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Monoethanolamine (MEA), diethanolamine (DEA) and methyldiethanolamine (MDEA) are substances used in the CO 2 capture industrial process. The inconvenience of their use is that these species have low thermal stabilities, are volatile, and in the presence of air undergo oxidation processes to form corrosive products. This work proposed the incorporation of MEA, DEA and MDEA in a mesoporous silica substrate as an alternative for CO 2 adsorption. The mesoporous materials have a high surface area and a large pore size. The high material porosity enabled the incorporation of a large quantity of ethanolamine. The presence of MEA inside the silica pores promoted the acceleration of the decomposition process. The materials prepared using a mixture of mesoporous silica and DEA and MDEA had an optimal CO 2 capture efficiency than the isolated ethanolamines. This increased CO 2 capture efficiency was most significant in the sample prepared using MDEA. The increase of CO 2 efficiency capture by the incorporated material was 30% higher compared with free MDEA. DEA and MDEA incorporated in mesoporous silica had a higher CO 2 capture efficiency in the second and third adsorption cycles than free DEA and MDEA. The study showed that the incorporation of DEA and/or MDEA in mesoporous silica may increase CO 2 capture efficiency. [ABSTRACT FROM AUTHOR]

Monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine (MDEA) and triethanolamine (TEA) are used in industrial processes for CO 2 capture. However, these substances have some disadvantages because they are volatile, oxidised easily and their regeneration consumes large amounts of energy. The objective of this work was to study the thermal behaviour of these species. Utilising thermogravimetry, it was possible to study the kinetics of their thermal decomposition/volatilisation, enabling the estimation of the activation energy (Ea) and other kinetic parameters. Other techniques were also utilised for the characterisation of these materials: elemental analyses and gas chromatography coupled with mass spectrometry (GC/MS). TEA had the highest thermal stability of the ethanolamines studied. The thermal decomposition of DEA occurred in two steps: the first was due to an intramolecular reaction producing MEA and ethylene oxide and the second was the decomposition of residual material. The order of thermal stability is: primary amine < secondary amine < tertiary amine. However, the efficiency of CO 2 capture is inversely related to the thermal stability. Steric impediment inhibits the reaction between the ethanolamine and CO 2 . Thus, although MEA is less stable than the other ethanolamines, it is the species that with the greater CO 2 capture efficiency. [ABSTRACT FROM AUTHOR]

Surfactants are utilised as templates in the synthesis of mesoporous materials. Normally, they are removed using a calcination process, however, careful removal is necessary to conserve the properties of the material. This work proposed surfactant removal from SBA-15 mesoporous silica using a Soxhlet extractor and different solvents. The thermal decomposition of the template was studied in order to understand the process of calcination of SBA-15. The results show that the calcination process influences the properties of the material. All of the utilised solvents enabled the removal of template. Some solvents such as water, acetonitrile and dichloromethane promoted template removal primarily from the surface of the material and others such as ethanol, acetone and methanol promoted the removal of template from within the porous silica. All samples were calcined after the extraction process, however the properties of the resulting materials were different. The greater the template removal, the greater was the surface area and pore size of the materials. Increased pore size caused decreased wall thickness. Methanol was the best of the studied solvents in terms of template removal. The extraction time required was studied and 6 h was necessary to complete the process. Soxhlet extraction is not efficient for the complete removal of template from mesoporous materials. However, the reduced quantity of template in the matrix means that less aggressive calcination is required, and therefore the properties of the mesoporous material can be preserved. [ABSTRACT FROM AUTHOR]

Abstract: In 2006, the first report of a nanostructured material as adjuvant was described establishing the effectiveness of the ordered mesoporous SBA-15 silica as an immune adjuvant. The present study evaluated the SBA-15 capacity to modulate the immune responsiveness of High and Low responder mice immunized with BSA encapsulated/adsorbed in SBA-15 by the intramuscular or oral route and the adjuvant effect was compared with the responsiveness induced by BSA in aluminum hydroxide salts or emulsified in Incomplete Freund adjuvant. These results demonstrate the ability of the non-toxic SBA-15 nanoparticles to increase the immunogenicity and repair the responsiveness of the constitutively low responder individuals inducing both the IgG2a and the IgG1 isotypes, independently of the immune cell committed and conditioning the low phenotype. This new adjuvant may reveal novel therapeutic targets for immune modulation and vaccine design. [ABSTRACT FROM AUTHOR]

Modern thermal analysis techniques are frequently used because of their ability to provide detailed information about both the physical and the energetic properties of a substance. In the present work, the thermal decomposition of zidovudine (AZT) was studied using differential scanning calorimetry (DSC) and thermogravimetry/derivative thermogravimetry (TG/DTG). Thermal analysis was supplemented using elemental analysis (C, H, and N), infrared (IR) spectroscopy, and X-ray powder diffraction to characterize the solid intermediates products. Volatile products of the thermal decomposition of AZT were studied by a system composed of the TG/DTA coupled gas chromatography/mass spectrometry (GC/MS). The physical–chemical properties and compatibilities of several commonly used pharmaceutical excipients with AZT were evaluated using thermal methods. The results showed that the product originated from the first thermal decomposition stage corresponds to the cleavage followed by elimination of the azide group and consequent formation of thymine. The second event corresponds to thermal decomposition of thymine. TG/DTA–GC/MS system identified thymine’s decomposition products as furan and 2-furanmethanol like volatile species. Comparison of the thermoanalytical profiles of the mixtures with individual compounds did not give any evidence of interactions. [Copyright &y& Elsevier]

In this paper the interaction between nickel(II) and di-2-pyridyl ketone benzoylhydrazone (DPKBH) was studied. The synthesized complex shows the formula: Ni(DPKBH)2. IR spectra show that interaction of the ligand with nickel(II) occurs through the CO group since the νCO frequency changed from 1686 cm−1 in the free ligand to lower frequencies in the complex. Two other interactions can be attributed to nitrogens from the azo and the pyridine group. Conductometric titrations showed the coordination of DPKBH to Ni(II) via anionic form. Thermal decomposition and differential scanning calorimetry (DSC) at 10 °C min−1 in N2 are different for the ligand and the complex. The results from elementary analysis, mass spectrometry and the continuous variation method are given and discussed. [Copyright &y& Elsevier]