Sulphur nuclear properties

In 1976 he was appointed to Associate Professor for Technical Chemistry at the University Hannover. His research group experimentally investigated the interrelation of adsorption, transfer processes and chemical reaction in bubble columns by means of various model reactions a) the formation of tertiary-butanol from isobutene in the presence of sulphuric acid as a catalyst b) the absorption and interphase mass transfer of CO2 in the presence and absence of the enzyme carboanhydrase c) chlorination of toluene d) Fischer-Tropsch synthesis. Based on these data, the processes were mathematically modelled Fluid dynamic properties in Fischer-Tropsch Slurry Reactors were evaluated and mass transfer limitation of the process was proved. In addition, the solubiHties of oxygen and CO2 in various aqueous solutions and those of chlorine in benzene and toluene were determined. Within the framework of development of a process for reconditioning of nuclear fuel wastes the kinetics of the denitration of efQuents with formic acid was investigated. 

In many cases, experimental data have been discussed in terms of variations of the paramagnetic contribution, nuclear shielding constant (Equation (2)). Empirical correlations with parameters related to the electronic properties of other substituents in the molecule (electronegativities, Hammett substituent constants etc.) have been found. This kind of investigation has provided useful information about the electronic structure of the sulphur atom in different bonding situations and most of all about the electronic properties of the S-O bond, which is still a rather controversial matter. 

Within the last two decades, significant progress has been achieved in the theoretical computation of NMR spectroscopic parameters,110 particularly of nuclear screening constants. Theoretical calculations of 33S NMR parameters have received a certain attention for two main reasons (i) they can help in identifying and elucidating the structural properties of sulphur-containing molecules, and (ii) they can provide important information on the electron distribution and bonding situation around the sulphur atom. 

Nuclear analogues of cephalosporins containing two sulphur atoms (e.g. (205) [142,143] and (206) [143,144]) belong to this group, but some of their chemistry and properties were summarized in Part 1. Highly-substituted l-oxa4-aza-... 

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