【摘 要】
:
Oximes are occurred usually as a mixture of Z-and E-isomers in nature and in preparation.Due to the interconversion of oximes [1,2],the Z-and E-isomers are difficult to be separated completely.In this
【机 构】
:
Dept.of Chem.& Chem.Eng.,Foshan Univ.,Foshan 528000,China
【出 处】
:
The 6th International Conference on Separation and Technolog
论文部分内容阅读
Oximes are occurred usually as a mixture of Z-and E-isomers in nature and in preparation.Due to the interconversion of oximes [1,2],the Z-and E-isomers are difficult to be separated completely.In this study,heptanaldoxime and phenylacetaldoxime were synthesized from their respective aldehydes.The products are being heated in solvent causes Z-isomer-to-E-isomer conversion as time increases,to establish equilibrium.Mass spectrometry cannot readily distinguish the each isomer where molecular ions and firagmentation patterns are essentially the same.The isomerisation was revealed by 1D GC and NMR spectra,respectively.In addition,the equilibrated mixture of isomers was investigated by 1D GC on both polar and nonpolar column phases.The results showed that the interconversion rate on polar column phase (SolGel WAX) is faster than on nonpolar column phase (Sol Gel-lms),and higher temperature or higher pressure in either polar or nonpolar column lead to higher extent of interconversion,which resulted in the more difficult isomers separation.1D GC (wax column) does not lead to the separation of Z-and E-isomers because of a broad overlapping band which comprise the interconversion zone.GC × GC was arranged for the isomers separation of oximes,and it provided discrete separation on the second column,of the overlapping peaks on the first column (Figure.1).
其他文献
The seeds of Ziziphus jujuba Mill var.spinosa (Bunge) Hu ex.H.F.Chou (Rhamnaceae,Zizyphi Spinosi Semen,ZSS) are used as a sedative medicine in China [1].In recent research,however,we found that two fl
High-speed countercurrent chromatography (HSCCC) is a continuous and efficient liquid-liquid chromatography.Because there is no solid support,the separation of substances are achieved based on the dif
N-methylpyrrolidine is used as raw material for synthesis of cefepime hydrochloride.A N-methylpyrrolidine group which may be decomposed from cephalosporin-ene skeleton lies in three side chain of cefe
Poly (vinyl acetate-trialIyl isocyanurate-divinylbenzene) matrix coupled with oligo-β-cyclodextrin was synthesized to separate puerarin.The porous surface morphology and porous structure were investig
Room Temperature Ionic Liquids (RTILs),owing to their attributes,e.g.,negligible vapor pressure,have been expected to be the green solvents which could substitute the widely used volatile organic solv
A worldwide use of reverse osmosis (RO) is increasing in seawater desalination and brackish water treatment (1-4).However,many desalination plants using membrane filtration continuously have had probl
Hybrid membranes of chitosan(CS)/poly(vinyl pyrrolidone)(PVP)/1,2-bis(triethoxysilyl) ethane(BTEE) were prepared via a sol-gel method for pervaporation [1-3].The membranes were characterized by Fourie
Ellagic acid is currently considered for use as a cancer chemopreventive drug.It has also been reported that EA can inhibit the mutagenicity and carcinogenicity in a wide range of mutagents [1-3].EA h
Recently,Korea and Japan have been investigating low-rank coal upgrading technology using solvent extraction.The solvent extraction is the technology to separate only combustible matters from low-rank
To compare the chemical composition of volatile oils in herbal pair Flos caryophylli-Wenyujin extracted by different polar solvents,petroleum ether,ethyl acetate,and ethanol were used in this work.The