Karen L Zuleta H was born in Bogotá in 1997. She is a student at the Jorge Tadeo Lozano University in the Chemical Engineering program. She is currently doing her research in theoretical and computational chemistry that involve molecular structure, energetic, and binding.
This research focused on the computational study of intermolecular interactions responsible for the geometric preferences and stability of (ethanol)8-water heterononamers. The B3LYP functional was used as implemented in Gaussian 09. The potential energy surface was explored using the ab-initio molecular dynamics method (ADMP) and a stochastic method (Simulated Annealing) to find starting structures that were optimized with the B3LYP/6-31+G (d) approximation; obtaining 9 stable heterononamers. After reoptimizing those structures including dispersion correction (D3) and a larger base, B3LYP-D3/6-311++G(d,p), the number of stable structures was reduced to 7. The major structural changes were different orientations of the alkyl chains. It was calculated that the most stable heterononamer (Hnon-I) has an isomeric population of 98%. From this structure were designed and optimized homologous structures with only ethanol and with only methanol molecules, as well as a (methanol)8-water structure. Measurements made including geometric, energetic, and topological data. The binding energy (nonamerization) is the difference between the energy of the heterononamer and the sum of the energy of each isolated monomer. In the same way other state functions were calculated (ΔH, ΔS, and ΔG). As an example, the following are the energetic data of Hnon-I: ΔE=-303.68 kcal/mol; ΔH=-339.29 kcal/mol; ΔS=275.32 kcal/K*mol, and ΔG=4.16 kcal/mol. These results imply that the formation of Hnon-I is a highly exothermic and non-spontaneous process. It was found that the cycles formed by O-H---O interactions are fundamental for stabilizing the (hetero) nonamer regardless of their nature. Weaker interactions (C-H---O and H---H) were revealed by means of the molecular graphs calculated through the topological analysis of electron density according to the Quantum Theory of Atoms in Molecules.
Nellya G Grigorieva is a Doctor of Science, Leader Researcher in the Catalysts Preparation Laboratory at the Institute of Petrochemistry and Catalysis, Russian Academy of Sciences. Under her leadership, new heterogeneous-catalytic methods for the production of components for gasolines, diesel and jet fuels, synthetic lubricants by oligomerization of C5-C-16 linear olefins, cyclenes and vinylarenes, selective methods for producing oxygen-containing derivatives of norbornene and styrene, methods for the synthesis of α, β-unsaturated aromatic ketones, basic N-heterocyclic compounds in the presence of crystalline and amorphous aluminosilicates have been developed.
The oligomerization products of α-olefins are widely used as high-octane components of fuels, lubricants, solvents, plasticizers, etc. The production of oligomers includes the catalytic oligomerization and the hydrogenation of the products obtained. The drawbacks of Bronsted and Lewis acids, metalorganic catalysts, used in these processes, are well known and it stimulates the search for new, more efficient and environmentally friendly catalytic systems. The aim of this work is to develop heterogeneous catalytic methods for oligomerization of light (C5) and higher α-olefins (C8-C16) based on the use of mesoporous aluminosilicates ASM. Aluminosilicates ASM (Si/Al ratio=40, 80 and 160) were prepared by sol-gel synthesis. Catalytic transformations of α-olefins C5-C16 were carried out in autoclave at temperature 60-250ºС for 1-5 hours, the catalyst content was 10-30% wt. It has been established that aluminosilicates exhibit high activity in the oligomerization of C5-C16 olefins. The maximum conversion of olefins was observed on a sample with a molar ratio of Si/Al=40, which has the highest acidity. The selectivity for pentene oligomers on an ASM-40 sample reaches 100%, and di-tri- and tetramers are present in the oligomers. Oligomerization of octene and decene proceeds with the formation of predominantly dimers (37-50%) and trimers (32-39%). The selectivity for dodecene oligomers is 74%, and for hexadecene oligomers -66%. Dimers and trimers remain products of oligomerization, although the content of trimers decreases from 20% (C12) to 9% (C16). Note that, unlike zeolites, we did not observe the formation of degradation products of the initial monomers and the obtained oligomers on mesoporous aluminosilicates. This indicates the absence or very low cracking activity of these catalysts.