Zur reaktionstechnischen und fluiddynamischen stabilität von multirohrreaktoren für die massepolymerisation

Due to the very strong variation of the viscosity of the reaction mass with increasing monomer conversion, three stationary states for the tubes of a multitubular system with cooling vessel can be found. As a consequence, a maldistribution of the fluid arises, so that the reactor stability and the polymer quality are negatively influenced. The recycling of the reaction mass is a helpful method to increase the reactor stability. In this paper some fundamental aspects of the use of multitubular reactors for the polymerization of styrene are studied.     

Desaktivierung von technischen Silber-Trägerkatalysatoren für die Herstellung von Ethylenoxid

Deactivation of industrial supported silver catalysts for ethylene oxide production. In view of the model character of the reaction and the unique nature of the catalyst system, it is of interest to study the deactivation behaviour of technical supported silver catalysts for the production of ethylene oxide. In the present study the influence of the catalyst components support, silver, promoter and inhibitor upon the deactivation behaviour is described. The results of chemical, physical and technical investigations of various catalysts and catalyst components are presented. The investigations show that a decrease in the surface area of the exposed silver and increased deposition of chloride are responsible for catalyst deactivation. The possible influence of alkali promoters is discussed and modifications to the catalyst which have been described in the literature as influencing the deactivation are also evaluated.     

Über die Verwendung von Dicyclohexylcarbodiimid/3-Hydroxy-4-oxo-3,4-dihydro-chinazolin für die Synthese des C-terminalen Hexapeptidamids von Substanz P

On the Use of Dicyclohexylcarbodiimide/3-Hydroxy-4-oxo-3,4-dihydro-chinazoline in Synthesis of the C-Terminal Hexapeptide Amide of Substance P The C-terminal hexapeptide amide of substance P was synthesized in high yield by using 3-hydroxy-4-oxo-3,4-dihydro-chinazoline/dicyclohexylcarbodiimide for the stepwise elongation and fragment condensation. Contrary to the reaction of 1-hydroxybenzotriazole it was possible to prepare activated esters of 3-hydroxy-4-oxo-3,4-dihydro-chinazoline in crystalline form.     

Produktdesign von Kunststoffen für die Waschmittelindustrie

Water soluble polymers in the detergent industry represent on the one hand parts of the formulations of washing powder to improve the washing result, and are used on the other hand as foils for the packaging of liquid detergent portions. Insoluble, thermoplastic polymers (PE, PP, PET) are needed as packaging materials for solids, pastes, suspensions and liquids in the form of laminated cardboard, boxes, bags, bottles, buckets and tubes. The polymers can be tailored to the application. For this purpose, not only the possibilities of the reaction and synthesis technology are available, but the addition of additives manages the adjustment of the required physical, technical and optical properties, such as color and durability. In an extrusion process, the plasticized or melted material gets the product shape; any form can be produced. The packaging should convince not only in forms and functions, but also throughout the aesthetics relating to the specific brand. The product design is the sum of these parameters.