The present work describes the use of Ion Mobility Spectrometry (IMS) as a detection method for specific thermolysis products with respect to the early recognition of fires. By using additional analytic methods such as simultaneous differential thermal analysis/thermogravimetry (DTA/TG), gas chromatography/mass spectrometry (GC/MS) and Infrared spectrometry (IR) the specific thermolysis products depent on the temperature of the fire load were characterized and identified. While considering possible interference like e.g. varying atmospheric humidity the limits of detection and determination of the detectable gasses by IMS were determined.

In the context of this work, a computer program is developed for the simulation of the interference fringe patterns of laboratory-scale pool-fires of organic fuels. With the help of this simulation tool, the formation as well as the dynamics of typical structural components in the interference fringe patterns in the flame neck and the flame plume are modelled. A model conception for the formation of the interference fringe patterns in the flame plume is developed. The temperature field is modelled as a relatively cold convection column, into which a large amount of statistically distributed hot volume elements with gaussian temperature distribution is inserted. The simulation with this model conception shows the typical structure of the measured interference fringe patterns in the flame plume with good congruence. The physical meaning of the velocity of the interference fringe pattern shift within the areas of the flame neck and the flame plume is examined. It is shown in particular that the temporally averaged shifting velocity in vertical direction in the flame neck can be identified as a temporally averaged ascent rate of the flame gases within the region of the thermal boundary layer. For the flame plume, the shifting velocity can be interpreted as a flow velocity averaged over time and the line of sight.

In this work an efficient system on the basis of the Curie point pyrolysis and the ion mobility spectrometry will be developed. Ten types of polymeric materials were examined as test-substances: polyurethanes, polyvinyl chloride, acrylonitrile -, 1,3-butadiene -, styrene-copolymer, polystyrene, polybutylene terephthalate, polymethyl methacrylate, polyamide, polyethylene, polypropylene and polycarbonate. To the evaluation of the analysis-results cluster analysis and the radius-basis-function-network were used. The received results have shown that the PY/IMS-system is well suitable in connection with multivariate analysis for the identification of the above-mentioned plastics

In examine the photocycloadditions of the title compounds the following questions are of interest: 1. Aside of [2+2]-cycloadditions to the C(2)=C(3) bonds, can any cycloaddition occur to the benzoid ring? 2. Which factors govern the regio- and stereoselectivity? Irradiation of either benzo[b]pyrrole-, -furane- or -thiophene-2-carboxylates in the presence of 2-morpholinopropennitril in cyclohexane leads, in a highly regioselective reaction, to [2+2] photoadducts. The regioselectivity seems to follow the formation of the most stable intermediate 1,4-biradicals. No photocycloadditions of the title alkene have been observed with 4-acceptor substituted benzo[b]pyrroles.

Algal alginates are of great importance for industrial applications. Since their properties depend on the kind of algae and the time of harvesting, supply problems caused price fluctuations. Hence, current research focuses on alternative alginate sources. Back in the 60s, exopolysaccharides similar to algal alginates were found. They were produced by mucoid Pseudomonas aeruginosa strains which embed themselves in a slime matrix containing bacterial alginates. The focus of this thesis was a comparisons of the physico-chemical properties of bacterial and algal alginates. The main results of the performed investigations are as follows: a) both substances aggregate in highly diluted solutions, b) bacterial alginates have a bigger molar mass than algal alginates, c) their mean squared radii of gyration are bigger than those of algal alginates, d) the second osmotic virial coefficients of these systems are negative and temperature dependent, e) acetylation of alginates support the aggregation, f) bacterial alginate do not gel analog to the egg box mechanism.

During the electronic excitation of 4-halo-1-acylnaphthalenes in the presence of a-cyanoenamines one could not only observe the typical cycloaddition, but also substitution of the halogen through C-3 of the cyanoenamine in a high degree. The photoreaction of halogenated 1-acetonaphthones as well as 1-methyl naphthoates with a-cyanoenamines resulted as a rule in two substitution products and regioselective in two "head/tail" 1,2-cycloadducts. One exception is 4-chloro-methyl-1-naphthoate with an additional "head/head"-adduct. The main product in all explored reactions is the E-substitutionproduct. The halogen substituent has an influences on the reaction pathway; 4-bromoacylnaphthalenes show much higher yields of substitutionproduct, which is due to the lower dissociation energy of the C-Br bond. As expected the halogenated methylketones show higher reactivity than the methyl ester. The methylketones prefer 1,2-Cycloadducts with donor-anti and the esters with donor-syn orientation. There is every reason to be ieve that the reaction mechanism for the formation of the substitution products is based on an electron transfer from the olefin to the triplet excited aromatic compound.

Pharmaceutical adjuvants or excipients are important ingredients of medicaments. These substances are used as support and for building the matrix for the active ingredients. In this way, the active ingredients will be realised in accurately and defined way at the specific site of action. In this study, the most important pharmaceutical adjuvants are characterised and analysed via near infrared-spectroscopic methods. The powdery samples were measured by means of diffuse reflectance with six NIR-spectrometer. The obtained NIR-spectra were used to build a near infrared spectra library based on SpecInfo systems of the firm Chemical Concepts. Furthermore, discrimination analysis were carried out, while reference spectra were compared with the database for performing an identity control.

Two moderate electron-deficient propenoic acid derivatives have been investigated, with special emphasis on their reaction behaviour in cycloaddition reactions and comparison as to their capto-dative nature. In all reactions it was observed that the dehydroamino acid derivative resembles more an acrylic acid derivative than a capto-dative olefin. In reactions with various nitrones only 5,5'-disubstituted isoxazolidines were observed as products.

No description available.

In dieser Arbeit wird der Einfluß von exo- und endocyclischen isolobalen Substitutionenin A4E3, P5E2X, beta-P4E3IR und alpha-P4E3XY untersucht (A=P und/oder As, E =S und/oder Se, X=Halogen, R=CHI2, Y=Halogen.) Die einzelnen Verbindungsklassen wurden synthetisiert und die 31P und 77Se-NMR-Werte bestimmt. Die ermittelten 31P/77Se-NMR-Daten und die 31P/77Se-NMR-Daten aus der Literatur bildeten die Grundlagen zur Untersuchung des Einflusses der isolobalen Substitution. Dazu werden die Elektronegativität der Liganden, Bindungswinkel und die 31P/77Se-NMR-Parameter miteinander in Beziehung gebracht. Dabei wurde ein linearer Zusammenhang zwischen Bindungswinkeln und chemischer Verschiebung bzw. Kopplungskonstanten in den A4E3-Verbindungen beobachtet. Des weiteren konnten lineare Zusammenhänge zwischen der Elektronegativität der exocyclischen Liganden (meist Halogene)und bestimmten NMR-Werten gefunden werden. Beide Phänomene konnten zurückgeführt werden auf den s-Anteil der Bindungen und/oder die Elektronendichte der betrachteten Kerne. Des weiteren wird eine Übersicht der Präparationsmethoden und eine einheitliche Benennung der Kerne in den Phosphorchalkogengerüsten vorgestellt. Die 31P/77Se-NMR-Daten der vorgestellten Phosphorchalkogenide werden im Anhang nach Strukturklassen geordnet aufgeführt (ca. 500 Verbindungen). Keywords: Phosphor, Selen, Schwefel, Iod, Brom, Chlor, Arsen, NMR, 31P, 77Se, Tetraphosphortrisulfid, P4S3, alpha-Tetraphosphortrichalkogendihalogenid, alpha-P4S3I2,beta-Tetraphosphortrichalkogendihalogenid, beta-P4S3I2, Pentaphospordichalkogenhalogenid, P5S2I, Elektronegativität, Hybridisierung, Fermi-Kontakt-Term