The industrially important organic compound 1,3-propanediol （1,3-PDO） is mainly used as a building block for the production of various polymers. In the present study, response surface methodology protocol was follow...The industrially important organic compound 1,3-propanediol （1,3-PDO） is mainly used as a building block for the production of various polymers. In the present study, response surface methodology protocol was followed to determine and optimize fermentation conditions for the maximum production of 1,3-PDO using marine-derived Klebsiella pneumoniae HSL4. Four nutritional supplements together with three independent culture conditions were optimized as follows： 29.3 g/L glycerol, 8.0 g/L K2HPO4, 7.6 g/L （NH4）2SO4, 3.0 g/L KH2PO4, pH 7.1, cultivation at 35℃ for 12 h. Under the optimal conditions, a maximum 1,3-PDO concentration of 14.5 g/L, a productivity of 1.21 g/（L＇h） and a conversion of glycerol of 0.49 g/g were obtained. In comparison with the control conditions, fermentation under the optimized conditions achieved an increase of 38.8% in 1,3-PDO concentration, 39.0% in productivity and 25.7% in glycerol conversion in flask. This enhancement trend was further confirmed when the fermentation was conducted in a 5-L fermentor. The optimized fermentation conditions could be an important basis for developing low- cost, large-scale methods for industrial production of 1,3-PDO in the future.展开更多
A new visual method for quantitative measurement of frothers effect and flotation efficiency was presented. A self-designed electrolytic cell was chosen as the reaction environment with sodium chloride (NaCl) as the e...A new visual method for quantitative measurement of frothers effect and flotation efficiency was presented. A self-designed electrolytic cell was chosen as the reaction environment with sodium chloride (NaCl) as the electrolyte. Constant current, supplied by a self-designed power supplier and fixed cathode and anode equipment, guaranteed the constant bubble volume per unit time. Even aperture of the cathode material guaranteed the original bubbles size to be uniform. Bubble generating equipment was connected with a microscopical camera. Statistic data collected by high speed charge-coupled device (CCD) and processed by software Sigmascan and Matlab could reflect bubble characteristics. The efficiency of dipropylene glycol monomethyl ether (DPM) and tripropylene glycol n-butyl ethel (TPnB) were measured at the same condition, and 2×10-4 mol/L and 5×10-2 mol/L were found to be the inflexions of bubble size changes.展开更多
A new solid acid catalyst,SO4^2-/TiO2 modified with tin,was prepared using a sol-gel method and its physicochemical properties were revealed by nitrogen adsorption-desorption,X-ray powder diffraction,scanning electron...A new solid acid catalyst,SO4^2-/TiO2 modified with tin,was prepared using a sol-gel method and its physicochemical properties were revealed by nitrogen adsorption-desorption,X-ray powder diffraction,scanning electron microscopy,Fourier transform infrared spectroscopy,infrared spectroscopy of adsorbed pyridine,temperature-programmed desorption of ammonia and thermal gravimetric analysis.The structure,acidity and thermal stability of the SO4^2-/TiO2-SnO2 catalyst were studied.Incorporating tin enlarged the specific surface area and decreased crystallite size of the SO4^2-/TiO2 catalyst.The total acid sites of the modified catalyst increased and Bronsted acid strength remarkably increased with increasing tin content.The decomposition temperature of sulfate radical in the modified catalyst was 100 ℃ greater and its mass loss was more than twice that of the SO4^2-/TiO2 catalyst.The SO4^2-/TiO2-SnO2 catalyst was designed to synthesize 1,6-hexanediol diacrylate by esterification of 1,6-hexanediol with crylic acid.The yield of 1,6-hexanediol diacrylate exceeded 87% under the optimal reaction conditions：crylic acid to 1,6-hexanediol molar ratio = 3.5,catalyst loading = 7%,reaction temperature = 130 ℃ and reaction time = 3 h.The modified catalyst exhibited excellent reusability and after 10 cycles the conversion of 1,6-hexanediol was above 81%.展开更多
Lithium-ion conductor Liz.3Alo.3Ti1.7（P04）3 with an ultrapure NASICON-type phase is syn- thesized by a 1,2-propylene glycol （1,2-PG）-assisted sol-gel method and characterized by differential thermal analysis-therm...Lithium-ion conductor Liz.3Alo.3Ti1.7（P04）3 with an ultrapure NASICON-type phase is syn- thesized by a 1,2-propylene glycol （1,2-PG）-assisted sol-gel method and characterized by differential thermal analysis-thermo gravimetric analysis, X-ray diffraction, scanning elec- tron microscopy, electrochemical impedance spectroscopy, and chronoamperornetry test. Due to the use of 1,2-PG, a homogeneous and light yellow transparent precursor solu- tion is obtained without the precipitation of Ti4＋ and A13＋ with PO43- Well crystallized Lil.3Alo.3Til.7（PO4）3 can be prepared at much lower temperatures from 850 ~C to 950 ~C within a shorter synthesis time compared with that prepared at a temperature above 1000 ~C by a conventional solid-state reaction method. The lithium ionic conductivity of the sintered pellets is up to 0.3 mS/cm at 50 ℃ with an activation energy as low as 36.6 k J/tool for the specimen pre-sintered at 700 ℃ and sintered at 850 ℃. The high conductivity, good chemi- cal stability and easy fabrication of the Li1.3Al0.3Ti1.7（PO4）a provide a promising candidate as solid electrolyte for all-solid-state Li-ion rechargeable batteries.展开更多
基金Supported by the Scientific Research Project of Marine Public Welfare Industry of China(No.201205020-4)the Knowledge Innovation Project of Chinese Academy of Sciences(No.KSCX2-EW-G-12B)the Administration of Ocean and Fisheries of Guangdong Province(No.GD2012-D01-002)
文摘The industrially important organic compound 1,3-propanediol （1,3-PDO） is mainly used as a building block for the production of various polymers. In the present study, response surface methodology protocol was followed to determine and optimize fermentation conditions for the maximum production of 1,3-PDO using marine-derived Klebsiella pneumoniae HSL4. Four nutritional supplements together with three independent culture conditions were optimized as follows： 29.3 g/L glycerol, 8.0 g/L K2HPO4, 7.6 g/L （NH4）2SO4, 3.0 g/L KH2PO4, pH 7.1, cultivation at 35℃ for 12 h. Under the optimal conditions, a maximum 1,3-PDO concentration of 14.5 g/L, a productivity of 1.21 g/（L＇h） and a conversion of glycerol of 0.49 g/g were obtained. In comparison with the control conditions, fermentation under the optimized conditions achieved an increase of 38.8% in 1,3-PDO concentration, 39.0% in productivity and 25.7% in glycerol conversion in flask. This enhancement trend was further confirmed when the fermentation was conducted in a 5-L fermentor. The optimized fermentation conditions could be an important basis for developing low- cost, large-scale methods for industrial production of 1,3-PDO in the future.
基金Project(50834006) supported by National Natural of Science Foundation of China
文摘A new visual method for quantitative measurement of frothers effect and flotation efficiency was presented. A self-designed electrolytic cell was chosen as the reaction environment with sodium chloride (NaCl) as the electrolyte. Constant current, supplied by a self-designed power supplier and fixed cathode and anode equipment, guaranteed the constant bubble volume per unit time. Even aperture of the cathode material guaranteed the original bubbles size to be uniform. Bubble generating equipment was connected with a microscopical camera. Statistic data collected by high speed charge-coupled device (CCD) and processed by software Sigmascan and Matlab could reflect bubble characteristics. The efficiency of dipropylene glycol monomethyl ether (DPM) and tripropylene glycol n-butyl ethel (TPnB) were measured at the same condition, and 2×10-4 mol/L and 5×10-2 mol/L were found to be the inflexions of bubble size changes.
文摘A new solid acid catalyst,SO4^2-/TiO2 modified with tin,was prepared using a sol-gel method and its physicochemical properties were revealed by nitrogen adsorption-desorption,X-ray powder diffraction,scanning electron microscopy,Fourier transform infrared spectroscopy,infrared spectroscopy of adsorbed pyridine,temperature-programmed desorption of ammonia and thermal gravimetric analysis.The structure,acidity and thermal stability of the SO4^2-/TiO2-SnO2 catalyst were studied.Incorporating tin enlarged the specific surface area and decreased crystallite size of the SO4^2-/TiO2 catalyst.The total acid sites of the modified catalyst increased and Bronsted acid strength remarkably increased with increasing tin content.The decomposition temperature of sulfate radical in the modified catalyst was 100 ℃ greater and its mass loss was more than twice that of the SO4^2-/TiO2 catalyst.The SO4^2-/TiO2-SnO2 catalyst was designed to synthesize 1,6-hexanediol diacrylate by esterification of 1,6-hexanediol with crylic acid.The yield of 1,6-hexanediol diacrylate exceeded 87% under the optimal reaction conditions：crylic acid to 1,6-hexanediol molar ratio = 3.5,catalyst loading = 7%,reaction temperature = 130 ℃ and reaction time = 3 h.The modified catalyst exhibited excellent reusability and after 10 cycles the conversion of 1,6-hexanediol was above 81%.
文摘Lithium-ion conductor Liz.3Alo.3Ti1.7（P04）3 with an ultrapure NASICON-type phase is syn- thesized by a 1,2-propylene glycol （1,2-PG）-assisted sol-gel method and characterized by differential thermal analysis-thermo gravimetric analysis, X-ray diffraction, scanning elec- tron microscopy, electrochemical impedance spectroscopy, and chronoamperornetry test. Due to the use of 1,2-PG, a homogeneous and light yellow transparent precursor solu- tion is obtained without the precipitation of Ti4＋ and A13＋ with PO43- Well crystallized Lil.3Alo.3Til.7（PO4）3 can be prepared at much lower temperatures from 850 ~C to 950 ~C within a shorter synthesis time compared with that prepared at a temperature above 1000 ~C by a conventional solid-state reaction method. The lithium ionic conductivity of the sintered pellets is up to 0.3 mS/cm at 50 ℃ with an activation energy as low as 36.6 k J/tool for the specimen pre-sintered at 700 ℃ and sintered at 850 ℃. The high conductivity, good chemi- cal stability and easy fabrication of the Li1.3Al0.3Ti1.7（PO4）a provide a promising candidate as solid electrolyte for all-solid-state Li-ion rechargeable batteries.
