Ionic liquids predominantly consist of ionic species[1]and have low melting points[2]usually less than 373 K.They were widely used in organic syn-thesis as green solvents or catalysts[3,4].Recently,Cooper et al[5]repo...Ionic liquids predominantly consist of ionic species[1]and have low melting points[2]usually less than 373 K.They were widely used in organic syn-thesis as green solvents or catalysts[3,4].Recently,Cooper et al[5]reported the preparation of an AEL type aluminophosphate molecular sieve using 1-ethyl-3-methylimidazolium bromide([emim]Br)ionic liq-uid as both the solvent and template.They named the novel attractive procedure ionothermal synthesis to distinguish it from the hydrothermal process.The AEL type aluminophosphate molecular sieve has no acidic sites because of its electrically neutral struc-ture[6].However,introducing Si species to substitute P in the framework will impart mild acidity to the AEL type molecular sieve and make it active for a va-riety of heterogeneous acidic catalytic reactions such as the hydroisomerization of alkane[7.8].In this work,Si species were introduced into the synthesis mixture and the silicoaluminophosphate molecular sieve with AEl structure was ionothermally synthe-sized.Meanwhile,the effect of Si species amount on the product properties was investigated.展开更多
A transparent gel-like mesoporous silicoaluminophosphate material （SAP） with molar ratio of Si/Al = 20 was synthesized by hydrothermal method. The physicochemical features of SAP were characterized by XRD, XRF, BET,...A transparent gel-like mesoporous silicoaluminophosphate material （SAP） with molar ratio of Si/Al = 20 was synthesized by hydrothermal method. The physicochemical features of SAP were characterized by XRD, XRF, BET, SEM and FT-IR spectroscopy of pyridine adsorption techniques. The results indicated that incorporation of phosphorus （P） into aluminasilica system altered the basic textural characteristics of aluminasilica. Especially after hydrothermal treatment, the material with large special surface area （up to 492 m2/g） exhibited a good performance on hydrothermal stability. Moreover, the phosphorus modifier can not only increase the amount of Br／＂{o}nsted acidic sites （up to 48.44 μmol/g） and the percentage of weak acidic sites in total acidic sites, but also regulate the acid type, such as the ratio of B/L （Lewis acid/Br？nsted acid） increased to 1.15. The performances of samples as matrices for the catalytic cracking of heavy VGO were investigated. At 520 ℃, the catalysts showed much higher gasoline and diesel oil yields achieving to 45.59 wt% and 19.20 wt%, respectively, and lower coke selectivity （2.86%） than conventional FCC matrices, such as kaolin and amorphous silica-alumina.展开更多
Nitrogen oxides（NOx：NO,NO2）are a concern due to their adverse health effects.Diesel engine transport sector is the major emitter of NOx.The regulations have been strengthened and to comply with them,one of the two ...Nitrogen oxides（NOx：NO,NO2）are a concern due to their adverse health effects.Diesel engine transport sector is the major emitter of NOx.The regulations have been strengthened and to comply with them,one of the two methods commonly used is the selective catalytic reduction of NOxby NH3（NH3-SCR）,NH3being supplied by the in-situ hydrolysis of urea.Efficiency and durability of the catalyst for this process are highly required.Durability is evaluated by hydrothermal treatment of the catalysts at temperature above 800℃.In this study,very active catalysts for the NH3-SCR of NOxwere prepared by using a silicoaluminophosphate commercial zeolite as copper host structure.Characterizations by X-ray diffraction（XRD）,scanning electron microscopy（SEM）and temperature programmed desorption of ammonia（NH3-TPD）showed that this commercial zeolite was hydrothermally stable up to 850℃ and,was able to retain some structural properties up to950℃.After hydrothermal treatment at 850℃,the NOxreduction efficiency into NH3-SCR depends on the copper content.The catalyst with a copper content of 1.25 wt.%was the most active.The difference in activity was much more important when using NO than the fast NO/NO2reaction mixture.展开更多
Commercial silicoaluminophosphate molecular sieves (SAPO-34) received alkali treatment with either NaOH (0.2, 0.01, 0.005, or 0.001 M) or NH4OH (0.005 M). Treatment with NaOH (0.005 M) increased the water adsorption i...Commercial silicoaluminophosphate molecular sieves (SAPO-34) received alkali treatment with either NaOH (0.2, 0.01, 0.005, or 0.001 M) or NH4OH (0.005 M). Treatment with NaOH (0.005 M) increased the water adsorption initial rate of SAPO-34 by 1.4-fold. The alkali treatment introduced Na+ adsorption sites into the SAPO-34. The desorption ratio (adsorption at 30°C and desorption at 100°C) was 88.2% higher than the original rate (84.3%). On the other hand, after alkali treatment of SAPO-34 using NH4OH (0.005 M), calcination resulted in the highest desorption ratio at 91.3%. When combined with calcination, alkali treatment with NH4OH introduced H+adsorption sites into SAPO-34, H+ adsorption sites feature low levels of interaction with water, which enhanced the desorption ratio, but decreased the initial adsorption rate. These results indicate that treating commercial SAPO-34 with 0.005 M NaOH enhances both the adsorption and desorption behaviors.展开更多
A novel micro-mesoporous silicoaluminophosphate(MUS-5) with controlled morphology has been first synthesized in a two-step route.The physical properties of the silicoaluminophosphate were characterized using XRD,SEM,T...A novel micro-mesoporous silicoaluminophosphate(MUS-5) with controlled morphology has been first synthesized in a two-step route.The physical properties of the silicoaluminophosphate were characterized using XRD,SEM,TEM,nitrogen adsorption-desorption and NH3-TPD techniques.When the pH value of the solution system was varied in the range from 2.0 to 5.0,three different morphologies of silicoaluminophosphate including chain-like,flower-like and barrel-like morphology were obtained.Catalytic tests showed that the silicoaluminophosphate exhibited higher catalytic activity compared with the conventional microporous SAPO-5 under the same conditions for catalytic cracking of 1,3,5-triisopropylbenzene heavy aromatics.The remarkable catalytic reactivity was mainly attributed to the presence of the hierarchical porosity in the silicoaluminophosphate catalyst.展开更多
The hydroxyl groups and their acidic properties of AlPO_4-5, SAPO-5 and HZSM-5 havebeen examined by means of IR spectroscopy using the adsorption of D_2O and pyridine asa probe. Four hydroxyl groups characterized by t...The hydroxyl groups and their acidic properties of AlPO_4-5, SAPO-5 and HZSM-5 havebeen examined by means of IR spectroscopy using the adsorption of D_2O and pyridine asa probe. Four hydroxyl groups characterized by the bands near 3745, 3677, 3630 and 3520cm^(-1) are clearly observed and they are acidic on the sample of SAPO-5. Only two very weakbands at 3677 and 3630 cm^(-1) on AlPO_4-5 could be found. The experiments further indicatethat both of Bronsted and Lewis acid sites are present on the SAPO-5. From NH_3-TPD itis found that the HZSM-5 contains two types of acid sites, medium and strong, while theSAPO-5 contains only one type of medium acid sites. The order of a total amount ofacidity and acid strength is HZSM-5>SAPO-5>AlPO_4-5.展开更多
文摘Ionic liquids predominantly consist of ionic species[1]and have low melting points[2]usually less than 373 K.They were widely used in organic syn-thesis as green solvents or catalysts[3,4].Recently,Cooper et al[5]reported the preparation of an AEL type aluminophosphate molecular sieve using 1-ethyl-3-methylimidazolium bromide([emim]Br)ionic liq-uid as both the solvent and template.They named the novel attractive procedure ionothermal synthesis to distinguish it from the hydrothermal process.The AEL type aluminophosphate molecular sieve has no acidic sites because of its electrically neutral struc-ture[6].However,introducing Si species to substitute P in the framework will impart mild acidity to the AEL type molecular sieve and make it active for a va-riety of heterogeneous acidic catalytic reactions such as the hydroisomerization of alkane[7.8].In this work,Si species were introduced into the synthesis mixture and the silicoaluminophosphate molecular sieve with AEl structure was ionothermally synthe-sized.Meanwhile,the effect of Si species amount on the product properties was investigated.
基金supported by the National Program on Key Basic Research Project(973Program)(Grant No.2012CB215000)the Fundamental Research Funds for the Central Universities(Grant No.12CX04038A)the Graduate Student Innovation Foundation of China University of Petroleum(Grant No.CX-1211)
文摘A transparent gel-like mesoporous silicoaluminophosphate material （SAP） with molar ratio of Si/Al = 20 was synthesized by hydrothermal method. The physicochemical features of SAP were characterized by XRD, XRF, BET, SEM and FT-IR spectroscopy of pyridine adsorption techniques. The results indicated that incorporation of phosphorus （P） into aluminasilica system altered the basic textural characteristics of aluminasilica. Especially after hydrothermal treatment, the material with large special surface area （up to 492 m2/g） exhibited a good performance on hydrothermal stability. Moreover, the phosphorus modifier can not only increase the amount of Br／＂{o}nsted acidic sites （up to 48.44 μmol/g） and the percentage of weak acidic sites in total acidic sites, but also regulate the acid type, such as the ratio of B/L （Lewis acid/Br？nsted acid） increased to 1.15. The performances of samples as matrices for the catalytic cracking of heavy VGO were investigated. At 520 ℃, the catalysts showed much higher gasoline and diesel oil yields achieving to 45.59 wt% and 19.20 wt%, respectively, and lower coke selectivity （2.86%） than conventional FCC matrices, such as kaolin and amorphous silica-alumina.
基金the UREENOX project (ANR-11-VPTT-002) funded by the French ANR (L'Agence National de la Recherche)the French ANR for financial supportThe Institute of Chemistry of Poitiers (IC2MP) for the management of the UREENOX project
文摘Nitrogen oxides（NOx：NO,NO2）are a concern due to their adverse health effects.Diesel engine transport sector is the major emitter of NOx.The regulations have been strengthened and to comply with them,one of the two methods commonly used is the selective catalytic reduction of NOxby NH3（NH3-SCR）,NH3being supplied by the in-situ hydrolysis of urea.Efficiency and durability of the catalyst for this process are highly required.Durability is evaluated by hydrothermal treatment of the catalysts at temperature above 800℃.In this study,very active catalysts for the NH3-SCR of NOxwere prepared by using a silicoaluminophosphate commercial zeolite as copper host structure.Characterizations by X-ray diffraction（XRD）,scanning electron microscopy（SEM）and temperature programmed desorption of ammonia（NH3-TPD）showed that this commercial zeolite was hydrothermally stable up to 850℃ and,was able to retain some structural properties up to950℃.After hydrothermal treatment at 850℃,the NOxreduction efficiency into NH3-SCR depends on the copper content.The catalyst with a copper content of 1.25 wt.%was the most active.The difference in activity was much more important when using NO than the fast NO/NO2reaction mixture.
文摘Commercial silicoaluminophosphate molecular sieves (SAPO-34) received alkali treatment with either NaOH (0.2, 0.01, 0.005, or 0.001 M) or NH4OH (0.005 M). Treatment with NaOH (0.005 M) increased the water adsorption initial rate of SAPO-34 by 1.4-fold. The alkali treatment introduced Na+ adsorption sites into the SAPO-34. The desorption ratio (adsorption at 30°C and desorption at 100°C) was 88.2% higher than the original rate (84.3%). On the other hand, after alkali treatment of SAPO-34 using NH4OH (0.005 M), calcination resulted in the highest desorption ratio at 91.3%. When combined with calcination, alkali treatment with NH4OH introduced H+adsorption sites into SAPO-34, H+ adsorption sites feature low levels of interaction with water, which enhanced the desorption ratio, but decreased the initial adsorption rate. These results indicate that treating commercial SAPO-34 with 0.005 M NaOH enhances both the adsorption and desorption behaviors.
基金supported by the National Basic Research Program of China (2003CB615802)
文摘A novel micro-mesoporous silicoaluminophosphate(MUS-5) with controlled morphology has been first synthesized in a two-step route.The physical properties of the silicoaluminophosphate were characterized using XRD,SEM,TEM,nitrogen adsorption-desorption and NH3-TPD techniques.When the pH value of the solution system was varied in the range from 2.0 to 5.0,three different morphologies of silicoaluminophosphate including chain-like,flower-like and barrel-like morphology were obtained.Catalytic tests showed that the silicoaluminophosphate exhibited higher catalytic activity compared with the conventional microporous SAPO-5 under the same conditions for catalytic cracking of 1,3,5-triisopropylbenzene heavy aromatics.The remarkable catalytic reactivity was mainly attributed to the presence of the hierarchical porosity in the silicoaluminophosphate catalyst.
基金Project supported by the National Natural Science Foundation of China.
文摘The hydroxyl groups and their acidic properties of AlPO_4-5, SAPO-5 and HZSM-5 havebeen examined by means of IR spectroscopy using the adsorption of D_2O and pyridine asa probe. Four hydroxyl groups characterized by the bands near 3745, 3677, 3630 and 3520cm^(-1) are clearly observed and they are acidic on the sample of SAPO-5. Only two very weakbands at 3677 and 3630 cm^(-1) on AlPO_4-5 could be found. The experiments further indicatethat both of Bronsted and Lewis acid sites are present on the SAPO-5. From NH_3-TPD itis found that the HZSM-5 contains two types of acid sites, medium and strong, while theSAPO-5 contains only one type of medium acid sites. The order of a total amount ofacidity and acid strength is HZSM-5>SAPO-5>AlPO_4-5.
