Refernces
10.1021/cs5004454
The research presents a novel synthesis strategy for preparing 2-5 nm metallic silver nanoparticles (AgNPs) supported on tungsten oxide (WO3) nanorods for the selective oxidation of propylene to propylene oxide (PO) using molecular oxygen. The catalyst, prepared in the presence of cetyltrimethylammonium bromide (CTAB), polyvinylpyrrolidone (PVP), and hydrazine, exhibits a PO production rate of 6.1 × 10-2 mol gcat -1 h-1, comparable to industrial ethylene-to-ethylene oxide production rates. The Ag/WO3 catalyst shows 15.5% propylene conversion with 83% PO selectivity at 250 °C and 2 MPa pressure. The study highlights that the synergistic effect between AgNPs and WO3 nanorods is crucial for PO formation, with the rod-like morphology of WO3 facilitating the dispersion of AgNPs and the activation of molecular oxygen. The catalyst's performance is attributed to the formation of Ag2O species during the reaction, which selectively converts propylene to PO.
10.1002/anie.200801852
The research focuses on the development of a highly active and recyclable catalytic system for the copolymerization of carbon dioxide (CO2) and propylene oxide. The purpose of this study was to improve upon existing catalytic systems, which had limitations in terms of activity, leading to higher catalyst costs and potential toxicity due to metal residue in the resin. A significant conclusion of the research was the ability to separate and recover the catalyst by filtration through a short pad of silica gel, yielding a resin with negligible metal residue (1–2 ppm). The recovered catalyst could be reused without significant loss of performance, which is a crucial step towards the commercialization of CO2/propylene oxide copolymers. The chemicals used in the process included various cobalt–salen complexes, propylene oxide, and silica gel for catalyst recovery.
10.1246/cl.1977.517
The study investigates the synthesis of 1,2-propanediol formates using carbon dioxide, hydrogen, and methyloxirane as direct starting materials, catalyzed by transition metal complexes such as tris(triphenylphosphine)chlororhodium. The researchers discovered a novel reaction where carbon dioxide was catalytically fixed with hydrogen and methyloxirane to form 1,2-propanediol formates (1a, 1b, and 2) as main products, along with by-products propylene carbonate (3) and 1,2-propanediol (4). The study highlights the significance of this reaction compared to previous ones, as it does not involve active-hydrogen compounds. Instead, an oxirane is used, which is expected to insert into the transition metal-formato bond to form an intermediate complex. The study also notes the formation of formic acid in the reaction products and suggests the possibility of another reaction path involving the direct reaction of formic acid with an oxirane.
10.1016/j.tetlet.2008.07.146
The study investigates the synthesis of diethyl c-hydroxy-a,a-difluoromethylenephosphonates through the ring-opening reactions of epoxides. Key chemicals involved include titanium tetrachloride (TiCl4), which acts as a Lewis acid to promote the ring-opening of epoxides, and lithium diethyl difluoromethylenephosphonate, which serves as a nucleophile. The study explores the reactivity of various epoxides, such as propylene oxide, 1,2-butene oxide, styrene oxide, and cyclohexene oxide, with these reagents. The reactions are regioselective, favoring attack at the less hindered site of the epoxide ring. The study also examines the use of Grignard reagents, which act as both nucleophiles and Lewis acids, leading to the formation of halohydrins. The synthesized compounds have potential applications in the design of non-hydrolyzable analogues of biologically active phosphate esters and as substrates for certain enzymes.
F+, 
T
F+:Highly flammable;
