Copper Complexes Obtained from the Schiff Base of Quinoline-2-Aldehyde and Aliphatic Diamines

Schiff base bis (2— quinolidene)- diamine gives a purple-red complex with copper ions with a λ_max at 530 mμ. The optimum pH for production of this complex is approximately 9.5. None of the metallic ions of the analytical groups II and III give rise to red complexes with the above Schiff base. Manganous (Mn²⁺) and stannous (Sn²⁺)ions as well as reducing agents such as hydrazine or hydroxylamine exert a catalytic effect on the rate of formation of these copper complexes. The thermal stability of the copper complex formed from the Schiff bases (2-quinoline-aldehyde with NH₂-(CH₂)_n-NH₂) is greater for diamine for which n = 4–6 than for n = 2–3.     

The search for optimum solutions for melting insulator glass

The effect of the temperature conditions of melting and the design features of the glass melting furnaces on the increase in the specific removal of glass melt in processing quenched insulating parts of high-voltage suspension insulators is demonstrated. Designs are proposed for glass melting furnaces and glass melting temperature regimes whose use will increase the economy of manufacturing insulators.     

Corundum-zircon crucibles for induction melting of nickel alloys

Refractories and Industrial Ceramics -     

Hydrogenation of triple bonds to double bonds in conjugated methyl octadecadiynoate and methyl santalbate

A study was made of the noncatalytic hydrogenation of acetylenic bonds in fatty esters tocis double bonds using various metals in different solvent systems. The best results were obtained with 15% propanol in water using iron. The yields ofcis double bonds for the nonconjugated diynoate and monoynoate ranged from 90% to 99% and for the conjugated diynoate the yields ranged from 56% to 77%. In the reduction of methyl santalbate to a conjugated diene, the yields were ca. 85%. Presented at the AOCS Meeting, New Orleans, April 1970. E. Market. Nutr. Res. Div., ARS, USDA.     

Nucleation of isolated PO4 units on CeO2 driven by high temperatures and the effect on its oxygen storage and release properties

The chemical nature of P-containing species of varying concentration present in CeO₂ after impregnation with (NH₄)₂HPO₄ and calcination at 1273 K, and their effects on the oxygen storage and release (OSR) properties of ceria are reported for the first time. The samples were characterized by different techniques and the results were compared with those recently reported on the same samples but calcined at 873 K. When P-containing ceria solids were calcined at 1273 K, CePO₄ (monazite) was the predominant P-containing species on the surface of ceria, confirming previous studies that showed that monazite exists for those samples in which the surface P loading (P atoms per nm⁻²) is larger than 5.5. For lower surface P concentrations, isolated orthophosphate units are present at the surface and within the subsurface region of the solid. Severe sintering of CeO₂ after calcination at 1273 K resulted in P concentrations >5.5 P atoms·nm⁻² in all samples. Isolated PO₄ units that could initially be present in the samples calcined at 873 K nucleated and CePO₄ was formed when samples were calcined at 1273 K. OSR properties of CeO₂ deteriorated progressively when P loading increased due to the presence of larger crystals of the very stable Ce(III) phase of CePO₄ at the surface of the P-containing ceria solids.     

HYDRODYNAMIC MODELLING IN AN AIR-LIFT LOOP REACTOR

A simple hydrodynamic model is proposed for use in the design, scale-up and characterization of external loop air-lift reactors. The approach is based upon a momentum balance for the flow loop coupled with a drift-flux equation for the reactor riser and establishes a rational basis for a predictive model relating gas throughput to induced liquid flow and gas hold-up in a range of air-lift reactors. The effective resistance of the reactor, k, defined in terms of the total loss coefficients of the reactor and the aerated height of the two-phase riser, was identified to allow for the quantification of the influence of reactor design on the hydrodynamic variables. An extensive body of data for the air-water system, collected on two reactors with active volumes of 0·055 m³ and 0·3 m³, is presented and used, in conjunction with literature data encompassing a wide range of reactor geometries and flow conditions, to define a unique relationship between flow behaviour and reactor configuration. The model, which accounts for the prevailing flow regime in the reactor, provides a direct method of predicting hydrodynamic behaviour in relatively non-viscous systems.     

Mass transfer at the electrodes of the ‘falling-film cell’

In the falling-film cell the electrolyte flows as a thin film in the channel between an inclined plane plate and a sheet of expanded metal which work as electrodes. The present work gives the mass transfer coefficients at both electrodes; the experimental variables are the electrolyte flow-rate, the angle of inclination of the channel and the interelectrode distance. The results allow three different flow regimes to be characterized. At low flow rates, there exists a particular regime where capillary effects are present; in this regime the mass transfer coefficient decreases with increasing flow rate, which is interesting from the point of view of possible industrial electrolytic applications.Nomenclature b width of the inclined channel - D diffusion coefficient - d interelectrode distance - e _m mean film thickness - Grashof number, based ond - Grashof number, based onL - ¯k overall mass transfer coefficient, defined by Equation 9 - L electrode length - Q _v volumetric flow rate - volumetric flow rate per unitQ _vl width of channel - Reynolds number - Schmidt number - Sherwood number, based ond - Sherwood number, based onL - mean velocity of the liquid film - inclination angle of the channel with respect to the horizontal - kinematic viscosity of them electrolyte     

Thermal Conductivity/Diffusivity of Silicon Carbide Whisker Reinforced Mullite

The thermal conductivity and diffusivity of silicon carbide whisker reinforced mullite was shown to increase with whisker content. This effect was much greater for vapor-liquid-solid (VLS) whiskers than for rice-hull (RH) whiskers. This suggests that the thermal conductivity for the VLS whiskers was significantly higher than for the RH whiskers. Due to preferred orientation of the whiskers, thermal conductivity and diffusivity of the composite samples exhibited significant anisotropy.     

Fatty acid desaturase systems of hen liver and their inhibition by cyclopropene fatty acids

Hen liver preparations which desaturate stearic acid at the 9,10 position to form oleic acid have been found to desaturate other saturated fatty acids of carbon chain length from 12 to 20 and 22. The 9,10-monoenoic fatty acid of the same chain length as the substrate fatty acid is the major product formed. Minor amounts of the 10,11- and 11, 12-monoenoic acids are also formed. Maximum desaturation occurred with the C₁₄ fatty acid substrate and with the fatty acids C₁₇ and C₁₈, suggesting the presence of at least two desaturating systems. The cyclopropene fatty acids, sterculic and malvalic acids, inhibited the desaturation of all thefatty acids at the 9,10 position but desaturation at the 10,11 and 11, 12 positions was affected only slightly. The effect is not due to inhibition of the primary activating enzyme, the long chain acyl CoA synthetase. Sterculic acid is a more effective inhibitor than either malvalic acid or sterculyl alcohol, probably because these cyclopropene compounds do not block the desaturating site of the enzyme as completely as sterculic acid.