Benzene(BEN)and cyclohexane(CYH),which have very close boiling points and a binary azeotrope,are the most difficult binary components in the separation of aromatic and non-aromatic hydrocarbons.This study further expl...Benzene(BEN)and cyclohexane(CYH),which have very close boiling points and a binary azeotrope,are the most difficult binary components in the separation of aromatic and non-aromatic hydrocarbons.This study further explored the separation mechanism and industrial application prospects of BEN+CYH mixtures separated by a dicationic ionic liquid(DIL)[C_(5)(MIM)_(2)][NTf_(2)]_(2) based on experimental research.The calculation results of the Conductor-like Screening model Segment Activity Coefficient(COSMO-SAC)model show that selectivity and solvent capacity of the DIL are significantly improved.The effects of different anions and cations on the micro-structure distribution and diffusion behavior of BEN+CYH system were investigated by quantum chemistry(QC)calculations and molecular dynamics(MD)simulations.The results indicate that the anion[NTf_(2)]_(2)has low polarity,uniform charge distribution,and a dual role of hydrogen bonding andπ-πbonding,and the cation[C_(5)(MIM)_(2)]^(2+) has stronger interaction with BEN and higher selectivity than conventional cations.The liquid-liquid extraction and extractive distillation(LLE-ED)process using an optimized 65 mol/mol DIL+35 mol/mol H_(2)O mixed solution as the extractant was proposed,which solved the problem of low product purity in the LLE process and high energy consumption in the ED process.Under the best operating conditions,the purity of CYH product was 99.9%,the purity of BEN product was 99.6%,the recovery rate of BEN reached 99.9%,and the recovery rate of DIL reached 99.9%.The heat-integrated LLE-ED process reduced total annual cost by 21.6%,and reduced CO_(2) emissions by 48.0%,which has broad industrial application prospects.展开更多
A series of new halogen-free dicationic ionic liquids(ILs)with different alkyl chain lengths were prepared,and the relationship between the alkyl chain length,physicochemical and tribological properties of ILs,and the...A series of new halogen-free dicationic ionic liquids(ILs)with different alkyl chain lengths were prepared,and the relationship between the alkyl chain length,physicochemical and tribological properties of ILs,and their role as neat lubricant for steel–steel friction pairs,was investigated.Evaluation of stability during hydrolysis and copper strip corrosion test results show that synthetic ILs are stable and not corrosive to metal contacts,due to the halogen-free anions.The friction and wear test results indicate that ILs with long alkyl chains have excellent friction-reducing and anti-wear properties,especially at high temperatures.Based on the surface three-dimensional(3D)profiles,electrical contact resistance,scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),and the X-ray photoelectron spectrometry(XPS)analysis of the worn surfaces of steel discs,we can conclude that the efficiency of ILs is due to the formation of high quality tribofilms that consist of both tribochemical reaction and ordered absorption films.展开更多
In this work,an effective,task specific,dicationic,podand-like ionic liquid was synthesized and applied to improve the capability features of click reaction.Moreover,to broaden the scope and decreasing the serious lim...In this work,an effective,task specific,dicationic,podand-like ionic liquid was synthesized and applied to improve the capability features of click reaction.Moreover,to broaden the scope and decreasing the serious limitations of preparation methods of organic azides,a simple green procedure for the preparation of alkyl azides,the fundamental starting materials in click reactions,from alcohols under solvent-free conditions and microwave irradiation has been reported,for the first time.展开更多
基金This work is financially supported by the National Key R&D Program of China(2017YFB0602401).
文摘Benzene(BEN)and cyclohexane(CYH),which have very close boiling points and a binary azeotrope,are the most difficult binary components in the separation of aromatic and non-aromatic hydrocarbons.This study further explored the separation mechanism and industrial application prospects of BEN+CYH mixtures separated by a dicationic ionic liquid(DIL)[C_(5)(MIM)_(2)][NTf_(2)]_(2) based on experimental research.The calculation results of the Conductor-like Screening model Segment Activity Coefficient(COSMO-SAC)model show that selectivity and solvent capacity of the DIL are significantly improved.The effects of different anions and cations on the micro-structure distribution and diffusion behavior of BEN+CYH system were investigated by quantum chemistry(QC)calculations and molecular dynamics(MD)simulations.The results indicate that the anion[NTf_(2)]_(2)has low polarity,uniform charge distribution,and a dual role of hydrogen bonding andπ-πbonding,and the cation[C_(5)(MIM)_(2)]^(2+) has stronger interaction with BEN and higher selectivity than conventional cations.The liquid-liquid extraction and extractive distillation(LLE-ED)process using an optimized 65 mol/mol DIL+35 mol/mol H_(2)O mixed solution as the extractant was proposed,which solved the problem of low product purity in the LLE process and high energy consumption in the ED process.Under the best operating conditions,the purity of CYH product was 99.9%,the purity of BEN product was 99.6%,the recovery rate of BEN reached 99.9%,and the recovery rate of DIL reached 99.9%.The heat-integrated LLE-ED process reduced total annual cost by 21.6%,and reduced CO_(2) emissions by 48.0%,which has broad industrial application prospects.
基金The authors acknowledge financial support from the National Key Research and Development Program of China(2018YFB0703802)the National Natural Science Foundation of China(Grant Nos.51705504,21972153,and 51675512)+3 种基金the China Postdoctoral Science Foundation Funded Project(2019M653798)the Youth Innovation Promotion Association of CAS(2018454)the pre-research project in the manned space field(040101)the Gansu Province Science and Technology Plan(18ZD2WA011).
文摘A series of new halogen-free dicationic ionic liquids(ILs)with different alkyl chain lengths were prepared,and the relationship between the alkyl chain length,physicochemical and tribological properties of ILs,and their role as neat lubricant for steel–steel friction pairs,was investigated.Evaluation of stability during hydrolysis and copper strip corrosion test results show that synthetic ILs are stable and not corrosive to metal contacts,due to the halogen-free anions.The friction and wear test results indicate that ILs with long alkyl chains have excellent friction-reducing and anti-wear properties,especially at high temperatures.Based on the surface three-dimensional(3D)profiles,electrical contact resistance,scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),and the X-ray photoelectron spectrometry(XPS)analysis of the worn surfaces of steel discs,we can conclude that the efficiency of ILs is due to the formation of high quality tribofilms that consist of both tribochemical reaction and ordered absorption films.
基金the Shahid Chamran University of Ahvaz for its financial support(No.2013)
文摘In this work,an effective,task specific,dicationic,podand-like ionic liquid was synthesized and applied to improve the capability features of click reaction.Moreover,to broaden the scope and decreasing the serious limitations of preparation methods of organic azides,a simple green procedure for the preparation of alkyl azides,the fundamental starting materials in click reactions,from alcohols under solvent-free conditions and microwave irradiation has been reported,for the first time.