Zusammensetzung,Präparation und Eigenschaften von Rapsphospholipiden

Composition, Preparation and Functionality of Rapeseed Phospholipids It is well known that phospholipids are byproducts of rape seed processing. Nevertheless they have only a small application field because of sensoric problems, undesirable colour and a lack of knowledge on relationship between structure and action. In this study the phospholipid composition of rape seeds of different breeding quality is characterized. The possibilities to prepare the main phospholipid constituents are analyzed. The functionality (interfacial behaviour) of phospholipid classes are tested in two experiments in order to receive more basic information on these compounds.     

Glas- und tieftemperaturrelaxation von copolyestern der terephthalsäure

The relaxation mechanisms of linear saturated copolyesters of terephthalic acid are influenced by the chemical structure of the used aliphatic, aromatic, and cyclic diols or dicarbonic acids. The glass transition temperatures of the copolyesters are in the range from -30 to 90°C. The numerical value of T_G can be calculated by the increment method with a mean error of ±5°C. Since this method can be applied also to other polymer systems or some other physical parameters a general procedure for optimizing the increments is given. With reference to known relaxation criterions the molecular motions of the copolyesters above and below T_G are identified. The two relaxation mechanisms below T_G show a statistical distribution of the different components of acids and diols along the chain. The γ′-relaxation is caused by orientational motions of carbonyl groups and depends on the chemical structure of the neighbouring segments. On the contrary the γ″-process is not influenced by the molecular environment and is caused by hindered rotation of CH₂-groups.     

Strukturaufklärung cyclischer Fettsäure-methylester I: Zusammensetzung von Gemischen aromatischer Fettsäure-methylester aus den Cyclisierungs- und Aromatisierungsprodukten von Leinöl- und Holzöl-Fettsäure-methylestern,Linolsäure und Linolsäure-methylester

Structure Determination of Methyl Esters of Cyclic Fatty Acids I: Composition of Mixtures Containing Methyl Esters of Aromatic Fatty Acids Obtained from Products of Cyclisation and Aromatisation of Linoleic Acid, Methyl Linoleate and Methyl Esters of Linseed and Tung Oil Fatty Acids The composition of methyl ester mixtures of aromatic fatty acids obtained by alkaline cyclisation and catalytic aromatisation of linoleic acid and methyl linoleate was determined. All the isomeric o-alkyl substituted methyl esters of aromatic fatty acids (I) (n = 0 to 11) could be identified by IR-, UV-, mass-spectrometry, gas-chromatography and by comparison with synthetic substances. The distribution of isomers in mixtures obtained by various procedures was determined by gas-chromatography. o-dodecyl phenol was found to be a by-product in the catalytic aromatisation of free linoleic acid.     

Zur Synthese von Polyfluoralkylestern der Fluorsulfonyl-difluoressigsäure und der α-Trifluormethylfluoressigsäure

On the Synthesis of Polyfluoroalkylesters of Fluorosulfonyl-difluoroacetic Acid and α-Trifluoromethylfluoroacetic Acid .     

Zusammensetzung und Aufbau der Triglyceride von Muttermilch und einiger Rohstoffe für Säuglingsnahrung

Composition and Structures of Triglycerides of Human Milk and Some Base Components for Infant Milk Formulas Following HPLC separation of human milk triglycerides with a silver-loaded ion exchange and an RP-18-phase column, the 50 substantial fractions obtained were characterized by gas chromatography of triglycerides and fatty acid methyl esters as well as by the analysis of intramolecular distribution on a reduced scale using ethyl magnesium bromide. Exploitation of all data available resulted in the detailed structures of 106 triglycerides, representing 81 g/100 g human milk fat. A substitute for producing infant milk formulas should be adapted to the composition and fatty acid distribution of those 14 substantial triglycerides which are present in human milk fat with more than 1 g/100 g, amounting to a total of 42 g/100 g. Among several fats and oils analyzed, only lard and a recent product were found to contain palmitic acid also predominantly in the 2-position. Therefore, other base components would require a directed fractionation and/or interesterification to be best adapted to human milk fat.     

Über die copolymerisation von acrylamid mit vinylestern der 2,4-dichlorphenoxyessigsäure und 2,4-dichlorphenoxybuttersäure

Copolymers with prolonged growth regulating activity for agriculture were prepared by the copolymerization of acrylamide with vinyl esters of 2,4-dichlorophenoxy acetic acid and 2,4-dichlorophenoxy butyric acid. Some kinetic relations were established. Reactivity ratios for the systems acrylamide-vinyl ester of phenoxyacetic acid (r₁ = 4,08 ± 0,08 and r₂ = 0,943 ± 0,16) and acrylamide-vinyl ester of 2,4-dichlorophenoxy butyric acid (r₁ = 1.50 ± 0,09 and r₂ = 1,02 ± 0,18) were determined. Conditions of preparing water soluble copolymers with good yield and sufficient high content of physiologically active units were established.     

Regeneration von Abfallschwefelsäure

Regeneration of spent sulphuric acid . Several processes are available for the regeneration of spent sulphuric acid. Generally, the dilute acids containing at least 20% of H₂SO₄ are preconcentrated to 60 – 70% and then either further concentrated to over 90% or decomposed to SO₂. Purifying operations can be combined with these steps. Spent sulphuric acid highly contaminated with inorganic and organic compounds can frequently only be regenerated after a prior purification step, e. g. by extraction of electrolysis. Dilute spent sulphuric acid containing less than 20% of H₂SO₄ can also be regenerated, but the costs incurred by evaporation increase out of proportion with decreasing sulphuric acid concentration.     

Zur kinetik und teilchenbildung der fällungspolymerisation von acrylsäure in gegenwart von polystyrol-block-polyethylenoxid-copolymeren

A surfactant system containing polystyrene-block-poly(oxyethylene) and water was used for the free radical precipitation polymerization of acrylic acid in toluene. The use of this stabilizing system makes it possible to produce poly(acrylic acid) dispersions with a particle diameter ranging from 50 to 300 nm and solid contents up to 40 wt.-%, which remain stable for months. The rate of polymerization, which was measured on-line in a reaction calorimeter shows a strong autocatalytic behavior. The maximum of the polymerization rate and the corresponding time of appearance depend strongly on the water content. The influence of the composition of the surfactant (block length), its concentration and the concentration of initiator and monomer on the polymerization rate and the particle diameter were studied. Especially by varying the block length of the copolymer, the number of particles, respectively the particle diameter, can be controlled. To describe the course of the polymerization process, a model based on the theory of homogeneous particle nucleation is suggested. The influence of water on the swelling equilibrium of the poly(acrylic acid) particles is taken into account.     

Chromatographischer und spektroskopischer Vergleich des Autoxidationsprozesses von Öl- und Elaidinsäure

Chromatographic and Spectroscopic Comparison of the Autoxidation Process of Oleic and Elaidic Acid The autoxidation process of cis-9-octadecenoic and trans-9-octadecenoic acid was studied using thin-layer chromatography, gasliquid chromatography, nuclear magnetic resonance spectroscopy and infra-red spectroscopy. On the basis of results obtained and by comparison with the “classical methods”, such as the course of peroxide value, and changes in acid value and iodine value, a scheme has been proposed to characterize the initial phase of the autoxidation process of oleic and elaidic acids.     

Neuere Erkenntnisse und Anwendungen bei der elektrischen Abscheidung von Stäuben und Nebeltröpfchen

New insights and applications in the electrostatic precipitation of dusts and mists. The introduction deals with the basic design, the mode of operation, and the fields of application of dry and wet type electrostatic precipitators. A few important parameters which influence the migration velocity are discussed. Contrary to what the classical theory states, greater passage widths lead to higher migration velocities of the particles and thus to a higher specific efficiency. The methods for conditioning flue gases of power stations are considered, as are the experimental results obtained in an industrial-scale SO₃ conditioning plant. A new field of application is seen in the steel industry through the use of a dry type electrostatic precipitator of special design. New plastic precipitator developments for the chemical industry are discussed, and the articles closes with an account of the efforts invested in developing hot gas precipitators for higher temperatures and pressures in connection with the introduction of new power station concepts.     

Zur Konstitution des Reaktionsproduktes aus Phenacylthioglykolsäure und Thioglykolsäure

On the Structure of the Reaction Product from Thioglycolic Acid and Phenacyl Thioglycolic Acid The reaction product obtained from phenacyl thioglycolic acid and thioglycolic acid is shown to represent 1,1,2-tris-(carboxymethylthio)-2-phenylethane 4 , and not 1,1,2-tris-(carboxymethylthio)-1-phenylethane 3 as suggested earlier in the literature. Analogously, phenacyl benzyl sulfide 2 and benzyl mercaptan yield 1, 1, 2-tris-(benzylthio)-2-phenylethane 5 . The reaction mechanisms are discussed on the basis of synthetic and n.m.r. spectroscopic studies.     

Epoxydationen mit Peressigsäure I: Zur Kenntnis der Peressigsäure und vergleichende Epoxydationen von Sojabohnenöl

Epoxidations with Peracetic Acid I: The Peracetic Acid and Related Epoxidations of Soybean Oil Progressive formation of peracetic acid by the action of hydrogen peroxide on acetic acid was studied. In the presence of ethyl acetate and by employing acetic anhydride, water free peracetic acid was obtained. In the epoxidation of soybean oil the maximum epoxide content of the same is dependent on the reaction conditions, especially on the degree of homogeneity of the reaction partners and the acidic catalyst.     

Die oxidation von butadienstyrolkautschuk und daraus gewonnenem vulkanisat mit salpetersäure

The interaction between butadiene-styrene-rubber Bulex-1500 (a commercial product containing 25 to 30% of styrene links) and a vulcanisate based on it and nitric acid was studied. It was established that a measurable yield of several reaction products may be obtained: Butadiene-styrene-rubber yields oxidized rubber, polyfunctional oligomer, and oxalic acid; the vulcanisate yields oxidized vulcanisate, polyfunctional oligomer, and oxalic acid. The effect of the conditions of oxidation (particle size, time, temperature) on the yield of the reaction products was studied. The conditions needed to obtain optimum yield of a given reaction product were determined. The influence of the styrene links from the molecule of butadienestyrene-rubber on the yield was studied and a comparison with butadiene rubber was made. It was established that oxalic acid is a product of a number of oxidation-decomposition processes in nitric acid medium, and a scheme of its formation was suggested. It was proved that oxidation-decomposition processes and nitration occur simultaneously. It was suggested that the interaction of nitric acid with butadienestyrene-rubber and its vulcanisate may be used to utilize waste products obtained from them.