Fettpolymere – Herstellverfahren und Eigenschaften

The radical polymerization of esters of acrylic, methacrylic or crotonic acid with fatty alcohols proved to be an efficient method for production of polymers with hydrophobic moieties. By co-polymerisation with hydrophilic co-monomers - such as maleic anhydride - copolymers with a broad spectrum of properties can be designed. As an example the copolymerisation of fatty crotonates with maleic anhydride was studied in detail. The reaction was carried out as bulk polymerisation in a semi-batch process. By this method the compatibility problems of the two monomers, which have very different hydrophilicities could be overcome. The product acts as a very effective fat liquoring agent in leather treatment: the maleic moieties cause an outstanding fixing of the agent on the leather and the fatty crotonate moieties create a very smooth leather. Terpolymers of fatty acrylates, hydrophilic monomers and terpenes could also be synthesized in a similar way. These terpolymers proved to be useful as dispersing agents for pigments in paints and varnishes.     

3β-Chlorsteroide – Ernährungsphysiologische und toxikologische Eigenschaften in Mäusen

3β-Chlorosteroids - Nutritional and Toxicological Effects in Mice 3-Chlorosteroids, e.g. 3-chlorocholest-5-ene and 3-chlorostigmast-5-ene, are formed from the corresponding sterols during the industrial hydrolysis of proteins for the production of flavor enhancers. In future, these compounds may also attract attention as environmental contaminants. A simple method for the fractionation and quantitative determination of 3β-chlorosteroids by C₁₈ reversed-phase HPLC has been developed and used for the analysis of these chlorinated steroids in protein hydrolysates. In addition, the biological effects of orally administrated 3β-chloro-steroids were tested in mice that were fed 3β-chlorocholest-5-ene and 3β-chlorostigmast-5-ene in doses of 1 and 10 mg/animal/day. The results of our study showed that body and organ weights as well as feed intake of the various experimental groups were not significantly different from those of the control group. The quantitative determination of 3β-chlorosteroids in organs and tissues revealed that intestinal absorption of 3β-chlorocholest-5-ene was higher than that of 3β-chlorostigmast-5-ene. Highest concentration of 3β-chlorocholest-5-ene was detected in liver and adipose tissue. Absorption and distribution in tissues as well as metabolism of both radioactive 3β-chloro-[4-¹⁴C]cholest-5-ene and 3β-chloro-[4-¹⁴C]stigmast-5-ene have also been studied in mice. At 2 hours after stomach incubation of the two substrates, large proportions of radioactivity had passed through the small intestine and were concentrated in the contents of caecum and colon. Only small proportions of radioactivity were detected outside the alimentary canal, predominantly in the liver. Histopathological examination of sections of organs and tissues such as stomach, duodenum, liver, kidneys, and spleen showed no indications of irreversible cell damages caused by 3β-chlorosteroids.     

Struktur und spektrale Eigenschaften des Pentamethinmerocyanins 5‐(Dimethylamino)pentadienal in Lösung – Eine kombinierte DFT–SCI–SCRF–Studie

In order to estimate the solvent effect on molecular structure and on NMR and UV spectral data of 5‐(dimethylamino)penta‐2,4‐dien‐al(1) ( 1 , R = Me) the compound was calculated by first‐principles methods. Density functional theory was employed for structural optimization with solvent effects simulated by the recently refined COSMO continuum model. According to the calculations the molecular structure of 1 (R = Me) is noticeably affected by polar solvents resulting in a reduced bond length alternation. The relaxation of the molecular geometry in polar solvents is clearly reflected in the calculated ¹³C NMR chemical shifts calculated by GIAO‐DFT and in the absorption wave numbers of the intense lowest‐energy electronic transition calculated by SCI. Although the optimum geometry of the solute molecule in the solvents was calculated the magnitude of the solvatochromic shift is underestimated. The calculated solvatochromic effect in water is enhanced if the specific solvent‐solute interactions are considered by addition of one water molecule to 1 (R = Me) in the solvent cavity.     

Zur Produktgestaltung kohäsiver Pulver – Mechanische Eigenschaften,Kompressions‐ und Fließverhalten

Product Design of Cohesive Powders – Mechanical Properties, Compression and Flow Behavior The three yield conditions of a powder continuum (incipient yield, stationary flow, consolidation) are formulated on basis of particle mechanics by the model ?stiff particles with soft contacts“. So that the direct influence of contact behaviour on flow behaviour is analytically shown. The powder compression behaviour is characterised by a compressibility index. Additionally the compression rate and the specific compression work are explained. So that the correlation between contact compliance, adhesion force intensification and powder flowability can be physically consistent evaluated. The response functions of extreme stressing and flow conditions at material conversion processes, storage and transport can be sufficiently described by these models. Obviously, suitable conclusions may be also drawn to design marketable products of processing industries.     

Emissionen – Emissionsminderung bei Anlagen zur Gewinnung und Bearbeitung pflanzlicher Öle

Air Pollution – Reduction of Air Pollution for Plants to Produce and Process Vegetable Oils The waste gas flows and the connected air pollution for a typical plant to process softseeds up to a capacity of about 50t/h and a refinery of about 15 t/h are given and suited measures for the reduction of air pollution are described. On current occasion the paper refer to the VDI-Richtlinie Nr. 2592.     

Fünfring-Cycloamidine – Neue farbige Heterocyclen mit ungewöhnlichen Eigenschaften. I. Synthese und spektrale Besonderheiten

5-Ring-Cycloamidines – Deeply Coloured Heterocycles with Unusual Properties. I. Synthesis and Spectral Features The cycloacylation reaction of benzamidines with bis-imidoylchlorides 1 derived from oxalic acid was investigated. For example, treatment of benzamidine with 1 gives the new 4H-imidazoles ( 3a–l ) in yields up to 92%. Because of rapid H-transfer processes in solution, the NMR-spectra of 3a–l show only a single signal set. Apart from prototropism, 3c shows interesting properties as an amphoteric heterocycle. The protonation of 3c is accompanied by a change of color from orange to blue. Probably, protonation takes place on the exocyclic imino nitrogen to give a cyanine type chromophor. The resulting cation can also be regarded as an antiaromatic 1,3-diazacyclopentadienylium system. In order to investigate the influence of exocyclic substituents at nitrogen on the UV/VIS absorption, compounds 3d–h were synthesized. Whereas electron withdrawing groups cause hypsochromic shifts of the first UV/VIS absorption band, the dimethylamino group shifts this band bathochromically as exemplified by 3e . This novel cycloamidine shows strong acidochromism with bathochromic shifts of more than Δλ_max = 150 nm.     

Fünfring-Cycloamidine – Neue farbige Heterocyclen mit ungewöhnlichen Eigenschaften. II. Molekül- und Elektronenstruktur

5-Ring-Cycloamidines – Deeply Colored Heterocycles with Unusual Properties. II. Molecular- and Electronic Structure The crystal and molecular structure of two N,N′-aryl-5-amino-imidazole-4-imides were detected by X-ray analysis. The structural parameters are discussed in conjunction with theoretical data obtained by density functional and ab initio quantum theory. The interpretation of the molecular structures derived from the X-ray diffraction study is made more difficult by statistic disorder or by enclosure of water in the crystal. The theory predicts a planar 5-amino-imidazole-4-imide parent structure with an energy barrier to H-transfer of about 25 kcal/mol (DFT RB3LYP/6-311+G** and ab initio G2(MP2) calculations). The CC bond of the five-membered ring is exceedingly long. CC-bond length elongation is also reported for oxalbisamidine. The structure of the parent compound is discussed in terms of polymethinic and antiaromatic substructures. Weinholds's Natural Bond Orbital (NBO) scheme and Natural Resonance Theory (NRT) as well as Schleyer's criterion of the Nucleus Independent Chemical Shift (NICS) is consulted to reveal the very nature of the unique bond system.     

Liposomen – Strukturen und Herstellung

The general public has only recently become familiar with liposomes through their use in cosmetics although a wide range of applications has long been known in the scientific literature. Depending upon the pertinent application very different liposomes are required, which has led to a large number of methods for their production. This article describes the principal processes: rotor/stator dispersion, the injection method, dialysis, extrusion, and homogenisation. The most suitable methods for industrial use are rotor/stator emulsification, the injection method, extrusion, and homogenisation. Examination of commercially available liposome-containing products shows that high-value products such as cosmetics and pharmaceuticals predominate – commercial use of liposomes is often limited by the sophisticated production methods and expensive raw materials.