Einfluß der Reaktionsbedingungen bei der Chlormethylierung von Styrol

The influence of trioxane, inhibitor (CuCl₂), solvent (isopropanol), water, and catalyst concentration, and temperature in the chloromethylation of styrene has been studied. A two level statistical design of experiments was used. Conversion and selectivity were fitted by multiple linear regression. Two equations have been obtained. The influence of the conditions in the reaction is shown in these two equations.     

Sicherheitsüberlegungen bei der Planung von Chemieanlagen

Safety considerations in the planning of chemical plant. Viewed from the standpoint of safety engineering the planning of a chemical plant can be defined as follows. Persons and articles of material value are to be protected from thermal, mechanical, and chemical action during the entire lifetime of the plant. Protection must be effective in the plant and in its vicinity. Possible causes of such effects are discussed. Analysis of the causes leads to derivation of the measures to be implemented in order to counter all kinds of failure. A distinction is made between primary or preventive safety measures. They have the aim of avoiding the occurrence of any failure. However, since failure can never be completely ruled out, measures are also outlined which are intended to minimize the consequences of failures. These are called secondary or constructive measures. Various points are considered in detail with the aid of selected examples.     

Bildung von Hydroperoxy-epidioxiden bei der Autoxidation von Linolsäurephenylester

Formation of Hydroperoxy-epidioxides during the Autoxidation of Phenyl Linoleate Phenyl linoleate was autoxidized at 37° C for 72 hours. Among the peroxides formed the phenyl 13-hydroperoxy-erythro and threo-10, 12-epidioxy-8(E)-octadecenoates and the phenyl 9-hydroperoxy-erythro and threo-10, 12-epidioxy-13(E)-octadecenoates were detected by co-chromatography (HPLC) with reference substances which had been prepared by photosensitized oxidation of phenyl linoleate. The hydroperoxy-epidioxides were silylated and analysed by mass spectrometry. The hydroperoxy-epidioxides comprised about 5% of the peroxides. The presence of α-tocopherol inhibited the formation of the hydroperoxy-epidioxides.     

Vergleich der Verteilungskurven der Katalysatorkorngrößen bei der Hydrierung von Fetten

Comparison of the Distribution Curves of the Particle Sizes of Catalysts in the Hydrogenation of Fats In the present paper the particle sizes of 14 hydrogenation catalysts and 2 kinds of commercial kieselguhr were studied using a laser analyzer. Assuming a log-normal distribution the distribution curves for the particle sizes were treated by the least-squares method. From the μ and σ parameters obtained the different characteristics of the catalysts were discussed.     

Fehlerquellen bei der anwendungstechnischen Prüfung von Anstrichfilmen

Sources of Error in the Testing of Paint Films In order to obtain exact and reproducible results in the testing of paint films the testing methods and the environmental conditions must be maintained constant. It is important to maintain an uniform thickness of the layer. This is achieved by means of a centrifugal device which can be employed even for surfaces that are not plane.     

Bemühungen der Landwirtschaft bei der Qualitätserzeugung von Raps

Efforts of Agriculture Concerning Quality Production of Rape Seed As a leading co-worker of the Chapter of Agriculture the author is responsable for the rape seed culture in Schleswig-Holstein. With an arable acreage of 108000 ha in 1987 rape seed is besides wheat the main culture on the arable soil of this northern federal state. In the fruit series of Schleswig-Holstein rape seed represents indeed an unrenouncable significant product. Maintenance and promotion of rape seed culture, utilization of all possible marketing chances are therefore the guide lines for the efforts of agriculture in the sense of this subject. First the “draft for change to 00-rape seed in Schleswig-Holstein”, developed in June 1987, is represented as an introduction into the problems. Nearly each sentence contains comprehensive “efforts of agriculture” which are explained further in the following. A review to experiences concerning the introduction of rape seed with only small amounts of erucic acid, a prospect to further, already being or possible developments are finally reported.     

Bestimmung der Temperaturabhängigkeit der Inhibierungsperiode und der Radikalbildungskonstante von AIBN bei der Polymerisation von Methylmethacrylat

The dependence on temperature of the specific reaction rate quotient of the inhibition period has been determined as by dilatometric measurement of the inhibition period caused by dissolved oxygen, and by the initial rate of the methyl methacrylata polymerisation, using azoisobutyronitrile (AIBN) aa initiator. In the examined concentration range the initial polymerisation rate and the reciprocal of the inhibition period are strictly proportional to the root of the initiator concentration, the yield of free initiator radicals is thus independent of the initiator concentration. It is, therefore, possible to determine the radical forming constant k_R of AIBN represented by the equation The fraction of the radicals recombining in the cage can be determined from k_R and the decomposition constant k_z; at 60°C for example it amounts to 24%. This value corresponds very well to the value obtained by the gas-chromatographic investigation of the recombination products by VOGT and DULOG.     

Anwendung von Tensiden bei der mechanischen Flüssigkeitsabtrennung

Use of Surfactants for Mechanical Liquid Separation . Mechanical dewatering of finegrained solid materials can be improved by the addition of surfactants. As interface-active substances surfactants reduce surface tension and consequently the capillary forces within the bed of solid particles. A hydrophobization of the solid surface due to the adsorption of surfactants may contribute to further reduction of moisture as well. The development of non-foaming surfactants enables the use without distrubing other ongoing processes by the formation of foam. Investigations on the interaction between the adsorption behaviour, type of material surface, and contact time during dewatering processes support the optimization of dewatering agents. The use of surfactants is an attractive means of improving or replacing other methods of mechanical dewatering.     

Anwendung von Flockungsmitteln bei der mechanischen Flüssigkeitsabtrennung

Use of flocculants in the mechanical separation of liquids . The mechanical separation of liquids from turbid water or sewage sludges depends primarily on the size and density of the suspended particles. The process of separation by sedimentation, filtration, or centrifugation becomes increasingly difficult with decreasing size of the suspended particles and decreasing density difference between solid and liquid. The addition of flocculants in ppm amounts destabilizes the dispersion and flocculation sets in. Thus flocculants agglomerate suspended particles, improve the separation, and accelerate the overal separation process. The synthetic organic high polymers used in the treatment of municipal and industrial waste water are characterized by their chemical composition, their molar mass, and their charge density.     

Verfahrenstechnische Kriterien bei der Auswahl von Flüssigkeitspumpen

Process technological criteria in the selection of liquid pumps . The safety and availability of liquid pumps for process technology plants is of prime importance, because the breakdown of a “critical” pump can close an entire plant and through interruption of production often causes inestimable costs. Some important considerations in selecting the correct pump are therefore given, with regard to mode of action and versatility, from the point of view of process technology. Economic considerations can only be briefly dealt with.