In order to study the polar substituent effect almost with no steric effect in organophosphorus chemistry,a series of 4-substituted-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane 1-oxides(1)and p-substituted phenylphospho...In order to study the polar substituent effect almost with no steric effect in organophosphorus chemistry,a series of 4-substituted-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane 1-oxides(1)and p-substituted phenylphosphonates(2)and corresponding mono hexyl esters(3)as model were synthesized.^(31)P-NMR chemical shifts of compounds(1)in methanol and deuterioacetone were determined.The Δδ values reflect 4-sbstituent po- lar effect.The ^(31)P-NMR of compounds(2)and(3)and the pKa of compounds(3)were also measured.The results showed that the trend of polar effects of substituents in both carboxylic and organophosphates chemistry are similar,and the change of polar effects in variation with the alkyl groups is not significant.展开更多
Investigation of the relationship between chemical structure and extraction properties of organic ligands can, in very practical terms, contribute both to the discovery of new selective extractants and to the progress...Investigation of the relationship between chemical structure and extraction properties of organic ligands can, in very practical terms, contribute both to the discovery of new selective extractants and to the progress of extraction chemistry in general. Since the metal extraction, which is based on the formation of complex by organic ligands with metal ions or corresponding ionic species, may展开更多
The electronic structures of 17 perchlorofluoroolefins and perfluoroolefins were calculated using the MNDO method.Based on these calculations combined with the perturbation theory,a good structure-reactivity relations...The electronic structures of 17 perchlorofluoroolefins and perfluoroolefins were calculated using the MNDO method.Based on these calculations combined with the perturbation theory,a good structure-reactivity relationship of perchlorofluoroolefins has been established.In the case of internal ole- fins,the direction of nucleophilic attack is governed not only by the perturbation energy of the ground state,but also by the stability of the anionic intermediate and the activation energy of the reaction.展开更多
MNDO and MM2(85)methods were used to study the conformation and the structure- reactivity relationship of neutral and acidic phosphorus esters.The calculation results indicate that for the most stable conformation,the...MNDO and MM2(85)methods were used to study the conformation and the structure- reactivity relationship of neutral and acidic phosphorus esters.The calculation results indicate that for the most stable conformation,the charge density of phosphoryl oxygen(q_O)is determined not only by the electronegativity of the substituents,but also by the conformation of the alkoxyl groups on the phosphorus atom.Meanwhile,the conformation of the alkoxyl group provides,as a rule, more important influence on the charge density of the phosphoryl oxygen.However,the energy of the highest occupied molecular orbital(EHOMO)is basically dependent on the eletronegativity of the substituents,while the donating ability or the withdrawing ability of the neutral phosphorus com- pounds is mainly governed by the EHOMO but not the q_O.This is also true for other kinds of the neutral oxygen-containing compounds.展开更多
alkoxy-propylamines, C12H25O（CH2）3NH2, C14H29O（CH2）3NH2, C16H33O（CH2）3NH2, C18H37O-（CH2）3NH2 were synthesized from aliphatic alcohol and acrylonitrile. The flotation tests of kaolinite, pyrophyllite and illite...alkoxy-propylamines, C12H25O（CH2）3NH2, C14H29O（CH2）3NH2, C16H33O（CH2）3NH2, C18H37O-（CH2）3NH2 were synthesized from aliphatic alcohol and acrylonitrile. The flotation tests of kaolinite, pyrophyllite and illite were conducted. The flotation mechanisms were explained in view of the structures of reagents and aluminium silicate minerals, zeta potential and Fourier transform infrared spectrum measurements. The results show that the synthesized r-alkoxy-propylamines are more effective than dodecyl amine for flotation of kaolinite, pyrophyllite and illite. For flotation kaolinite and illite, the collecting ability is in the order of C18H37O（CH2）3NH2>C16H33O-（CH2）3NH2>C14H29O（CH2）3NH2>C12H25O（CH2）3NH2, but the r-alkoxy-propylamines types of collectors have almost the same collecting ability on pyrophyllite, which demonstrating that γ-alkoxy-propylamines are new selective collectors for reverse floatation to remove aluminium silicate minerals from bauxite.展开更多
The design and fabrication of solid nanomaterials are the key issues in heterogeneous catalysis to achieve desired performance.Traditionally,the main theme is to reduce the size of the catalyst particles as small as p...The design and fabrication of solid nanomaterials are the key issues in heterogeneous catalysis to achieve desired performance.Traditionally,the main theme is to reduce the size of the catalyst particles as small as possible for maximizing the number of active sites.In recent years,the rapid advancement in materials science has enabled us to fabricate catalyst particles with tuna-ble morphology.Consequently,both size modulation and morphology control of the catalyst particles can be achieved inde-pendently or synergistically to optimize their catalytic properties.In particular,morphology control of solid catalyst particles at the nanometer level can selectively expose the reactive crystal facets,and thus drastically promote their catalytic performance.In this review,we summarize our recent work on the morphology impact of Co_(3)0_(4),CeO_(2)and Fe_(2)0_(3)nanomaterials in catalytic reactions,together with related literature on morphology-dependent nanocatalysis of metal oxides,to demonstrate the importance of tuning the shape of oxide-nanocatalysts for prompting their activity,selectivity and stability,which is a rapidly growing topic in heterogeneous catalysis.The fundamental understanding of the active sites in morphology-tunable oxides that are enclosed by reactive crystal facets is expected to direct the development of highly efficient nanocatalysts.展开更多
Fluorinated liquid crystal monomers(LCMs)are begun to emerge as new persistent organic pollutants.Herein,the structure-reactivity relationships of fluorinated LCMs 1,2,3-trifluoro-5-[3-(3-propylcyclohexyl)cyclohexyl]b...Fluorinated liquid crystal monomers(LCMs)are begun to emerge as new persistent organic pollutants.Herein,the structure-reactivity relationships of fluorinated LCMs 1,2,3-trifluoro-5-[3-(3-propylcyclohexyl)cyclohexyl]benzene(TPrCB),1,2-difluoro-4-[trans-4-(trans-4-propylcyclohexyl)cyclohexyl]benzene(DPrCB),4-[(trans,trans)-4'-(3-Buten-1-yl)[1,10-bicyclohexyl]-4-yl]-1,2-difluoro-benzene(BBDB)and 1-[4-(4-ethylcyclohexyl)cyclohexyl]-4(trifluoromethoxy)benzene(ECTB)subject to photocatalysis-generated oxidation species were investigated.The degradation rate constant of BBDB was 3.0,2.6,and 6.8 times higher than DPrCB,TPrCB and ECTB,respectively.The results reveal that BBDB,DPrCB and TPrCB had mainly negative electrostatic potential(ESP)regions which were vulnerable to electrophilic attack by h^(+),·OH and·O_(2)^(-),while ECTB was composed of mainly positive ESP regions which were vulnerable to nucleophilic attack by·OH and·O_(2)^(-).The detoxification processes of BBDB,DPrCB and TPrCB included carbon bond cleavage and benzene ring opening.However,the methoxy group of ECTB reduced the nucleophilic reactivity on the benzene ring,leading to slower detoxification efficiency.These findings may help to develop LCMs treatment technologies based on structure-reactivity relationships。展开更多
基金Project Supported by National Science Foundation of China.
文摘In order to study the polar substituent effect almost with no steric effect in organophosphorus chemistry,a series of 4-substituted-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane 1-oxides(1)and p-substituted phenylphosphonates(2)and corresponding mono hexyl esters(3)as model were synthesized.^(31)P-NMR chemical shifts of compounds(1)in methanol and deuterioacetone were determined.The Δδ values reflect 4-sbstituent po- lar effect.The ^(31)P-NMR of compounds(2)and(3)and the pKa of compounds(3)were also measured.The results showed that the trend of polar effects of substituents in both carboxylic and organophosphates chemistry are similar,and the change of polar effects in variation with the alkyl groups is not significant.
基金Project supported by the National Natural Science Foundation of China
文摘Investigation of the relationship between chemical structure and extraction properties of organic ligands can, in very practical terms, contribute both to the discovery of new selective extractants and to the progress of extraction chemistry in general. Since the metal extraction, which is based on the formation of complex by organic ligands with metal ions or corresponding ionic species, may
基金Part Ⅶ was published in Tetrahedron Letter,31,1307 (1990).
文摘The electronic structures of 17 perchlorofluoroolefins and perfluoroolefins were calculated using the MNDO method.Based on these calculations combined with the perturbation theory,a good structure-reactivity relationship of perchlorofluoroolefins has been established.In the case of internal ole- fins,the direction of nucleophilic attack is governed not only by the perturbation energy of the ground state,but also by the stability of the anionic intermediate and the activation energy of the reaction.
基金the National Natural Science Foundation of China and the Key Laboratory of Computer Chemistry of Chinese Academy of Sciences.
文摘MNDO and MM2(85)methods were used to study the conformation and the structure- reactivity relationship of neutral and acidic phosphorus esters.The calculation results indicate that for the most stable conformation,the charge density of phosphoryl oxygen(q_O)is determined not only by the electronegativity of the substituents,but also by the conformation of the alkoxyl groups on the phosphorus atom.Meanwhile,the conformation of the alkoxyl group provides,as a rule, more important influence on the charge density of the phosphoryl oxygen.However,the energy of the highest occupied molecular orbital(EHOMO)is basically dependent on the eletronegativity of the substituents,while the donating ability or the withdrawing ability of the neutral phosphorus com- pounds is mainly governed by the EHOMO but not the q_O.This is also true for other kinds of the neutral oxygen-containing compounds.
文摘alkoxy-propylamines, C12H25O（CH2）3NH2, C14H29O（CH2）3NH2, C16H33O（CH2）3NH2, C18H37O-（CH2）3NH2 were synthesized from aliphatic alcohol and acrylonitrile. The flotation tests of kaolinite, pyrophyllite and illite were conducted. The flotation mechanisms were explained in view of the structures of reagents and aluminium silicate minerals, zeta potential and Fourier transform infrared spectrum measurements. The results show that the synthesized r-alkoxy-propylamines are more effective than dodecyl amine for flotation of kaolinite, pyrophyllite and illite. For flotation kaolinite and illite, the collecting ability is in the order of C18H37O（CH2）3NH2>C16H33O-（CH2）3NH2>C14H29O（CH2）3NH2>C12H25O（CH2）3NH2, but the r-alkoxy-propylamines types of collectors have almost the same collecting ability on pyrophyllite, which demonstrating that γ-alkoxy-propylamines are new selective collectors for reverse floatation to remove aluminium silicate minerals from bauxite.
基金supported by the National Natural Science Foundation of China(20923001,21025312)
文摘The design and fabrication of solid nanomaterials are the key issues in heterogeneous catalysis to achieve desired performance.Traditionally,the main theme is to reduce the size of the catalyst particles as small as possible for maximizing the number of active sites.In recent years,the rapid advancement in materials science has enabled us to fabricate catalyst particles with tuna-ble morphology.Consequently,both size modulation and morphology control of the catalyst particles can be achieved inde-pendently or synergistically to optimize their catalytic properties.In particular,morphology control of solid catalyst particles at the nanometer level can selectively expose the reactive crystal facets,and thus drastically promote their catalytic performance.In this review,we summarize our recent work on the morphology impact of Co_(3)0_(4),CeO_(2)and Fe_(2)0_(3)nanomaterials in catalytic reactions,together with related literature on morphology-dependent nanocatalysis of metal oxides,to demonstrate the importance of tuning the shape of oxide-nanocatalysts for prompting their activity,selectivity and stability,which is a rapidly growing topic in heterogeneous catalysis.The fundamental understanding of the active sites in morphology-tunable oxides that are enclosed by reactive crystal facets is expected to direct the development of highly efficient nanocatalysts.
基金supported by the Guangdong Basic and Applied Basic Research Foundation(No.2020B1515020038)the Pearl River Talent Recruitment Program of Guangdong Province(2019QN01L148)+3 种基金the National Natural Science Foundation of China(21876063 and 22076064)the Guangdong Special Support Program(2019TX05L129)the Guangdong(China)Innovative and Entrepreneurial Research Team Program(2016ZT06N258)the Special Fund Project for Science and Technology Innovation Strategy of Guangdong Province(2019B121205004).
文摘Fluorinated liquid crystal monomers(LCMs)are begun to emerge as new persistent organic pollutants.Herein,the structure-reactivity relationships of fluorinated LCMs 1,2,3-trifluoro-5-[3-(3-propylcyclohexyl)cyclohexyl]benzene(TPrCB),1,2-difluoro-4-[trans-4-(trans-4-propylcyclohexyl)cyclohexyl]benzene(DPrCB),4-[(trans,trans)-4'-(3-Buten-1-yl)[1,10-bicyclohexyl]-4-yl]-1,2-difluoro-benzene(BBDB)and 1-[4-(4-ethylcyclohexyl)cyclohexyl]-4(trifluoromethoxy)benzene(ECTB)subject to photocatalysis-generated oxidation species were investigated.The degradation rate constant of BBDB was 3.0,2.6,and 6.8 times higher than DPrCB,TPrCB and ECTB,respectively.The results reveal that BBDB,DPrCB and TPrCB had mainly negative electrostatic potential(ESP)regions which were vulnerable to electrophilic attack by h^(+),·OH and·O_(2)^(-),while ECTB was composed of mainly positive ESP regions which were vulnerable to nucleophilic attack by·OH and·O_(2)^(-).The detoxification processes of BBDB,DPrCB and TPrCB included carbon bond cleavage and benzene ring opening.However,the methoxy group of ECTB reduced the nucleophilic reactivity on the benzene ring,leading to slower detoxification efficiency.These findings may help to develop LCMs treatment technologies based on structure-reactivity relationships。
