A series of zwitterionic‐type quaternary ammoniums(ZTQAs)with varying lengths of alkyl chains combined with KI were synthesized and considered as catalysts for the coupling reaction of CO2 and various terminal epoxid...A series of zwitterionic‐type quaternary ammoniums(ZTQAs)with varying lengths of alkyl chains combined with KI were synthesized and considered as catalysts for the coupling reaction of CO2 and various terminal epoxides.The prolonged alkyl chain of ZTQAs exhibited temperature‐responsive self‐separation in propylene carbonate(PC).The interaction between ZTQAs and KI was confirmed by X‐ray photoelectron spectroscopy and quantum chemical calculations.This interaction strengthened the nucleophilicity of the I?ion,favoring the catalytic reaction.The 3‐(dimethyltetradecylammonium)propane sulfonate(DTPS)/KI showed an excellent yield of PC(95.1%)at 125°C,1.5 MPa,and 1 mol%loading of catalyst.The precipitate formed spontaneously from the catalytic system,providing high catalytic activity of the homogeneous catalyst,as well as easy recovery of the heterogeneous catalyst.展开更多
Rare earth elements and yttrium(REY)in coal deposits are considered promising alternative sources for these resources owing to their increasing global demand.This paper reports the geochemical characteristics of REY i...Rare earth elements and yttrium(REY)in coal deposits are considered promising alternative sources for these resources owing to their increasing global demand.This paper reports the geochemical characteristics of REY in the Late Permian coals from an underground K1a seam section of the Zhongliangshan coalfield in Chongqing,southwestern China.The mineralogy,degree of enrichment,distribution patterns,modes of occurrence,and sediment origin of REY were investigated.Compared with the average of world coals,the concentration of REY in the K1a coals were normal,dominated by light REY(LREY),with less medium and heavy REY(MREY,HREY).The fractionation degree of the MREY and HREY are higher than that of LREY in most K1a coal samples,deduced from the mixed enrichment type of REY,mainly including M-H-type,and a few L-M type and H-type.In addition,the combination of anomalies of Ce,Eu,Gd,and Al_(2)O_(3)/TiO_(2) parameters,the terrigenous materials in the K1a coal were derived from the felsic-intermediate rocks at the top of the Emeishan basalt sequence,and the samples were affected by seawater intrusion during early peat accumulation.Although the minerals primarily consist of kaolinite,illite,pyrite,and small amounts of quartz,calcite and anatase,REY are correlated with ash yield,SiO2,and Al_(2)O_(3),revealing that the REY mainly occur in aluminosilicate minerals,especially kaolinite and illite.Meanwhile,REY positively relate to P_(2)O_(5) and Zr,which may exist in phosphate-containing minerals or zircon.Furthermore,most samples in the K1a coal or ash do not reach the cut-off grade for the beneficial recovery of REY.With the exception of central Guizhou,southwestern Chongqing,and the junction of western Guizhou and northeastern Yunnan,the REY content in coals from southwestern China are high,and its by-products are suitable as potential REY sources.展开更多
基金supported by the National Natural Science Foundation of China(41330317,21403051)the Natural Science Foundation of Hebei province(B2016402030,B2017402079)+2 种基金the Science and Technology Foundation of Universities of Hebei Province(ZD2015113)the Science and Technology Research Development Program of Handan(1621211041-3,1622201049-2)the Program for One Hundred Innovative Talents in Universities of Hebei Province(BR2-204)~~
文摘A series of zwitterionic‐type quaternary ammoniums(ZTQAs)with varying lengths of alkyl chains combined with KI were synthesized and considered as catalysts for the coupling reaction of CO2 and various terminal epoxides.The prolonged alkyl chain of ZTQAs exhibited temperature‐responsive self‐separation in propylene carbonate(PC).The interaction between ZTQAs and KI was confirmed by X‐ray photoelectron spectroscopy and quantum chemical calculations.This interaction strengthened the nucleophilicity of the I?ion,favoring the catalytic reaction.The 3‐(dimethyltetradecylammonium)propane sulfonate(DTPS)/KI showed an excellent yield of PC(95.1%)at 125°C,1.5 MPa,and 1 mol%loading of catalyst.The precipitate formed spontaneously from the catalytic system,providing high catalytic activity of the homogeneous catalyst,as well as easy recovery of the heterogeneous catalyst.
基金This research was supported by the National Natural Science Foundation of China(Grant Nos.U1903207,42172191,41972176,and 42002184)Natural Science Foundation of Hebei(No.D2021402013)+1 种基金Fundamental research Funds of China University of Mining and Technology(No.2020CXNL11)Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Rare earth elements and yttrium(REY)in coal deposits are considered promising alternative sources for these resources owing to their increasing global demand.This paper reports the geochemical characteristics of REY in the Late Permian coals from an underground K1a seam section of the Zhongliangshan coalfield in Chongqing,southwestern China.The mineralogy,degree of enrichment,distribution patterns,modes of occurrence,and sediment origin of REY were investigated.Compared with the average of world coals,the concentration of REY in the K1a coals were normal,dominated by light REY(LREY),with less medium and heavy REY(MREY,HREY).The fractionation degree of the MREY and HREY are higher than that of LREY in most K1a coal samples,deduced from the mixed enrichment type of REY,mainly including M-H-type,and a few L-M type and H-type.In addition,the combination of anomalies of Ce,Eu,Gd,and Al_(2)O_(3)/TiO_(2) parameters,the terrigenous materials in the K1a coal were derived from the felsic-intermediate rocks at the top of the Emeishan basalt sequence,and the samples were affected by seawater intrusion during early peat accumulation.Although the minerals primarily consist of kaolinite,illite,pyrite,and small amounts of quartz,calcite and anatase,REY are correlated with ash yield,SiO2,and Al_(2)O_(3),revealing that the REY mainly occur in aluminosilicate minerals,especially kaolinite and illite.Meanwhile,REY positively relate to P_(2)O_(5) and Zr,which may exist in phosphate-containing minerals or zircon.Furthermore,most samples in the K1a coal or ash do not reach the cut-off grade for the beneficial recovery of REY.With the exception of central Guizhou,southwestern Chongqing,and the junction of western Guizhou and northeastern Yunnan,the REY content in coals from southwestern China are high,and its by-products are suitable as potential REY sources.
