A Rapid and Convenient Synthesis of Acylals from Aldehydes and Acetic Anhydrides Catalyzed by SnCl_4/SiO_2

A variety of aldehydes were converted into acylals in excellent yields with acetic anhydride in the presence of a catalytic amount of tin (IV) chloride supported on silica gel at room temperature.

Modification of Ni/SiO_2 Catalysts by Means of a Novel Plasma Technology

Atmospheric high frequency cold plasma jet was applied to modify Ni/SiO2 catalysts. The catalysts prepared by two different methods with plasma jet were compared with conventional catalysts. BET, XRD, H2-TPD and high-resolution transmission electron microscopy （HRTEM） were used to characterize these catalysts. The results showed that the catalyst prepared with plasma jet had higher nickel dispersion, larger specific surface area and smaller nickel particle size, about 5 nanometres. Detailed analyses revealed that improved structure and characteristic of the plasma catalyst were benefited from the large amount of hydrogen atoms in the plasma jet, by which the catalyst reduction can be easily achieved in shorter period of time at lower temperature, thus avoiding sintering and conglomeration of the active particles and the support. The activity of catalysts was investigated in the methane reforming with CO2. It is shown that the conversions of CH4 and CO2, the yields of H2 and CO were all significantly increased for the plasma catalysts.

Determination of seven active components in Salvia miltiorrhiza herb by matrix solid phase dispersion combined with ion liquid extraction followed by high performance liquid chromatography

A low cost,rapid and sensitive preparation method of silica gel supported ionic liquid(SGSIL)combined with matrix solid phase dispersion(MSPD)followed by high performance liquid chromatography(HPLC)with ultraviolet detection(UV)is proposed,and it was applied to determine the seven active compounds in Salvia Miltiorrhiza herb.SGSIL and ionic liquid[BMIM]BF4 were used as the adsorbent and the green elution reagent in the MSPD procedure.Several extraction conditions including type of filler and elution solvent,the volume of elution solvent,material liquid ratio were optimized.Under the optimum conditions,the SGSIL-MSPD-HPLC method showed a low limit of detection(LOD,S/N=3)of 0.0122-0.8788μg/mL for standard solution,limit of quantification(LOQ,S/N=10)of 0.0406-2.9292μg/mL for standard solution,wide linear range from 1.56 to 2000μg/mL for all compounds for standard solution,correlation coefficients(r)of more than 0.9990,acceptable reproducibility(relative standard deviations,RSDs<3.54%),and precision of RSDs<3.36%for intra-day,RSDs<3.50%for inter-day.The satisfactory recoveries ranged from 96.4 to 102.5,with RSDs less than 3.45%.The developed SGSIL-MSPD method is easier and more suitable for the determination of the seven active compounds in Salvia Miltiorrhiza herb than the traditional ultrasonic extraction.It was an effective and efficient method for the extraction and quantification of the seven active compounds in traditional Chinese herbal samples.

Efficient Multi-component Synthesis of Highly Substituted Imidazoles Utilizing P2O5/SiO2 as a Reusable Catalyst

Phosphorus pentoxide supported on silica gel （P2O5/SiO2） has been used as an efficient and reusable catalyst for the one-pot pseudo four-component synthesis of 2,4,5-trisubstituted imidazoles from benzil or benzoin, aldehydes, and ammonium acetate. It was also used for four-component preparation of 1,2,4,5-tetrasubstituted imidazoles from benzil or benzoin, aldehydes, primary amine, and ammonium acetate under thermal solvent-free conditions. The remarkable features of this new procedure are high conversions, cleaner reaction, simple experimental and work-up procedures and also the catalyst can be easily separated from the reaction mixture and reused several times without any loss of its activity.