Katalytische Oligomerisierung von Fettstoffen

Catalytic Oligomerization of Fatty Derivatives A new catalytic reaction is presented to oligomerize conjugated fatty acids or esters under mild reaction conditions. Metal salts such as tin dichloride, tin tetrachloride, titanium tetrachloride or iron trichloride are used as catalysts, and yields of oligomers of 70% are reached. In particular, a bimetallic catalyst system of molybdenum pentachloride and tin dichloride proved to be highly active. Especially remarkable is the distribution of the oligomers: Instead of a Schulz-Flory-distribution with dimers as main products a Poisson-distribution is formed with trimers as most important oligomers.     

Katalytische und thermische Abluftreinigung

Thermal and Catalytic Purification of Effluent Air. Since the Federal laws dated 1. 4. 1974 and 28. 8. 1974 have been passed, many industrial plants now belong to the category of plants which require to purify the effluent air. Such plants to which these laws are applicable owing to odor nuisance to the immediate surroundings include those belonging to fat industry, food industry, animal fat rendering industry, fiber industry etc. In the present communication, two processes for the purification of effluent air are described, namely, combustion process working at 700°–900° C and the catalytic oxidation process working at 250°–400°x C. Possible means for recovering the heat of combustion as well as the investment and operation costs are discussed.     

Katalytische Spaltung substituierter 1,3-Dioxane

Catalytic Cleavage of Substituted 1,3-Dioxane The catalytic cleavage of 4-phenyl-1,3-dioxane and 4-methyl-4-phenyl-1,3-dioxane using palladium or CuO Cr₂O₃ BaCrO₄ catalysts was studied in this work. The hydrogenolysis of cited 1,3-dioxanes using CuO Cr₂O₃ BaCrO₄ catalyst gives 3-phenyl-1-propanole and 3-phenyl-1-butanole, resp. in high yields. It is possible to obtain these primary alcohols also by pressureless cleavage using the palladium catalysts in a hydrogen atmosphere. The cleavage of 4-phenyl-1,3-dioxane in the inert atmosphere produced propiophenone selectivelly. The byproducts of the reactions were identified and the reaction scheme of the catalytic cleavage is suggested.     

Katalytische sauerstoffelektrode in sauren lösungen

Porous, twolayered carbon-Teflon electrodes are described possessing a relatively high catalytic activity as regards the oxygen reduction in acidic solutions. This catalytic activity has been achieved by using polymeric phthalocyanine (Pc) compounds with iron as the central atom.The influence on the activity from the concentration of teflon and Pc as well as from the applied pressure has been investigated.A considerable increase of electrochemical activity with increasing Pc-concentration was observed. A teflon concentration of about 10% was found to be an optimum value. Increased pressure favoured the electrochemical performance, but did not influence the slow change of the potential with time.     

Katalytische und elektrochemische Aktivität einiger Metall-Polyphthalocyanine

The catalytic properties of Fe, Co, Cu, Ni and Mg polyphthalocyanines in the reaction of hydrogen peroxide decomposition and their electrochemical properties in the reaction of oxygen reduction have been investigated. The accordance of the orders of catalytic and electrochemical activities of the investigated metallic polyphthalocyanines has been stated. The influence of reaction environment on catalytic and electrochemical activities also has been found. It has been established, that the linear dependence between reaction rate constant of hydrogen peroxide and its electrical conductivity, for iron polyphthalocyanine soluble in concentrated sulphuric acid can be observed.     

Reaktionstechnische untersuchungen über die Katalytische ammoxydation von 4-picolin

The kinetics of the catalytic gas phase ammoxidation of 4-picoline to isonicotino-nitrile have been studied in a fixed-bed integral reactor on an alox-vanadiumoxide catalyst in the temperature range of 290–400°C. By fixing a mean reaction temperature, it was possible to simulate a pseudo-isothermal reaction system with the aid of an analogue-computer and to calculate the velocity constants on the basis of a macrokinetic model. On that basis mean axial temperature/concentration profiles of the most important components (4-picoline, isonicotinamide, isonicotino-nitrile, tare, total oxidized products) were calculated with a digital-computer, taking into consideration the heat transport. The calculated values were in good agreement with the experimental data. The ammoxidation reaction is controlled by pore-diffusion phenomena. The activation energy of the 4-picoline conversion was 12 kcal/mole in the diffusion region, and 21 kcal/mole for the chemical controlled reaction.Besides the main reactions, two consecutive reactions were found, one was the reaction of ammonia with isonicotino-nitrile to isonicotinamidine, and the second was the reaction of isonicotinal-dehyde to 4-pyridyl-N(4-picoline aldimino)-carbinole.     

Katalytische Verknüpfung ungesättigter Fettstoffe mit Formaldehyd

Catalytic Addition of Formaldehyde to Unsaturated Oleochemicals The addition of formaldehyde to unsaturated oleochemicals is catalyzed both by halides of noble metals, as for instance by ruthenium-trichloride or hexachloroplatinum acid, and by other compounds such as boron trifluoride or tintetrachloride. 1:1, 2:1 and in traces also 4:1 adducts of formaldehyde are formed. The reaction can be carried out in the solvent propylene carbonate at mild temperatures (70–110°C) with short reaction times. The yield of the adducts is in the range of 70–80%. A mechanism is proposed in which the activating properties of the catalyst are described.     

Katalytische Abluftreinigung: Verfahrenstechnische Aufgaben und neue Lösungen

Catalytic air purification; Challenges and new solutions. The integration of regenerative heat exchange into the catalyst bed allows for the autothermal operation of catalytic air purification with a low content of combustible gas. Concentrations corresponding to an adiabatic temperature rise of less then 20 °C can be processed without an additional heat source; in case of higher concentratons a side stream withdrawal allows for the utilization of the total heat of combustion at the highest reactor temperature. The feedback of heat due to the integrated heat exchange gives rise to an unusual reactor behaviour. An analogy of fixed bed reactor operation with countercurrent heat exchange is used to derive simple equations for reactor design and operation. If conventional catalyst packings are replaced by monolithic catalysts, substantial reduction in pressure loss and/or packed bed volume can be obtained. The corresponding relations are briefly discussed.