catalyst based on the recycling experiments and FT-IR spectra.
پژوهشگران	عبدالرضا رضائی فرد (نفر اول)، معصومه جعفرپور (نفر دوم)، مریم رستمی نسب (نفر سوم)، سلینا التف (نفر چهارم)، کلاس میلهولز (نفر پنجم)، اکسل کلاین (نفر ششم به بعد)