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 γ-strahleninduzierte polymerisation an oberflächen von feststoffpulvern

Experiments with fine grained powders of silica gel, kaolinite and calciumcarbonate have been carried out, in order to prove whether the ⁶⁰Co-γ-preirradiation method is applicable for grafting methylmethacrylate (MMA) and styrene onto the surface of these powders. It is demonstrated that significant amounts of polymer may be grafted by this method. The degree of grafting (PG) increases with increasing absorbed dose and approaches a limiting value (PG^max) at high doses. Measured values of PG_F^max (expressed in units of g polymer per m² surface of powder) are the same within an order of magnitude for all substances. Therefore, it is concluded, that the polymerization is started by activecentersgenerated previously at the powder surface and that the maximum concentration of active centers attainable at the particle surface is about the same for all powders. Differences of PG^max_f-values obtained with the various substances are presumably due to the fact that the grafted powders contain a fraction of not covalently bonded and in spite of this not extractable polymer in narrow pores. Evidence for this was obtained by initiating the polymerization of MMA with AIBN at 50°C in the presence of a highly porous sample of silica gel. In this case PG_F = 2 × 10^?4g polymer/m² was obtained which compares with PG^max_F = 8 × 10^?4g polymer/m² for the preirradiated solid. It is assumed that at least a portion of the polymer grafted by the preirradiation method is not bonded covalently. The polymer portion which is not bonded covalently and is not extractable should be a function of the number and the width of the pores. It should vary, therefore, with the substance.     

Über die Synthese von α-Pyridonen aus Ketonen und Harnstoff

The Synthesis of α-Pyridones from Ketones and Urea By acid-catalyzed reaction of ketones with urea, the condensed α-pyridones 2, 8, 9, 10, 12a–d are formed.     

Über die Herstellung von Cellulasen und die enzymatische Spaltung von Cellulose

Production of cellulases and enzymatic cleavage of cellulose . Recent work on production of cellulolytic enzymes and on enzymatic degradation of cellulose is described. For optimum enzyme production by Trichoderma reesei under carefully balanced growth conditions, cellulose levels as high as 2% may be employed. Nitrogen deficit may be economically avoided by adding organic nitrogen in the form of distiller's spent grain and dried ground T. reesei cell mass. Semicontinuous production has been shown to offer further special advantages. Cellulase activity may be directly monitored automatically in a computer-controlled pilot fermentation system. Xylitol and furfural process wastes have been shown to be suitable substrates for cellulase, requiring little or no costly pretreatment. The rate of cellulose hydrolysis is considerably increased by combined use of T. reesei and cellobiase active microorganisms such as Aspergillus phoenicia.     

Synthese von ω-Acetyl-α-methylenpolyencarbonsäureestern

Synthesis of ω-Acetyl-α-methylenpolyene Carboxylic Esters The α-methylenpolyene carboxylic acids 1 and 2 are highly active against Gram-positive bacteria. If this activity arises from an interference with the cell membranes, then an abrupt change in biological properties is to be expected with growing chain length of simple model compounds. To make these tests possible, we describe here the synthesis of a series of homologue esters of type 40 . Their synthesis was achieved by Wittig reactions of polyene αω-dialdehydes 6 with acetyl-methylentriphenylphosphoran 5a and the protected carboxy-methylmethylen triphenylphosphonium salt 8 .     

Über die Photochromie der Fulgide. IX Untersuchungen zur Photochemie des α-3,5-Dimethyoxyphenyl-δ-δ-dimethylfulgids

The Photochromism of Fulgides. IX. Investigations of the Photochemistry of α-3,5-Dimethoxyphenyl-δ,δ-dimethylfulgide The mechanism of photoisomerization of α-3,5-dimethoxyphenyl-δ, δ-dimethylfulgide was investigated by means of u.v./vis- and fluorescence spectroscopy. The quantum yields of E-Z isomerization and cyclisation were determined in various solvents and at different temperatures. Triplet sensitization of E-Z isomerization by several sensitizers has been found. The thermal dark reactions of the deep coloured species were reinvestigated.     

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 Herstellung eines transparenten Oleogels unter Verwendung von Polyacrylsäure - Carbopol® 934

Transparent Oleogels on the Basis of Polyacrylic Acid - Carbopol® 934 Transparent Oleogels were prepared on the basis of polyacrylic acid (Carbopol® 934) and mixtures of mono- and diglycerides of fatty acids with chain length C₈-C₁₂ (Imwitor® 742). After pre-gelination of the polyacrylic acid the mixture is partially neutralized with special oleophiles amines, f. e. n-butylamin or dibutylamin. To prevent separations of the mono-and-diglycerides a little amount of the triglycerid C₈-C₁₂ (Miglyol® 812) is added. After mixing the resulting oleogels are transparent.     

Über α-substituierte Phosphonate. XXI. Zur Bildung von hydroxyarylsubstituierten Methan-bis-phosphonsäuretetraestern

α-Substituted Phosphonates. XXI. On the Formation of Hydroxyaryl-substituted Methane-bis-phosphonic Acid Tetraesters α-Amino-α-(4-hydroxy-3,5-di-tert.-butyl-phenyl)-methanephosphonic acid diethylester 1 can be converted by different methods to (4-hydroxy-3,5-di-tert.-butyl-phenyl)-bis-phosphonic acid tetraethylesters 2 . Course and intermediates of these smoothly proceeding reactions are investigated.     

ÜBer die gegenseitige durchdringung von polymerknäueln im θ-zustand

The degree of mutual penetration of random coils close to the ?-point was investigated by evaluation of the maximum conversion of the reaction of a OH-groups containing polymethylmethacrylate (PMMA) with a COCl-groups containing PMMA in a mixture of benzene and n-hexane. We have found, that the degree of coil penetration in ?-solvents has the same value as in good solvents, namely 5 to 20% of the coil volume with a polymer concentration of 10 to 30 wt.-%. Sterical factors are discussed as the reason for the small mutual penetration of the coils. Because of 1-T/? = 0 no energy barrier can be present.     

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.