The effect of diboron trioxide(B_2O_3) on the crushing strength and smelting mechanism of high-chromium vanadium–titanium magnetite pellets was investigated in this work. The main characterization methods were X-ray ...The effect of diboron trioxide(B_2O_3) on the crushing strength and smelting mechanism of high-chromium vanadium–titanium magnetite pellets was investigated in this work. The main characterization methods were X-ray fluorescence, inductively coupled plasma–atomic emission spectroscopy, mercury injection porosimetry, X-ray diffraction, metallographic microscopy, and scanning electron microscopy–energy-dispersive X-ray spectroscopy. The results showed that the crushing strength increased greatly with increasing B_2O_3 content and that the increase in crushing strength was strongly correlated with a decrease in porosity, the formation of liquid phases, and the growth and recrystallization consolidation of hematite crystalline grains. The smelting properties were measured under simulated blast furnace conditions; the results showed that the smelting properties within a certain B_2O_3 content range were improved and optimized except in the softening stage. The valuable element B was easily transformed to the slag, and this phenomenon became increasingly evident with increasing B_2O_3 content. The formation of Ti(C,N) was mostly avoided, and the slag and melted iron were separated well during smelting with the addition of B_2O_3. The size increase of the melted iron was consistent with the gradual optimization of the dripping characteristics with increasing B_2O_3 content.展开更多
Anti-vicinal diboronates were fabricated from easily available diarylethynes and B2pin2via a basecatalyzed domino-borylation-protodeboronation(DBP)strategy under transition-metal-free conditions.Under the standard con...Anti-vicinal diboronates were fabricated from easily available diarylethynes and B2pin2via a basecatalyzed domino-borylation-protodeboronation(DBP)strategy under transition-metal-free conditions.Under the standard conditions,reactants with a range of different classes of functional groups on the rings,such as Me O,Me S,CF3O,Me2N,TMS,I,Br,Cl,F,and the thiophene ring,were tolerated.Downstream transformation of the vicinal diboronates provided a facile pathway for obtaining vicinal diols by mild oxidation with Na BO3,and a new deuteriation technique was developed in order to acquire1,2-diarylethanes-1,2-d2and 1,2-diarylethanes-1,1,2,2-d4.The new deuteriation strategy developed in this study may provide a new research direction for deuteriation chemistry.展开更多
Organoboron compounds have become important intermediates for the construction of new compounds in synthetic chemistry and pharmaceutical chemistry,and it has been found that pinacol biborate(B_(2)pin_(2))as the boron...Organoboron compounds have become important intermediates for the construction of new compounds in synthetic chemistry and pharmaceutical chemistry,and it has been found that pinacol biborate(B_(2)pin_(2))as the boron source and Cu^(Ⅱ) organophosphorus complex(L)as the catalyst can effectively realize the hydrogen-reduced borylation products and dehydrohydrated borylation products of aryl olefins.The reaction regioselectivity involvingβ-C positions of aryl olefins can be controlled by regulating the ligand and additive types.The formation mechanism of the product is conducted at LCu^(Ⅰ)Bpin formed from Cu^(Ⅱ),L and B_(2)pin_(2).Subsequently the substrate aryl olefins undergo addition reaction to form the active intermediate PhCH(LCu^(Ⅰ))CH_(2)Bpin.Followed by the metathesis of the active intermediate with water to form hydrogen reduction products,the same active intermediate can be oxidized with 2,2,6,6-tetramethylpiperidoxyl(TEMPO)to form trans dehydrogenation products.展开更多
Hexagon plate-like Al8B4C7 powders were success- fully synthesized using a mixture of diboron trioxide, ac- tivated carbon and aluminum or alumina by a carbotherreal reduction process. The effect of A1 source and star...Hexagon plate-like Al8B4C7 powders were success- fully synthesized using a mixture of diboron trioxide, ac- tivated carbon and aluminum or alumina by a carbotherreal reduction process. The effect of A1 source and start- ing materials additions on synthesis of Al8B4C7 was in- vestigated. The phase composition and microstructure of Al8B4C7 powder were characterized by means of XRD, SEM and EDS. The main phase compositions of the products synthesized Jkom A1, B2O3 and activated carbon are Al8B4C7 and A120C. Al2O3 can replace Al to synthe- size Al8B4C7. AlsB4C7 grains synthesized from Al2O3, B2O3 and activated carbon are hexagon plate-like and have a thickness of 10 tzm and a size of about 100 tzm.展开更多
The highly regio-and stereoselective hydroborations of unactivated internal alkynes with diboron compound catalyzed by Cu（OTf）2 with spiro（phosphoamidite） as ligand in the presence of Cs2CO3 in water was developed...The highly regio-and stereoselective hydroborations of unactivated internal alkynes with diboron compound catalyzed by Cu（OTf）2 with spiro（phosphoamidite） as ligand in the presence of Cs2CO3 in water was developed.This protocol was applied efficiently in the aqueous synthesis of multi-substituted vinylboranes.展开更多
基金financially supported by the National Key Technology Research and Development Program of the Ministry of Science and Technology of China (No. 2015BAB19B02)the National Program on Key Basic Research Project of China (No. 2013CB632603)
文摘The effect of diboron trioxide(B_2O_3) on the crushing strength and smelting mechanism of high-chromium vanadium–titanium magnetite pellets was investigated in this work. The main characterization methods were X-ray fluorescence, inductively coupled plasma–atomic emission spectroscopy, mercury injection porosimetry, X-ray diffraction, metallographic microscopy, and scanning electron microscopy–energy-dispersive X-ray spectroscopy. The results showed that the crushing strength increased greatly with increasing B_2O_3 content and that the increase in crushing strength was strongly correlated with a decrease in porosity, the formation of liquid phases, and the growth and recrystallization consolidation of hematite crystalline grains. The smelting properties were measured under simulated blast furnace conditions; the results showed that the smelting properties within a certain B_2O_3 content range were improved and optimized except in the softening stage. The valuable element B was easily transformed to the slag, and this phenomenon became increasingly evident with increasing B_2O_3 content. The formation of Ti(C,N) was mostly avoided, and the slag and melted iron were separated well during smelting with the addition of B_2O_3. The size increase of the melted iron was consistent with the gradual optimization of the dripping characteristics with increasing B_2O_3 content.
基金supported by the National Natural Science Foundation of China (21772046)the Natural Science Foundation of Fujian Province (2016J01064)the Subsidized Project for Cultivating Postgraduates’ Innovative Ability in Scientific Research of Huaqiao University
文摘Anti-vicinal diboronates were fabricated from easily available diarylethynes and B2pin2via a basecatalyzed domino-borylation-protodeboronation(DBP)strategy under transition-metal-free conditions.Under the standard conditions,reactants with a range of different classes of functional groups on the rings,such as Me O,Me S,CF3O,Me2N,TMS,I,Br,Cl,F,and the thiophene ring,were tolerated.Downstream transformation of the vicinal diboronates provided a facile pathway for obtaining vicinal diols by mild oxidation with Na BO3,and a new deuteriation technique was developed in order to acquire1,2-diarylethanes-1,2-d2and 1,2-diarylethanes-1,1,2,2-d4.The new deuteriation strategy developed in this study may provide a new research direction for deuteriation chemistry.
文摘Organoboron compounds have become important intermediates for the construction of new compounds in synthetic chemistry and pharmaceutical chemistry,and it has been found that pinacol biborate(B_(2)pin_(2))as the boron source and Cu^(Ⅱ) organophosphorus complex(L)as the catalyst can effectively realize the hydrogen-reduced borylation products and dehydrohydrated borylation products of aryl olefins.The reaction regioselectivity involvingβ-C positions of aryl olefins can be controlled by regulating the ligand and additive types.The formation mechanism of the product is conducted at LCu^(Ⅰ)Bpin formed from Cu^(Ⅱ),L and B_(2)pin_(2).Subsequently the substrate aryl olefins undergo addition reaction to form the active intermediate PhCH(LCu^(Ⅰ))CH_(2)Bpin.Followed by the metathesis of the active intermediate with water to form hydrogen reduction products,the same active intermediate can be oxidized with 2,2,6,6-tetramethylpiperidoxyl(TEMPO)to form trans dehydrogenation products.
基金supported by projects of the National KeyTechnology R&D Program(Grant No.2011BAB03B04)the Natural Science Foundation of China(NSFC)(Grant No.51274156)
文摘Hexagon plate-like Al8B4C7 powders were success- fully synthesized using a mixture of diboron trioxide, ac- tivated carbon and aluminum or alumina by a carbotherreal reduction process. The effect of A1 source and start- ing materials additions on synthesis of Al8B4C7 was in- vestigated. The phase composition and microstructure of Al8B4C7 powder were characterized by means of XRD, SEM and EDS. The main phase compositions of the products synthesized Jkom A1, B2O3 and activated carbon are Al8B4C7 and A120C. Al2O3 can replace Al to synthe- size Al8B4C7. AlsB4C7 grains synthesized from Al2O3, B2O3 and activated carbon are hexagon plate-like and have a thickness of 10 tzm and a size of about 100 tzm.
文摘The highly regio-and stereoselective hydroborations of unactivated internal alkynes with diboron compound catalyzed by Cu（OTf）2 with spiro（phosphoamidite） as ligand in the presence of Cs2CO3 in water was developed.This protocol was applied efficiently in the aqueous synthesis of multi-substituted vinylboranes.
基金Project supported by the National Natural Science Foundation of China(Nos.91745110,21673261,21603245,21633013,21703265,21872156,21802150)the Natural Science Foundation of Jiangsu Province(Nos.BK20181194,BK20180247)+1 种基金the Young Elite Scientist Sponsorship Program by China Association for Science and Technology(No.YESS20170217)the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2018458)~~
