Polymere und Copolymere mit reaktionsfähigen Gruppen. Copolymerisation von Glycidyl-β-methylitaconat und Styrol

In part I of this series the results of sedimentation velocity experiments with the polyelectrolyte Polyvinylpyrrolidone-Blancophor are described. The combination of the Svedberg formula and an equation of Tiselius describing the charge- and salt-effects gives the possibility to describe the change of the frictional coefficient as a function of charge and screening quantitatively. The resulting frictional coefficients resp. the dimensions of the coil of this polyelectrolyte change in a wide range with the charge density and the counterion concentration.     

Selektivhydrierung von Fettstoffen mit metallorganischen Mischkatalysatoren nach Ziegler-Sloan-Lapporte I: Selektive Hydrierung von Linolsäuremethylester und Modelldienen mit isolierten Doppelbindungen

Selective Hydrogenation of Fats and Derivatives Using Ziegler-Type Organometallic Catalysts I: Selective Hydrogenation of Methyllinoleat and Other Dienic Compounds with Isolated Double Bonds Homogeneous catalysts of Ziegler-Sloan-Lapporte-type, containing nickel, cobalt or palladium, were used to hydrogenate methyllinoleate under very mild conditions selectively to monounsaturated products. The question, wether this selectivity is caused by the 1,4-position of the olefinic double bonds, led to hydrogenation experiments with non-conjugated α,ω-dienes of different chain length. A significant selectivity was only observed for the reduction of 1,4-pentadiene to pentene, dienes with greater distance between the double bonds than in linoleic acid were hydrogenated with less selectivity. To explain these facts, a kinetic model, including catalyst-substrate-complexes of different stabilities, is proposed.     

Methoden zur Bestimmung von Haar- und Hautoberflächenfett (Sebum) bei Mensch und Versuchstier - dargestellt am Beispiel der Rückfettung nach häufiger Haarwäsche

Methods for the Determination of Hair and Skin Surface Lipids (Sebum) in Man and Experimental Animals Exhibited in Example of Refattening after Frequent Shampooing Some methods for quantitative determination of skin and hair surface lipids (sebum) in man are comparatively discussed. Further animal models for determination of the concentration of sebum are commentated. Using. the animal model of Ebling and Skinner we found, that the frequency of shampooing did not change the concentration of sebum on the hair of male rats.     

Bestimmung von flüchtigen Fettsäuren durch GC-MI-FTIR – Kombination von Gaschromatographie mit FTIR-Spektroskopie nach der Technik der Matrixisolation

Examination of Matrix Isolated Fourier Transform Infrared Spectras of Volatile Free Fatty Acids IR-spetroscopy in organic analytic is a well known method for the determination of functional groups and the identification of organic molecules. Sensitivity is especially high, when polar compounds are investigated. One of the few exceptions are the fatty acids. Due to the dimerisation of the carboxyclic group, part of the interesting range of the spectrum is covered by this dimer band. Moreover, the interpretable part of the spectrum is only of moderate resolution. By using GC-MI-FTIR, low temperature IR-Spectra of the fatty acids are available in not yet known resolution. Among the various fatty acids there are a number of structure specific criteria, which allow a definite identification even in trace levels, without previous derivatisation.     

Schnelle und präzise Bestimmung des Gesamtglucosinolatgehaltes von Rapssamen-Vergleich der Röntgenfluoreszenzanalyse mit Gaschromatographie und Hochdruckflüssigkeitschromatographie

Rapid and Precise Determination of Total Glucosinolate Content in Rapeseed – Comparison of X-Ray Fluorescence Spectroscopy with Gaschromatography and High-Performance-Liquid-Chromatography The introduction of oilseed-rape cultivars poor in glucosinolates within the EG requires methods which allow a separation of the yield batches by the glucosinolate content. By means of the indirect determination of the glucosinolate content by X-ray-spectroscopy a method is introduced that produces a high correlation with conventional procedures (r² = 99% for GC-reference samples, r² = 92% for GC single data, r² = 96% for HPLC single data; deviations from average values: GC-reference samples 1.3%; single analyses of GC and HPLC 7.4 respectively 3.1%) and that needs only 4 minutes for one complete determination and is easily to perform.     

Photolyse von ternären Fe(III)-Komplexen mit Oxalat- und Phenolat-Liganden

Photolysis of Ternary Fe(III)-Complexes with Oxalate and Phenolate Ligands The overall iron(II) quantum yields of the photolysis of mixed ligand complexes [Fe(C₂O₄)_3−nL_n]³⁻ (L = salicylate, sulfosalicylate or the dianion of catechol, sodium 3,5-sulfocatechol, tetrachlorcatechol) in aqueous solution within the spectral region 436 nm ≤ ^λ_irr. ≤ 546 nm are much smaller than those of the complexes [Fe(C₂O₄)_3−n(H₂O)_2n]³⁻²ⁿ (n = 0; 1; 2). This means that the intramolecular photoredoxreaction between iron(III) and the oxalate ligand is not sensitized by the L→Fe(III) charge transfer excitation. Moreover, filter effects through photoinactive complexes [FeL₂(H₂O)₂]⁻ or [FeL(H₂O)₄]⁺ probably give rise to the strong decrease of the quantum yields.     

Konstitution und Redoxstabilität von Kupfer(II)-Komplexen mit substituierten Hydrazinen

Constitution and Redox Stability of Copper(II)-Complexes with Substituted Hydrazines CuCl₂ reacts with substituted hydrazines forming chelates of the Cu^IIL₂Cl₂ type (L = RCONHNH₂, RCONHN(C₆H₅)₂, RCONHNHCOR, H₂NNHCO(CH₂)_nCONHNH₂) which are characterized by quantitative analysis, i.r. and e.p.r. spectra. The complex polyhedron exhibits the geometry of a tetragonally distorted octahedron of C_2v symmetry. The complexes undergo intramolecular redox decomposition in acetonitril forming Cu(I) species. The rate constants increase with decreasing half wave oxydation potential and decreasing Homo energy of the hydrazine ligands, respectively.     

Anwendung der ICP-AES zur Bestimmung von Spurenelementen in der öl- und fettverarbeitenden Industrie

Application of ICP-AES for the Determination of Trace Elements in the Oil- and Fat-Processing Industry The determination of trace elements, also in the oil and fat processing industry, has gained more and more importance during the last years. An analytical method suitable for a high sample throughout as well as the possibility of multi-element analyses is the Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). By using the ICP-AES). By using the ICP-AES it is possible to determine immediately elements even in tracts in oils, fats and fatty acids after dissolution with an organic solvent. The obtainable detection limits are always below 1 mg/kg. The linear measurement range is 10³ to 10⁵ above the detection limit. The relative standard deviations are 1–3%, for several elements below 1%. By extraction of the metals with nitric acid from the samples, the detection limit is distinctly improved. The direct determination of phosphorous and sulfur in oils using the ICP-AES is possible.     

Flockung und Entwässerung von Klärschlamm mit Hilfe von Polyelektrolyten

An investigation was performed with the aim of ascertaining how a digested sewage sludge could be converted into mechanically stable flocs through the addition of a flocculating agent, while achieving the best possible dewatering efficiency with the lowest possible dosage of flocculation agent. In order to obtain conclusive results which can be transferred to large-scale plants, the effectiveness of the flocculating agents and the various flocculation procedures were tested in a patented, mobile, computer-assisted flocculation and dewatering apparatus. The sewage sludge was conditioned with flocculating agents which had previously been thoroughly characterized in terms of their chemical structure, charge density and molar mass. The cationic flocculating agents had charge densities ranging from 25–55 mol-% and molar masses from 1.5 · 10⁶–12.9 · 10⁶ g mol^?, whereas the anionic flocculating agent had a charge density of 36 mol-% and a molar mass of 7.6 · lo6 g mol^?. In contrast to other suspensions already investigated, for sewage sludge it was found that no improvement can be achieved in the already very high dewatering level when cationic monoflocculation is used (laboratory trial: 95% filtrate yield by mass after 4 s). Nor was it possible to reduce the optimum dosage by using the dual procedure. In addition, it was possible to show that the chemical structure, i.e. the nature of the polyelectrolyte, and the molar mass of the cationic polyelectrolytes investigated exert a by far larger influence on the dewatering efficiency than the charge density in a range between 25 and 55 mol-%. Furthermore, it has also been observed that the conditioning efficiency of the polyelectrolytes increases as the molar mass rises and the chemical structure influences the dewatering result primarily through the position of the charge-bearing group.     

Selektivhydrierung von Fettstoffen mit metallorganischen Mischkatalysatoren nach Ziegler-Sloan-Lapporte III: Selektivhydrierung von gesättigten und ungesättigten Fettnitrilen zu gesättigten und ungesättigten,primären und sekundären Fettaminen

Selective Hydrogenation of Fats and Derivates Using Ziegler-Type Organometallic Catalysts III: Selective Hydrogenation of Saturated and Unsaturated Fatty Acid Nitriles to Saturated and Unsaturated Primary and Secundary Amines A tallow oil nitrile fraction with 66% oleonitrile and 27% stearonitrile was hydrogenated under use of homogeneous nickel- or cobalt-metallorganic catalysts from Ziegler-type with high selectivity to the corresponding saturated primary and secondary amines or under conservation of the double bond in the oleonitrile to unsaturated primary or secondary fatty amines. The realized selectivities were: 97% for stearylamine, 100% for oleylamine, 97% for distearylamine and 76% for dioleylamine.     

Veränderungen des Gesamtglucosinolatgehaltes von Rapssaat während der Abreife nach Analysen mit Glucose-, HPLC-, H1-(Sulfatase-) und RFA-Methode

Changes in the Total Glucosinolate Content in Rapeseed during Maturation Analyzed by Glucose, HPLC, H-1 (Sulfatase) and X-RF Method The aim of the reported research work was the investigation and quantification of the development of the total glucosinolate content in rapeseed during maturation in order to give a contribution to explain the deviations of results from different analytical methods on identical samples. Results derived by X-RF and H-1 (sulfatase-) method were independent from the stage of maturation. However, the results of HPLC- and glucose release analyses showed continuously increasing values up to harvesting. The supposed reasons for this phenomenon are temporal modifications in the structure of the sidechain and glucose rest of the glucosinolate molecule. The reported results should be observed in intercomparisons of methods of glucosinolate analysis as well as in the certification of seeds and consum batches of oilseed rape. The fact that long before harvest the results derived by X-RF and H-1 method show a constant level offers the opportunity of a prognosis of the probable quality of certain seed batches by means of a pre-harvest analysis.     

Experimentelle Bestimmung von Wärmeübergang und Druckverlust in Multiportflachrohren

Heat transfer and pressure drop data of three smooth multiport minichannels featuring hydraulic diameters > 1 mm are presented. Experiments were conducted under single phase convection of heptane and under convection of condensing R134a. Two specifically designed testing facilities feature a novel measurement setup to register the amount of condensate generated and to measure the temperatures of the refrigerant and minichannel wall. The results for the smallest minichannel geometrie show that the assumption of an increasing heat transfer rate with decrasing hydraulic diameter is not generally valid.