A facile and efficient method for the synthesis of tetrasubstituted olefins in supercritical carbon dioxide was developed by using carbon nanotubes-supported palladium nanoparticles (Pd/CNTs) as the catalyst. Compared...A facile and efficient method for the synthesis of tetrasubstituted olefins in supercritical carbon dioxide was developed by using carbon nanotubes-supported palladium nanoparticles (Pd/CNTs) as the catalyst. Compared with common Pd/C, Pd/CNTs could more effectively catalyze the reaction of dibromo-substituted olefins with boronic acids, affording the corresponding tetrasubstituted olefins with moderate to good yields. This environmentally benign route with an easy-to-handle catalyst provides an appealing alternative to the currently available methods.展开更多
Various agricultural crop residues including corn stover,corn cob,and sorghum stalk with a moisture content of 75 wt%were subjected to a long pretreatment(12–60 h)with supercritical CO_2(scCO_2),at low temperature(50...Various agricultural crop residues including corn stover,corn cob,and sorghum stalk with a moisture content of 75 wt%were subjected to a long pretreatment(12–60 h)with supercritical CO_2(scCO_2),at low temperature(50–80°C)and a pressure of 17.5–25.0 MPa.The sugar yields from the enzymatic hydrolysis(EH)of the pretreated samples were as much as three-to fourfold greater than those afforded by the raw materials.However,when pretreatment was conducted within a short time(e.g.0.5 h),as previously reported in the literature,only a slight increase in the EH sugar yields was observed.The proposed sc CO_2pretreatment mechanism demonstrated the role of moisture in the system.Wetting,softening,and swelling were observed to mainly affect the lignocellulose when a suitable amount of water was added.Finally,the samples were analysed by X-ray diffraction and scanning electron microscopy,before and after pretreatment,to investigate the changes in the microscopic structure of the biomass.展开更多
Palladium-catalyzed homo-coupling of arylboronic acids could proceed smoothly with a commercially available resin functionlised by phosphino or amino group as the ligand in supercritical carbon dioxide thereby offerin...Palladium-catalyzed homo-coupling of arylboronic acids could proceed smoothly with a commercially available resin functionlised by phosphino or amino group as the ligand in supercritical carbon dioxide thereby offering a simple and efficient protocol for the synthesis of symmetrical bi-aryl molecules and their higher homologues.展开更多
A novel and green method for the synthesis of dimethyl pyridine-3,5-dicarboxylate has been developed. It is PdCl2-catalyzed heterocyclotrimerization of methyl acrylate with urea in methanol/supercritical carbon dioxid...A novel and green method for the synthesis of dimethyl pyridine-3,5-dicarboxylate has been developed. It is PdCl2-catalyzed heterocyclotrimerization of methyl acrylate with urea in methanol/supercritical carbon dioxide. The target compound was obtained with a 75% isolated yield under the optimized con-ditions.展开更多
The multi-SCCO2 （supercritical carbon dioxide） release and dry process based on our specialized SCCO2 semiconductor process equipment is investigated and the releasing mechanism is discussed. The experiment results ...The multi-SCCO2 （supercritical carbon dioxide） release and dry process based on our specialized SCCO2 semiconductor process equipment is investigated and the releasing mechanism is discussed. The experiment results show that stuck cantilever beams were held up again under SCCO2 high pressure treatment and the repeatability of this process is nearly 100%.展开更多
The solubility of red palm oil （RPO） in supercritical carbon dioxide （scCO2） was determined using a dynamic method at 8.5-25 MPa and, 313.15-333.15 K and at a fixed scCO2 flow rate of 2.9 g. mn -1 using a full fac...The solubility of red palm oil （RPO） in supercritical carbon dioxide （scCO2） was determined using a dynamic method at 8.5-25 MPa and, 313.15-333.15 K and at a fixed scCO2 flow rate of 2.9 g. mn -1 using a full factorial design. The solubility was determined under low pressures and temperatures as a preliminary study for RPO par- ticle formation using scCO2. The solubility of RPO was 0.5-11.3 mg. （g CO2） -1 and was significantly affected by the pressure and temperature. RPO solubility increased with pressure and decreased with temperature. The Adachi-Lu model showed the best-fit for RPO solubility data with an average relative deviation of 14% with a high coefficient of determination, R2 of 0.9667, whereas the Peng-Robinson equation of state thermodynamic model recorded deviations of 17%-30%.展开更多
基金Supported by the National Natural Science Foundation of China (Grant Nos. 20332030, 20572027, 20625205 and 20772034) Guangdong Natural Science Foundation (No. 07118070).
文摘A facile and efficient method for the synthesis of tetrasubstituted olefins in supercritical carbon dioxide was developed by using carbon nanotubes-supported palladium nanoparticles (Pd/CNTs) as the catalyst. Compared with common Pd/C, Pd/CNTs could more effectively catalyze the reaction of dibromo-substituted olefins with boronic acids, affording the corresponding tetrasubstituted olefins with moderate to good yields. This environmentally benign route with an easy-to-handle catalyst provides an appealing alternative to the currently available methods.
基金financially supported by the National Natural Science Foundation of China (21376045, 21506027)Chinese Postdoctoral Science Foundation (2015M571307)+1 种基金Petrochemicals Joint Fund between the National Natural Science Foundation of China, the China National Petroleum Corporation (U1662130)the Fundamental Research Funds for the Central Universities
文摘Various agricultural crop residues including corn stover,corn cob,and sorghum stalk with a moisture content of 75 wt%were subjected to a long pretreatment(12–60 h)with supercritical CO_2(scCO_2),at low temperature(50–80°C)and a pressure of 17.5–25.0 MPa.The sugar yields from the enzymatic hydrolysis(EH)of the pretreated samples were as much as three-to fourfold greater than those afforded by the raw materials.However,when pretreatment was conducted within a short time(e.g.0.5 h),as previously reported in the literature,only a slight increase in the EH sugar yields was observed.The proposed sc CO_2pretreatment mechanism demonstrated the role of moisture in the system.Wetting,softening,and swelling were observed to mainly affect the lignocellulose when a suitable amount of water was added.Finally,the samples were analysed by X-ray diffraction and scanning electron microscopy,before and after pretreatment,to investigate the changes in the microscopic structure of the biomass.
文摘Palladium-catalyzed homo-coupling of arylboronic acids could proceed smoothly with a commercially available resin functionlised by phosphino or amino group as the ligand in supercritical carbon dioxide thereby offering a simple and efficient protocol for the synthesis of symmetrical bi-aryl molecules and their higher homologues.
基金the National Natural Science Foundation of China (Grant Nos. 20332030, 20572027, 20625205 and 20772034)Guangdong Natural Science Foundation (Grant No. 07118070)
文摘A novel and green method for the synthesis of dimethyl pyridine-3,5-dicarboxylate has been developed. It is PdCl2-catalyzed heterocyclotrimerization of methyl acrylate with urea in methanol/supercritical carbon dioxide. The target compound was obtained with a 75% isolated yield under the optimized con-ditions.
基金Project supported by the National Natural Science Foundation of China(No.60976017)
文摘The multi-SCCO2 （supercritical carbon dioxide） release and dry process based on our specialized SCCO2 semiconductor process equipment is investigated and the releasing mechanism is discussed. The experiment results show that stuck cantilever beams were held up again under SCCO2 high pressure treatment and the repeatability of this process is nearly 100%.
基金supported by Geran Putra IPS(Vote No.:9469400),University Putra Malaysia
文摘The solubility of red palm oil （RPO） in supercritical carbon dioxide （scCO2） was determined using a dynamic method at 8.5-25 MPa and, 313.15-333.15 K and at a fixed scCO2 flow rate of 2.9 g. mn -1 using a full factorial design. The solubility was determined under low pressures and temperatures as a preliminary study for RPO par- ticle formation using scCO2. The solubility of RPO was 0.5-11.3 mg. （g CO2） -1 and was significantly affected by the pressure and temperature. RPO solubility increased with pressure and decreased with temperature. The Adachi-Lu model showed the best-fit for RPO solubility data with an average relative deviation of 14% with a high coefficient of determination, R2 of 0.9667, whereas the Peng-Robinson equation of state thermodynamic model recorded deviations of 17%-30%.
