51 research outputs found
Data solubility and parameters of adjustments (α and β) of phenanthrene in supercritical CO2 employing the modified Redlich–Kwong equation
No full textThis article contains data related to the research article entitled “Calculation method for determining Phenanthrene solubility in supercritical CO2 employing Redlich–Kwong modified equation” (Colpas et al., 2018) [1]. The presented data gives information on the physical properties of the solute and the solvent. The experimental solubilities of phenanthrene in equilibrium and those calculated using the modified Redlich–Kwong equation with the inclusion of the adjustment parameters α and β are shown, see Colpas et al. (2018) [1] and “Modified Redlich–Kwong equation of state for supercritical carbon dioxide” (Heidaryan and Jarrahian, 2013) [7]. The mean squared error (MSE) was calculated for the supercritical Phenanthrene–CO2 system at different temperatures above the critical point of the solvent
An Easy Method to Prepare D3 and C2-TATP Crystals
No full textD3 and C2 TATP structures interconvert at room temperature. Herein, an easy method to isolate both conformers is shown that consists of multiple recrystallization steps using different solvent and heating to boiling. Spectroscopic and physical measurements, such as Raman spectroscopy, X-ray diffraction, and melting point analysis, showed that clear and opaque crystals, respectively, represent different conformations of TATP. Additionally, the transition energy between both conformers was estimated using the Raman shifts.Espinosa Fuentes, Eduardo Antonio-4a2aee36-a6fd-4d38-92d3-66e15483bf70-0Colpas Castillo, Fredy-a58dfeef-b7d3-4dd6-b70d-f3ac2c117bf8-0Meza Fuentes, Edgardo-48e4de07-6e97-4229-9267-6ccec7edc159-0Ropero, Jorge-6f3ff826-2f63-4c62-a4a3-f49661251c1e-
Theoretical study of the humic acid interactions with Al3+, Ca2+, Mg2+, Zn2+, K+ and NH4+ cations at DFT level of theory and PCM solvation model
No full textIn this paper, two models of humic acids, the Temple-Northeastern-Birmingham (TNB) and Kolla models, were studied. Also, the complexation reaction of the structures formed by the interaction of the TNB and Kolla models with Al3+, Ca2+, Mg2+, Zn2+, K+ and NH4+ cations, common in agricultural soils, was studied. These calculations were made for the complexes, at PM6 and DFT/LANL2DZ level of theory, both in vacuum and in aqueous medium. We found a strong affinity between Kolla and TNB models, and Al3+, Ca2+, Mg2+, Zn2+, K+ and NH4+ cations, influenced by the solvent that affected the interaction sites; the solvent increased the rate of reactivity and affinity for the cations in nucleophilic regions and decreased it in electrophilic regions of the structures. Calculations of molecular electronic potential, MEP and atomic charges, the local smoothness, Fukui functions and the HSAB principle adequately described the HA/cations interactions which were affected by the number of hydrogen bonds. The most reactive sites were the hydroxyl, phenolic, carbonyls oxygens and nitrogens at both vacuum and aqueous medium, especially carbonyl oxygens. These results are consistent with the properties of HA that make them attractive as components of agricultural soils.Espinosa Fuentes, Eduardo Antonio-4a2aee36-a6fd-4d38-92d3-66e15483bf70-600Colpas Castillo, Fredy-a58dfeef-b7d3-4dd6-b70d-f3ac2c117bf8-600Meza Fuentes, Edgardo-48e4de07-6e97-4229-9267-6ccec7edc159-60
Un método fácil de preparar cristales d3 y c2-tatp.
No full textD3 and C2 TATP structures interconvert at room temperature. Herein, an easy method to isolate both conformers is shown that consists of multiple recrystallization steps using different solvent and heating to boiling. Spectroscopic and physical measurements, such as Raman spectroscopy, X-ray diffraction, and melting point analysis, showed that clear and opaque crystals, respectively, represent different conformations of TATP. Additionally, the transition energy between both conformers was estimated using the Raman shiftsLas estructuras D3 y C2 TATP se interconvierten a temperatura ambiente. En este documento, se muestra un método fácil para aislar a los dos conformadores que consiste en múltiples etapas de recristalización que utilizan diferentes disolventes y calentamiento a ebullición. Las medidas espectroscópicas y físicas, como la espectroscopia Raman, la difracción de rayos X y el análisis del punto de fusión, mostraron que los cristales claros y opacos, respectivamente, representan diferentes conformaciones de TATP. Además, la energía de transición entre ambos conformadores se estimó utilizando los turnos RamanEspinosa Fuentes, Eduardo Antonio-4a2aee36-a6fd-4d38-92d3-66e15483bf70-0Colpas Castillo, Fredy-a58dfeef-b7d3-4dd6-b70d-f3ac2c117bf8-0Meza Fuentes, Edgardo-48e4de07-6e97-4229-9267-6ccec7edc159-0Ropero, Jorge-6f3ff826-2f63-4c62-a4a3-f49661251c1e-
Evaluación de la capacidad de adsorción acuosa de plomo mediante intercambiadores catiónicos preparados a partir de aserrín por medio del método de xantación.
No full textTesis (Químico) -- Universidad de Cartagena. Facultad de Ciencias Exactas y Naturales. Programa de Química, 2015El principal interés de este trabajo es modificar químicamente la superficie del aserrín con el fin de aumentar su capacidad para remover metales pesados de soluciones acuosas y evaluar su factibilidad para adsorber Pb, determinando sus capacidades de adsorción
Verificación De La Asignación Vibracional Teórica De DADP Usando Marcaje Isotópico
No full textThis work deals with the comparison of the theoretical assignment of the DADP vibrational spectrum with the experimental displacements by isotopic labeling. For this, the DADP-C4 and DADP-C2 isotopomers were synthesized from acetone labeled isotopically in the methyl and the carbonyl carbon atoms, respectively. The acetone and DADP-isotopomer compounds were characterized using Raman and infrared spectroscopy. Theoretical assignments were taken from previous studies on the potential energy distribution of a vibrational mode, which provide an approach to the internal coordinates related to each band. The selective isotopic labeling allowed us to approach to the dependence of each band, because the energy of a molecular vibration also depends on the reciprocal mass of the atoms involved. In general, the results showed that some bands assigned experimentally do not coincide with the theoretical assignments by quantum mechanical simulations.Espinosa Fuentes, Eduardo Antonio-4a2aee36-a6fd-4d38-92d3-66e15483bf70-600Meza Fuentes, Edgardo-48e4de07-6e97-4229-9267-6ccec7edc159-600Colpas Castillo, Fredy-a58dfeef-b7d3-4dd6-b70d-f3ac2c117bf8-600Castro Suarez, John R.-77b5d30a-fab1-4a70-818b-12a0f9529c42-600Chiquillo Correa, Gilberto-6c98bcf3-c81a-4b04-930a-ba7ad0290627-600Mora, Malka-6a6f03ac-44da-4475-b29f-d25fd4a93266-60
A Fragmentation Mechanism Of Homemade Explosive TMDD Using DART-MS And Isotopic Labeling
No full textA fragmentation mechanism and characterization for the first time using Direct Analysis in Real Time-Time of Flight-Mass Spectrometry (DART-TOF-MS) of the tetramethylene diperoxide dicarbamide (TMDD) compound were presented. The MS-spectrum may support other research about devices and detection in real scene. The mass spectrum of TMDD obtained using DART ionization in the positive-ion detection mode exhibited a strong peak at m/z 254 representing an ammonium adduct ([TMMD·NH4]+). There was another peak at m/z 237, which represented the protonated molecule ([TMDD·H]+) of TMDD. These two peaks corroborated the identity of the analyte. The DART-MS spectra of the TMDD-isotopomer successfully corroborated the respective molecular tails. The principal fragmentation residues also showed coherence according to the number of isotopically labeled atoms on the TMDD structure. In contrast with other organic peroxides analyzed by this technique, TMDD exhibited substantial fragmentation. The theoretical modeling results showed that the fragmentation mechanism of the TMDD ion adduct is strongly dependent of the TMDD ring flexibility and the hydrogen bonding formed between the nitrogen and oxygen atoms and the atmospheric proton.Zarate Pedroza, Alexander-8c539d20-b2ab-4a04-8a96-a4ed0c230165-600Colpas Castillo, Fredy-a58dfeef-b7d3-4dd6-b70d-f3ac2c117bf8-600Alcázar Franco, Daniel Jesús-dbf6b1ea-fa4f-44e8-ad2c-245c2b8e5130-600Cabrera Lafaurie, Wilman Alfonso-27c63423-590c-44fa-b0f8-dd76a3dd033f-600Espinosa Fuentes, Eduardo Antonio-4a2aee36-a6fd-4d38-92d3-66e15483bf70-60
Verification of the vibrational theoretical assignment of the DADP using isotopic labelling
No full textThis work deals with the comparison of the theoretical assignment of the DADP vibrational spectrum with the experimental displacements by isotopic labeling. For this, the DADP-C4 and DADP-C2 isotopomers were synthesized from acetone labeled isotopically in the methyl and the carbonyl carbon atoms, respectively. The acetone and DADP-isotopomer compounds were characterized using Raman and infrared spectroscopy. Theoretical assignments were taken from previous studies on the potential energy distribution of a vibrational mode, which provide an approach to the internal coordinates related to each band. The selective isotopic labeling allowed us to approach to the dependence of each band, because the energy of a molecular vibration also depends on the reciprocal mass of the atoms involved. In general, the results showed that some bands assigned experimentally do not coincide with the theoretical assignments by quantum mechanical simulations
Espectroscopia de Absorción Atómica. Manual teórico-practico
No full textTrabajo de ascenso - - Universidad de Cartagena. Facultad de ciencias Exactas y Naturales. Programa de Química Farmacia, 1997La presente investigación busca promover la implementación de prácticas, Espectroscopia de absorción atomic
ADSORCIÓN DE MERCURIO Y CADMIO EN CARBÓN SUBBITUMINOSO OXIDADO-XANTADO, SULFONADO O ACTIVADO Y RESINA SINTÉTICA COMERCIAL
No full textLa combustión del carbón de bajo rango produce impactos ambientales por su bajo calor de combustión y alto contenido de heteroátomos, lo que ha promovido sus usos alternativos, como adsorbente. Un carbón subbituminoso (CS), se oxidó con aire a 150°C, en un lecho fijo, durante cuatro horas y se xantó con disulfuro de carbono en solución básica, a 30°C. Este carbón xantado (CX), se evaluó para la adsorción de Hg2+ y Cd2+ de soluciones acuosas de 0,100, 1,000, 12,48, 124,8 y 998,3mg/L; los metales, se determinaron por espectrometría de absorción atómica. CX se comparó con CS, CS sulfonado y CS activado (CAp), además de un carbón activado comercial (CAC) y una resina sintética comercial (RC), en términos de su capacidad de adsorción de metales. RC mostró la más alta capacidad de adsorción (factor de concentración 98%), seguido por CX (factor de concentración 96%). En general, el Hg2+ se adsorbió menos que el Cd2+ y las capacidades de adsorción siguieron el orden, de mayor a menor: RC, CX, CAp, CS, y CAC. CX también mostró una mejor adsorción de Cd2+, 81% vs. 15%, que un carbón xantado no oxidado, lo que muestra que la oxidación previa del carbón aumentó la cantidad de grupos oxigenados que, a su vez, aumentaron la xantación
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