Über die Struktur cyclisierter Fettsäureester

The Structure of Cyclised Fatty Acid Esters It is proved that the cyclic fatty acids which are obtained from tung and linseed oils by alkali-treatment contain mainly two types of products. Approximately 30% of these consist of 1,2-disubstituted cyclohexadiens, whose one double bond of the ring is in the 1-position and the other one is conjugated to the former. Approximately 60% of the mixture is comprised of ω-(2-alkyliden-cyclohexenyl)-fatty acid esters. The double bond in the ring is predominantly in the 3-position. As a result of the rearrangement of double bonds before cyclisation, R′varies from C₂ to C₁₁ and R″ from C₀ to C₉.     

Über die Härtungsreaktion von Phenol-Formaldehyd-Harzen I

Investigating the viscosity of a phenol formaldehyde resin, the rate equation for the curing process of the resin has been determined. According to the measurements the equation is as follows: Using of the integrated form of this equation the rate constants of the curing process relating to different temperatures as well as the value of the activation energy have been determined.     

Über die vernetzung eines ungesättigten äthylen-propylen-terpolymer-kautschuks

The various aspects of the sulfur vulcanization chemistry and mechanism of ?Nordel”? hydrocarbon rubber, an ethylene-propylene terpolymer, are discussed. The chemical nature of the reactions undergone by the accelerators has been found to be analogous to those observed for natural rubber and SBR. During vulcanization approximately 50% of the double bonds are saturated, and approximately one crosslink is formed for each two double bonds initially present. The type of crosslink formed has been examined and the vulcanization kinetics studied with the aid of a Monsanto rheometer.     

Über die Härtungsreaktion von Phenol-Formaldehyd-Harzen II

On the, basis of dilatometric and calorimetric measurements, a method is given for the investigation of the curing process of industrial phenolic resins and for the determination of the rate constants of its brutto reactions.     

Über die Darstellung isomerenfreier verzweigter Carbonsäuren

Preparation of Branched Carboxylic Acids Free from Isomers A method for the preparation of branched saturated and unsaturated carboxylic acids, free from isomers, from tertiary γ-lactones by means of alkyl aluminium chlorides is reported. Saturated branched carboxylic acids were obtained in high yields by the reaction with ethyl aluminium chloride, whereas the reaction with diethyl aluminium chloride yielded the unsaturated acids. Splitting of lactones with mixtures of both the ethyl aluminium chlorides gave mixtures of saturated and unsaturated acids. The structure of the unsaturated carboxylic acid was determined by hydrogenation, ozonolysis, iodine value and gas chromatography.     

Über die Auswahl von Polymerisationsreaktoren

Choice of polymerization reactors . Industrial syntheses of polymers always yield a highly complex product whose adequate characterization often requires application-oriented tests in addition to chemical and physical parameters. In contrast to the synthesis of low-molecular mass substances subsequent corrections, e. g. by distillation or crystallization, are usually impossible. Extremely detailed reaction control is of paramount importance. Polyreactions can be classified according to kinetic aspects (monomer linkage with and without termination reaction, linkage of polymers). Apart from homogeneous bulk polymerization, there are the heterogeneous processes of precipitation-, bead-, and emulsion-polymerization. The polymerization reactors can be assigned to the known ideal types (batch reactor, continuous plug flow reactor, series of stirred tanks, and continuous stirred tank reactor). High viscosity often thwarts thorough mixing in bulk polymerization and segregation may occur. The article surveys the variants of the reactor types used for various polyreactions and polymerization processes in industry and examines the reasons for this choice. Most commonly used is the batch reactor, followed by the cascade of stirred tanks. Continuous polymer-linkage (polycondensation, polyaddition) is frequently performed in a series of several different kinds of reactors.     

Über die Standzeit thermoplastischer Polymerer

The effect of different machanical strains on polyethylene, polypropylene, polyvinylchloride and polyxymethylen was studied. Similar type long-time properties of thermoplastic polymers were found in a wide interval of strains. The long-time characteristic of each thermoplastic material could be given in semi-logarithmic coordinates In τ vs. σ, by a family of S-type curves, typical for a given temperature. Strain exhibits a clear maximum corresponding to the formation of a neck which is observed only in a narrow interval of stress. The mechanical and chemical degradation occuring under constant mechanical stress is considered. The effect of the chemical and light-stabilizers on the mechanical degradation was studied. It is shown that the long-time stability of the polymers could be extended considerably by applying structure modifying agents.     

Über die Kinetik der Fettkristallisation

Kinetics of Fat Crystallization The course of fat crystallization is similar to that of aggregation and flocculation of colloids. Rate formulae for aggregation and flocculation, previously derived empirically from experimental data, are applied to data on the crystallization of fats and for comparison on the separation of emulsions. The data are linearized. The rate constants are determined as functions of the solid fat index.     

Über die Adsorption von Fettsäuren an Ionenaustauschern

Adsorption of Fatty Acids on Ion Exchangers The author examined the adsorption of saturated fatty acids C₁₀ to C₁₈ on strong- and weak-basic anion exchangers in the presence of n-hexane, acetone and 96% ethanol. The extent of adsorption on dried anion exchangers is small, and in nonpolar solvents, the effective capacity amounts to 5% of the theoretical capacity. With wetted resins, not the polarity of the solvents but the dissociation of the functional groups of the exchanger is the factor determining adsorption. Since the adsorbing ability of the exchanger is limited by the length of the fatty acid molecules, the effective capacity of strongly basic exchangers amounts only to one-third or a half of the theoretical capacity.     

Über die Unschädlichkeit von Enzymen in Waschmitteln

Harmlessness of Enzymes in Washing Agents Before introducing them into the market, the enzymatic washing agents were subjected to extensive tests. As regards acute toxicity through oral intake as well as skin irritation and skin sensitivity no difference was found between the enzyme-containing products and those which did not contain the enzymes. Accordingly, the use of enzymatic washing agents do not offer any hazard to the health of housewives.     

Über die Herstellung der Imidazoline von Fettsäuren

Preparation of Imidazolines of Fatty Acids The formation of imidazolines was studied in the reaction of diethylene triamine with fatty acids and oils. With the aid of IR- and UV-spectroscopy, it could be proved that imidazolines are formed at temperatures between 150° - 200° C. Aminoamides are also formed at these temperatures. Above 280° C, decomposition takes place, and low molecular nitrogen compounds, including probably ammonia, are formed.     

Über die Synthese einiger Polyhydrazidcarbon- und -sulfonsäuren

Pyromellitic dianhydride (PMDA) was condensed with oxalic- and malonic-acid dihydrazides. The optimum experimental conditions have been worked out and the viscosity values were determined. The polyhydrazid carbonic acids so obtained were converted to the corresponding polymidimidcompounds by means of thermal cyclisations. Similar polycondensations were carried out with 3,3′-disulfo-4,4′-dicarboxy-diphenylsulfondianhydride and different hydrazides. The same dianhydride was also used for the synthesis of the carbodihydrazide. Further a sulfondihydrazide was prepared from 4,4′-ditolysulfon-3,3′-disulfochlorid.     

Über die Selbsterwärmung der Sonnenblumensaat beim Lagern

Contribution to the Investigation of Selfheating of Sunflowerseed during Storage Some informations are given in this work on the cause and development of fire in silos for sunflowerseed storage and the way of solving this problem in analyzed. The selfheating process has been investigated in laboratory conditions. Numerous factors that influence the beginning and development of the process, like: moisture, oil content, hull quality, impurities, have been investigated. On the basis of the laboratory investigations and data obtained from real fires, some suggestions connected with the building of silos and work in them are given, with the aim of decreasing the possibility of the development of selfheating. Some suggestions are also given for the improvement of the intervention in case of fire in the silos for sunflower-seed storage.     

Über den Einfluß der Grenzflächenspannung auf die Haftfestigkeit

The values of adhesion between four diffrent adhesive,and (i) steel substrates whose surface energy had been altered by adsorption, and (ii) several polymer having different surface energies, had been measured. The results show that the adhesion has a maximum value when the surface energy of the hardened adhesive is equals to that of the substrate, i.e. when the interfacial energy adhesive/substrate is a minimum. The adhesion of the adhesives to the polymer was much smaller than to the steel sprcimens and the dependence of the adhesion onm the interfacial energy was sharper in the case of the polymers. The decrease of the adhesion with increasing interfacial energy was fiund to be greater if the liquid adhesive wets the substrate badly than the steel speciman.