Dipolmomente und Konformation von 3- und 4-Brom- und Chlorheteracyclohexanen

Dipole Moments and Conformation of 3- and 4-Bromo and Chloro Heteracyclohexanes The dipole moments of some 3- and 4-bromo and chloro heteracyclohexanes are measured by the method of Debye and calculated both by the quantum-mechanical method CNDO/2 and vector addition method. The determination of conformational free energy is made on the basis of measured dipole moments μ of the conformation mixture and the calculated dipole moments μ_e and μ_a of the pure conformers. The results are discussed in relation to n.m.r.-results.     

Bildung und Koaleszenz von Blasen und Tropfen

Formation and coalescence of bubbles and droplets. Generation and coalescence of bubbles and droplets are essential requirements for technical reactions and exchange processes. The paper deals with the dispersion of gases and liquids with the aid of single orifices and of sieve plates in liquids of various viscosities under gravity and centrifugal conditions and furthermore with the mechanical foam separation and with the coalescence of drops on inclined plates. The paper summarizes results from the literature as well as from the Sonderforschungsbereich (SFB) 153 at the Technical University of Munich.     

Informations- und Datenverarbeitung im Apparate- und Anlagenbau

Processing of information and data in construction of equipment and plant . Computers are playing an everincreasing role in plant construction. Partly integrated programming solutions have meanwhile become available for many sectors of the engineering and commercial sides of plant design. The design and construction of larger plants, which because of the necessity to save on energy and raw material consumption and to conform with ecologically unobjectionable standards are becoming more and more complex, is virtually impossible without the aid of computers. And this development trend is still continuing. At present efforts are mainly directed at the use of computers in the preparation of engineering drawings and to the assembly of partly integrated processing steps of larger integrated complexes. Projects of this nature are often beyond the capabilities of individual firms and demand cooperative development. Apart from a few exceptions, electronic data processing has not been exploited in plant construction beyond the commercial side. Even NC machines are frequently not employed in plant construction, mainly because of the custom-built nature of the components. Essential rationalization even in this area poses the question of the extent to which a wider use of electronic data processing might be helpful.     

Optische Konzentrations- und Temperatur-Messung in Aerosolen und Sprays

Optical measurement of concentration and temperature in aerosols and sprays. This article surveyes progress in the development and application of optical methods, particullarly in Raman scattering and fluorescence for the analysis of aerosols and sprays. The main emphasis lies on examination of the particle phase. Fundamentals and state of the art in the determination of molecular composition of the particle phase with the aid of linear and simulated Raman scattering are described and the role of structural resonance discussed. Various models are presented for distinguishing between the contribution of the liquid and the gas phase to Raman scattering and fluorescence. Finally, new developments pertaining to the measurement of droplet temperature in aerosols and sprays are described.     

Siloxanylpyrroline und -pyrrolinium Derivate. Synthese und Charakterisierung

The synthesis of the title compounds was carried out by hydrosilylation of 1,4-dichlorobut-2-yne ( 1 ) with defined siloxanes ( 2a-c ) using a platinum catalyst, followed by the reaction of the received 1,4-dichloro-2-siloxanyl-but-2-enes ( 3a-c ) with primary, secondary and tertiary amines, respectively. N-Alkyl-3-(siloxanyl)pyrrolines ( 4,5,6 ) were reacted with alkyl bromides and sultones, respectively. The products were characterized by elemental analysis and ¹³C-n.m.r.-spectroscopy and posses remarkable surface activity. The X-ray crystal structure of N-ethyl-3-(1,1,1,3,5,5,5-heptamethyltrisiloxan-3-yl)pyrroline hydrochloride was determined.     

Ziele und Methoden der elektrochemischen Verfahrens- und Reaktionstechnik

Objectives and methods of electrochemical process and reaction engineering . Electrolysis processes are distinguished from ?normal”? chemical processes in several respects: (1) The electrical energy consumed is expensive and assumed the role of an expensive raw material. (2) Mass transfer in electrolytes is sluggish and limits space time yield to relative low values. (3) The rate of reaction is dictated by the applied electrode potential and this determines the cell voltage and energy efficiency of electrolysis processes. Effective electrocatalysts diminish energy consumption per unit mass of product. (4) The relatively poor electrical conductivity of electrolytes leads to construction of special closely spaced cells with narrow cell gaps. It is important to select the operation conditions of, e. g. organo-electrosyntheses to minimise the efforts involved in isolation and purification of the product.     

Experimentelle und theoretische Betrachtungen der Methanol- und direkten DME-Synthese im Labor- und Technikums-Maßstab

Engineering of strongly exothermic heterogeneously catalyzed reactions to industrial size is challenging. Synthesis of methanol and direct dimethyl ether synthesis serve as example for such type of reactions and related experimental results are described. Results from laboratory as well as technical scale are provided. The experiments show the variation of two main operational parameters: reaction temperature and CO₂ content at reactor inlet.     

Nebenwirkungen von Salben- und Creme-Grundlagen und deren Konservierungsmitteln

Side-Effects of Ointment- and Creme-Bases and Their Preserving Agents Out of 130 patients with chronic venous insufficiency of the lower leg 27% were sensitive towards esters of hydroxybenzoic acid, 14.5% towards sorbic acid, and 12% towards Unguentum Lanette. A large number of patients were allergic towards hexachlorophene. It was difficult to explain the positive reaction towards cetyl pyridiniumchloride and hexyl resorcin. It is worth mentioning the positive tests which 16 patients showed towards a few recent emulsifiers, such as Span® 80, Span® 60 and Tween® 40. Emphasis is made on complete declaration of the ingredients of pharmaceutical and cosmetic preparations.