Synthesekontrolle und Charakterisierung höherer Peptide durch Anwendung der 13C-NMR-Spektroskopie

Control of Synthesis and Characterization of Higher-Molecular Peptides by Means of ¹³C n.m.r. Spectroscopy The ¹³C n.m.r. spectra of the C-terminal bovine insulin decapeptide derivative Boc-Glu(OBzl)-Arg(H⁺)-Gly-Phe-Phe-Tyr(Bzl)-Thr(Bzl)-Pro-Lys(Z)-Ala-OBzl as well as the amino acid and peptide intermediates used in its synthesis, have been measured and assigned as extensively as possible. The use of ¹³C n.m.r. spectroscopy as a method for controlling the synthesis and for the characterization of higher-molecular peptides is discussed.     

Vinylierung höherer Carbonsäuren an Katalysatorschmelzen

Vinylation of Higher Carboxylic Acids on Catalyst Melt After some references about the possibilities of the use of vinyl esters of higher carboxylic acids, some known methods for the synthesis of these are described in short. A new method is then reported whereby the vinylation of the α-position of branched chain higher carboxylic acids is discussed.     

Untersuchung molekularer Wechselwirkungen in homologen Reihen höherer Phenyl-alkyl-carbinole

Investigation of Molecular Interactions in Homologous Series of Higher Phenylalkylcarbinols The correlation between the structure of phenylalkylcarbinols and their solubility in methanol was investigated. Simultaneously a model of the molecular interactions was tested, basing on the dipolcharacter of chemical compounds as well as on the forces which take part in the molecular interactions. Because of the presence of the alkyl radical in the molecule of the mentioned compounds it is possible to associate phenylalkylcarbinols to two different homologous series with even and odd numbers of carbon atoms. The correlation between the structure and the solubility in polar solvents, shown by the example of phenylalkycarbinols and of methanol, confirms the validity of the discussed model.     

Über Naturwachse XI: Synthesen und Gas-Chromatographie höherer Cyclohexylparaffine

Natural Waxes XI: Synthesis and Gas Chromatography of Higher Cyclohexyl Paraffins Eight cyclohexyl nonadecanes, 1-cyclopentyl eicosane, and three methyl pentacosanes were prepared by Grignard syntheses to serve as model substances in the investigation of minor components of natural waxes. The retention volumes of the pure substances on three different stationary phases (Apiezon L, SE-30, QF-1) were determined by gas chromatography and their mass and infrared spectra were taken. The effect of the position of substituent on the elution behaviour was studied on a series of cyclohexyl and methyl paraffins. The anomalous behaviour of 2-methyl pentacosan, as reported earlier, was confirmed.     

Veresterung höherer Fettsäuren I Kinetische Untersuchungen der Veresterung mit Methanol

Esterification of Higher Fatty Acids I: Kinetic Studies on the Esterification with Methanol Kinetic relationships used so far for the esterification of various fatty acids were found to have limited validity. A new kinetic equation has been proposed, which can be widely applied, especially in regions of high concentration of the reacting substances. The relationships between the orders of reaction, rate constants, catalysts, and temperature are given in addition to the corresponding relationships between rate constants and initial composition of the reaction mixtures.     

Verlustfreie Katalysatorrezirkulation durch ein neuartiges Verfahrensprinzip bei der Hydroformylierung höhermolekularer Olefine

Free-of-loss Catalyst Recycling in the Hydroformylation of Higher Molecular Olefins by a Novel Process Technology In this paper a novel homogenous-heterogeneous procedure for the hydroformylation reaction of higher molecular olefins is presented, at which the reaction itself is homogeneously catalyzed and only after the reaction the catalyst complex is heterogenized only for separation. This procedure is achieved by using the lithium salt of triphenylphosphine monosulfonic acid (Li-TPPMS) as complex ligand for the hydroformylation catalyst and methanol as solubilizer. Li-TPPMS and its complexes with metal carbonyls are highly soluble in water and methanol, but completely insoluble in almost all other organic solvents. After the reaction the methanol is distilled off. The catalyst system becomes insoluble and can be separated from the reaction product by filtration or by extraction with water. The aqueous catalyst solution is evaporated to dryness and the catalyst system dissolved in methanol for a new reaction.     

Begasen höherviskoser Flüssigkeiten

Aeration of relatively viscous liquids . The article considers the flooding point and stirrer performance, as well as mass transfer in agitator vessels and bubble columns, in relatively viscous (aqueous glucose and glycerol solutions as well as millet broth) and non-Newtonian liquids (aqueous CMC and PAA solutions). Numerous experimental results published in the available literature and several obtained by the author provide a basis for these considerations. All the experimental results are presented in the framework of similarity theory. Thus it also proves possible to present the k_La values in sorption characteristics. In order to achieve this aim, a representative viscosity is introduced for non-Newtonian liquids, both in agitator vessels and in bubble columns. The comprehensive and comparative account reflects the current state of the art. Design data and dimensioning criteria are given for certain systems and working ranges. Comparison between agitator vessels and bubble columns on the basis of the design data derived permits predictions to be made regarding the suitability of various articles of equipment. Some of the results have already been reported [1].     

Mikrostrukturuntersuchungen an porösen Feststoffen durch Physisorptionsmessungen

Studies of the microstructure of porous solids by physisorption measurements . The principal experimental methods for studying the microstructure of porous solids are based on physisorption measurements. The resulting sorption isotherms can yield data such as surface area and pore radius distribution, which are of great importance for development and characterization of porous catalysts. After a brief presentation of available measuring equipment, the main concern of this survey is the evaluation of sorption isotherms. In particular, methods for determining the micropore contribution to the total pore volume and the pore radius distribution in the micropore range are examined critically with regard to their reliability.