摘要:

AbstractAfter “cooling”, the hot tritium atoms formed above thermal energies by nuclear reactions abstract or replace hydrogen atoms, and replace substituents X (e.g. alkyl, NH2, NO2, OH, COOH, F, Cl, Br, or I) in organic compounds. Isotope effects have been observed for protonated vs. deuterated compounds in several hot reactions. Models and mechanisms are discussed for the abstraction and replacement, for specific reactions on certain carbon atoms, and for the isotope effects. These are based on steric, bond‐energy, and kinetic considera

ISSN:0570-0833    

DOI:10.1002/anie.196407691

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractThe structures of proton‐addition complexes of aromatic hydrocarbons were hitherto known only with respect to their stoichiometric compositions but can now be clarified by ultraviolet, infrared, and NMR spectroscopic methods. For example, it has been possible to prove by NMR soectroscopy that the expected addition of protons into 9,10‐dimethyl‐[a] benzanthracene actually does take place. Two isomeric proton adducts of toluene have been found by means of infrared spectra. On addition of protons, the ultraviolet spectra of aromatics change considerably; excellent agreement is sometimes observed between the band maxima calculated by quantum mechanics and those found by exper

ISSN:0570-0833    

DOI:10.1002/anie.196407761

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractThe preparation and the use of gradient layers for thin‐layer chromatography are described. On a gradient layer there are three flow surfaces, all differing in their separation behavior. It is therefore possible to determine, for example, the basicity and/or activity which gives the optimum separation for a mixture of substances. Gradient thin‐layer chromatography was also carried out at low temperatures, after the effect of temperature on the separation of various mixtures had been stud

ISSN:0570-0833    

DOI:10.1002/anie.196407841

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractA new process is described for the separation of mixtures of materials by multiplicative distribution, which is characterized by repeated addition of the mixture throughout the whole process and by material exchange during the countercurrent flow of finite amounts of one, and infinitesimally small amounts of the other phase. The intrinsic features of the mode of action of the old distribution processes and the new one are developed, and their relationship to one another is discussed. In this connection, an attempt is made to clarify the confused situation in the terminology of this field by introducing clearer definitions. Reflux and “displacement distribution”, another new distribution process, are treated briefly in two final secti

ISSN:0570-0833    

DOI:10.1002/anie.196407911

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196408001

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196408012

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196408023

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196408032

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196408042

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.196408052

出版商:Hüthig&Wepf Verlag    

年代:1964

数据来源: WILEY