2005 Fiscal Year Final Research Report Summary
Task specific ionic liquids - Paradigm-Shift into an active solvent beyond a static medium.
| Project/Area Number |
16350025
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Organic chemistry
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| Research Institution | Oita University |
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Principal Investigator |
ISHIKAWA Yuichi Oita Univ., Dept.of Applied Chemistry, Associate Prof., 工学部, 助教授 (30184500)
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| Project Period (FY) |
2004 – 2005
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| Keywords | ionic liquids / porphyrin syntheses / biphasic reaction / imidazolium / bulky anion / ion-paired salt / free-ion paired salt / ionic form and reaction |
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| Research Abstract |
From this research project as to functional ionic liquids, we obtained two facts ; one is regarded for porphyrin formation in ionic liquids and anther revealed the relation between reactivity and salt from of ionic liquid.
1. For the one-flask reaction producing TPP and NC-TPP, which is to consume heavily dichloromethane, an IL is employed as a reaction medium aiming at reducing the halogenated solvent. Some ILs with MSA can produce the porphyrins in a similar yield to the halogenated solution as long as the water content and the fluidity are conditioned to be the optimum state. When the 1-alkyl-3-methylimidazolium salts are selected as medium, a trade-off relation between the water content and the fluidity in terms of the alkyl chain length governs the productivity of the porphyrins. The acidic IL, TSIL-1, being in the biphasic mode catalyzed the condensation reaction in dichloromethane even in high reactant concentration, producing porphyrins in a comparable yield to the homogeneous r
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eaction, despite high viscosity and the presence of ample remained water of the acidic IL. The acidic IL is reusable at least 10 times without loss of catalytic activity. These facts contribute to shift the porphyrin preparation into the 'Green' process from the harmful solvent consumer.
2. When a molecular solvent is selected for the reaction including an ionic intermediate (C^+ and A^-), it is necessary to understand the ion-states such as the contact ion pair (C^+A^-) and the solvent-separated free ions (C^+...A^-). Nevertheless, the ion-states has been less focused on the chemistry of the ionic liquids, ILs. This would be partly because the cations and anions of an undiluted IL are considered to be forcibly enrolled in the contact ion pair as a matter of course. In the second work, we demonstrate the first piece of evidence that the size of the ions can play a crucial role for the ion-states of the IL by which a reaction in the IL can be regulated. Estimating properly the ion-states is indispensable for the ILs, not only for a molecular solution containing ionic species. Careful consideration of the ion-sizes could be instrumental in making predictions of the ion-states of the undiluted ILs. Less
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