A BrOnsted-Lewis (B-L) conjugated solid superacid HPW-SbF_5/SiO_2 wassynthesized by a two-step method. This B-L acid shows high acid strength, high activity, goodselectivity and moderate stability in alkylation of iso...A BrOnsted-Lewis (B-L) conjugated solid superacid HPW-SbF_5/SiO_2 wassynthesized by a two-step method. This B-L acid shows high acid strength, high activity, goodselectivity and moderate stability in alkylation of isobutane/butene due to strong interactionbetween the BrOnsted acid and the Lewis acid, as confirmed by the results of IR, NMR and XPS. Undera mild reaction condition (30℃, 15-35xl0~5 Pa), the conversion of butene was maintained at 100% for110 hours on stream and the main products were C_8 and TMP. The results of alkylation conductedunder various operating conditions indicated that the activity was improved by increasing theloading content of HPW and SbF_5. The selectivity of TMP in the products was enhanced when theisobutane/butene ratio in the feedstock was increased. The existence of some intermediates was alsoreported.展开更多
Samples of a cobalt-based alloy that underwent a surface treatment were evaluated.The samples,which were obtained by casting alloy ASTM F 75,were ground and polished on one side until a mirror finish was obtained.The ...Samples of a cobalt-based alloy that underwent a surface treatment were evaluated.The samples,which were obtained by casting alloy ASTM F 75,were ground and polished on one side until a mirror finish was obtained.The samples were encapsulated in wollastonite(W)using uniaxial pressure,treated at 1220~C for 1 h and subsequently tempered in water.The characterisation of the sample indicated that part of the ceramic encapsulating material was mechanically incorporated on the metallic surface by growth of the oxide layer of the alloy.After thermal treatment,a series of specimens were submerged in a solution with 5-fold simulated body fluid(5SBF)for 3,5 and 21 days.Characterisation by scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS)and X-ray diffraction(XRD)indicated nucleation and growth of a homogenous layer of apatite,beginning on the third day when the sample was submerged.展开更多
基金supports from the National Natural Science Foundation of China and SINOPEC are acknowledged
文摘A BrOnsted-Lewis (B-L) conjugated solid superacid HPW-SbF_5/SiO_2 wassynthesized by a two-step method. This B-L acid shows high acid strength, high activity, goodselectivity and moderate stability in alkylation of isobutane/butene due to strong interactionbetween the BrOnsted acid and the Lewis acid, as confirmed by the results of IR, NMR and XPS. Undera mild reaction condition (30℃, 15-35xl0~5 Pa), the conversion of butene was maintained at 100% for110 hours on stream and the main products were C_8 and TMP. The results of alkylation conductedunder various operating conditions indicated that the activity was improved by increasing theloading content of HPW and SbF_5. The selectivity of TMP in the products was enhanced when theisobutane/butene ratio in the feedstock was increased. The existence of some intermediates was alsoreported.
基金the financial support of Tecnología e Innovación en Maquinados S.A de C.V
文摘Samples of a cobalt-based alloy that underwent a surface treatment were evaluated.The samples,which were obtained by casting alloy ASTM F 75,were ground and polished on one side until a mirror finish was obtained.The samples were encapsulated in wollastonite(W)using uniaxial pressure,treated at 1220~C for 1 h and subsequently tempered in water.The characterisation of the sample indicated that part of the ceramic encapsulating material was mechanically incorporated on the metallic surface by growth of the oxide layer of the alloy.After thermal treatment,a series of specimens were submerged in a solution with 5-fold simulated body fluid(5SBF)for 3,5 and 21 days.Characterisation by scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS)and X-ray diffraction(XRD)indicated nucleation and growth of a homogenous layer of apatite,beginning on the third day when the sample was submerged.
