Massenspectroskopie von Naturstoffen. XV. Vergleichende Kationen-Anionen-Massenspektroskopie von Azidogibberellinen

Mass Spectrometry of Natural Products. XV. Comparative Positive-Negative Ion Mass Spectrometry of Azidogibberellins The fragmentation behaviour of 1-azido-3-hydroxy-gibberellin derivatives has been studied by means of positive and negative ion mass spectrometry, high resolution and metastable transitions. The results obtained allow a mass spectrometric distinction to be made between epimers with different stereochemistry of the ring A substituents.     

Massenspektroskopie von Naturstoffen. XIII. Massenspektroskopische Untersuchungen von A-nor-Allobetulanen

Mass Spectroscopy of Natural Products. XIII. Mass Spectroscopic Investigations of A-nor-Allobetulanes The mass spectroscopic fragmentation behaviour of A-nor-allobetulanes with several substituents at C-2 is discussed. The skeleton fragmentation is comparable to that of C-3-substituted allobetulanes. The nature of the substituent at C-2 influences both the abundance of typical skeleton fragments and the formation of specific ions.     

Massenspektroskopie von Naturstoffen. I. Vergleichende Anionen-Kationen-Massenspektroskopie von 2,3,4,6-Tetra-O-acetyl-β-D-glucopyranosylestern

Mass Spectroscopy of Natural Compounds. I. Comparative Investigation of Anion-Cation Mass Spectra of 2,3,4,6-Tetra-O-acetyl-β-D-glucopyranosyl Esters The electron attachment mass spectra (anion mass spectra) of 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl esters with different structures of the acids are discussed and compared with the corresponding electron impact spectra. In contrast to the cation mass spectra the molecular ion peak appears in all the anion mass spectra.     

Vergleichende Untersuchungen zur Arylaminierung von Benzofuroxan-Derivaten

Comparative Studies on Arylamination of Benzofuroxan Derivatives The amination of benzofuroxan 2a and monosubstituted benzofuroxans 2b – e with alkali metal salts of formanilides 1 and sodium acetanilides 6 is described. Thus, the reaction of 2a with 6a – d gives the benzotriazole 1-oxides 3a – d . The benzofuroxans 2b and 2c react with sodium formanilides to give the isomeric mixtures 3f / 3g and 3h / 3i . Potassium 4-nitroformanilide reduces 2a furnishing benzofurazan 7 . Nitrobubstituted benzofuroxans such as 2d and 2e undergo a carbocyclic amination leading to the benzofurazans 8 and 9 .     

Vergleichende Untersuchungen zur Bestimmung des Gesamtglucosinolatgehaltes von Rapssamen

Comparison of Methods for the Determination of Total Glucosinolate Content in Rapeseed For the determination of the total glucosinolate content in rapeseed samples there are several different methods currently in use in the Federal Republic of Germany. Apart from the official EC-method (GLC), the rapeseed samples were also analysed by national methods (HPLC, glucose, X-ray-fluorescence-spectroscopy) and rapid screening methods (00-DIP-test, miniphotometer-test, reflectometer-test). All these methods have been compared with each other, using samples from last year's harvest. In most cases, the GLC results are lower than those of the national methods or rapid tests.     

Untersuchungen zur Sulfochlorierung von Paraffinen. VII. Untersuchungen über die Chlorierung von definierten Alkansulfochloriden

Studies on Sulphochlorination of Paraffins. VII. Studies on the Chlorination of Individual Alkane Sulphochlorides The products of the chlorination of individual C₂–C₆ alkane sulphochlorides were studied by means of ¹³C-n.m.r. spectroscopy. In no case a geminal chloro sulphochloride could be found, and only in very few cases chlorination at vicinal C H-bonds took place. As in the sulphochlorination of alkane sulphochlorides the C H-bonds geminal and vicinal to the sulphochloride group are strongly descativated. The results of ¹³C-n.m.r. analyses were confirmed by the results of gaschromatography of the sulphonic acid dimethyl amides, formed by the reaction of the chlorination mixtures with dimethyl amine.     

Vergleichende Untersuchungen zur Trennleistung von Lösefraktionierungen

With the aid of polystyrenes with different polydispersity (M?_w/M?_n = 2,6 to 1,01) the effect of the charge, the γ-gradient, the interval Δgamma; between two fractions and the contact time on the discontinuous and continuous solution fractionation was tested. For the discontinuous fractionation of samples with broad distributions no effect was found on the integral distribution curve by the variation of these experimental conditions. For narrower distributions (M?_w/M?_n ≤ 1,5) however it is necessary to pay attention to following points: 1st the charge must be below 2mg/g sand, 2nd the γ-gradient must be specially accommodated to the conditions of solubility, 3rd the interval Δγ should be smaller than 0,002 and 4th the contact time should be at least two hours. With growing uniformity the charge has to be reduced further and the contact time has to be increased. Compared to the discontinuous solution fractionation the continuous fractionation produces insufficient results under equal experimental conditions. Even for broad distributions the charge and the y-gradient must be reduced for approaching the results of the discontinuous fractionation. Furthermore the elution chromatography shows no improvement compared to the simple continuous fractionation. All column methods — including the BAKER WILLIAMS fractionation — can be shown to be single stage processes.     

Entwicklung und Projektierung von Anlagen zur Hochdruck-Extraktion von Naturstoffen

Development and planning of plant for the high-pressure extraction of natural products . Important criteria in the designing of plant for the recovery of carrier or extract are reviewed, especially for the extraction of natural products with supercritical CO₂. The quantities to be determined in the planning of a large-scale plant are outlined and a typical process, the extraction of spices, is discussed in detail. The plant components and assemblies are presented together with their particular process engineering and construction characteristics. Finally, the thermodynamic aspects are dealt with in more detail and ways of optimizing a large-scale plant and reducing the power consumption are outlined. Particular attention is paid to the question of optimization regarding the most economic method of operation of such a plant in the future.     

Komprimierte Gase zur Gewinnung von Naturstoffen

Extraction of Natural Substances by Dense Gases Dense gases, especially carbon dioxide, are gaining more and more interest worldwide for the extraction of lipophilic natural substances. Different methods for the determination of the solubility are available and information is rapidly obtained by coupling of micro extraction with thin-layer chromatography. It could be shown that extractibility depends upon the size of the molecules and the structure and number of the functional groups. A micro preparative gravimetric procedure facilitates up to 2600 bar the determination of the solubility of oils, fats and similar substances which are difficult to detect. The possibilities for a preparative extraction of natural substances are demonstrated on examples of our own work. Special attention is given to high pressure extraction of vegetable and animal oils and fats. The state of development and future possibilities are shown in patents and further literature.     

Vergleichende Untersuchungen zur Bestimmung der sauren Oberflächenoxide von Gasrußen

An attempt is made to quantitatively determine acidic surface oxides on some carbon blacks. The applicability of some analytical methods is discussed. The results of neutralisation reactions suggest that four different surface groups exist. It is taken as reference method. Because of this very slow method it is discussed whether there exist some faster and comparable methods. A comparison is done to investigate changes in surface groups of a special chemically treated, bleached carbon black. To impart jetness to paint films carbon blacks are widely used. To treat carbon blacks with a special chemical process may influence the stability of black paint systems. The surface groups of carbon blacks vary in their acidity. Neutralisation reactions with bases of different strength, an indirect titration, are compared with direct titration in a non aqueous solution and with silylation reactions.     

Vergleichende Untersuchung von kommerziellen Fritiermedien

Experimental Comparison of Commercial Deep-Frying Fats. 20 commercial deep-frying fats (consistent and semi fluid) and 2 ‘High Oleic Sunflower Oils’ (HOS-Oils) were investigated for peroxide value, smoke point, fatty acid composition, iodine value, melting point and the relative deep-frying stability (RFS). The RFS was determined by monitoring the increase of the dielectric constant during deep-frying. For not hydrogenated consistent fats (palm fats) the RFS ranged from 9.5 to 12.6 h, for partially hydrogenated consistent fats the RFS was between 14.6 and 19.3 h, for semi fluid fats between 7.4 to 17.4 h, and for HOS-oils the RFS amounted to 15h. The concentration of poly unsaturated fatty acids (PUFA) correlated negatively (r=—0.89; p<0.01) with the RFS of hydrogenated consistent fats. semi fluid fats and HOS-oils. Palm fats showed a different RFS/PUFA ratio. A significant correlation (r=—0.89; p<0.01) was observed between the RFS and the initial polarity of fresh fats.