A novel fibrous silica Y zeolite (HSi@Y) loaded with Pt has been studied based on its ability to produce protonic acid sites originating from molecular hydrogen. The Pt/HSi@Y was prepared using seed assisted crystalli...A novel fibrous silica Y zeolite (HSi@Y) loaded with Pt has been studied based on its ability to produce protonic acid sites originating from molecular hydrogen. The Pt/HSi@Y was prepared using seed assisted crystallization followed by protonation and Pt-loading. The product formed had a spherical morphology with bicontinuous lamellar with a diameter in the range of 500-700 nm. The catalytic activity of the Pt/HSi@Y has been assessed based on light linear alkane (C5-C7) isomerization in a micro-catalytic pulse reactor at 423-623 K. A pyridine IR study confirmed that the introduction of fibrous silica on Y zeolite increased the Lewis acid sites corresponding with the formation of extra-framework Al which led to the generation of more protonic acid sites. A hydrogen adsorbed IR study showed that the protonic acid sites which act as active sites in the isomerization were formed via dissociative-adsorption of molecular hydrogen releasing electrons to the nearby Lewis acid sites. Thus, it is suggested that the presence of Pt and HSi@Y with a high number of Lewis acid as well as weak Bronsted acid sites improved the activity and stability in C5, C6 and C7 isomerization via hydrogen spill-over mechanism.展开更多
The results of commercial application of two types of C_8 aromatics isomerization catalysts under different feed conditions were compared to gain an insight in the techno-economical basis for selecting proper technolo...The results of commercial application of two types of C_8 aromatics isomerization catalysts under different feed conditions were compared to gain an insight in the techno-economical basis for selecting proper technological route at the plant.The comparison reveals differences in every aspect of feed consumption,unit capacity,product output,product distribution,and unit process parameters depending upon which catalyst type is adopted by the integrated PX complex.The type of aromatics isomerization catalyst has its influence on the plant scale,the construction cost,the process unit capacity and the product cost,with the magnitude of its impact varying with changing feed conditions.展开更多
The isomerization of n-pentane to generate high-quality blending components for clean gasoline was catalyzed by several amide-AlCl3-based ionic liquid(IL) analogs with various amides as donor molecules. The catalytic ...The isomerization of n-pentane to generate high-quality blending components for clean gasoline was catalyzed by several amide-AlCl3-based ionic liquid(IL) analogs with various amides as donor molecules. The catalytic performance of these IL analogs was evaluated in a magnetic agitated autoclave operated in batch mode.IL analog based n-methylacetamide(NMA)-AlCl3 with the amide/AlCl3 molar ratio of 0.65 showed excellent performance toward n-pentane isomerization because 0.65 NMA-1.0 AlCl3 had a low viscosity and bidentate coordination structure. The influences of reaction time, reaction temperature, and stirring speed on the catalytic performance were also investigated. Optimal reaction conditions comprised the reaction time of 1 h, the reaction temperature of 40 °C, and the stirring speed of 1500 r·min-1. Under optimal condition, the n-C5 conversion,research octane number(RON) increment, total liquids yield, and isoparaffin yield in isomerized oil were56.80%, 13.51, 89.90 wt%, and 44.32 wt%, respectively. A new mathematical model was constructed to predict the relationships among RON increment, RON increment/n-C5 conversion ratio, and n-C5 conversion. The new model indicated that an appropriate conversion per pass of n-C5 did not exceed 50%–55%. Various cycloparaffin additives were used to improve the catalytic performance of 0.65 NMA-1.0 AlCl3. The n-C5 conversion increased from 56.80% to 67.32%. The RON increment, total liquids yield, and isoparaffin yield reached 17.83, 97.36 wt%,and 63.74 wt%, respectively.展开更多
The SiO2 and g-Al2O3 supported MoOx catalyst and a MoOx-SiO2 catalyst have been studied in a conventional fixed-bed flow reactor for n-alkanes isomerization. It is shown that the MoOx-SiO2 catalyst with SiO2 framewor...The SiO2 and g-Al2O3 supported MoOx catalyst and a MoOx-SiO2 catalyst have been studied in a conventional fixed-bed flow reactor for n-alkanes isomerization. It is shown that the MoOx-SiO2 catalyst with SiO2 framework, in which the bulk MoOx phase is large enough to form typical mesoporous structure, is promising in terms of its advantages of both improved mechanical strength and high catalytic properties over the supported MoOx and bulk MoOx catalyst.展开更多
The unsaturated germylenoid H2C=GeLiF has been studied by using DFT method at the B3LYP/6-311＋G （d, p） level. Geometry optimization calculations indicate that H2C=GeLiF has three equilibrium configurations, in whic...The unsaturated germylenoid H2C=GeLiF has been studied by using DFT method at the B3LYP/6-311＋G （d, p） level. Geometry optimization calculations indicate that H2C=GeLiF has three equilibrium configurations, in which the p-complex is the lowest in energy and the most stable structure. Two transition states for isomerization reactions of H2C=GeLiF are located and the energy barriers are calculated. For the most stable one, vibrational frequencies and infrared intensities have been predicted.展开更多
The catalyst NiW/HSAPO-11 was prepared by impregnating Ni and W onto HSAPO-11 zeolite with two different methods. The isomerization and aromatization properties were investigated with an microreactor using n-octane ...The catalyst NiW/HSAPO-11 was prepared by impregnating Ni and W onto HSAPO-11 zeolite with two different methods. The isomerization and aromatization properties were investigated with an microreactor using n-octane as a feedstock. NiW/HSAPO-11 shows a high hydroconversion activity of n-octane, and the optimum operating parameters for the catalyst to produce high octane number products were: 400℃, 2.0MPa, VH2:Vn-octane= 400:1, liquid hourly space velocity LHSV=1.0h-1. Under the optimum reaction condition, the conversion efficiency, C5 liquid + product selectivity, isomerization and aromatization product selectivity were 69.80%, 56.95%, 79.73% and 1.29% respectively. The catalyst (S1) impregnated with Ni and W after the HSAPO-11 zeolite was combined with Al2O3 matrix, performed better than the catalyst (S2) impregnated with Ni and W before combining with the Al2O3 matrix.展开更多
The mechanism and related reaction paths in the hydroisomerization of n-pentane were studied by DFT calculations at the B3LYP/6-311＋＋G^＊＊ level. Two possible transition states were theoretically predicted and ve...The mechanism and related reaction paths in the hydroisomerization of n-pentane were studied by DFT calculations at the B3LYP/6-311＋＋G^＊＊ level. Two possible transition states were theoretically predicted and verified by the vibration frequency analysis as well as the calculations of intrinsic reaction coordinates （IRC）. Furthermore, the related reaction barriers were evaluated by single point energy at the MP2/6-311＋＋G^＊＊ level with zero point vibration correction of DFT method. Thus, it is concluded that the isomerization might go through two pathways.展开更多
The effect of iridium loading on the properties and catalytic isomerization of n-heptane over Ir-HZSM-5 is studied. Ir-HZSM-5 was prepared by impregnation method and subjected to isomerization process in the presence ...The effect of iridium loading on the properties and catalytic isomerization of n-heptane over Ir-HZSM-5 is studied. Ir-HZSM-5 was prepared by impregnation method and subjected to isomerization process in the presence of flowing hydrogen gas. XRD and BET studies show that the presence of iridium stabilizes the crystalline structure of HZSM-5, leading to more ordered framework structure and larger surface area. TGA and FTIR results substantiate that iridium species interacts with OH group on the surface of HZSM-5. Pyridine FT-IR study verifies the interaction between iridium and surface OH group slightly increased the Bro¨nsted and Lewis acid sites without changing the lattice structure of HZSM-5. The presence of iridium and the increase of strong Lewis acid sites on HZSM-5 were found to bring an increase about 4.1%, 33.2% and 11.8% in conversion, selectivity and yield of n-heptane isomerization, respectively.展开更多
A solid superacid catalyst Pt-SO42-/ZrO2-A12O3 for n-pentane isomerization, was prepared by incipient-wetness impregnation. Preparetion conditions, namely, calcination temperature, concentration of sulfuric acid solut...A solid superacid catalyst Pt-SO42-/ZrO2-A12O3 for n-pentane isomerization, was prepared by incipient-wetness impregnation. Preparetion conditions, namely, calcination temperature, concentration of sulfuric acid solution used in impregnation and Al2O3 concentration, were varied to investigate the effects on catalytic performance of Pt-SO42-/ZrO2-A12O3. The results showed that the PtSZA catalyst exhibited excellent catalytic performance for n-pentane isomerization. Under optimized preparation conditions of calcination temperature of 650°C, reaction time for 3 h, concentration of sulfuric acid solution for 0.5 mol/L, 30% of Al2O3 concentration and 0.3% of Pt concentration, the n-pentane conversion and isopentane selectivity of Pt-SO42-/ZrO2-A12O3 could reach up to 62.17% and 91.60%, respectively.展开更多
Ni/PtHY with different Ni loadings was prepared by impregnating HY with hexachloroplatinic acid solution and Ni2＋/N,N-dimethylformamide solution. An increase in the Ni loading decreased the crystallinity, specific su...Ni/PtHY with different Ni loadings was prepared by impregnating HY with hexachloroplatinic acid solution and Ni2＋/N,N-dimethylformamide solution. An increase in the Ni loading decreased the crystallinity, specific surface area and meso-micropores of the catalysts. Ni interacted with hydroxyl groups to produce IR absorption bands at 3740-3500 cm-1, Increasing Ni loadings resulted in a decrease in the intensities of the broad bands at 3730-3500 cm-1 and the sharp band at 3740 cm-1 with simultaneous development of new absorbance band at 3700 cm-1 that was attributed to （-OH）Ni. The acidity of the samples did not significantly change with Ni loadings up to 1.0 wt%, which indicated that Ni mostly interacts with non-acidic silanol groups （terminal- and structural-defect OH groups）. The presence of Ni decreased the activity of PtHY toward the isomerization of n-pentane because of a decrease in the number of active protonic-acid sites that formed from molecular hydrogen. IR and ESR studies confirmed that Pt facilitated the formation of protonic-acid sites from molecular hydrogen, whereas Ni, even when combined with Pt, didn＇t exhibit such ability. The absence of protonic-acid sites from molecular hydrogen significantly decreased the yield of iso-pentane and markedly increased the cracking products.展开更多
The effect of sulfate ion （SO4^2-） loading on the properties of Pt/SO4^2-ZrO2 and on the catalytic isomerization of n-butane to/so-butane was studied. The catalyst was prepared by impregnation of Zr（OH）4 with H2SO...The effect of sulfate ion （SO4^2-） loading on the properties of Pt/SO4^2-ZrO2 and on the catalytic isomerization of n-butane to/so-butane was studied. The catalyst was prepared by impregnation of Zr（OH）4 with H2SO4 and platinum solution followed by calcination at 600 ℃. Ammonia TPD and FT-IR were used to confirm the distribution of acid sites and the structure of the sulfate species. Nitrogen physisorption and X-ray diffraction were used to confirm the physical structures of Pt/SO4^2-ZrO2. XRD pattern showed that the presence of sulfate ion stabilized the metastable tetragonal phase of zirconia and hindered the transition of amorphous phase to monoclinic phase of zirconia. Ammonia TPD profiles indicated the distributions of weak and medium acid sites observed on 0.1 N and 1.0 N sulfate in the loaded catalysts. The addition of 2.0 N and 4.0 N sulfate ion generated strong acid site and decreased the weak and medium acid sites. However, the XRD results and the specific surface area of the catalysts indicated that the excessive amount of sulfate ion collapsed the structure of the catalyst. The catalysts showed high activity and stability for isomerization of n-butane to iso-butane at 200 ℃ under hydrogen atmosphere. The conversion of n-butane to iso-butane per specific surface area of the catalyst increased with the increasing amount of sulfate ion owing to the existence of the bidentate sulfate and/or polynucleic sulfate species （（ZrO）2SO2）, which acts as an active site for the isomerization.展开更多
Highly active solid superacid catalysts for n-butane isomerization, SZ/A1_2O_3-P, were prepared by supporting SO-(4-2)/ZrO2, (SZ) on y-A1_2O_3 carrier using a precipitation method. The activities of some catalysts wer...Highly active solid superacid catalysts for n-butane isomerization, SZ/A1_2O_3-P, were prepared by supporting SO-(4-2)/ZrO2, (SZ) on y-A1_2O_3 carrier using a precipitation method. The activities of some catalysts were enhanced significantly j The activity of the most active sample. 60%SZ/Al_2O3-P, was even about 2 times more active than that of the SZ catalyst.展开更多
This article describes the physico-chemical characterization of the sulfated zirconia catalysts prepared from zirconyl chloride, acetic acid and ammonium persulfate system under structure-directing-free and calcined a...This article describes the physico-chemical characterization of the sulfated zirconia catalysts prepared from zirconyl chloride, acetic acid and ammonium persulfate system under structure-directing-free and calcined at 650°C. The catalysts were characterized via an array of characterization techniques such as surface acidity and texture measurements, X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-VIS), scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDXS), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IR), thermogravimetric measurement (TG) coupled with a quadrupole mass spectrometer (MS), inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and/or mass spectrometry (ICP-MS). It is clear from TG-MS, ICP-AES, and IR analyses that the precursor of the catalyst is a sulphur species-doped zirconium oxy-hydroxyl acetate complex. The presence of zirconium-bound sulfate groups results in the superacidity of the catalyst and hence high activity in n-hexane isomerization. It is shown from nitrogen adsorption and desorption, FESEM, and HRTEM measurements that the materials exhibit mesoporous and nanocrystalline structure.展开更多
基金supported by the Universiti Teknologi Malaysia through Research University Grant No. 13H61 and 19H04
文摘A novel fibrous silica Y zeolite (HSi@Y) loaded with Pt has been studied based on its ability to produce protonic acid sites originating from molecular hydrogen. The Pt/HSi@Y was prepared using seed assisted crystallization followed by protonation and Pt-loading. The product formed had a spherical morphology with bicontinuous lamellar with a diameter in the range of 500-700 nm. The catalytic activity of the Pt/HSi@Y has been assessed based on light linear alkane (C5-C7) isomerization in a micro-catalytic pulse reactor at 423-623 K. A pyridine IR study confirmed that the introduction of fibrous silica on Y zeolite increased the Lewis acid sites corresponding with the formation of extra-framework Al which led to the generation of more protonic acid sites. A hydrogen adsorbed IR study showed that the protonic acid sites which act as active sites in the isomerization were formed via dissociative-adsorption of molecular hydrogen releasing electrons to the nearby Lewis acid sites. Thus, it is suggested that the presence of Pt and HSi@Y with a high number of Lewis acid as well as weak Bronsted acid sites improved the activity and stability in C5, C6 and C7 isomerization via hydrogen spill-over mechanism.
文摘The results of commercial application of two types of C_8 aromatics isomerization catalysts under different feed conditions were compared to gain an insight in the techno-economical basis for selecting proper technological route at the plant.The comparison reveals differences in every aspect of feed consumption,unit capacity,product output,product distribution,and unit process parameters depending upon which catalyst type is adopted by the integrated PX complex.The type of aromatics isomerization catalyst has its influence on the plant scale,the construction cost,the process unit capacity and the product cost,with the magnitude of its impact varying with changing feed conditions.
基金Supported by the National Natural Science Foundation of China(21802047)the Scientific Research Funds of Huaqiao University(600005-Z17Y0073).
文摘The isomerization of n-pentane to generate high-quality blending components for clean gasoline was catalyzed by several amide-AlCl3-based ionic liquid(IL) analogs with various amides as donor molecules. The catalytic performance of these IL analogs was evaluated in a magnetic agitated autoclave operated in batch mode.IL analog based n-methylacetamide(NMA)-AlCl3 with the amide/AlCl3 molar ratio of 0.65 showed excellent performance toward n-pentane isomerization because 0.65 NMA-1.0 AlCl3 had a low viscosity and bidentate coordination structure. The influences of reaction time, reaction temperature, and stirring speed on the catalytic performance were also investigated. Optimal reaction conditions comprised the reaction time of 1 h, the reaction temperature of 40 °C, and the stirring speed of 1500 r·min-1. Under optimal condition, the n-C5 conversion,research octane number(RON) increment, total liquids yield, and isoparaffin yield in isomerized oil were56.80%, 13.51, 89.90 wt%, and 44.32 wt%, respectively. A new mathematical model was constructed to predict the relationships among RON increment, RON increment/n-C5 conversion ratio, and n-C5 conversion. The new model indicated that an appropriate conversion per pass of n-C5 did not exceed 50%–55%. Various cycloparaffin additives were used to improve the catalytic performance of 0.65 NMA-1.0 AlCl3. The n-C5 conversion increased from 56.80% to 67.32%. The RON increment, total liquids yield, and isoparaffin yield reached 17.83, 97.36 wt%,and 63.74 wt%, respectively.
文摘The SiO2 and g-Al2O3 supported MoOx catalyst and a MoOx-SiO2 catalyst have been studied in a conventional fixed-bed flow reactor for n-alkanes isomerization. It is shown that the MoOx-SiO2 catalyst with SiO2 framework, in which the bulk MoOx phase is large enough to form typical mesoporous structure, is promising in terms of its advantages of both improved mechanical strength and high catalytic properties over the supported MoOx and bulk MoOx catalyst.
基金Supported by NNSFC (20473029)the Fund for Doctor of Yantai University (HY05B30)the Open Project Program of Key Laboratory for Supramolecular Structure and Materials of Ministry of Education, Jilin University
文摘The unsaturated germylenoid H2C=GeLiF has been studied by using DFT method at the B3LYP/6-311＋G （d, p） level. Geometry optimization calculations indicate that H2C=GeLiF has three equilibrium configurations, in which the p-complex is the lowest in energy and the most stable structure. Two transition states for isomerization reactions of H2C=GeLiF are located and the energy barriers are calculated. For the most stable one, vibrational frequencies and infrared intensities have been predicted.
文摘The catalyst NiW/HSAPO-11 was prepared by impregnating Ni and W onto HSAPO-11 zeolite with two different methods. The isomerization and aromatization properties were investigated with an microreactor using n-octane as a feedstock. NiW/HSAPO-11 shows a high hydroconversion activity of n-octane, and the optimum operating parameters for the catalyst to produce high octane number products were: 400℃, 2.0MPa, VH2:Vn-octane= 400:1, liquid hourly space velocity LHSV=1.0h-1. Under the optimum reaction condition, the conversion efficiency, C5 liquid + product selectivity, isomerization and aromatization product selectivity were 69.80%, 56.95%, 79.73% and 1.29% respectively. The catalyst (S1) impregnated with Ni and W after the HSAPO-11 zeolite was combined with Al2O3 matrix, performed better than the catalyst (S2) impregnated with Ni and W before combining with the Al2O3 matrix.
基金Supported by the Foundation of Education Committee of Liaoning Province (No. 990321076)
文摘The mechanism and related reaction paths in the hydroisomerization of n-pentane were studied by DFT calculations at the B3LYP/6-311＋＋G^＊＊ level. Two possible transition states were theoretically predicted and verified by the vibration frequency analysis as well as the calculations of intrinsic reaction coordinates （IRC）. Furthermore, the related reaction barriers were evaluated by single point energy at the MP2/6-311＋＋G^＊＊ level with zero point vibration correction of DFT method. Thus, it is concluded that the isomerization might go through two pathways.
基金supported by the Ministry of Science,Technology and Innovation,Malaysia through E-Science Fund Research Project(No.03-01-06-SF0564 and 03-01-06-SF0289)the Hitachi Scholarship Foundation for the Gas Chromatograph Instrument Grant
文摘The effect of iridium loading on the properties and catalytic isomerization of n-heptane over Ir-HZSM-5 is studied. Ir-HZSM-5 was prepared by impregnation method and subjected to isomerization process in the presence of flowing hydrogen gas. XRD and BET studies show that the presence of iridium stabilizes the crystalline structure of HZSM-5, leading to more ordered framework structure and larger surface area. TGA and FTIR results substantiate that iridium species interacts with OH group on the surface of HZSM-5. Pyridine FT-IR study verifies the interaction between iridium and surface OH group slightly increased the Bro¨nsted and Lewis acid sites without changing the lattice structure of HZSM-5. The presence of iridium and the increase of strong Lewis acid sites on HZSM-5 were found to bring an increase about 4.1%, 33.2% and 11.8% in conversion, selectivity and yield of n-heptane isomerization, respectively.
文摘A solid superacid catalyst Pt-SO42-/ZrO2-A12O3 for n-pentane isomerization, was prepared by incipient-wetness impregnation. Preparetion conditions, namely, calcination temperature, concentration of sulfuric acid solution used in impregnation and Al2O3 concentration, were varied to investigate the effects on catalytic performance of Pt-SO42-/ZrO2-A12O3. The results showed that the PtSZA catalyst exhibited excellent catalytic performance for n-pentane isomerization. Under optimized preparation conditions of calcination temperature of 650°C, reaction time for 3 h, concentration of sulfuric acid solution for 0.5 mol/L, 30% of Al2O3 concentration and 0.3% of Pt concentration, the n-pentane conversion and isopentane selectivity of Pt-SO42-/ZrO2-A12O3 could reach up to 62.17% and 91.60%, respectively.
基金supported by the Ministry of Higher Education, Malaysia through Fundamental Research (Grant Scheme No. 78670)the UTM Short Term Research (Grant No. 77330)
文摘Ni/PtHY with different Ni loadings was prepared by impregnating HY with hexachloroplatinic acid solution and Ni2＋/N,N-dimethylformamide solution. An increase in the Ni loading decreased the crystallinity, specific surface area and meso-micropores of the catalysts. Ni interacted with hydroxyl groups to produce IR absorption bands at 3740-3500 cm-1, Increasing Ni loadings resulted in a decrease in the intensities of the broad bands at 3730-3500 cm-1 and the sharp band at 3740 cm-1 with simultaneous development of new absorbance band at 3700 cm-1 that was attributed to （-OH）Ni. The acidity of the samples did not significantly change with Ni loadings up to 1.0 wt%, which indicated that Ni mostly interacts with non-acidic silanol groups （terminal- and structural-defect OH groups）. The presence of Ni decreased the activity of PtHY toward the isomerization of n-pentane because of a decrease in the number of active protonic-acid sites that formed from molecular hydrogen. IR and ESR studies confirmed that Pt facilitated the formation of protonic-acid sites from molecular hydrogen, whereas Ni, even when combined with Pt, didn＇t exhibit such ability. The absence of protonic-acid sites from molecular hydrogen significantly decreased the yield of iso-pentane and markedly increased the cracking products.
文摘The effect of sulfate ion （SO4^2-） loading on the properties of Pt/SO4^2-ZrO2 and on the catalytic isomerization of n-butane to/so-butane was studied. The catalyst was prepared by impregnation of Zr（OH）4 with H2SO4 and platinum solution followed by calcination at 600 ℃. Ammonia TPD and FT-IR were used to confirm the distribution of acid sites and the structure of the sulfate species. Nitrogen physisorption and X-ray diffraction were used to confirm the physical structures of Pt/SO4^2-ZrO2. XRD pattern showed that the presence of sulfate ion stabilized the metastable tetragonal phase of zirconia and hindered the transition of amorphous phase to monoclinic phase of zirconia. Ammonia TPD profiles indicated the distributions of weak and medium acid sites observed on 0.1 N and 1.0 N sulfate in the loaded catalysts. The addition of 2.0 N and 4.0 N sulfate ion generated strong acid site and decreased the weak and medium acid sites. However, the XRD results and the specific surface area of the catalysts indicated that the excessive amount of sulfate ion collapsed the structure of the catalyst. The catalysts showed high activity and stability for isomerization of n-butane to iso-butane at 200 ℃ under hydrogen atmosphere. The conversion of n-butane to iso-butane per specific surface area of the catalyst increased with the increasing amount of sulfate ion owing to the existence of the bidentate sulfate and/or polynucleic sulfate species （（ZrO）2SO2）, which acts as an active site for the isomerization.
文摘Highly active solid superacid catalysts for n-butane isomerization, SZ/A1_2O_3-P, were prepared by supporting SO-(4-2)/ZrO2, (SZ) on y-A1_2O_3 carrier using a precipitation method. The activities of some catalysts were enhanced significantly j The activity of the most active sample. 60%SZ/Al_2O3-P, was even about 2 times more active than that of the SZ catalyst.
文摘This article describes the physico-chemical characterization of the sulfated zirconia catalysts prepared from zirconyl chloride, acetic acid and ammonium persulfate system under structure-directing-free and calcined at 650°C. The catalysts were characterized via an array of characterization techniques such as surface acidity and texture measurements, X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-VIS), scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDXS), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IR), thermogravimetric measurement (TG) coupled with a quadrupole mass spectrometer (MS), inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and/or mass spectrometry (ICP-MS). It is clear from TG-MS, ICP-AES, and IR analyses that the precursor of the catalyst is a sulphur species-doped zirconium oxy-hydroxyl acetate complex. The presence of zirconium-bound sulfate groups results in the superacidity of the catalyst and hence high activity in n-hexane isomerization. It is shown from nitrogen adsorption and desorption, FESEM, and HRTEM measurements that the materials exhibit mesoporous and nanocrystalline structure.
文摘目的分析体质量指数(Body mass index,BMI)与老年慢性心力衰竭(Chronic heart failure,CHF)患者血浆胱抑素C(cystatinC,Cys-C)、N末端B型利钠肽原(N-terminal pro-B-type natriuretic peptide,NT-proBNP)水平相关性,并分析血浆Cys-C、NT-proBNP评估老年CHF患者预后价值。方法选择2021年7月—2022年10月在本院接受治疗的192例老年慢性心力衰竭(CHF)患者作为研究对象,按照BMI指数分为肥胖组(49例)、超重组(68例)和正常组(75例)三组。对比各亚组患者血浆Cys-C、NT-proBNP水平差异,采用Pearson相关性分析的方式探究老年CHF患者BMI指数与血浆Cys-C、NT-proBNP相关性,对入组患者实施12个月随访,将患者按照预后情况区分为死亡组和存活组,对比两亚组患者血浆Cys-C、NT-proBNP水平差异并评估预后评估价值。结果肥胖组患者血浆Cys-C、NT-proBNP水平高于超重组,超重组患者血浆Cys-C、NT-proBNP水平高于正常组,差异具有统计学意义(P<0.05);入组老年CHF患者的BMI指数与其血浆Cys-C、NT-proBN水平均呈现明显的正相关性(r=0.7104,P<0.0001)(r=0.6603,P<0.0001);随访12个月显示,死亡组患者的血浆Cys-C、NT-proBNP水平显著高于存活组患者,差异具有统计学意义(P<0.05);血浆Cys-C、NT-proBNP对老年CHF预后评估曲线下面积(area under curv,AUC)为0.6930(P=0.0009)、0.7982(P<0.0001)。结论老年CHF患者随BMI指数升高,血浆Cys-C、NT-proBNP水平逐渐升高,血浆Cys-C、NT-proBNP对老年CHF临床结局具有一定的预测价值,进一步研究有推广应用于老年CHF预后评估潜力。
