Auslegung und Maßstabsvergrößerung von Kristallisatoren

Design and scale-up of crystallizers . Industrial scale crystallizers have to be designed in such a way that the crystalline product has the design particle size distribution, crystal form, and purity. Data on multiphase flow, solubility, balances of mass, energy, and number of crystals, kinetics (crystal growth rate and nucleation rate), and heat transfer are required. The present article discusses problems of kinetics in greater detail than other aspects. Multiphase flow is considered only briefly and heat transfer not at all. Familiarity with the terms homogeneous and heterogeneous (primary) and secondary nucleation [1, 2] is also assumed. This contribution is based on evaluation of available literature.     

Kostenvorausberechnung von Apparaten und Anlagen — Möglichkeiten und Grenzen

Costing of equipment and plants – possibilities and limitations. The costing of individual items of equipment and of complete plants differs considerably with respect to design as well as to the accuracy and time-requirement of the calculation method. These calculations are included in the usual way in economic evaluations of plants in order to assess the overall profit situation of a plant project. Numerous publications on this subject have appeared in recent years. They are evaluated in this report with reference to the abovementioned aspects. Besides the cost-precalculation methods used in project engineering, a few systematic costing methods are proposed for the planning-, erecting- and operating-period of a plant. This facet of the subject is also critically examined.     

Untersuchung und Beurteilung von PAK in Speisefetten und -ölen

Investigation and Legal Evaluation of Polycyclic Aromatic Hydrocarbons in Vegetable Fats and Oils The analysis of 40 native and refined commercially available vegetable fats and oils reveals the influence of the environment and the treatment on the contamination with PAHs. Totally refined oils and fats have no or only a low contamination of PAHs whereas grapeseed oil contains PAHs to a high extent. This fact has to be deduced to the old-fashioned drying process of the pressed grapes. The analytical procedure with HPLC and fluorimetric detection was done after alcaline hydrolysis. The PAHs were extracted using the distribution between DMF, cyclohexane and water. The legal evaluation of high contaminated is discussed in regard of national and international regulations.     

Nucleoside von Fluorzuckern,XV. Synthese von Thymin-Nucleosiden der 6-Fluor-D-glucopyranose und 6-Fluor-D-galaktopyranose

Nucleosides of Fluorine Carbohydrates. XV. Synthesis of Thymine Nucleosides of 6-Fluoro-D -glucopyranose and 6-Fluoro-D -galactopyranose 1-β-D -glucopyranosyl thymine 1 and 1-β-D -galactopyranosyl thymine 13 react with equimolar amounts of tosyl or mesyl chloride to give predominantly the 6′-O-sulphonyl derivatives 6 and 7 or 14 and 15 . Simultaneously small amounts of the 2′,6′-di-O-sulphonyl derivatives 4 and 5 are obtained. The tosyl derivative 6 reacts easily with alkali fluoride to give the 6′-deoxy-6′-fluoro nucleoside 10 . In contrast to the glucose series the corresponding conversion of the 6′-sulphonyloxy-galactose derivatives is difficult to achieve. The condensation of 2,3,4-tri-O-acetyl-6-O-tosyl-D -glucopyranosyl bromide 2 or 6-deoxy-6-fluoro-1,2,3,4-tetra-O-acetyl-D -galactopyranose 18 with 2,4-bis-O-trimethylsilyl thymine 3 affords, after deacetylation, 6 and 1-(6′-deoxy-6′-fluoro-β-D -galactopyranosyl)thymine 20 , respectively.