The hierarchical mesoporous Zn/ZSM-5 zeolite catalyst was prepared by NaOH treatment and Zn impregnation, and its application in the conversion of methanol to gasoline （MTG） was studied. N2 adsorption-desorption res...The hierarchical mesoporous Zn/ZSM-5 zeolite catalyst was prepared by NaOH treatment and Zn impregnation, and its application in the conversion of methanol to gasoline （MTG） was studied. N2 adsorption-desorption results showed that the mesopores with sizes of 2-20 nm in HZ5/0.3AT was formed by 0.3 M NaOH alkali treatment. The zeolite samples after modification were also characterized by XRF, AAS, XRD, SEM and NH3-TPD methods. Zn impregnated catalyst Zn/HZ5/0.3AT exhibited dramatic improvements in catalytic lifetime and liquid hydrocarbons yield. The selectivity of aromatic hydrocarbons was also improved after Zn impregnation. It is suggested that the mesopores of Zn/HZ5/0.3AT enhanced the synergetic effect of Zn species and acid sites and the capability to coke tolerance, which were confirmed by the results of catalytic test and TGA analysis, respectively.展开更多
Although prebiotic activities of alginate and agar oligosaccharides isolated from seaweeds have been reported, it remains unknown whether seaweed polysaccharides have prebiotic activity. In this study, we isolated pol...Although prebiotic activities of alginate and agar oligosaccharides isolated from seaweeds have been reported, it remains unknown whether seaweed polysaccharides have prebiotic activity. In this study, we isolated polysaccharides from four species of seaweeds, such as Grateloupia fi licina(GFP), Eucheuma spinosum(ESP), Ulva pertusa(UPP), and A scophyllum nodosum(ANP), and characterized their structures and prebiotic ef fects in vitro. The results showed that these polysaccharides were dif ferent in total sugar and sulfate contents as well as monosaccharide composition. GFP and ESP significantly promoted bifi dobacterium proliferation and 0.1% ESP and 0.4% GFP resulted in the highest proliferation rates of beneficial bacteria, whereas UPP and ANP inhibited the growth of beneficial bacteria at all tested concentrations(0.1%–0.5%). The different behaviors of the four seaweed-originated polysaccharides might be refl ected by differences in monosaccharide composition and structure. Therefore, polysaccharides isolated from GFP and ESP could be utilized as prebiotics. However, more studies must be carried out in vivo.展开更多
Chiral spirocyclic compounds have attracted the attention of scholars and scientists owing to their potential applications in the pharmaceutical industry as either active pharmaceutical ingredients, catalysts in synth...Chiral spirocyclic compounds have attracted the attention of scholars and scientists owing to their potential applications in the pharmaceutical industry as either active pharmaceutical ingredients, catalysts in synthesizing active enantiomers, or as surface modifiers on silica particles to resolve entantiomers. In this study, five spiro compounds of 3,9-diphenyl-2,4,8,10-tetraoxaspiro[5.5]-undecane（1）, 3,9-（4-methoxyphenyl）-2,4,8,10-tetraoxaspiro [5.5] -undecane（2）, 3,9-（4-methylphenyl）-2,4,8,10-tetraoxaspiro [5.5] -undecane（3）, 4,4＇-（2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl）dibenzoic acid（4） and 3,9-di（4-formyl-phenyl）-2,4,8,10-tetraoxa-spiro[5.5]-undecane（5） were synthesized by grinding pentaerythritol with benzaldehyde, 4-methoxybenzaldehyde, 4-methylbenzaldehyde, 4-carboxybenzaldehyde or terephthalaldehyde monoacetal in the presence of InI3r3 under solvent-free conditions. A normal phase HPLC method was successfully developed to resolve entantiomers of compounds 1--5 on a chiral column. Specific optical rotation of R or S entantiomers（1） was determined and the corresponding configurations were proposed based on Lowe＇s rule.展开更多
A non-dispersive extraction technique, using an emulsion liquid membrane within a hollow-fiber-contactor for the extraction and enrichment of Nd^3＋ from the dilute feed aqueous, was applied. The emulsion system is co...A non-dispersive extraction technique, using an emulsion liquid membrane within a hollow-fiber-contactor for the extraction and enrichment of Nd^3＋ from the dilute feed aqueous, was applied. The emulsion system is consisted of span80 [ sorbitian monooleate], paraffin oil, D2EHPA [ 2-（ 2-ethylhexyl- phosphonic acid）], kerosene as well as HCl solution. The extraction under various conditions such as the span80 concentrations, the flow rate of aqueous, the extraction time and HCl concentrations in receiving phase were studied. Results show that the lower the flow rates of aqueous are, the higher the extraction percentage and enrichment-fold are, and the extraction percentage increases with the increasing of HCl concentrations. When the initial Nd^3＋ concentration in feed is maintained at 1000 mg· L^-1 and the emulsion is recycled with 70 times by a counter-flow,展开更多
Partial oxidation of methane（POM） co-fed with CO_2 to syngas in a novel catalytic BaCo_（0.6）Fe_（0.2）Ta_（0.2）O_（3-δ） oxygen permeable membrane reactor was successfully reported.Adding CO_2 to the partial oxi...Partial oxidation of methane（POM） co-fed with CO_2 to syngas in a novel catalytic BaCo_（0.6）Fe_（0.2）Ta_（0.2）O_（3-δ） oxygen permeable membrane reactor was successfully reported.Adding CO_2 to the partial oxidation of methane reaction not only alters the ratio of CO/H_2,but also increases the oxygen permeation flux and CH_4 conversion.Around 96%CH_4 conversion with more than 93%CO_2 conversion and 100%CO selectivity is achieved,which shows an excellent reaction performance.A steady oxygen permeation flux of 15 mL/（cm^2 min） is obtained during the 100-h operation,which shows good stability as well.展开更多
A supramolecular inclusion complex between β-cyclodextrin（β-CD） and α-naphthylacetic acid was prepared, and its crystal structure was investigated by single-crystal X-ray crystallography. The complex contains two...A supramolecular inclusion complex between β-cyclodextrin（β-CD） and α-naphthylacetic acid was prepared, and its crystal structure was investigated by single-crystal X-ray crystallography. The complex contains two β-CD molecules, one α-naphthylacetic acid, two ethanols and twenty-eight water molecules in the asymmetric unit, which could be formulated as [（C42H70O35）2·（C12H10O2）·（C2H5OH）2·28H2O]. Two β-CD molecules constitute a dimer by face-to-face contact of their secondary hydroxyl sides. At the interface of the dimer, one α-naphthylacetic acid molecule is sandwiched between two β-CD molecules. Each β-CD unit of the dimer includes one ethanol molecule in its cavity. The β-CD dimers are linked together via hydrogen bonding to form layers that are stacked in a brickwork-like pattern. The comparative study of some sandwich complexes elucidates that the interface of the β-CD dimer has a stronger inclusion capacity than the cavity of β-CD for some suitable planar vip molecules. The novel inclusion structure results from the competitive inclusion of α-naphthylacetic acid and ethanol.展开更多
In the last few decades,nitroimidazoles have been investigated mostly due to their properties as antibiotics,radiosensitizers and anti-protozoans[1 -3].Recently these nitroimidazoles,such as 2,4-dinitroimidazole,1-met...In the last few decades,nitroimidazoles have been investigated mostly due to their properties as antibiotics,radiosensitizers and anti-protozoans[1 -3].Recently these nitroimidazoles,such as 2,4-dinitroimidazole,1-methyl-2,4,5-trinitroimidazole and their energetic salts, have attracted renewed attention for their favorable explosive performance as well as improved safety characteristics[4,5].Because of the activity of cyano group,2-nitro-4,5-dicyano-1 H-imidazole (NDCI) could be used as an intermediate in the synthesis of novel energetic materials containing nitroimidazole moiety.NDCI has been synthesized by the procedure given by Yixin Lu and coworkers[6],where the diazotization reaction and the Sandmeyer reaction were separately achieved.NDCI was obtained by adding a solution of sodium nitrite to 2-diazo4,5-dicyanoimidazole which was generated by diazotization of 2-amino-4,5-dicyano-1H-imidazole ( ADCI ) with sodium nitrite in water-hydrochloric acid and collected by filtration.Dry 2-diazo-4,5-dicyanoimidazole was so sensitive to shock that its separation may cause explosion[7].展开更多
Active attapulbgite as adsorptive reagent, the adsorptive behavior of Mn(II) and Zn(II) was studied with Flame atomic absorption spectroscopy (FAAS) method. The mainly factors of influencing the adsorption and desorpt...Active attapulbgite as adsorptive reagent, the adsorptive behavior of Mn(II) and Zn(II) was studied with Flame atomic absorption spectroscopy (FAAS) method. The mainly factors of influencing the adsorption and desorption of Mn(II) and Zn(II) were discussed. The interference of coexisting ions was investigated, and the actual sample determination from adzuki beans, mung beans and phosphating waste water was conducted with good result.展开更多
A new method for determination of Cu（Ⅱ） by DDCT chelating resin preconcentration and thin layer resin phase spectrophotometry was developed. The method has a high sensitivity （ε455= 3.6×10^5L/mol·cm）, ...A new method for determination of Cu（Ⅱ） by DDCT chelating resin preconcentration and thin layer resin phase spectrophotometry was developed. The method has a high sensitivity （ε455= 3.6×10^5L/mol·cm）, which is 33 times higher than that of liquid phase spectrophotometry. It has a good selectivity （most coexisting ions could not influence determination） and an ideal precision [30μg Cu（Ⅱ）, n=6, RSD= l.67%]. The content of Cu（Ⅱ） in water, high purity rare earth and its oxide was determined. The detection limit of Cu（Ⅱ） is 5.3μg/L , and the linear range is 0-7.2μg/ml. The result is satisfactory.展开更多
A new method for the determination of Fe by thin layer resin phase spectrophotometry in alkali condition was reported. The complex anion formed by Fe（Ⅱ） and VA was absorbed on the 717w resin and Fe was determined b...A new method for the determination of Fe by thin layer resin phase spectrophotometry in alkali condition was reported. The complex anion formed by Fe（Ⅱ） and VA was absorbed on the 717w resin and Fe was determined by making thin layer. This method had a high sensitivity （ε620= 3.0×10^5L/mol.cm）, which was 15 times higher than that of liquid phase spectrophotometry. It had been proved a satisfactory precision （5.01μg Fe, n=6, RSD=1.8%）. The trace Fe in natural water was determined and the recovery was 97%.展开更多
Three new cobalt（II） coordination compounds, [Co（3,3＇-Hbpt）2（H2pm）（H20）2]＇2H20 （1）, [Co（4,4＇-Hbpt）（pm）0.5（H20）]＇3H20 （2） and [Co（3,4＇-Hbpt）（pm）0.5（H20）3]＇2H20 （3） （3,3＇-Hbpt = 3,5-bis...Three new cobalt（II） coordination compounds, [Co（3,3＇-Hbpt）2（H2pm）（H20）2]＇2H20 （1）, [Co（4,4＇-Hbpt）（pm）0.5（H20）]＇3H20 （2） and [Co（3,4＇-Hbpt）（pm）0.5（H20）3]＇2H20 （3） （3,3＇-Hbpt = 3,5-bis（3-pyridyl）-lH-1,2,4-triazole; 4,4＇-bpt = 3,5-bis（4-pyridyl）- 1H-1,2,4-triazole, 3,4＇-Hbpt = 3-（3-pyridyl）-5-（4＇-pyridyl）-lH-1,2,4-triazole and Hapm = pyromellitic acid） have been synthe- sized by hydrothermal reactions. Single-crystal X-ray diffraction reveals that compound 1 has a one-dimensional （1D） chain network, 2 exhibits a four-connected three-dimensional （3D） structure with 1D open channels encapsulated by water molecules, while 3 displays a regular two-dimensional （2D） architecture connected through 1D metal helical chains. In addition, the effi- cacy of compounds 1-3 as additives to promote the thermal decomposition of ammonium perchlorate （AP） is explored by dif- ferential scanning calorimetry （DSC）.展开更多
基金supported by the Fundamental Research Funds for the Central Universities, HUST (No. Z2009008)the National Natural Science Foundation of China (No. 20973068)
文摘The hierarchical mesoporous Zn/ZSM-5 zeolite catalyst was prepared by NaOH treatment and Zn impregnation, and its application in the conversion of methanol to gasoline （MTG） was studied. N2 adsorption-desorption results showed that the mesopores with sizes of 2-20 nm in HZ5/0.3AT was formed by 0.3 M NaOH alkali treatment. The zeolite samples after modification were also characterized by XRF, AAS, XRD, SEM and NH3-TPD methods. Zn impregnated catalyst Zn/HZ5/0.3AT exhibited dramatic improvements in catalytic lifetime and liquid hydrocarbons yield. The selectivity of aromatic hydrocarbons was also improved after Zn impregnation. It is suggested that the mesopores of Zn/HZ5/0.3AT enhanced the synergetic effect of Zn species and acid sites and the capability to coke tolerance, which were confirmed by the results of catalytic test and TGA analysis, respectively.
基金Supported by the Commonwealth Item of the State Oceanic Administration of the People’s Republic of China(Nos.201405038-2,201505033)Qingdao People’s Livelihood Science and Technology Projects(No.16-6-2-41-nsh)
文摘Although prebiotic activities of alginate and agar oligosaccharides isolated from seaweeds have been reported, it remains unknown whether seaweed polysaccharides have prebiotic activity. In this study, we isolated polysaccharides from four species of seaweeds, such as Grateloupia fi licina(GFP), Eucheuma spinosum(ESP), Ulva pertusa(UPP), and A scophyllum nodosum(ANP), and characterized their structures and prebiotic ef fects in vitro. The results showed that these polysaccharides were dif ferent in total sugar and sulfate contents as well as monosaccharide composition. GFP and ESP significantly promoted bifi dobacterium proliferation and 0.1% ESP and 0.4% GFP resulted in the highest proliferation rates of beneficial bacteria, whereas UPP and ANP inhibited the growth of beneficial bacteria at all tested concentrations(0.1%–0.5%). The different behaviors of the four seaweed-originated polysaccharides might be refl ected by differences in monosaccharide composition and structure. Therefore, polysaccharides isolated from GFP and ESP could be utilized as prebiotics. However, more studies must be carried out in vivo.
基金the National Natural Science Foundation of China(No.20472064)the Natural Science Foundation of Tian- jin city, China(No.040884311)
文摘Chiral spirocyclic compounds have attracted the attention of scholars and scientists owing to their potential applications in the pharmaceutical industry as either active pharmaceutical ingredients, catalysts in synthesizing active enantiomers, or as surface modifiers on silica particles to resolve entantiomers. In this study, five spiro compounds of 3,9-diphenyl-2,4,8,10-tetraoxaspiro[5.5]-undecane（1）, 3,9-（4-methoxyphenyl）-2,4,8,10-tetraoxaspiro [5.5] -undecane（2）, 3,9-（4-methylphenyl）-2,4,8,10-tetraoxaspiro [5.5] -undecane（3）, 4,4＇-（2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl）dibenzoic acid（4） and 3,9-di（4-formyl-phenyl）-2,4,8,10-tetraoxa-spiro[5.5]-undecane（5） were synthesized by grinding pentaerythritol with benzaldehyde, 4-methoxybenzaldehyde, 4-methylbenzaldehyde, 4-carboxybenzaldehyde or terephthalaldehyde monoacetal in the presence of InI3r3 under solvent-free conditions. A normal phase HPLC method was successfully developed to resolve entantiomers of compounds 1--5 on a chiral column. Specific optical rotation of R or S entantiomers（1） was determined and the corresponding configurations were proposed based on Lowe＇s rule.
文摘A non-dispersive extraction technique, using an emulsion liquid membrane within a hollow-fiber-contactor for the extraction and enrichment of Nd^3＋ from the dilute feed aqueous, was applied. The emulsion system is consisted of span80 [ sorbitian monooleate], paraffin oil, D2EHPA [ 2-（ 2-ethylhexyl- phosphonic acid）], kerosene as well as HCl solution. The extraction under various conditions such as the span80 concentrations, the flow rate of aqueous, the extraction time and HCl concentrations in receiving phase were studied. Results show that the lower the flow rates of aqueous are, the higher the extraction percentage and enrichment-fold are, and the extraction percentage increases with the increasing of HCl concentrations. When the initial Nd^3＋ concentration in feed is maintained at 1000 mg· L^-1 and the emulsion is recycled with 70 times by a counter-flow,
基金the financial support by Natural Science Foundation of China(Nos.U0834004 and 20936001)the Science-Technology Plan of Guangzhou City(No.2009J1-C511-1)the Fundamental Research Funds for the Central Universities,SCUT(No.2009220038)
文摘Partial oxidation of methane（POM） co-fed with CO_2 to syngas in a novel catalytic BaCo_（0.6）Fe_（0.2）Ta_（0.2）O_（3-δ） oxygen permeable membrane reactor was successfully reported.Adding CO_2 to the partial oxidation of methane reaction not only alters the ratio of CO/H_2,but also increases the oxygen permeation flux and CH_4 conversion.Around 96%CH_4 conversion with more than 93%CO_2 conversion and 100%CO selectivity is achieved,which shows an excellent reaction performance.A steady oxygen permeation flux of 15 mL/（cm^2 min） is obtained during the 100-h operation,which shows good stability as well.
基金Supported by the Natural Science Foundation of Hainan Province, China(No.808145)the Doctoral Foundation of Hainan Normal University, China(No.103303)the Key Discipline of Hainan Province Organic Chemistry, China(No.006).
文摘A supramolecular inclusion complex between β-cyclodextrin（β-CD） and α-naphthylacetic acid was prepared, and its crystal structure was investigated by single-crystal X-ray crystallography. The complex contains two β-CD molecules, one α-naphthylacetic acid, two ethanols and twenty-eight water molecules in the asymmetric unit, which could be formulated as [（C42H70O35）2·（C12H10O2）·（C2H5OH）2·28H2O]. Two β-CD molecules constitute a dimer by face-to-face contact of their secondary hydroxyl sides. At the interface of the dimer, one α-naphthylacetic acid molecule is sandwiched between two β-CD molecules. Each β-CD unit of the dimer includes one ethanol molecule in its cavity. The β-CD dimers are linked together via hydrogen bonding to form layers that are stacked in a brickwork-like pattern. The comparative study of some sandwich complexes elucidates that the interface of the β-CD dimer has a stronger inclusion capacity than the cavity of β-CD for some suitable planar vip molecules. The novel inclusion structure results from the competitive inclusion of α-naphthylacetic acid and ethanol.
文摘In the last few decades,nitroimidazoles have been investigated mostly due to their properties as antibiotics,radiosensitizers and anti-protozoans[1 -3].Recently these nitroimidazoles,such as 2,4-dinitroimidazole,1-methyl-2,4,5-trinitroimidazole and their energetic salts, have attracted renewed attention for their favorable explosive performance as well as improved safety characteristics[4,5].Because of the activity of cyano group,2-nitro-4,5-dicyano-1 H-imidazole (NDCI) could be used as an intermediate in the synthesis of novel energetic materials containing nitroimidazole moiety.NDCI has been synthesized by the procedure given by Yixin Lu and coworkers[6],where the diazotization reaction and the Sandmeyer reaction were separately achieved.NDCI was obtained by adding a solution of sodium nitrite to 2-diazo4,5-dicyanoimidazole which was generated by diazotization of 2-amino-4,5-dicyano-1H-imidazole ( ADCI ) with sodium nitrite in water-hydrochloric acid and collected by filtration.Dry 2-diazo-4,5-dicyanoimidazole was so sensitive to shock that its separation may cause explosion[7].
基金Jiangsu University Scientific Research Funding (No. 04JDG017)
文摘Active attapulbgite as adsorptive reagent, the adsorptive behavior of Mn(II) and Zn(II) was studied with Flame atomic absorption spectroscopy (FAAS) method. The mainly factors of influencing the adsorption and desorption of Mn(II) and Zn(II) were discussed. The interference of coexisting ions was investigated, and the actual sample determination from adzuki beans, mung beans and phosphating waste water was conducted with good result.
文摘A new method for determination of Cu（Ⅱ） by DDCT chelating resin preconcentration and thin layer resin phase spectrophotometry was developed. The method has a high sensitivity （ε455= 3.6×10^5L/mol·cm）, which is 33 times higher than that of liquid phase spectrophotometry. It has a good selectivity （most coexisting ions could not influence determination） and an ideal precision [30μg Cu（Ⅱ）, n=6, RSD= l.67%]. The content of Cu（Ⅱ） in water, high purity rare earth and its oxide was determined. The detection limit of Cu（Ⅱ） is 5.3μg/L , and the linear range is 0-7.2μg/ml. The result is satisfactory.
文摘A new method for the determination of Fe by thin layer resin phase spectrophotometry in alkali condition was reported. The complex anion formed by Fe（Ⅱ） and VA was absorbed on the 717w resin and Fe was determined by making thin layer. This method had a high sensitivity （ε620= 3.0×10^5L/mol.cm）, which was 15 times higher than that of liquid phase spectrophotometry. It had been proved a satisfactory precision （5.01μg Fe, n=6, RSD=1.8%）. The trace Fe in natural water was determined and the recovery was 97%.
基金supported by the National Natural Science Foundation of China(21073142,21173168and21127004)the Natural Science Foundation of Shaanxi Province(SJ08B09)the Natural Science Foundation of the Department of Education of Shaanxi Province(2010JK882,2010JQ2007and11JS110)
文摘Three new cobalt（II） coordination compounds, [Co（3,3＇-Hbpt）2（H2pm）（H20）2]＇2H20 （1）, [Co（4,4＇-Hbpt）（pm）0.5（H20）]＇3H20 （2） and [Co（3,4＇-Hbpt）（pm）0.5（H20）3]＇2H20 （3） （3,3＇-Hbpt = 3,5-bis（3-pyridyl）-lH-1,2,4-triazole; 4,4＇-bpt = 3,5-bis（4-pyridyl）- 1H-1,2,4-triazole, 3,4＇-Hbpt = 3-（3-pyridyl）-5-（4＇-pyridyl）-lH-1,2,4-triazole and Hapm = pyromellitic acid） have been synthe- sized by hydrothermal reactions. Single-crystal X-ray diffraction reveals that compound 1 has a one-dimensional （1D） chain network, 2 exhibits a four-connected three-dimensional （3D） structure with 1D open channels encapsulated by water molecules, while 3 displays a regular two-dimensional （2D） architecture connected through 1D metal helical chains. In addition, the effi- cacy of compounds 1-3 as additives to promote the thermal decomposition of ammonium perchlorate （AP） is explored by dif- ferential scanning calorimetry （DSC）.
