Efficient bifunctional catalyst lipase/organophosphonic acid-functionalized silica for biodiesel synthesis by esterification of oleic acid with ethanol

A Metal-Free Regioselective Multicomponent Approach for the Synthesis of Free Radical Scavenging Pyrimido-Fused Indazoles and Their Fluorescence Studies

This study deals with a new and efficient metal-free regioselective synthesis of pyrimido-fused indazoles with nitrogen ring junction motifs. We have developed a metal-free domino type reaction between 3-aminoindazole, aryl aldehydes and aceotophenones in the presence of KOH/DMF that leads to pyrimido[1,2-b]indazole analogues. Response Surface Methodology (RSM) coupled with a Box-Behnken design (BBD) were utilized for exploring the effect of base used (A), temperature of reaction (B) and (C), reaction time. This approach can allow access to a variety of pyrimidoindazole fluorophores and related compounds. The compound N,N-dimethyl-4-(2-phenylpyrimido[1,2-b]indazol-4-yl)aniline (4e) displays the maximum fluorescence intensity at 518 nm and shows a fluorescence quantum yield of 0.068. The synthesized pyramido-fused indazoles have been evaluated for their free radical scavenging activity and compound 4f showed good antioxidant activity.

Catalysts, kinetics and process optimization for the synthesis of methyl acrylate over Cs–P/γ-Al2O3

Bifunctional catalysts Cs–P/γ-Al₂O₃ were developed and firstly applied in a one-step synthesis of methyl acrylate using methyl acetate (Ma) and formaldehyde (FA).

One-pot synthesis of highly functionalized pyrimido[1,2-b]indazoles via 6-endo-dig cyclization

An efficient synthesis of nitrogen ring junction pyrimido-indazoles has been developed.

Esterification of oleic acid with methanol by immobilized lipase on wrinkled silica nanoparticles with highly ordered, radially oriented mesochannels

Mesoporous silica nanoparticles with a wrinkled structure (wrinkled silica nanoparticles, WSNs) having highly ordered, radially oriented mesochannels were synthesized by a solvothermal method. The method used a mixture of cyclohexane, ethanol, and water as solvent, tetraethoxysilane (TEOS) as source of inorganic silica, ammonium hydroxide as hydrolysis additive, cetyltrimethylammonium bromide (CTAB) as surfactant, and polyvinylpyrrolidone (PVP) as stabilizing agent of particle growth. Particle size (240nm to 540nm), specific surface areas (490m(2)g(-1) to 634m(2)g(-1)), surface morphology (radial wrinkled structures), and pore structure (radially oriented mesochannels) of WSN samples were varied using different molar ratios of CTAB to PVP. Using synthesized WSN samples with radially oriented mesochannels as support, we prepared immobilized Candida rugosa lipase (CRL) as a new biocatalyst for biodiesel production through the esterification of oleic acid with methanol. These results suggest that WSNs with highly ordered, radially oriented mesochannels have promising applications in biocatalysis, with the highest oleic acid conversion rate of about 86.4% under the optimum conditions.

Process optimization by response surface methodology for transesterification of renewable ethyl acetate to butyl acetate biofuel additive over borated USY zeolite

Response surface methodology revealed that 4% (w/w) B–USY zeolite is a stable (reusable for 6 cycles) and potential catalyst with a 96% yield of butyl acetate.

One step synthesis of ethyl levulinate biofuel by ethanolysis of renewable furfuryl alcohol over hierarchical zeolite catalyst

Response surface methodology (RSM) with Box–Behnken experimental design (BBD) demonstrated Hierarchical-HZ-5 as potential catalyst for ethanolysis of renewable furfuryl alcohol to ethyl levulinate biofuel with 99% FAL conversion and 73% EL yield.