Francisco Javier Poblete

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• Professor
• Professor (Assistant) at University of Castilla-La Mancha

In this study, the selective oxidation of aromatic aldehydes has been investigated using Ru(VI) as a catalyst and hexacyanoferrate (III) as a cooxidant in an alkaline medium. The reaction order with respect to the oxidant and the aromatic aldehyde is complex while the reaction order with respect to Ru(VI) is one. The proposed mechanism presents two...

Benzaldehyde and its derivatives are used as food supplements. These substances can be used mainly as flavorings or as antioxidants. Besides, peroxynitrite, an oxidizing agent, could be formed in canned food. Both species could react between them. The present article has focused on the kinetic study of the oxidation of aldehydes by peroxynitrite. A...

Benzaldehyde and its derivatives are used as food supplements, due to their properties as anti-oxidants and mainly as organoleptic substances. The degradation of these aldehydes produces benzoic acid and benzyl alcohol derivatives, both of which present high toxicity levels. On the other hand, peroxynitrite acts as an oxidizing agent, thus strategi...

The oxidation reactions of aliphatic alcohols using [Fe(CN) 6 ] ³⁻ in alkaline media catalysed by Ru(III) or Ru(VI) imply similar experimental rate equations. A substrate–catalyst complex is formed during the reaction. The complex decomposition produces Ru(IV) and Ru(II) species which react with hexacyanoferrate(III) in order to regenerate the cata...

In this work, we present the preliminary results of the archaeometric analysis of several ceramic and clay samples from two Celtiberian hillforts of the Iron Age from the Spanish Central Plateau: El Ceremeño and its cemetery (Early and Middle Iron Age) and the oppidum of Los Rodiles (Late Iron Age) including La Rodri-ga, a potter's workshop contemp...

The host-guest chemistry between cucurbit[7]uril (CB7) and a series of bolaform (Bn) surfactants with different chain lengths, n = 12 - 22, was the target of our study. [3]Pseudorotaxanes are formed when the alkyl chain of the bolaform has more than 14 carbon atoms. In these cases two CB7 molecules can be accommodated between the two head groups of...

The oxidation of sodium lactate, 2-methyl-2,4-pentanediol, 2,4-butanediol, 2-butanol and 2-propanol upon treatment with alkaline hexacyanoferrate(III) using a Ru(VI) catalyst is highly effective for the oxidation of alcohols by . The reaction mechanism proposed involves the oxidation of the alcohol by the catalyst, a process that occurs through the...

The equilibrium between propionaldehyde+propane-1,1-diol+2,4,6-triethyl-1,3,5-trioxane has been characterized, for the first time, in aqueous solution using NMR techniques. The diffusion coefficients and the molar percentages at different temperatures have been also reported.

The reaction of Orange II with peroxynitrous acid has been studied by a spectrophotometrical method. The reaction rate is complex because the order changes from zero to one in function of substrate and oxidant concentration. The influence of pH and ionic strength has been investigated, but their effect on the reaction rate appears to be negligible...

We report observations of primary and secondary atmospheric pollutants such as nitrogen oxides, sulfur dioxide, toluene, and ozone during the period February 2002 to August 2003 in Puertollano, an industrial area located in central–southern Spain. The measurements were performed using a commercial differential optical absorption spectroscopy instru...

A series of novel composites and nanocomposites xerogels based on acrylic acid, sepiolite and N,N′-methylenebisacrylamide were prepared using a solution polymerization technique at 70 °C. The quality of dispersion of the micronized sepiolite in the monomer is the crucial point for obtaining nanocomposites. A good dispersion explains the improvement...

The reactions of 2,3-butanediol by hexacyanoferrate(III) in alkaline medium using ruthenium compounds as catalysts have been studied spectrophotometrically. The effect on the reaction rate of concentration of substrate, oxidant, catalyst and basicity of the medium leads to similar experimental rate equations for both catalysts, Ru(III) and Ru(VI)....

Complexes of formula [RuCl2(arene)(κ1-dpim)] (dpim = 2-(diphenylphosphino)-1-methylimidazole) (arene = p-cymene, 1a; C6H6, 1b) were prepared by the reaction of [RuCl2(p-cymene)]2 or [RuCl2(C6H6)(CH3CN)] with dpim. Complexes 1a and 1b were structurally characterized by NMR spectroscopy and X-ray diffraction. The reaction of these precursors with BF4...

The oxidation reactions of 2-methyl-2,4-pentanediol upon treatment with alkaline hexacyanoferrate(III) using Ru(III) or Ru(VI) as catalysts are governed by two quasi-identical experimental rate equations, which show that both catalysts are equally effective for the oxidation of alcohols by . The reaction mechanism proposed involves the oxidation of...

The catalytic effect of CO2 on the kinetics and yields of peroxynitrite decomposition in the presence of cyanide complexes was investigated as a function of pH, substrate, bicarbonate and nitrite concentration.

A kinetic study of the oxidation of octacyanomolybdate(IV) by peroxynitrite has been performed using a stopped-flow technique. The variation of kobs with the concentration of Mo(CN)48-, pH and temperature have been investigated. A reaction mechanism that involves homolysis of HOONO to form •OH and •NO2 radicals is proposed. Octacyanomolybdate(IV) i...

A kinetic study of the oxidation of hexacyanoferrate(II) by peroxynitrite has been carried out, using a stopped-flow technique. The variation of the experimental rate constant over a wide concentration range of Fe(CN)(6)(4-) has been investigated under different experimental conditions in terms of pH, ionic strength and temperature. A correlation b...

Urban air pollution is one of the main environmental problems, owing to implications for public health and physical environment. In urban areas, the sources of atmospheric pollutants are distributed very inhomogeneously. Trace gas concentrations measured by conventional air quality monitoring stations are always influenced by small sources in their...

The kinetics of the Ru(VI)-catalyzed oxidation of benzyl alcohol by hexacyanoferrate(III), in an alkaline medium, has been studied using a spectrophotometric technique. The initial rates method was used for the kinetic analysis. The reaction is first order in [Ru(VI)], while the order changes from one to zero for both hexacyanoferrate(III) and benz...

The kinetics of Ru(VI)-catalyzed oxidation of 2-propanol by hexacyanoferrate(III) was investigated in alkaline media using a spectrophotometric technique. The reaction shows first order in [Ru(VI)], a Michaelis–Menten-type dependence on [2-propanol], a fractional order in [Fe(CN)$_{6}ˆ{3-}$] and a complicated variation on [OH−]. A reaction mechanis...

The kinetics of oxidation of butane-2,3-diol by alkaline hexacyanoferrate (III), catalyzed by ruthenium trichloride has been studied spectrophotometrically. The reaction rate shows a zero-order dependence on oxidant, a first-order dependence on |Ru(III)|T, a Michaelis-Menten dependence on |diol|, and a variation complicated on |OH−|. A reaction mec...

The oxidation kinetics of 2-butanol by alkaline hexacyanoferrate(III) catalyzed by sodium ruthenate has been studied spectrophotometrically. The initial rates method was used for kinetic analysis. The reaction rate shows a fractional-order in [hexacyanoferrate(III)] and [substrate] and a first-order dependence on [Ru(VI)]. The dependence on [OH−] i...

A concerted hydrogen-atom transfer one-electron transfer mechanism is proposed for the ruthenium(III)-catalysed oxidation of 2-methylpentane-2,4-diol by alkaline hexacyanoferrate(III).

The oxidation kinetics of propan-1-ol by alkaline hexacyanoferrate(III) catalyzed by ruthenium trichloride were studied spectrophotometrically. The initial rate method was used for kinetic analysis. The reaction rate shows a fractional order in [oxidant] and [substrate] and a first-order dependence on [RuCl3]. The dependence on [OH−] is complicated...

Gas-phase samples of CS2 exhibit a richly structured absorption spectrum in the near-ultraviolet region extending from roughly 2900 to 3800 Å. In this context, the fluorescence of the CS2 molecule was excited by a dye laser pumped by a Nd-YAG laser in the spectral interval 2800–3380 Å. From the analysis of the fluorescence emission decay of the CS2...

A systematic study of a Broida source producing atomic calcium in ground state $^1$S and first metastable $^1$D and $^3$P states is presented. The relative concentration of the metastables, produced by a DC discharge, is monitored with carrier gas pressure, heating power and discharge current, and it is observed that low values of these parameters...

The kinetics of oxidation of ethane-1,2-diol by alkaline hexacyanoferrate(III) catalyzed by ruthenium trichloride has been studied spectrophotometrically. The initial rates method was used for kinetic analysis. The reaction rate shows a fractional order dependence on [oxidant] and [diol], a first order dependence on [Ru(III)] and a complicated vari...

Nous avons etudie spectrophotometriquement la cinetique d'oxydation de l'ethane-1,2-diol par hexacyanoferrate(III) catalysee par le trichlorure de ruthenium. La methode des vitesses initiales a ete utilisee pour l'analyse cinetique. La vitesse de reaction montre, d'une part, un ordre fractionnaire par rapport a l'oxydant et au diol, et d'autre part...

By using two independent and different methods, absolute values of the reaction cross-sections have been determined for the following chemiluminescent reactions Ca(3P, 1D) + Cl4C(CHBr3) → CaX*(A, B) (X = Cl, Br) + Cl3C(CHBr2) and Ca(1D) + H2O → CaOH* + H Both chemiluminescence and laser-induced fluorescence spectra are reported. A comparison with r...

Laser induced fluorescence from resolved rovibrational levels (ν′, J′) of the electronically excited A(0+) state of BiBr has been observed. Fluorescence lifetimes for several rovibrational levels (ν′, J′) of the BiBr A(0+) state in the ν′ = 4–9 interval have been measured, and a study of their variation with pressure has been made. No significant v...

Absolute values of the total chemiluminescence cross-section for the beam-gas Ca( ³ P, ¹ D) + Cl 4 C → CaCl(A, B) + Cl 3 C and Ca( ³ P, ¹ D) + SF 6 → CaF(A, B) + SF 5 reactions have been measured at low collision energy, ET = 0.15 and 0.14eV, respectively. Both metastable atomic calcium states Ca( ³ P, ¹ D) were produced under low voltage dc-discha...

The kinetics of permanganic oxidation of DL-valine in a concentrated sulfuric acid medium (3.0–5.0 M) has been studied by spectrophotometry. The rate law found shows that the reaction is autocatalyzed by Mn(II) ions. The influence of the reagent and Mn(II) concentrations and acidity of the medium has been analyzed. A reaction mechanism is proposed...