In this paper, a new anionic metal-organic framework, [In(PBPTTBA)][(CH_3)_2 NH_2](BUT-29) has been synthesized through the reaction of tetratopic acid ligand with double Lewis pyridine sites, 4,4',4'',4&#...In this paper, a new anionic metal-organic framework, [In(PBPTTBA)][(CH_3)_2 NH_2](BUT-29) has been synthesized through the reaction of tetratopic acid ligand with double Lewis pyridine sites, 4,4',4'',4'''-(4,4'-(1,4-phenylene)bis(pyridine-6,4,2-triyl)) tetrabenzoic acid(H_4 PBPTTBA) and In(NO_3)_2·5H_2O and fully characterized by single-crystal X-ray diffraction(SXRD), powder X-ray diffraction(PXRD),thermogravimetric analysis(TGA), infrared spectroscopy(IR), and elemental analysis(EA). BUT-29 can be used as an efficient adsorbent for the selective removal of organic cationic dyes in N,N0-dimethylformamide(DMF) solution. The adsorption capacities of BUT-29 toward methylene blue and crystal violet at 298 K can reach 1119 mg/g and 832 mg/g, respectively. Moreover, the adsorbed dyes can be released in the DMF solution of LiNO_3 gradually.展开更多
The fundamental insights of the reaction mechanism,especially the synergistic effect between oxygen vacancies and basic sites,are highly promising yet challenging for Ru-based catalysts during carbon dioxide(CO_(2))me...The fundamental insights of the reaction mechanism,especially the synergistic effect between oxygen vacancies and basic sites,are highly promising yet challenging for Ru-based catalysts during carbon dioxide(CO_(2))methanation.Herein,a series of Rubased catalysts were employed to study the mechanism of CO_(2) methanation.It is found that Ru/CeO_(2) catalyst exhibits a much higher CO_(2) conversion(86%)and CH4 selectivity(100%),as well as excellent stability of 30 h due to the existence of abundant oxygen vacancies and weak basic sites.Additionally,the in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and density functional theory(DFT)calculations reveal that the formate formation step dominated the hydrogenation route on Ru/CeO_(2) catalyst,and the b-HCOO^(*)could be the key intermediate due to b-HCOO^(*)is more easily hydrogenated to methane than m-HCOO^(*).The systematic study marks the significance of precise tailoring of the synergistic relationship between oxygen vacancies and basic sites for achieving the desired performance in CO_(2) methanation.展开更多
This study evaluated the site-specific effects of projected future climate conditions on the productivity of jack pine (Pinus banksiana Lamb.) plantations over the next 50 years (2011-2061). Climatic parameters as pre...This study evaluated the site-specific effects of projected future climate conditions on the productivity of jack pine (Pinus banksiana Lamb.) plantations over the next 50 years (2011-2061). Climatic parameters as predicted by the Canadian Global Climate Model in association with a regional spatial climatic model, under 3 emissions scenarios (no change (NC), B1 and A2), were used as input values to a biophysical-based site-specific height-age model that was integrated into the CROPLANNER model and associated algorithm. Plantations managed under a basic silvicultural intensity on two site qualities at each of two geographically separated sites (northeastern and northwestern Ontario, Canada) were assessed. The results indicated that the stands situated on low-to-medium quality sites at both locations were largely unaffected by the predicted increase in temperature and precipitation rates. Conversely, however, stands situated on good-to-excellent quality sites grown under the B1 and A2 scenarios experienced consequential declines in stand development rates resulting in decreases in rotational mean sizes, biomass yields, recoverable end-product volumes, and economic worth. In addition to providing a plausible range of site-specific climate change outcomes on jack pine productivity within the central portion of the species range, these results suggest that future predictions that do not account for potential climate changes effects may overes- timate merchantable productivity on the higher site qualities by approximately 15%. As demonstrated, in- corporating biophysical-based site index functions within existing forest productivity models may repre- sent a feasible approach when accounting for climate change effects on yield outcomes of boreal species.展开更多
Ca/SBA-15 solid bases with different Ca/Si atomic ratios were prepared by a one-pot route and employed as catalysts for the production of poly（isosorbide carbonate） （PIC） from diphenyl carbonate and isosorbide via...Ca/SBA-15 solid bases with different Ca/Si atomic ratios were prepared by a one-pot route and employed as catalysts for the production of poly（isosorbide carbonate） （PIC） from diphenyl carbonate and isosorbide via a transesterification polymerization process. The relationship between physicochemical properties and catalytic performance for Ca/SBA-15 in this melt process was investigated by means of various characterization techniques. It was found that basic site amount and strength were responsible for this transesterification process; the weak and medium basic sites inclined to promote polycondensation reaction. It was worth noting that strong basic sites could favor the decomposition of the resultant P/C, resulting in the decrease of weight-average molecular weight （Mw） and yield, and the sample with Ca/Si atomic ratio of 0.4 exhibited the best catalytic performance, giving PIC with Mw of 4.88 × 10^4 g/mol and Tg of 169 ℃ at the optimal conditions. This excellent activity can be ascribed to the presence of rich basic sites and specific basic strength on the surface of 0.4Ca/SBA-15.展开更多
Mg-A1 mixed oxides with different Mg/A1 molar ratio were prepared by thermal decomposition of hydrotalcite-like precursors at 500℃for 5.0 h and used as catalysts for the transesterification of diphenyl carbonate with...Mg-A1 mixed oxides with different Mg/A1 molar ratio were prepared by thermal decomposition of hydrotalcite-like precursors at 500℃for 5.0 h and used as catalysts for the transesterification of diphenyl carbonate with 1,4-butanediol to synthesize high-molecular-weight poly(butylene carbonate)(PBC).The structure-activity correlations of these catalysts in this transesterification process were discussed by means of various characterization techniques.It was found that the chain growth for the formation of PBC can only be obtained through connecting-OH and-OC(C)OC6H5 end-group upon removing the generated phenol,and the sample with Mg/A1 molar ratio of 4.0 exhibited the best catalytic performance,giving PBC with Mw of 1.64×105 g/mol at 210℃for 3.0 h.This excellent activity depended mainly on the specific surface area and basicity rather than pore structure or crystallite size of MgO.展开更多
基金financially supported by the National Natural Science Foundation of China (NSFC, No. U1407119)
文摘In this paper, a new anionic metal-organic framework, [In(PBPTTBA)][(CH_3)_2 NH_2](BUT-29) has been synthesized through the reaction of tetratopic acid ligand with double Lewis pyridine sites, 4,4',4'',4'''-(4,4'-(1,4-phenylene)bis(pyridine-6,4,2-triyl)) tetrabenzoic acid(H_4 PBPTTBA) and In(NO_3)_2·5H_2O and fully characterized by single-crystal X-ray diffraction(SXRD), powder X-ray diffraction(PXRD),thermogravimetric analysis(TGA), infrared spectroscopy(IR), and elemental analysis(EA). BUT-29 can be used as an efficient adsorbent for the selective removal of organic cationic dyes in N,N0-dimethylformamide(DMF) solution. The adsorption capacities of BUT-29 toward methylene blue and crystal violet at 298 K can reach 1119 mg/g and 832 mg/g, respectively. Moreover, the adsorbed dyes can be released in the DMF solution of LiNO_3 gradually.
基金the National Natural Science Foundation of China(No.22102215)the Fundamental Research Funds for the Central Universities(Nos.21CX06013A and 22CX03001A)the State Key Laboratory of Heavy Oil Processing and the Key Project of China National Key R&D Plan(No.2018YFE0118200).
文摘The fundamental insights of the reaction mechanism,especially the synergistic effect between oxygen vacancies and basic sites,are highly promising yet challenging for Ru-based catalysts during carbon dioxide(CO_(2))methanation.Herein,a series of Rubased catalysts were employed to study the mechanism of CO_(2) methanation.It is found that Ru/CeO_(2) catalyst exhibits a much higher CO_(2) conversion(86%)and CH4 selectivity(100%),as well as excellent stability of 30 h due to the existence of abundant oxygen vacancies and weak basic sites.Additionally,the in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and density functional theory(DFT)calculations reveal that the formate formation step dominated the hydrogenation route on Ru/CeO_(2) catalyst,and the b-HCOO^(*)could be the key intermediate due to b-HCOO^(*)is more easily hydrogenated to methane than m-HCOO^(*).The systematic study marks the significance of precise tailoring of the synergistic relationship between oxygen vacancies and basic sites for achieving the desired performance in CO_(2) methanation.
文摘This study evaluated the site-specific effects of projected future climate conditions on the productivity of jack pine (Pinus banksiana Lamb.) plantations over the next 50 years (2011-2061). Climatic parameters as predicted by the Canadian Global Climate Model in association with a regional spatial climatic model, under 3 emissions scenarios (no change (NC), B1 and A2), were used as input values to a biophysical-based site-specific height-age model that was integrated into the CROPLANNER model and associated algorithm. Plantations managed under a basic silvicultural intensity on two site qualities at each of two geographically separated sites (northeastern and northwestern Ontario, Canada) were assessed. The results indicated that the stands situated on low-to-medium quality sites at both locations were largely unaffected by the predicted increase in temperature and precipitation rates. Conversely, however, stands situated on good-to-excellent quality sites grown under the B1 and A2 scenarios experienced consequential declines in stand development rates resulting in decreases in rotational mean sizes, biomass yields, recoverable end-product volumes, and economic worth. In addition to providing a plausible range of site-specific climate change outcomes on jack pine productivity within the central portion of the species range, these results suggest that future predictions that do not account for potential climate changes effects may overes- timate merchantable productivity on the higher site qualities by approximately 15%. As demonstrated, in- corporating biophysical-based site index functions within existing forest productivity models may repre- sent a feasible approach when accounting for climate change effects on yield outcomes of boreal species.
基金Supported by the National Natural Science Foundation of China(20906051)the Jiangsu Province Fundamental ResearchPlan(BK2009478)the Key Discipline Fund of Nanjing University of Technology
基金financially supported by the National Key R&D Program of China(No.2016YFB0301900)the Science and Technology Support Program of Sichuan Province(No.2015GZ0065)
文摘Ca/SBA-15 solid bases with different Ca/Si atomic ratios were prepared by a one-pot route and employed as catalysts for the production of poly（isosorbide carbonate） （PIC） from diphenyl carbonate and isosorbide via a transesterification polymerization process. The relationship between physicochemical properties and catalytic performance for Ca/SBA-15 in this melt process was investigated by means of various characterization techniques. It was found that basic site amount and strength were responsible for this transesterification process; the weak and medium basic sites inclined to promote polycondensation reaction. It was worth noting that strong basic sites could favor the decomposition of the resultant P/C, resulting in the decrease of weight-average molecular weight （Mw） and yield, and the sample with Ca/Si atomic ratio of 0.4 exhibited the best catalytic performance, giving PIC with Mw of 4.88 × 10^4 g/mol and Tg of 169 ℃ at the optimal conditions. This excellent activity can be ascribed to the presence of rich basic sites and specific basic strength on the surface of 0.4Ca/SBA-15.
基金financially supported by the National Key Technology Pillar Program(No.2013BAC11B05)Key Research and Innovation Program of Jiangsu Province(No.BE2015055)the Science&Technology Pillar Program in Sichuan Province(No.2016GZ0228)
文摘Mg-A1 mixed oxides with different Mg/A1 molar ratio were prepared by thermal decomposition of hydrotalcite-like precursors at 500℃for 5.0 h and used as catalysts for the transesterification of diphenyl carbonate with 1,4-butanediol to synthesize high-molecular-weight poly(butylene carbonate)(PBC).The structure-activity correlations of these catalysts in this transesterification process were discussed by means of various characterization techniques.It was found that the chain growth for the formation of PBC can only be obtained through connecting-OH and-OC(C)OC6H5 end-group upon removing the generated phenol,and the sample with Mg/A1 molar ratio of 4.0 exhibited the best catalytic performance,giving PBC with Mw of 1.64×105 g/mol at 210℃for 3.0 h.This excellent activity depended mainly on the specific surface area and basicity rather than pore structure or crystallite size of MgO.
