2000 Fiscal Year Final Research Report Summary
Dynamics of Molecular Aggregation for Polyaromatic Compounds by Means of Molecular Dynamic simulation
| Project/Area Number |
11650804
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
触媒・化学プロセス
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
KUMAGAI Haruo Hokkaido University, Grad.School of Eng., Research Associate, 大学院・工学研究科, 助手 (30234511)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Molecular Dynamics / Spin-spin relaxation time / ^1H-NMR / Polyaromatic compounds / Mesophase / Pitch |
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| Research Abstract |
Change in the molecular mobility of coal tar pitch during heat treatment and subsequent cooling process were observed using ^1H-NMR.Three components, G1, G2 and L having different transverse magnetization decays were detected in the pitch upon heating. Magnetization decays of G1 and L agreed well with those of mesophase and fully fused isotropic pitch respectively. When heat treatment time was shorter, no G1 was detected while mesophase were observed in the pitch after cooling, confirming mesophase formation upon cooling after heat treatment. It was found that the formation of mesophase upon cooling accompanies the complete conversion of G2 into G1 and that the G1 formed hardly fused again while reheated to 723K.Considering the results obtained from 1H-NMR study, the mechanisms for aggregation of polyaromatic compounds were investigated using molecular dynamic (MD) simulation. MD simulation was carried out using coronene or pyrene and alkyl naphthalene as the model compounds of polyaromatic compounds and matrix respectively. The aggregation of polyaromatic compounds affected with the length *nd number of alkyl chains attached on the matrix molecules. Van der Waals and electrostatics interaction provided strong driving force for aggregation of polyaromatic compounds. The aggregated polyaromatic compounds hardly dissociated again while reheating simulation process. The results obtained in the research project reveal that the aggregation process of polyaromatic compounds was governed with the nature of matrix molecules.
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