Bildung und Nachweis von Nitrosaminen in Lebensmitteln —ein kurzer Überblick

Formation and Analysis of Nitrosamines in Food Products —a Brief Review A brief review has been prepared to illustrate a number of current problems. The formation of nitrosamines in food products and the analysis of volatile nitrosamines in the ppb range and problems of the analysis of non-volatile nitrosamines are briefly discussed.     

Techniken und Anwendungen der Ultraschall-Zerstäubung – Ein Rückblick auf 35 Jahre Forschung und Entwicklung

Techniques and Applications of Ultrasonic Atomisation – 35 Years of Research and Development in Retrospect . In the course of the last 50 years, ultrasonic atomisation has developed from a somewhat exotic laboratory technique with few, hardly used applications to a well established one with a broad spectrum of applications. Today's optimised atomisers for process engineering applications operate at volume flows between a few ml/min and several 100 l/h and droplet diameters between 1 and about 150 micrometers. The technique can handle both ?normal”? liquids for therapeutic inhalation, for air humidifiers, carburettors, oil burners, etc. as well as solutions and suspensions for spray drying and melts of low to high melting temperatures and viscosities. The author reports on the development of ultrasonic atomisers and not only describes the physical principles and technical features of the various atomiser types but also considers borderline topics of droplet and particle generation with vibrating nozzles and cavitation chambers.     

Alkylethersulfate – ein Überblick aus anwendungstechnischer Sicht

Alkylethersulfates – A Review on Applications Alkylethersulfates based on fatty alcohols are commonly used in modern bath preparations and liquid cleansing agents. Their annual consumption in the Federal Republic of Germany amounts to about 20 000 t. Optimum properties for each application are achieved by varying the alkyl chain length and the degree of ethoxylation. Alkylethersulfates are harmless from toxicological viewpoint; they are biologically degradable. A ISO-visco-curve is proposed for the formulation of finished products. In this relationship, the amount of common salt required for a given viscosity is a function of the concentration of ethersulfate. 70% ether sulfate, without the addition of liquifying substances, is used in increasing amounts. Their processing is described.     

50 Jahre Technologie pflanzlicher Öle und Fette - ein Erfahrungsbericht

50 Years Technology of Vegetable Oils and Fats - a Report of Experiences In a survey about the development of the technology of vegetable oils and fats between 1932 and 1982 above all those areas are dealt, in which the author could contribute to the optimization of technological process steps and to the quality improvement of final products. It is described in detail: influence of solvent composition on benzine losts and on hydrocarbon retention in the oil seed extraction, improvement of the lecithin removal process, the entire desliming of extracted oils and its influence on raffinate quality, methods for determination of refining lost and for estimation of quality of raw and refined oils, comparison between various alkali-neutralization methods, relations between bleaching earth activity and oxidation stability of the oils, recovery of oil from used bleaching earth, distillative neutralization and determination of optimal deodorising conditions. The report is finished with hints on the importance of special fats for the fat processing industry obtained by hydrogenation, interesterification or fractionation.     

Übergangsmetalloxid- und Übergangsmetallacetylacetonat-katalysierte Olefinoxidation – ein Vergleich

Transition Metal Oxide- and Transition Metal Acetylacetonate-Catalyzed Olefine Oxidations – a Comparison The efficiencies of various homogeneous soluble transition metal acetylacetonates and of various heterogeneous transition metal oxides were studied to increase epoxide yields in autoxidation of olefins in liquid phase. The oxidation of cyclohexene, 1-octene, cis-4-octene, 3-ethyl-1-pentene and 2,4,4-trimethyl-1-pentene was investigated in absence of catalysts and in the presence of MoO₂(acac)₂ and MoO₃ as well as other oxides and heterogenized oxide-catalysts. The comparison of oxide- and acetylacetonate-catalysis gave a high similarity of both. MoO₃ acts preferentially as homogeneous catalyst too. Although other elements of heterogeneous catalysis were proved.     

Molmassebestimmung an Polyamiden und Reaktionsprodukten aus ε–Caprolactam und Phenylglycidether

Molar Mass Determination on Polyamides and on Reaction Products from ε-Caprolactam and Phenyl Glycidyl Ether Terminal groups (-NH₂, -COOH, -OH (-OH from termination reaction with epoxides)) of aliphatic oligo- and polyamides were titrated to determine the corresponding molar masses. ε-Caprolactam terminal groups were hydrolyzed to form -COOH permitting subsequent titration. The same samples were measured by using capillary viscometry, vapour pressure osmometry and size exclusion chromatography. It was shown that the molar masses obtained depend on the reaction process of the polyamide formation (anionic process with Na-caprolactam as initiator and activated anionic process with Na-caprolactam/N-acetylcaprolactam as initiator) and on the analytical method used. Molar masses from titration of terminal groups correspond to molar masses from capillary viscometry in sulfuric acid as solvent.     

75 Jahre Hydroformylierung – Oxoreaktoren und Oxoanlagen der Ruhrchemie AG und der Oxea GmbH von 1938 bis 2013

The hydroformulation reaction, also known as oxo synthesis or Roelen reaction, is the atom‐efficient and metal‐catalyzed addition of the constituents of synthesis gas, H₂ and CO, to the double bonds of alkenes. This reaction has been discovered in 1938 by Otto Roelen in the laboratories of the chemical company Ruhrchemie AG. After filing the patent application efforts to scale up the process to technical scale have been started. However, they have only partly been successful for the plants of the Ruhrchemie AG Oberhausen and its cooperation partner I.G. Farbenindustrie AG due to the difficult circumstances. After World War II the Ruhrchemie process based on cobalt catalysts and the Ruhrchemie/Rhône‐Poulenc process as the first important aqueous two‐phase processes with rhodium catalysts became the most important homogenously catalyzed chemical processes.     

Extraktion – ein historischer Rückblick

The extraction of plants with the aid of water is one of the oldest techniques known to humankind for obtaining aromatic principles and medicaments from these sources. Extraction vessels excavated in Mesopotamia can be dated back to around 3500 BC, and Sumerian clay tablets describing the preparation of medicaments which were found in the same region date from around 2100 BC. The Greek and Roman civilisations of antiquity inherited extraction together with other skills from their predecessors, and this knowledge was passed on to Christendom by Arabian scholars. Europe of the Middle Ages saw the development of pharmacy, medicine, and mining, as well as the sugar industry, all of which made active use of extraction with a wide range of solvents. Whereas technological applications of extraction were thus steadily increasing prior to the industrial revolution, the equipment used underwent hardly any changes up the end of the 18^th century. It was only in the 19^th century that active development of equipment, materials, and modes of operation started, while successful combination of theory and practice and treatment of extraction by the methods of engineering science had to wait until the 20^th century. This article reports about equipment, solvents, and extraction processes up to the beginning of the present century, and places then in a political and sociological context.     

Synthese von aliphatischen Aldehyden aus Alkanen und Kohlendioxid: Valeraldehyd aus Butan und CO2 – Machbarkeit und Grenzen

During the last decades, the engineering of chemical processes has focused more and more on energy efficiency and reduction of climate‐changing emissions. Regarding the synthesis of aldehydes, the photocatalytic dehydrogenation of alkanes to olefins, using visible (sun) light, and the subsequent hydroformylation of such olefins with CO₂ seem to be capable to achieve both targets. This work deals mainly with catalyst concepts for both reaction steps. Here, kinetic studies of the photocatalytic alkane dehydrogenation are presented, and the feasibility of hydroformylation using CO₂ is described in a continuous gas phase reaction. The problems that have to be solved befoe the technical application are discussed and an economic and ecological evaluation for both processes is carried out.     

Adsorptive Entfernung von Alkoxyphenolen aus Ketonen und Estern mit Aktivkohle – Experimente und Modellierung

Ultra pure chemicals are most notably used in electronics, optics, pharmaceutics and analytics. For the production of ultra pure liquids adsorptive removal of trace compounds and moisture is the preferred treatment. Adsorption experiments with the model system activated carbon/alkoxyphenol in ketones and esters as solvent are presented. Points of interest are the investigation of adsorption mechanisms as well as the measurement and modelling of adsorption isotherms.