Systematische Prozesssynthese mit Hilfe mathematischer Methoden

This paper presents a novel method for the process synthesis and optimisation, the so called Mixed Integer Non Linear Programming (MINLP). The speciality of this tool is that not only the operating parameters but also the structure of the process are simultaneously optimised. A necessary condition for this kind of optimisation is the definition of an appropriate superstructure, that contains all physically relevant processes including the optimal one. Therefore, it is advantageous to determine these superstructures based on the information relating to thermodynamic equilibrium. The methodology for the development of superstructures and the results of the optimisation are presented for several examples concerned with distillation, extractive distillation, azeotropic distillation, and reactive distillation.     

Analyse von Acrylnitril-Styrol-Copolymeren mit Hilfe der Pyrolyse-Gaschromatographie

Copolymers of acrylonitrile and styrene with various compositions and molecular weights have been pyrolysed at a temperature of 500°C. The degradation products have been separated by means of gaschromatography and 16 compounds were identified. The most important products are cyanic acid, acetonitrile, acrylonitrile, propionitrile, toluene, ethylbenzene and styrene. The formation of these products has been investigated quantitatively as a function of the composition of the copolymers. Plotting the quantitatively determined amount of the cyanic acid as a function of the copolymer composition a linear slope resulted. Thus a method was developed to analyse copolymers of acrylonitrile and styrene. The formed amounts of acetonitrile, acrylonitrile and propionitrile during pyrolysis are independent on the molecular weights of the copolymers.     

Versuche zur stufenweisen epoxid/methacrylat-photopolymerisation mit diaryliodoniumsalz-photoinitiatoren

DSC-investigations confirm the experimental result that the selective photopolymerization of MMA and phenylglycidether (PGE) from a mixture of both monomers is possible with diaryliodoniumsalts/benzoinmethylether as a photoinitiator. The separation of both processes is dependent on light-intensity and on the composition of the monomer mixture. From a monomer mixture (80 weight-% MMA and 20 Weight-% PGE) it is possible to polymerize selectively MMA with light intensity I = 0.7 mJ/s cm², if the reaction is cut off immediately after the appearence of the gel effect (30 minutes). The epoxide polymerization can be completed afterwards by means of unfiltered light from a Hg-pressure lamp. The time separation of both processes will only succeed if MMA is the main part of the monomer mixture.     

Quantitative Bestimmung von Phosphatidylcholin mit Hilfe der HPLC

Quantitative Determination of Phosphatidyl Choline by Means of HPLC A HPLC method for a fast quantitative determination of phosphatidyl choline in soya bean lecithine is described. The separation was carried out on Li Chrosorb SI 60. The detection took place at 206 nm. Comparing this method with the results of the up to now used choline determination by Reineckat precipitation and by statistical evaluation it could be significantly established that the HPLC method (variation coefficient 1.1) is superior to the Reineckat method (variation coefficient 2.6).