Enantiomeric Separation Of Phenoxy Acid Methyl Esters By Gas Chromatography Using Derivatized Beta Cyclodextrins As Stationary Phases
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Author | : Nadnudda Rodthongkum |
Publisher | : |
Total Pages | : 262 |
Release | : 2005 |
Genre | : Cyclodextrins |
ISBN | : 9789745325036 |
Download Enantiomeric Separation of Phenoxy Acid Methyl Esters by Gas Chromatography Using Derivatized Beta-cyclodextrins as Stationary Phases Book in PDF, Epub and Kindle
Author | : Tasanee Maha-ard |
Publisher | : |
Total Pages | : 128 |
Release | : 2009 |
Genre | : Gas chromatography |
ISBN | : |
Download Enantiomeric Separation of Phenoxy Acid Methyl Esters by Gas Chromatography Using 2,3,-di-O-methyl-6-0-tert-butyldimethylsilyl Derivatives of Alpha- and Gamma-cyclodextrins as Stationary Phases Book in PDF, Epub and Kindle
Author | : Pattama Changseeplag |
Publisher | : |
Total Pages | : 238 |
Release | : 2002 |
Genre | : Cyclodextrins |
ISBN | : 9789741718962 |
Download Enantiomeric Separation of Esters by Gas Chromatography Using Derivatized Bata-cyclodextrins as Stationary Phases Book in PDF, Epub and Kindle
Enantiomeric separations of some esters were studied by means of capillary gas chromatography using heptakis(2,3-di-O-methyl-6-O-tert-butyldimethylsilyl) cyclomaltoheptaose (or BSiMe) and heptakis(2,3-di-O-acetyl-6-O-tert-butyldimethylsilyl)cyclomaltoheptaose (or BSiAc) as stationary phases. The influence of analyte structure, e.g. the type and position of substituent together with ester chain length, on retention and enantioselectivity was systematically investigated. Thermodynamic data were also calculated in order to clarify the strength of analyte-stationary phase interaction and enantioselectivity towards these selected groups of esters. All esters with different substitution patterns were successfully separated with either BSiMe or BSiAc, or otherwise both of them. Generally, BSiAc phase exhibited greater enantioselectivity towards most analytes than BSiMe phase. From chromatographic and thermodynamic data obtained, it can be concluded that the structure of ester analytes plays an important role on separation. In most cases, the interaction of these two phases towards esters slightly increased with lengthening alkyl chain while enantioselectivity significantly decreased. Also, changing the position of substituent or chiral center caused changes in the interaction and enantioselectivity. Moreover, the degrees of interaction strength and sites as well as enantioselectivity of these esters depended upon the size and polarity of substituents.
Author | : Wilfried A. König |
Publisher | : |
Total Pages | : 184 |
Release | : 1992 |
Genre | : Science |
ISBN | : |
Download Gas Chromatographic Enantiomer Separation with Modified Cyclodextrins Book in PDF, Epub and Kindle
Author | : |
Publisher | : |
Total Pages | : |
Release | : 2004 |
Genre | : Cyclodextrins |
ISBN | : 9789741761289 |
Download Enantiomeric Separation of Epoxides by Gas Chromatography Using Derivatized Beta-cyclodextrin as Stationary Phase Book in PDF, Epub and Kindle
Eanatiomeric separations of aromatic epoxides were studied by means of capillary gas chromatography using heptakis(2,3,di-O-methyl-6-O-tert-butyldi methylisilyl)cyclomaltoheptaose (or BSiMe) and heptakis(2,3-di-O-acetyl-6-O-tert-butyldimethylsiloyl)cyclomaltoheptaose (or BSiAc) as chiral stationary phases. The effects of substitution types and position of styrene oxide derivatives on retention and enantioselectivity have been investigated. Thermodynamic data on the interaction of enantiomers with chiral stationary phases were collected in detail in order to clarify the strength of analyte-stationary phase interaction and enantioselectivity towards the selected groups of epoxides. All eposides with different substitution type and position were successfully separated with either BSiMe or BSiAc, or otherwise both of them. On both columns, the number, type, and position of analyte substitution have a strong influence on enantioselectivity. The type of substituent on cyclodextrin molecule (BSiMe vs.BSiAc) also affect enatioselectivity of epoxides greatly. Both columns can be used to compliment one another as their resolving abilities are quite opposite.
Author | : Weiyong Li |
Publisher | : |
Total Pages | : 138 |
Release | : 1991 |
Genre | : |
ISBN | : |
Download Enantiomeric Separation by Capillary Gas Chromatography Using Derivatized Cyclodextrin Stationary Phases Book in PDF, Epub and Kindle
Author | : Saithip Charoenchaiworakit |
Publisher | : |
Total Pages | : 154 |
Release | : 2014 |
Genre | : Amines |
ISBN | : |
Download ENANTIOMERIC SEPARATION OF AMINES BY GAS CHROMATOGRAPHY USING ACETYL-DERIVATIZED BETA-CYCLODEXTRIN AS STATIONARY PHASE Book in PDF, Epub and Kindle
The enantioseparation of 49 trifluoroacetyl amine derivatives was studied by gas chromatography using heptakis(2,3-di-O-acetyl-6-O-tert-butyldimethylsilyl)-beta-cyclodextrin (or BSiAc) as a chiral stationary phase. The effects of temperature and amine structure (type and position of substitution) on retention and enantioselectivity were studied. BSiAc could resolve enantiomers of 45 amines. For 1-phenylethylamines, the position of substitution played a major role on enantioseparation than the type of substitution: analytes with meta-substitution showed good enantioseparation. The effect of type of substitution at the stereogenic center was also investigated. BSiAc showed better enantioseparation towards 1-phenylpropylamines or 1-aminoindans than 1-phenylethylamines. However, BSiAc showed poor or no enantioseparation towards phenyl phenyl methanamines which have a large phenyl group at the stereogenic center. Among all analytes tested in this study, 3CF3 showed strong temperature dependency and could be completely enantioseparated with the shortest analysis time.
Author | : Stig G. Allenmark |
Publisher | : Ellis Horwood |
Total Pages | : 296 |
Release | : 1991 |
Genre | : Science |
ISBN | : |
Download Chromatographic Enantioseparation Book in PDF, Epub and Kindle
Author | : Rex W. Souter |
Publisher | : CRC Press |
Total Pages | : 256 |
Release | : 1985-12-10 |
Genre | : Medical |
ISBN | : 9780849361272 |
Download Chromatographic Separations of Stereoisomers Book in PDF, Epub and Kindle
Provides current knowledge about separation and interactions of asymmetric molecules, as well as experimental and commercial ma-terials such as columns, instruments, and derivatization reagents. Extensive applications are tabulated by both chromato-graphic technique and compound class, and discussions of recent special topics are useful in planning new work. This unique volume organizes most of the significant, currently available knowledge re-garding the chromatographic separations of stereoisomers. Both diastereomers and the more difficult, controversial area of enan-tiomers are covered in depth with respect to GC, HPLC, and classi-cal chromatographic techniques. Analytical, organic, pharmaceuti-cal, and other chemists as well as pharmacologists and bio-chemists are among those whose work appears in the more than 800 references cite.
Author | : Ornuma Konghuirob |
Publisher | : |
Total Pages | : 216 |
Release | : 2004 |
Genre | : Alcohol |
ISBN | : 9789745314641 |
Download Enantiomeric Separation of Alcohols by Gas Chromatography Using Cyclodextrin Derivatives as Stationary Phases Book in PDF, Epub and Kindle
Enantiomeric separations of 70 alcohols were studied by means of capillary gas chromatography using heptakis(2,3-di-O-¬methyl-6-O-tert-butyldimethylsilyl)cyclomaltoheptasose (or BSiMe) and octakis(2,3-di-O-¬methyl-6-O-tert-butyldimethylsilyl)cyclomaltooctaose (or GSiMe) as chiral stationary phases. The influence of analyte structure, e.g. the type and position of substituent, alcohol chain length, the position of chiral center, and main-structure of alcohols, on retention and enantioselectivity was systematically investigated. Thermodynamic data were also calculated to clarify the strength of analyte-stationary phase interaction and enantioselectivity towards the selected group of alcohols. All of alcohols studied, except for 35F and 2oct, were successfully separated with either BSiMe or GSiMe, or both of them. Generally, BSiMe phase exhibited grater enantioseparation towards most analytes than GSiMe phase. On both columns, the structure of alcohol analytes plays an important role on separation. Changing the position of substituent or chiral center causes changes in the interaction and enantioselectivity. The type and size of substituent also significantly affect enantioselectivity. In addition to the analyte structure, the size of cyclodextrin molecules greatly affects enantioselectivity.