Production of fatty alcohols from fatty acids

Detergent-range alcohols from natural feedstock can be produced by high pressure hydrogenation of either methyl esters or fatty acids. The increasing quantities of fats and oils on the world market secure a reliable and economically priced material. Although fatty acid is an abundant worldwide commodity, most alcohol producers hydrogenate methyl esters, because direct hydrogenation of fatty acids is difficult as the catalyst is sensitive to acid attack. The process described here makes it possible to hydrogenate fatty acids directly to alcohols of high quality without prior esterification. The reaction takes place in the liquid phase over a fine-grained copper chromite slurry in a single reactor vessel. A special reactor design with an optimum arragement of the feeding nozzles causing an appropriate circulation of the reacting components inside the reactor facilitates the rapid “in situ” esterification reaction. This minimizes the free fatty acid concentration in the reactor to nearly zero. This results in a low consumption of catalyst. The most important advantages of the process are: direct feed of fatty acids of various origins, use of reasonably priced raw materials such as soapstock fatty acids and lower grade tallow acids, no process steps with methanol, and excellent economics. The process is industrially proven.     

Prediction of the creep behaviour of metallic materials under step loading using a simple mechanical model

The creep exposure of metallic parts usually occurs under time-variable loading conditions. For the prediction of creep behaviour under step loading a simple mechanical model is employed. The model is based on the time dependence of the material structure during creep. Therefore, the characteristic parameters of the model are considered to be functions of time and are correlated with the time dependence of the material structure parameters. For the definition of these functions a structure mechanical model has been employed. The mean internal material resistance has been considered as an appropriate structure parameter. The characteristic parameters of the model are defined in each step loading on the basis of the change of the internal stress derivative. For the verification of the model prediction the numerical results are compared with experimental results of the austenitic steel X 8 CrNiMoNb 16 16 for the orthogonal cyclic stress function.     

Die Relativierung des Spannungsbegriffes in der zerstörenden Materialprüfung

Relativity of the notion “stress” in destructive materials testing. Later developments of certain important fields in destructive testing can be correlated with the modification undergone by the notion of stress in its practical application: In connection with highly elastical and plastical deformation this notion becomes more and more relative because of its dependence on the time scale of the test; in the field of random loading the idea of a maximum tolerable stress has to be replaced by the algorythmic handling of irregular loading histories; in fracture mechanics stress can no longer be considered independently and has to be linked to influences of local distortions. Both random fatigue and fracture mechanics can by no means be regarded as entirely solved problems. Some directions are discussed in which the answers to open questions might be found. Some consequences for the conception of new testing equipment are mentioned.     

Bildung farbiger Produkte aus Hexosen XVI. Untersuchungen zur Maillard-Reaktion [1]

Zusammenfassung Nach Umsetzung der Amadoriverbindung (7) aus Glucose und Piperidiniumacetat bzw. des Piperidinohexosereduktons (15) mit Furfurol konnten wir die gelbbraunen Substanzen (9a), (13b) und (17a) isolieren. Die Versuche zeigen, daß Zuckerumwandlungsprodukte, die eine endständige CH-acide Methylgruppe bzw. Methylengruppe enthalten wie (8), (12), (11) und/oder (10) bzw. (16) mit Carbonylverbindungen zu farbigen Produkten kondensieren.

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Formation of coloured compounds from hexoses XVI. Investigations Reaction [1]

Summary When 1-piperidino-l-deoxy-fructose, (7) an Amadori-compound, resp. the piperidino hexose reductone (15) is heated with furfural and an equimolar amount of acetic acid in ethanolic solution, a browning reaction is observed. From the mixture of products the yellow or dark yellow compounds (9a), (13b), and (17a) can be isolated. The results show, that sugar degradation products with a CH-acidic methyl group or active methylene group like (8), (12), and (11) and/or (10) resp. (16) react with carbonyl compounds to give coloured products.

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Die Arbeit wurde aus Mitteln des Fonds der Chemie finanziert