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Environmentally Friendly Electroorganic Synthesis in Ionic Liquids Toward a Solvent-Free Process

离子液体中的环保有机电合成迈向无溶剂工艺

基本信息

批准号：
16550090
负责人：
FUCHIGAMI Toshio
金额：
$ 2.37万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

项目摘要

Solvent free electroorganic synthesis is highly desirable from an environmental aspect. In recent years, room-temperature molten salts, namely ionic liquids, have proved to be a new class of promising solvents because of their good electroconductivity, nonflammability, thermal stability, nonvolatality, and reusability. Therefore, when ionic liquids are used as electrolytic media, organic electrolytic reactions, particularly electroorganic synthesis should be possible without any organic solvents. However, there have been still a limited number of papers dealing with organic electrosynthesis in ionic liquids. In this project, we have achieved the following subjects.1) Anodic fluorodesulfurization of 3-phenylthiophthalide, 4-phenylthio-1,3-dioxolan-2-one, and 1-arylthio-2,3,4,6-tetra-O-acetyl-β-D-glucopyranoside in ionic liquids like Et_3N・nHF (n=4,5) and Et_4NF・nHF (n=4,5) without any solvents provided the corresponding monofluorinated products exclusively in moderate to good yields. In … More sharp contrast, the anodic fluorination in Et_3N・3HF with and without co-solvent resulted in α-fluorination without desulfurization exclusively or preferentially. It was also demonstrated that the electrochemical fluorodesulfurization of 3-phenylthiophthalide under solvent free conditions was achieved repeatedly four times by the reuse of a fluoride salt, Et_4NF・4HF. Thus, we have shown the first example of fluorodesulfurization by the reuse of an ionic liquid fluoride salt. (n=4,5).2) The catalytic effect of a Co(II)salen mediator on the reduction of cyclic vio-dibromide was investigated in ionic liquids by cyclic volteammetry. Macro-scale controlled potential electrolysis gave the corresponding debrominated product in moderate to good yields. The workup after electrolysis in an ionic liquid proved to be much simpler than that in organic solvents. The possibility of reruse of the ionic liquid was demonstrated to some extent.3) Photocatalytic degradation of organic pollutants such as naphthol blue black, Amarance, and 2-chlorophenol (2CP) was carried out using TiO_2 in ionic liquids. The phtocatalytic degradation rate of the former two azo dyes were greatly enhanced in ionic liquids compared with those in water. In sharp contrast, the photodegradation of 2CP was not efficient in an ionic liquid, however, the degradation was enhanced under simultaneous ultrasonication.4) Anodic fluorination of cyclic thiocarbonates like 1,3-oxathiolane-2one was successfully carried out in ionic liquids like Et_4NF・4HF. Less

从环境方面来看，无溶剂有机电合成是非常需要的。近年来，室温熔盐即离子液体因其良好的导电性、不燃性、热稳定性、不挥发性和可重复使用性而被证明是一类有前途的新型溶剂。因此，当使用离子液体作为电解介质时，有机电解反应，特别是有机电合成应该可以在没有任何有机溶剂的情况下进行。然而，涉及离子液体有机电合成的论文数量仍然有限。本项目主要完成了以下课题： 1）3-苯硫基苯硫醚、4-苯硫基-1,3-二氧戊环-2-酮、1-芳硫基-2,3,4,6-四-O-乙酰基-β-D-吡喃葡萄糖苷在Et_3N·nHF（n=4,5）等离子液体中的阳极氟化脱硫没有任何溶剂的 Et_4NF·nHF (n=4,5) 仅以中等至良好的产率提供相应的单氟化产物。与此形成鲜明对比的是，在有或没有共溶剂的 Et_3N·3HF 中进行阳极氟化会导致 α-氟化，而无需专门或优先脱硫。还证明，通过重复使用氟化物盐Et_4NF·4HF，可在无溶剂条件下重复四次实现3-苯硫代苯硫醚的电化学氟化脱硫。因此，我们展示了通过再利用离子液体氟化物盐进行氟脱硫的第一个例子。 (n=4,5).2) 通过循环伏安法研究了离子液体中 Co(II)salen 介体对环状二溴化物还原的催化作用。宏观控制电位电解以中等至良好的产率产生相应的脱溴产物。事实证明，在离子液体中电解后的后处理比在有机溶剂中电解后的后处理简单得多。一定程度上证明了离子液体重复利用的可能性。3)以TiO_2为原料在离子液体中光催化降解萘酚蓝黑、苋菜素、2-氯苯酚(2CP)等有机污染物。与在水中相比，前两种偶氮染料在离子液体中的光催化降解速率大大提高。与此形成鲜明对比的是，2CP在离子液体中的光降解效率不高，但在同时超声处理下，降解效果增强。4)在Et_4NF·4HF等离子液体中，成功地对1,3-氧硫杂环戊烷-2one等环状硫代碳酸酯进行了阳极氟化。较少的