Zeolite ZSM-5 has been synthesized with the organosilicon compound γ-aminopropyl triethoxylsilane as structure-directing agent using the composition 10SiO2: Al2O3: 3-5Na2O: 0. 1-0.5R: 40-100H2O(molar ratios). First o...Zeolite ZSM-5 has been synthesized with the organosilicon compound γ-aminopropyl triethoxylsilane as structure-directing agent using the composition 10SiO2: Al2O3: 3-5Na2O: 0. 1-0.5R: 40-100H2O(molar ratios). First of all, γ-aminopropyl triethoxylsilane was quaternarized with bromoethane and ethyl alcohol. XRD, TG, DTA and SEM were used to characterize the sample. The investigation proves that the organosilicon compound resides intact at the channel intersections, and that the silicon atom In this species is located in a framework position. Prehydrolysis of the organosilane precursor is necessary for zeolite formation.展开更多
氨基酸稳定氮同位素(δ^(15)N)分析能准确有效地评估生物体的营养级以及氮在食物链中的流动。本研究优化了氨基酸氮同位素的分析方法:样品在酸性条件下水解后,释放出的蛋白质氨基酸经阳离子交换树脂纯化后,衍生为对应的N-新戊酰基,O-异...氨基酸稳定氮同位素(δ^(15)N)分析能准确有效地评估生物体的营养级以及氮在食物链中的流动。本研究优化了氨基酸氮同位素的分析方法:样品在酸性条件下水解后,释放出的蛋白质氨基酸经阳离子交换树脂纯化后,衍生为对应的N-新戊酰基,O-异丙醇(N-pivaloyl-isopropyl,NPP)酯,利用气相色谱-燃烧-同位素比值质谱仪(Gas chromatography-combustion-isotope ratio mass spectrometry,GC-C-IRMS)测定其δ^(15)N。经非极性气相色谱柱DB-5ms分离后,13种氨基酸NPP酯衍生物均可得到良好的基线分离。在样品量不低于20 ng N条件下,GC-C-IRMS方法的精密度优于1‰,测得的δ^(15)N值与EA-IRMS法测得的δ^(15)N值没有明显差异。阳离子树脂纯化前后各氨基酸δ^(15)N值差异低于1‰,表明没有产生明显的同位素分馏。采用本方法成功地估算了阿哈湖生态系统中常见水生生物的营养级,可作为研究氨基酸代谢以及生态系统特征的新方法。展开更多
Using amino-poly(ethylene glycol) and amino-propyl silica gel as initiator cores, two dendrimers were prepared by a two-step procedure. The progress of dendrimers during each step was monitored by infrared spectroscop...Using amino-poly(ethylene glycol) and amino-propyl silica gel as initiator cores, two dendrimers were prepared by a two-step procedure. The progress of dendrimers during each step was monitored by infrared spectroscopy and elemental analysis. Papain was crosslinked to the solid dendrimer with silica gel core by glutaraldehyde, and the enzymatic activity of the immobilized papain kept almost unchanged after repeated usage for fifteen times.展开更多
A simple and efficient procedure for the preparation of silica-bound N-propyl triethylenetetramine sulfamic acid(SBPTETSA) by the reaction of silica-bound N-propyl triethylenetetramine(SBPTET) with chlorosulfonic acid...A simple and efficient procedure for the preparation of silica-bound N-propyl triethylenetetramine sulfamic acid(SBPTETSA) by the reaction of silica-bound N-propyl triethylenetetramine(SBPTET) with chlorosulfonic acid in chloroform is described.Silica-bound N-propyl triethylenetetramine sulfamic acid was employed as a recyclable catalyst for the synthesis of 2-amino-4,6-diarylnicotinonitriles from the multi-component reaction of an acetophenone derivative,an aromatic aldehyde,malononitrile,and ammonium acetate under solvent-free conditions at 100 °C.The heterogeneous catalyst was recycled for five consecutive runs in the optimized multi-component reaction of 4-chloroacetophenone,4-chloroenzaldehyde,malononitrile,and ammonium acetate without significant loses to its catalytic activity.展开更多
文摘Zeolite ZSM-5 has been synthesized with the organosilicon compound γ-aminopropyl triethoxylsilane as structure-directing agent using the composition 10SiO2: Al2O3: 3-5Na2O: 0. 1-0.5R: 40-100H2O(molar ratios). First of all, γ-aminopropyl triethoxylsilane was quaternarized with bromoethane and ethyl alcohol. XRD, TG, DTA and SEM were used to characterize the sample. The investigation proves that the organosilicon compound resides intact at the channel intersections, and that the silicon atom In this species is located in a framework position. Prehydrolysis of the organosilane precursor is necessary for zeolite formation.
文摘氨基酸稳定氮同位素(δ^(15)N)分析能准确有效地评估生物体的营养级以及氮在食物链中的流动。本研究优化了氨基酸氮同位素的分析方法:样品在酸性条件下水解后,释放出的蛋白质氨基酸经阳离子交换树脂纯化后,衍生为对应的N-新戊酰基,O-异丙醇(N-pivaloyl-isopropyl,NPP)酯,利用气相色谱-燃烧-同位素比值质谱仪(Gas chromatography-combustion-isotope ratio mass spectrometry,GC-C-IRMS)测定其δ^(15)N。经非极性气相色谱柱DB-5ms分离后,13种氨基酸NPP酯衍生物均可得到良好的基线分离。在样品量不低于20 ng N条件下,GC-C-IRMS方法的精密度优于1‰,测得的δ^(15)N值与EA-IRMS法测得的δ^(15)N值没有明显差异。阳离子树脂纯化前后各氨基酸δ^(15)N值差异低于1‰,表明没有产生明显的同位素分馏。采用本方法成功地估算了阿哈湖生态系统中常见水生生物的营养级,可作为研究氨基酸代谢以及生态系统特征的新方法。
文摘Using amino-poly(ethylene glycol) and amino-propyl silica gel as initiator cores, two dendrimers were prepared by a two-step procedure. The progress of dendrimers during each step was monitored by infrared spectroscopy and elemental analysis. Papain was crosslinked to the solid dendrimer with silica gel core by glutaraldehyde, and the enzymatic activity of the immobilized papain kept almost unchanged after repeated usage for fifteen times.
基金supported by Persian Gulf University Research Council(PGU/FS/6-1/1390/705)
文摘A simple and efficient procedure for the preparation of silica-bound N-propyl triethylenetetramine sulfamic acid(SBPTETSA) by the reaction of silica-bound N-propyl triethylenetetramine(SBPTET) with chlorosulfonic acid in chloroform is described.Silica-bound N-propyl triethylenetetramine sulfamic acid was employed as a recyclable catalyst for the synthesis of 2-amino-4,6-diarylnicotinonitriles from the multi-component reaction of an acetophenone derivative,an aromatic aldehyde,malononitrile,and ammonium acetate under solvent-free conditions at 100 °C.The heterogeneous catalyst was recycled for five consecutive runs in the optimized multi-component reaction of 4-chloroacetophenone,4-chloroenzaldehyde,malononitrile,and ammonium acetate without significant loses to its catalytic activity.
