ABSTRACT
The biomass conversion technologies, especially different types of pyrolysis, have been intensively studied to improve biomass energy transformation suggesting a low impact on the environment. In particular, fast pyrolysis of biomass is considered to be a thermal process in which the starting material is converted to bio-oil, char and gas products. In this work, volatile organic compounds (VOCs) of the gaseous fraction of peanut shells fast pyrolysis were collected and identified at atmospheric pressure. Aromatic compounds, hydrocarbons, furans and other oxygenated compounds were identified using solid phase microextraction (SPME) and gas chromatography coupled to mass spectrometry (CG-MS) as a detection system. The composition of volatiles was analyzed and compared with the constituents of liquid fraction for comparative purposes. Atmospheric implications of the main compounds identified in the gases fraction were assessed by determining tropospheric lifetimes of the VOCs identified and its impact on environment at the local, regional or global scale.
Subject(s)
Volatile Organic Compounds , Arachis , Gas Chromatography-Mass Spectrometry/methods , Gases , Pyrolysis , Solid Phase Microextraction/methods , Volatile Organic Compounds/analysisABSTRACT
The synthesis, in vitro ligand binding study and in vivo Elevated Plus Maze test (EPM) of a series of pyrazolo[4,3-c]quinolin-3-ones (PQs) are reported. Multistep synthesis of PQs started from anilines and diethyl 2-(ethoxymethylene)malonate to give the quinolin-4-one nucleus, via the Gould-Jacobs reaction. These quinolinones were transformed to 4-chloroquinolines, which react with aryl-hydrazines affording the final compounds. PQs exhibited different potency in displacing specific [3H]Flunitrazepam binding from the benzodiazepine binding site at the γ-aminobutyric acid receptor (GABAA-R) depending on the substitution of the pyrazoloquinolone nucleus. PCA helped determine how different substituents contributed to the differential behavior of the PQs studied. Compounds with high affinity for the GABAA-R were tested regarding their anxiolytic properties in Wistar adult male rats using the Elevated Plus Maze (EPM). Thus, PQs with a p-methoxy phenyl group at N-1 (7b-ii and 7c-ii) displayed a remarkable anxiolytic activity at low doses (0.5-1.0â¯mg/kg). Meanwhile, PQs featuring an unsubstituted phenyl (7b-i) or p-fluoro phenyl group (7b-iii) at the N-1 showed anxiogenic effects in the EPM test.
Subject(s)
Anti-Anxiety Agents/pharmacology , Anxiety/drug therapy , Behavior, Animal/drug effects , Maze Learning/drug effects , Quinolones/pharmacology , Receptors, GABA-A/metabolism , Animals , Anti-Anxiety Agents/chemical synthesis , Anti-Anxiety Agents/chemistry , Dose-Response Relationship, Drug , Ligands , Male , Molecular Structure , Quinolones/chemical synthesis , Quinolones/chemistry , Rats , Rats, Wistar , Structure-Activity RelationshipABSTRACT
A conjugable analogue of the benzodiazepine 5-(2-hydroxiphenyl)-7-nitro-benzo[ e][1,4]diazepin-2(3 H)-one N 1-substituted with an aliphatic chain (CNZ acyl derivative, CAd) was synthesized. CAd inhibited FNZ binding to GABA A-R with an inhibition binding constant K i = 176 nM and expanded a model membrane packed up to 13 mN/m when penetrating from the aqueous phase. CAd exhibited surface activity with a collapse pressure pi = 18.8 mN/m and minimal molecular area A min = 49 A (2)/molecule at the closest molecular packing, resulting in full and nonideal mixing with a phospholipid in a monolayer up to a molar fraction x congruent with 0.1, decreasing its surface potential and contributing with a dipole that pointed its positive end toward the air and reoriented at the interface upon compression. These findings suggested that CAd could be stabilized at the membrane-water interface with its CNZ moiety stacked at the GABA A-R while its acyl chain can be inserted into the membrane depth.
Subject(s)
Benzodiazepines/chemical synthesis , Benzodiazepines/metabolism , Cell Membrane/metabolism , Receptors, GABA-A/metabolism , Binding, Competitive , Cell Membrane/chemistry , Ligands , Lipid Bilayers/chemistry , Lipid Bilayers/metabolism , Phospholipids/chemistry , Phospholipids/metabolism , Receptors, GABA-A/chemistry , Surface PropertiesABSTRACT
Homogeneous and heterogeneous flash vacuum pyrolysis (fvp) reactions of 2-(1H-1,2,3-benzotriazol-1-yl)phenylethanone (1) are reported. Heterogeneous reactions were carried out with Al-MCM-41 catalysts, mesoporous molecular sieves of the type M41S. In both cases, 7H-dibenzo[b,d]azepin-7-one (4) was the major product; however, in the catalytic reactions, yields and selectivity were very high. A mechanism for this reaction is also discussed.
ABSTRACT
Flash vacuum pyrolysis (fvp) reactions of NH-pyrazole (1) and 3,5-diphenylpyrazole (2) were investigated in the presence of anionic clays having hydrotalcite structure (HT). Solid catalysts with Mg:Al ratio equal to 2:1 containing carbonate (HT-1), nitrate (HT-2), and silicate (HT-3) as interlayer anions were employed. Between 400 and 600 degrees C, compound 1 remained almost unchanged and only unidentified volatile products were detected in small amounts. In contrast, 2 afforded benzonitrile (3) and phenylacetonitrile (4) by a ring fragmentation reaction at 450 degrees C. At a higher temperature (660 degrees C), the same products obtained in homogeneous fvp reactions, i.e., 2-phenylindene (5) and 3-phenylindene (6), were obtained showing no catalysis by HT under these conditions. Results showed that the yield is strongly dependent on the nature of the interlayer anion in the hydrotalcite structure. In comparison with reactions of 2 over zeolites, HTs exhibit selectivity for ring fragmentation reaction.
