Fuming Mei

One-pot synthesis of glycidol from glycerol and dimethyl carbonate over a highly efficient and easily available solid catalyst NaAlO2

The one-pot synthesis of glycidol from glycerol and dimethyl carbonate (DMC) was developed by using a solid base catalyst. A series of solid base catalysts have been investigated in this reaction. It was found that NaAlO2, a cheap and easily available raw material, was a highly efficient heterogeneous catalyst for the one-pot synthesis of glycidol, and it can be easily recovered and reused. Under the reaction conditions of a DMC–glycerol molar ratio of 2, catalyst–glycerol weight ratio of 3%, reaction time of 90 min, and temperature of 80–92 °C, the conversion of glycerol and the selectivity to glycidol reached 94.7% and 80.7%, respectively. Activity tests of the catalyst after exposure to the air showed that, to a certain extent, the NaAlO2 catalyst is tolerant to water and carbon dioxide, which makes the present system a practically interesting process for glycidol synthesis.

Effective and recoverable homogeneous catalysts for the transesterification of dimethyl carbonate with ethanol: Lanthanide triflates

The catalytic activities of metal triflates were tested for the transesterification of dimethyl carbonate (DMC) with ethanol. It was found that yttrium triflate was the most efficient homogeneous catalyst. When the transesterification reaction was catalyzed by yttrium triflate at 76–80°C, 7 h, ethanol to DMC in 6: 1 molar ratio, 0.35 mol % of catalyst based on DMC, the conversion of DMC was 89.2%, the selectivities of diethyl carbonate (DEC) and ethyl methyl carbonate (EMC) were 85.1 and 13.6%, respectively. Yttrium triflate was reused 5 times for the transesterification without loss of its catalytic activity.

Activities of Co(II) Schiff base complexes in the redox carbonylation of aniline and nitrobenzene to methyl N-phenyl carbamate

The series of cobalt(II) complexes with different Schiff base ligands was synthesized and used as catalyst for the redox carbonylation of aniline and nitrobenzene. Effects of reaction temperature, CO pressure, promoter, and catalyst additions on the conversion of substrate were studied. When Co[(OH)2saloph] — p-toluenesulfonic acid system was used as catalyst, the reaction was carried out at the next conditions: both Co[(OH)2saloph] and p-toluenesulfonic acid—0.2 mmol, aniline—20 mmol, nitrobenzene—10 mmol, methanol—30 ml, Co—5 MPa, temperature 170°C, reaction time 7 h. The highest conversion of nitrobenzene and selectivity of methyl N-phenyl carbamate were 54.5 and 92.2%, respectively.

Facile synthesis of 1,4-diketones via three-component reactions of α-ketoaldehyde, 1,3-dicarbonyl compound, and a nucleophile in water

Three-component reactions of alkylglyoxals, 1,3-dicarbonyl compounds, and a nucleophile were performed under aqueous and catalyst-free conditions, which produced 1,4-diketone scaffolds in a straightforward way. Many compounds, such as indole, azaindole, pyrrole, 2-methylfuran, N,N-dimethylaniline, N-methylaniline, thiophenol, and benzyl mercaptan, were all able to act as nucleophiles to react with alkylglyoxal and 1,3-dicarbonyl compounds. The mechanim of this reaction was also investigated. The obtained 1,4-diketones can be easily converted to many valuable chemicals.