Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Download Gas Chromatographic Enantiomer Separation With Modified Cyclodextrins full books in PDF, epub, and Kindle. Read online Gas Chromatographic Enantiomer Separation With Modified Cyclodextrins ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Author : Wilfried A. König
Publisher :
ISBN 13 :
Total Pages : 184 pages
Book Rating : 4.0/5 ( download)
Download or read book Gas Chromatographic Enantiomer Separation with Modified Cyclodextrins written by Wilfried A. König and published by . This book was released on 1992 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Wolfgang König
Publisher : Wiley-VCH
ISBN 13 : 9783527297122
Total Pages : 152 pages
Book Rating : 4.2/5 (971 download)
Download or read book Gas Chromatographic Enantiomer Separation with Modified Cyclodextrins written by Wolfgang König and published by Wiley-VCH. This book was released on 1999-01-06 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Weihua Tang
Publisher : Springer Science & Business Media
ISBN 13 : 3642376487
Total Pages : 266 pages
Book Rating : 4.6/5 (423 download)
Download or read book Modified Cyclodextrins for Chiral Separation written by Weihua Tang and published by Springer Science & Business Media. This book was released on 2013-05-24 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modified Cyclodextrins for Chiral Separation offers a review of the latest advances in developing modified cyclodextrins as chiral selectors for various chromatographic and electromigration techniques. Over the years, many descriptions of chiral separation have appeared in academic journals and books, but most of them have been devoted to either the development of analytical methods and protocols or the summary of different chiral selectors, including cyclodextrins for chiral separation applications. This is in marked contrast to this volume which focuses on the research endeavors concerning the development of cyclodextrin derivatives specifically as either chiral mobile phases for capillary electrophoresis, or chiral stationary phases for various chromatographic techniques including gas chromatography, or high-performance liquid chromatography and supercritical fluid chromatography. The ongoing thread in this book is the synthesis of structurally-defined cyclodextrin derivatives and their applications in enantiomer separation by means of different analytical techniques. Modified Cyclodextrins for Chiral Separation is intended for those who are interested in expanding their knowledge of cyclodextrin chemistry and chiral separation, and in what cyclodextrin modification can be made to suit the needs of chiral selectors for different analytical techniques. It primarily focuses on the state-of-the-art cyclodextrin chemistry which is the basis for all chiral selectors used in these chiral separation techniques. Weihua Tang, PhD, is a professor at the Key Laboratory of Soft Chemistry and Functional Materials, Ministry of Education, Nanjing University of Science and Technology, China. Siu-Choon Ng, PhD, is a professor at the Division of Chemical and Biomedical Engineering, School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore. Dongping Sun, PhD, is a professor at the Key Laboratory of Soft Chemistry and Functional Materials, Ministry of Education, Nanjing University of Science and Technology, China.
Download or read book Modified Cyclodextrins as Chiral Stationary Phases for Capillary Gas Chromatographic Separation of Enantiomers written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Cyclodextrin (CD) derivatives are widely used as chiral stationary phases in capillary gas chromatography. Their performance depends substantially on the side chains attached to the hydroxyl groups of the glucose moieties. In this study new classes of CD-derivatives suitable for gas chromatographic (GC) separation of enantiomers were synthesized by introducing (i) acetal functions and (ii) chiral acyl moieties at positions 2 and 3 of the glucose units. Octakis(2,3-di-O-methoxymethyl-6-O-tert-butyldimethylsilyl)-g-cyclodextrin (2,3- MOM-6-TBDMS-g-CD) obtained by reaction of 6-O-TBDMS-g-cyclodextrin with methoxymethylchloride (MOM-Cl) was synthesized as first representative of cyclodextrin GC stationary phases containing alkoxymethyl side chains. The structure was confirmed by NMR and mass spectrometry. The suitability of the material diluted in polysiloxane as GC stationary phase was shown. Enantioseparations could be achieved for a broad spectrum of chiral volatiles from various chemical classes. Structural influences of the analytes on the enantiodifferentiations were demonstrated. High separation factors were observed for the hydroxyketone acetoin (a = 1.8) and some methyl branched ketones. Pronounced enantioseparations were also determined for cyclic pentenolone and furanone derivatives. To investigate the impact of the size of the CD torus, the 2,3-MOM-derivatives of the b- and a-CD analogs were synthesized. The spectrum of compounds for which enantiomers could be separated on 2,3-MOM-6-TBDMS-b-CD was more limited and the enantioseparations achieved were generally less pronounced compared to the g-CD derivative. However, for 2-alkyl esters unusually high separation factors (a up to 4.31) were observed. Using 2-pentyl acetate as example, phenomena underlying the enantioseparation were investigated by determining thermodynamic parameters. The data showed that only one enantiomer is retained significantly on the chiral stationary phase whereas the other one behaves.
Download or read book Gas Chromatographic Enantiomer Separation of Atropisomeric PCBs Using Modified Cyclodextrins as Chiral Phases written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Adel Khalil Mish'al
Publisher :
ISBN 13 :
Total Pages : 366 pages
Book Rating : 4.:/5 (895 download)
Download or read book Gas Chromatographic Enantiomer Separation with Modified _-cyclodextrins written by Adel Khalil Mish'al and published by . This book was released on 1997 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Adel Khalil Abdulla Mish'al
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (127 download)
Download or read book Gas Chromatographic Enantiomer Separation with Modified B-cyclodextrin written by Adel Khalil Abdulla Mish'al and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Eisuke Takahisa
Publisher :
ISBN 13 :
Total Pages : 230 pages
Book Rating : 4.:/5 (163 download)
Download or read book Modified Cyclodextrins as Chiral Stationary Phases for Capillary Gas Chromatographic Separation of Enantiomers written by Eisuke Takahisa and published by . This book was released on 2005 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Sheree N. Allen
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (787 download)
Download or read book The Preparation of Novel Modified Cyclodextrins and Their Application in Enantioseparations by Gas Chromatography written by Sheree N. Allen and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Since biological processes depend on the stereospecific creation and conversion of chiral molecules, each enantiomer of a molecule can have a different biological effect. While numerous synthetic drugs are sold in racemic form for reasons of cost and convenience, in many cases one of the two enantiomers of a drug will cause undesirable and perhaps even devastating effects. Therefore, effective methods for the separation and quantification of enantiomers are of great importance. Enantiomers can be separated only with the use of systems containing an optically active chiral selector. Modified cyclodextrins (CDs) are widely used as chiral selectors by virtue of their ability to form inclusion complexes. Because of the remarkably high efficiency, and sensitivity of chiral gas chromatography (GC), chiral separations by this method represent a preferred method for enantiomer analysis. The basic property of CDs that allows them to be successful for enantiomer separations is their ability to form selective inclusion complexes with a wide variety of organic molecules. The preparation and application of modified cyclodextrins for the GC separation of enantiomers is a focal point of this research. In effort to identify useful new derivatives, modifications involving unique and separate reaction of the secondary hydroxyl groups and/or annulations bridging the secondary oxygens have been examined. Several new cyclodextrin derivatives, e.g. per(6-OTBS-2,3-O-diformyl)-[beta]-CD, per(6-OTBS-2,3-O-cyclodimethylsilyl)-[beta]-CD, per(6-deoxy-2,3-O-cyclodimethylsilyl)-[beta]-CD and a mixed formyl/acetyl phase have been synthesized and evaluated as components of stationary phases for capillary GC. The efficiency of each new phase to separate enantiomers was evaluated against a 30 analyte panel to evaluate the influence of the different substituents on the selectivity. These enantioseparations were also compared to those observed on four commercially available chiral phases using the same 30 analyte panel. Overall, this work resulted in nine new CD derivatives and the discovery of a new chiral selector that is comparable in efficiency to what is currently commercially available.
Author : Volker Schurig
Publisher : Springer
ISBN 13 : 3319032399
Total Pages : 286 pages
Book Rating : 4.3/5 (19 download)
Download or read book Differentiation of Enantiomers I written by Volker Schurig and published by Springer. This book was released on 2013-12-16 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series Topics in Current Chemistry presents critical reviews of the present and future trends in modern chemical research. The scope of coverage is all areas of chemical science including the interfaces with related disciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the non-specialist reader, whether in academia or industry, a comprehensive insight into an area where new research is emerging which is of interest to a larger scientific audience. Each review within the volume critically surveys one aspect of that topic and places it within the context of the volume as a whole. The most significant developments of the last 5 to 10 years are presented using selected examples to illustrate the principles discussed. The coverage is not intended to be an exhaustive summary of the field or include large quantities of data, but should rather be conceptual, concentrating on the methodological thinking that will allow the non-specialist reader to understand the information presented. Contributions also offer an outlook on potential future developments in the field.
![Download Design and Synthesis of Novel [beta]-cyclodextrins and Their Application as Chiral Stationary Phases for Gas Chromatography PDF Online Free](https://books.google.com/books/content/images/frontcover/DX6zAQAACAAJ?fife=w200-h370)
Author : Tiffany R. Turner Hayden
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (787 download)
Download or read book Design and Synthesis of Novel [beta]-cyclodextrins and Their Application as Chiral Stationary Phases for Gas Chromatography written by Tiffany R. Turner Hayden and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Enantiomers can be directly separated only with use of systems containing a chiral selector. Cyclodextrins (CDs) and modified cyclodextrins have been used as chiral selectors for their ability to form host-guest complexes with various analytes. The scaffold of the CD allows for assembly of functional groups with controlled geometry. CDs can be readily modified through substitution of the hydroxyl groups, giving rise to derivatives with significantly different properties, especially increased solubility and controlling the hydrophobicity of the cavity. Even though CDs can be readily modified, the syntheses can be tedious and complicated with various protecting group strategies to control the reactivity of the various alcohols. The preparation of modified cyclodextrins for use as chiral stationary phases (CSP) for gas chromatography (GC) is the focal point of this research. Our effort to identify useful new [beta]-CD derivatives involved attempts to make bridged (annulated) derivatives, could increase the thermal stability of the derivatives, and change the length, width and polarity of the CD cavity. To date, there are no reports of annulated CD derivatives in the chemical literature. In the process of evaluating a wide range of electrophiles that could accomplish annulation, several new [beta]-CD derivatives, i.e., per(6-O-TBS-2,3-O-cyclodimethylsilyl)- [beta]-CD, per(6-O-TBS-2,3-O-cyclodiphenylsilyl)- [beta]-CD, per(6-O-Pivaloyl-2,3-O-cyclodimethylsilyl)-[beta]-CD, per(6-deoxy-2,3-O-methyl)- [beta]-CD, and per(6-deoxy-2,3-O-allyl)- [beta]-CD, were synthesized. Two of the new derivatives were evaluated as components of stationary phases for GC, per(6-O-TBS-2,3-Ocyclodimethylsilyl)-[beta]-CD and per(6-deoxy-2,3-O-methyl)-[beta]-CD. Overall, this work resulted in five new CD derivatives.
Author : Weiyong Li
Publisher :
ISBN 13 :
Total Pages : 138 pages
Book Rating : 4.:/5 (25 download)
Download or read book Enantiomeric Separation by Capillary Gas Chromatography Using Derivatized Cyclodextrin Stationary Phases written by Weiyong Li and published by . This book was released on 1991 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Pattama Changseeplag
Publisher :
ISBN 13 : 9789741718962
Total Pages : 238 pages
Book Rating : 4.7/5 (189 download)
Download or read book Enantiomeric Separation of Esters by Gas Chromatography Using Derivatized Bata-cyclodextrins as Stationary Phases written by Pattama Changseeplag and published by . This book was released on 2002 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 : Nadnudda Rodthongkum
Publisher :
ISBN 13 : 9789745325036
Total Pages : 262 pages
Book Rating : 4.3/5 (25 download)
Download or read book Enantiomeric Separation of Phenoxy Acid Methyl Esters by Gas Chromatography Using Derivatized Beta-cyclodextrins as Stationary Phases written by Nadnudda Rodthongkum and published by . This book was released on 2005 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Ornuma Konghuirob
Publisher :
ISBN 13 : 9789745314641
Total Pages : 216 pages
Book Rating : 4.3/5 (146 download)
Download or read book Enantiomeric Separation of Alcohols by Gas Chromatography Using Cyclodextrin Derivatives as Stationary Phases written by Ornuma Konghuirob and published by . This book was released on 2004 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Author : Wilfried A. König
Publisher :
ISBN 13 :
Total Pages : 128 pages
Book Rating : 4.3/5 (91 download)
Download or read book The Practice of Enantiomer Separation by Capillary Gas Chromatography written by Wilfried A. König and published by . This book was released on 1987 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Bezhan Chankvetadze
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (248 download)
Download or read book Chiral Separations written by Bezhan Chankvetadze and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
