Anwendung von modernen Methoden der statistischen Versuchsplanung bei der Entwicklung von Lackrohstoffen

Application of Modern Methods for the Statistical Planing of Experiments in the Development of Raw Materials for Paints Generally, the action of several factors should be investigated in the development of raw materials for paints. For this purpose, complete or fractional factorial plans of experiments are useful. Such plans should be oriented towards the ultimate aim of the experiments. The author has found during the development of low-profile hard polyester resins and filling resins that from factorial planing of experiments with 2–5 variables at two niveaus, the essential variables, their effects of first and second order as well as the direction of continuation of the experiments can be determined. In an example the Plackett-Burman-procedure is discussed which is especially suited for preliminary testing in the case of 5 or more variables. The optimization of a process requires the application of experimental plans in which the variables are varied at least at 3 niveaus. When more than 3 variables are investigated, it is advantageous to use factorial plans that are complemented by incomplete blocks. As an example the optimization of an epoxy primer using the Box-Behnken design is discussed.     

Anwendung der UV-Spektrophotometrie bei der Untersuchung der Oxydation und Polymerisation von Fetten

Application of UV-Spectrophotometry in the Investigation of Oxidation and Polymerisation of Fats In the direct UV-method, the first maximum of extinction at wave-length 243 nm of heated sunflower oil is related to viscosity, refractive index and specific weight, but not related to peroxide value and aldehyde content. In these experiments the oils were heated in air, in air current and in current of nitrogen.     

Untersuchungen zur Charakterisierung von Fritierfetten aus der Praxis

Investigations for Characterising Frying Fats According to A. Mankel the simultaneous consideration of the acid value, the content of petroleum ether insoluble oxidised fatty acids and the smoke point is suitable to evaluate the quality of used frying fats and oils. At present this combination is generally considered as the best method of evaluation. Quick tests, which can be carried out adjacent to the fryer and whereby only the content of free fatty acids is measured, have only a limited significance. A novel quick test, the ?Fritest®”? of Messrs. Merck, is supposed to assess the oxidation products – as the saponification colour number does. But the ?Fritest®”? does not take the colour of the fat in account which would partially eliminate the influence of the inherent colour of the fat as also the influence of the frying goods. We carried out this test with soyabean, sunflower and hardened groundnut oil used for frying. In the case of sunflower oil samples from three fryers with different frying goods the ?Fritest®”? indicated the necessity of oil renewal and deterioration of the oil resp. although there was no deterioration recognizable according to the criteria of Mankel. Producers and publications recommend the use of hardened groundnut oil for frying. One such oil which had been used under conditions similar to commercial practice was found by ?Fritest®”? to be not satisfying the specifications of food regulations. In the case of soyabean oil used for fish frying the ?Fritest®”? as well as Mankel's criteria indicated deterioration. K. Lang and coworkers could, however, not observe any detrimental physiological properties on rats as a result of feeding trials with these oils over many years.     

Verhalten und Beurteilung von Fritierfetten in der Praxis

Behaviour and Assay of Frying Fats in the Practice Studies on coconut oil palm oil, peanut oil, soybean oil and hardened peanut and fish oils revealed that the oils rich in polyenoic acids as well as animal fats are unsuitable for prolonged use in frying. The content of oxidized fatty acids, saponification colour number, flavour, acid value, smoke point and appearance served as criteria for assay. The limiting values determining whether the frying fat is edible, and the significance of each of these characteristic properties used for such evaluations are discussed. Finally, a new rapid method is introduced for the direct determination of the degree of oxidative deterioration in frying plants. This methods can be practiced without a prior knowledge of chemistry.     

Zur Anwendung von Lanthanoid-Verschiebungsreagenzien bei der NMR-spektroskopischen Untersuchung von Gemischen monofunktioneller Kohlenwasserstoffe

Application of Lanthanide Shift Reagents in ¹H-N.M.R.-Spectroscopic Investigations of Mixtures of Monofunctional Hydrocarbons The influence of n.m.r. shift reagents on the ¹H-n.m.r.-spectra of mixtures has been investigated. Hydrocarbons of the type CH₃(CH₂)_nX (X =  OH,  CHO,  COR,  COOCH₃,  COOH,  OR with R = Methyl-, Ethyl-, n-Propyl-, n-Butyl- and n = 1,2) served as model substances. The components of the mixtures compete with the shift reagent. Relative equilibrium constants have been calculated to describe this behavior in mixtures. Several equations have been deduced and tested to describe the induced shifts of the protons in mixtures. These equations are applicable to qualitative and quantitative analysis of unknown mixtures.     

Chromatographische Untersuchungen der hydrophoben Eigenschaften von Tocopherolen

Chromatographic Investigation of Hydrophobicity of Tocopherols We applied TLC and HPLC in purpose to compare hydrophobicity of α-,-β-,-γ- and δ-tocopherol. The obtained results were correlated with those of the quantum-mechanical calculations and with the respective steric effects. It was established that the investigated tocopherols can arranged in the below given order in respect of the sinking hydrophobic properties: α-tocopherol >β-tocopherol < γ-tocopherol < δ-tocopherol.     

Epoxid-Reaktionen. V. Untersuchung von Teilreaktionen der Epoxidharz- Vorprodukt-bildung durch chromatographische Methoden

Epoxide Reactions. V. Chromatographic Studies of Some Reactions Involving Epoxide Formations A reverse phase liquid chromatographic method has been applied for the quantitative determination of some products in epoxide forming reactions. The reaction of chlorohydrinethers of bisphenol A with aqueous sodium hydroxide has been studied quantitatively under different conditions. The influence of side products originating from epichlorohydrin on the course of the main reaction is discussed. In addition preparative liquid chromatographic methods have been developed to separate epoxide oligomers and some chlorohydrinethers of bisphenol A.     

Untersuchung von Steringemischen IV: Das Retentionsverhalten freier Sterine bei der Gas-Chromatographie

Studies on Sterol Mixtures IV: Retention Behaviour of Free Sterols in Gas Chromatography Retention behaviour of a number of free sterols was studied by gas chromatography using SE-30, UCCW-982, OV-17 and OV-25 as stationary phases. In a similar manner as tested for steryl acetates, the separation factors were determined for sterol pairs which differ by one constitutional characteristic. The efficiency of separation of the stationary phases OV-17 and OV-25 were found to be distinctly superior to those of less polar phases. Sterols having Δ²⁴(²⁵)-double bonds are especially well separated from their saturated counterparts. Steryl acetates exhibit on all four stationary phases longer retention times compared to free sterols whereas the trimethylsilyl ether derivatives show on SE-30 and UCCW-982 columns longer and in OV-17 and OV-25 columns greatly reduced retention times.     

Untersuchung verbesserter Methoden zur Vermeidung von Entrainment in Rektifikationskolonnen

Unwanted entrainment of droplets to succeeding process areas is one of the main challenges for efficient operation of separation processes like rectification or evaporation. Fluctuation in temperatures, pressures or flow rates lead to operating conditions that cause entrainment. This results in significant losses both in means of energy and costs. Therefore, new approaches to reduce entrainment were investigated in a joint project with focus on rectification processes.     

Elektronenmikroskopische Untersuchung der Salbenstruktur I: Untersuchung von Vaselin

Electron Microscopic Investigation of Ointment Structure I: Investigation of Vaselines The structure of fibril-lattices of vaseline is studied with the help of a freeze-etching technique. From the electron microscopic pictures it can be concluded that vaseline represents a colloidal fibrilary system and that the fibrils comprise of fibrous threadlike bundles.     

Bestimmung der polaren Anteile in Fritierfetten

Determination of Polar Components in Frying Fats The DGF-Einheitsmethode C-III 3b (81) for the column chromatographic determination of polar components in frying fats is presented. This method was checked in a collaborative test with 14 participants. The evaluation of the results was done according to the statistical rules given in ”?Amtliche Sammlung von Untersuchungsverfahren nach § 35 LMBG' (Lebensmittel- und Bedarfsgegenständegesetz). At mean values of about 27% the value for the repeatability is 1.7% (absolute), and for the reproducibility is 2.8% (absolute).     

Calorimetrische Untersuchung der Vernetzung von Epoxidharzen

Reaction enthalpies of commercial epoxide resins crosslinked with primary, secondary or tertiary amines, anhydrides, a (BF₃) amine complex, respectively, were determined by differential scanning calorimetry. The accuracy of the ΔH_R-values is 2,5–3%. If the initial state of the reaction mixture is homogeneous and fluid and there is no three-dimensional network in the final state, enthalpies of -143 kJ/mol are determined. Reactions sometimes start at room temperature, so reaction enthalpies must be extrapolated. If the initial state is glassy or cristalline, reaction enthalpies of -100 to -129 kJ/mol are determined. Addition of a swelling agent results in higher values of ΔH_R. It is concluded, that for a complete reaction the above mentioned value is attained.     

Untersuchung der Ölzahl therapeutischer Vaseline - Kritische Wertung der Methoden

Examination of the Bleeding Number of Therapeutical White Petrolates - Evaluation of Methods The authors examined the bleeding number of 15 therapeutical white petrolates of different composition with four methods. They analysed the defects of each method by giving the values of standard deviation and the variation coefficient. They studied the correlation between the results by correlation and regression analysis and through this the essential elements of the method. They established that it is the method based on gravimetric measurement that gives occurate and characteristic results. They found a correlation between the structural viscosity of the vaselines, the solvating capacity of structure-forming components and values of the bleeding number.