Preparation of acetonides from soybean oil, methyl soyate, and fatty esters

Parts-Per-Million Level Loading Cyclometalated Ru(II)-NHC Catalyzed Selective Oxidation of Olefins to Carbonyls

Oxidative cleavage of olefins is a useful reaction in organic synthesis. The most well-known catalytic system is the osmium based Lemieux-Johnson catalyst, which generally requires high catalyst loading and tends to suffer from rapid overoxidation to produce the acid predominantly. Hence, the development of a mild, general, and selective method toward the oxidative cleavage of alkenes to carbonyl compounds is highly desired. In this work, a highly efficient ruthenium-based catalyst for olefin oxidation has been demonstrated by employing a fused π-conjugated imidazo[1,5-a]quinoxaline (ImQx) based NHC ligand with bidentate C(carbanion) CNHC motif. Strong C-donor ligands, paired with a rigid backbone and ruthenium redox activity, provided exceptionally high catalytic activity and a long lifetime for olefin oxidation. Complex showed high catalytic activity and a long lifetime, TONs are several million. The catalyst tolerates numerous functional groups and can be applicable to challenging biomass, natural products, sugar, amino acids, and fatty acid-derived substrates. Based on kinetic studies, thermodynamic activation parameters, and DFT study, the mechanistic finding demonstrated that [3+2] cycloaddition reaction is the key step in the oxidation process. The use of the by-product NaIO3 in the catalytic efficiency has been disclosed for the first time.

Cyclometalated Ruthenium-Complex-Catalyzed Selective Oxidation of Olefins to Carbonyls

Cyclometalated ruthenium(II)-complex-catalyzed selective oxidative scission of olefins to carbonyls is described. A strong C-donor ligand, paired with a rigid backbone and redox activity of ruthenium, provided high catalytic activity and a long lifetime for olefin oxidation. The catalyst tolerates numerous functional groups and applies to challenging biomass-, natural-product-, sugar-, amino-acid-, and fatty-acid-derived substrates.

Toughening Anhydride-Cured Epoxy Resins Using Fatty Alkyl-Anhydride-Grafted Epoxidized Soybean Oil

The aim of this work is to develop a series of advanced biobased tougheners for thermosetting epoxy resins suitable for high-performance applications. These bio-rubber (BR) tougheners were prepared via a one-step chemical modification of epoxidized soybean oil using biobased hexanoic anhydride. To investigate their toughening performance, these BR tougheners were blended with diglycidyl ether of bisphenol A epoxy monomers at various weight fractions and cured with anhydride hardeners. Significant improvements in fracture toughness properties, as well as minimal reductions in glass transition temperature (T_g), were observed. When 20 wt % of a BR toughener was utilized, the critical stress intensity factor and critical strain energy release rate of a thermosetting matrix were enhanced by >200 and >500%, respectively, whereas the T_g was reduced by only 20 °C. The phase-separated domains were evenly dispersed across the fracture surfaces as observed through scanning electron microscopy and atomic force microscopy. Moreover, domain sizes were demonstrated to be tunable within the micrometer range by altering the toughener molecular structure and weight fractions. These BR tougheners demonstrate the possibility of achieving toughness while having the thermal properties of standard bisphenol epoxy thermosetting resins.

Preparation of functionalized castor oil derivatives with tunable physical properties using heterogeneous acid and base catalysts

Functionalized castor oil derivatives are achieved from epoxidized castor oil through ring opening and transesterification reactions using heterogeneous catalysts.