A. Bernalte-García

Characterization study of char and activated carbon prepared from raw and extracted rockrose

Abstract Using raw rockrose ( Cistus Ladaniferus, L. ) and rockrose extracted into petroleum ether, the effect of extraction on the thermal behaviour and chemical-physical properties of chars and activated products was studied. Chars were prepared by heat treatment of the starting materials under dynamic and isothermal conditions over the temperature range 200–1000°C. Activations of two carbonized products, which were obtained at 600°C, was accomplished in air, CO 2 , or steam at 850°C until burnoff 40%. Techniques used were thermogravimetry, gas adsorption, mercury porosimetry, density measurements and FT-IR spectroscopy. Extraction delayed the rockrose pyrolysis, as inferred from the thermal behaviour of the starting materials and by the composition and texture of the chars prepared between 200–600°C. At higher temperatures, extraction reduced the ash content of chars and mitigated the loss produced in the surface area and the microporosity. Differences in textural properties of activated carbon depended on the starting material and the activating agent, being especially significant between air and CO 2 or steam. The FT-IR spectra of the carbonized and activated products displayed absorption bands compatible with the presence in the materials of surface olefinic CC double bonds, aromatic rings, and oxygen functional groups.

Coordination chemistry of thiazoline/thiazolidine derivatives. I: Crystal structure of 2-(2-pyridyl)imino-N-(2-thiazolin-2-yl)thiazolidine (PyTT) and study of its interaction with nickel(II)

Abstract The crystal structure of 2-(2-pyridyl)imino-N-(2-thiazolin-2-yl)thiazolidine (PyTT) is reported. The compound diaquabis[2-(2-pyridyl)imino-N-(2-thiazolin-2-yl)thiazolidine]nickel(II) chloride trihydrate has been isolated and characterized by IR, UV–Vis–NIR diffuse reflectance and X-ray diffraction. The complex cation has crystallographic C2 symmetry. The environment around the nickel atom may be described as a distorted octahedral geometry with the metallic atom coordinated to two water molecules [Ni–O(1)=2.114(2) A], two thiazolinic nitrogens [Ni–N(1)=2.061(2) A] and two imino nitrogens [Ni–N(3)=2.086(2) A]. Hydrogen bonding is present in the structure inter-linking PyTT ligands, water molecules and chloride ions.

Studies of the thermal decomposition of (2-thiazolin-2-yl)hydrazine hydrochloride and some metal derivative complexes

Abstract The compound (2-thiazolin-2-yl)hydrazine hydrochloride (TzHyHCl) and the complexes [Ni(TzHy)2(H2O)2]Cl2·2H2O, [ZnCl(TzHy)2]Cl and [Cd(TzHy)(μ-Cl)2]n·nH2O have been studied using spectral (IR and electronic) and thermal (TG and DSC) methods.

The coordination chemistry of thiazoline/thiazolidine derivatives. II: synthesis and characterization of [CoCl2(PyTT)] and [ZnCl2(PyTT)] [PyTT = 2-(2-pyridyl)imino-n-(2-thiazolin-2-yl)thiazolidine]

Abstract The compounds dichloro[2-(2-pyridyl)imino-κ N  N -(2-thiazolin-κ N -2-yl)thiazolidine]cobalt(II) and dichloro[2-(2-pyridyl)imino-κ N  N -(2-thiazolin-κ N -2-yl)thiazolidine]zinc(II) have been isolated and characterized by single crystal X-ray diffraction and IR spectroscopy. Moreover, the cobalt(II) complex has been studied by means of magnetic susceptibility measurements and UV–Vis–NIR diffuse reflectance. Both complexes are isostructural. The environment around the cobalt(II) and zinc(II) atoms may be described as a distorted tetrahedral geometry with the metallic atoms coordinated to two chlorine atoms [CoCl(1)=2.241(1) A; CoCl(2)=2.221(1) A], [ZnCl(1)=2.235(1) A; ZnCl(2)=2.211(1) A], one thiazoline nitrogen [CoN(1)=1.982(2) A], [ZnN(1)=2.021(2) A] and one imino nitrogen [CoN(3)=2.009(1) A], [ZnN(3)=2.056(2) A].

The coordination chemistry of (2-thiazolin-2-yl)hydrazine hydrochloride (TzHyHCl)—II. Study of its interaction with zinc(II) and cadmium(II)

Abstract The complexation equilibria of (2-thiazolin-2-yl)hydrazine hydrochloride (TzHyHCl) with zinc(II) and cadmium(II) have been studied in aqueous solution at 298 K and 0.1 M ionic strength in NaClO 4 . The formation constants were determined and are discussed in terms of the characteristics of the ligand. The compounds [ZnCl(TzHy) 2 ]Cl and [Cd(TzHy)( μ -Cl) 2 ] n · n H 2 O have been isolated and their crystal structures determined. In the Zn II compound, the geometry around the central atom is a distorted trigonal-bipyramid composed of four nitrogen atoms from two TzHy ligands and one chlorine. The Ca II complex is polymeric, with octahedrally coordinated cadmium linked into infinite chains by double (μ-chloro) bridges. The coordination sphere around each cadmium center is completed by two nitrogen atoms from a TzHy ligand. In both cases, the crystal structure is stabilized by an extensive hydrogen-bond network.

Catalysis by alkali and alkaline-earth metals of the gasification in CO2 and steam of chars from a semi-anthracite with high inorganic matter content

Abstract A study has been made of the catalytic effect of some compounds of the alkali and alkaline-earth metals on the gasification reactions in CO 2 and in steam of chars from a semi-anthracite with a high inorganic matter content. The extent of char gasification depends on the gaseous reactant, type of anion, type of metal, concentration of the catalyst and gasification temperature. Na, especially when added as NaOH, proved to be the most active catalyst. Reactivity results were studied by taking into account the change in the physical state of the catalyst during heat treatment and the chemical characteristics of the coal.

Thermogravimetric study of anthracite gasification in CO2 catalyzed by black liquor

Publisher Summary This chapter presents the thermogravimetric study of anthracite gasification in CO2 catalyzed by black liquor. Studies on the catalyzed gasification of carbons indicate that alkali metal compounds behave as catalysts and that especially the carbonates and the hydroxides of sodium and potassium are substances showing a high catalytic activity. They are dealt with expensive chemicals and therefore, their large-scale use will lower the profitability of the process of carbon conversion. This fact justifies the search for inexpensive catalysts which, at the same time, can be used without detriment to the catalytic performance. Black liquor is a by-product from the kraft pulp production in paper mills. It is an aqueous liquid consisting of a mixture of two fractions, one organic in nature and the other inorganic. The latter contains several metals, including sodium and potassium as major components.

Complexes of two mannose α-amino acid derivatives with zinc and cadmium

Abstract Complexes of zinc(II) and cadmium(II) with 2-amino-2-deoxy- d -glycero- d -talo heptonic acid (HMa) and 2-(benzylamino)-2-deoxy- d -glycero- d -talo heptonic acid (BnMa) have been obtained. The complexes were characterized by elemental analysis, IR spectroscopy and X-ray powder diffraction. These complexes have a 1:2 metal-to-ligand ratio and an octahedral structure. Coordination occurs through the nitrogen atom of the amino group and oxygen atoms of the bridging carboxylate group. The thermal behaviour of the complexes has also been studied.

Effects of the substituents of pyrazole/thiazine ligands on nuclearity of Cu(II) nitrate complexes

[Cu(H2O)(PzTz)2](NO3)2 (1), [Cu(μ-NO3)(NO3)(DMPzTz)] n (2), and [{Cu(NO3)(DPhPzTz)}2(μ-NO3)2] (3) [PzTz = 2-(1-pyrazolyl)-1,3-thiazine, DMPzTz = 2-(3,5-dimethyl-1-pyrazolyl)-1,3-thiazine, DPhPzTz = 2-(3,5-diphenyl-1-pyrazolyl)-1,3-thiazine] have been prepared and characterized by elemental analysis, electronic spectroscopy, IR spectroscopy, electron paramagnetic resonance spectroscopy, magnetic susceptibility measurements, and single-crystal X-ray diffraction. Influence of ligand size on coordination to Cu(II) has been analyzed. The three complexes are five-coordinate and the coordination geometry can be described as a distorted trigonal bipyramid for 1 or a distorted square pyramid for 2 and 3. As a consequence of the strain induced by the ligands, 1 is a monomeric complex cation whereas 2 is a polymer and 3 is a dimer.

A thermal and IR study of metal complexes of 2-amino-2-deoxy-d-glycero-l-gluco heptonic acid

Abstract Complexes of 2-amino-2-deoxy- d- glycero- l -gluco heptonic acid (GH) and Mn(II), Fe(II), Co(II), Ni(II), and Cu(II) have been synthesised and characterised by elemental analysis and IR spectroscopy. The complexes have a general formula: [M(G) 2 (H 2 O) 2 ] with variable water of hydration, except for the Cu(II) compound which is anhydrous [Cu(G) 2 ]. The thermal behaviour of these complexes has been studied by TG and DSC techniques. The thermal data indicate that for the Co(II), Ni(II), and Cu(II) complexes, the ligand is chelated via the carboxylate − and amino functional groups, whereas for the Mn(II) and Fe(II) complexes, the amino group remains protonated and does not bond to the metal.