Institutiones Doctrinæ Christianæ, Sive Compendium Theologiæ Dogmaticæ & Moralis : Methodo Catechetica concinnatum ad usum Seminarii Episcopalis Iprensis

Auctore Petro Ludovico Danes CastelanoErster Band mit FrontispizAus dem Vorbesitz des Klosters Rheinau mit entsprechendem Verbalexlibris auf dem Titelblat

Generalis temporum notio brevissimè exhibens vicissitudinem rerum humanarum ab orbe condito usque ad aetatem nostram, / auctore Petro Ludovico Danes Casletano, Sacrae Theologiae...

Port. con viñeta xil.Cabeceras y capitales grab. xil. en págs. 3 y 7Encuadernado en pielSello de la Biblioteca del Colegio Universitario de CáceresApostillas marginalesReclamoSuperiorum Permissu, ac Privilegii

Kinetics and instabilities in the extraction of Co(II) by sodium di-(2-ethylhexyl) phosphate at the water/toluene interface. I. Kinetics and mechanism

A toluenic solution of sodium di-(2-ethylhexyl) phosphate (NaD2EHP) was allowed to react with an aqueous solution of Co(II) in a nonagitated system. Two layers of NaD2EHP emulsions in water appeared: a dilute emulsion A and an opaque emulsion B located below the toluenic phase. Furthermore, spontaneous convective motions were observed. The kinetics of complexation was investigated by spectrophotometry. The influence of four factors was studied: the Co2+ concentration Cm, the NaD2EHP concentration Cd, the inert anti-emulsifier (KBr) concentration Ce, and the hydration degree Ih of the surfactant. When Cm was increased, the reaction rate w exhibited a maximum at Cm = 15 moles m-3 and then a minimum at Cm = 30 moles m-3. The whole dependence w(Cm, Cd, Ce, Ih) is explained by a double location of a superficial reaction with proper reaction orders of 1 relative to Co2+ and 0 relative to NaD2EHP. The results show that, in the absence of forced convection, the rate w of the Co(II) extraction is the sum w1 + w2 where w1 is the reaction rate at the surface of the droplets in layer B and w2 represents the reaction rate at the macroscopic W/O interface. An increase in Cm resulted in a strong reduction of the intensity E of the emulsification. Conversely, an increase in E led to an increase in the droplet area and therefore an increase in w1, while w2 was reduced via an increase in the resistance to the diffusion of Co2+ through the aqueous interstices of emulsion B. © 1989.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Kinetics and instabilities in the extraction of Co(II) by sodium di-(2-ethylhexyl) phosphate at the water/toluene interface. II. Spontaneous turbulence induced by interfacial reactions

Spontaneous turbulences induced by interfacial reactions in liquid/liquid systems (STIR) and their accelerating effects on the total reaction rate are examined. A model of the mechanism of STIR and of its kinetic effects on the nonagitated system H2O/CoBr2/NaD2EHP/toluene (where NaD2EHP is sodium di-(2-ethylhexyl) phosphate) is proposed. STIR arise from inhomogeneous accumulation of the Co(D2EHP)2 complex in a layer B which appears between the aqueous and the organic bulk phases. This surfactant-rich layer offers strong resistance to the diffusion of Co2+ ions from the aqueous phase toward the interfacial reaction site. The STIR intensity I is equal to the product v2 × E between the superficial reaction rate v2 and the intensity E of the emulsification (represented by the ratio se/Smi between the overall droplet area se in layer B and the surface smi of the macroscopic water/toluene interface). The v2 reaction rate is also influenced by STIR according to v2 = Cm/[1/kc + E/(k′ + k″ I)], where kc is a chemical rate constant, and k′ and k″ are actual rate constants. The ratio E/(k′ + k″ I) represents the mass transfer resistance and Cm the metal-ion concentration in the aqueous phase. The model is in good agreement with the experimental dependence I(Cm) and v(Cm). © 1989.SCOPUS: ar.jinfo:eu-repo/semantics/publishe