| Summary: | 碩士 === 國立中正大學 === 化學研究所 === 92 === Abstract
The research goal of this thesis is to study organometallic Lewis acids catalyzed aldehyde trimerization reactions under various conditions. As for the green chemistry concern, our strategies are to design processes to shorten reaction time, to increase product yields, to cut down energy usage, and to reduce chemical wastes.
The precursor [A(2-py3)]M(CO)3 (A = P, OP, M=W, Mo) can be prepared in one pot in several minutes under microwave irradiation conditions. The method gave high purity products in exclusive yields without further purification. The direct reaction of [A(2-py3)]M(CO)3 (A= P, OP, M=W,Mo) and 2 equiv. of NOBF4 afforded [A(2-py)3]M(CO)(NO)2}(BF4)2 (A = P, OP, M=W, Mo) which can be stored as a crystalline solid in air for monthes without significant decomposition. The resulting compounds are very water-soluble and possesses strong Lewis acidity upon loss of the CO ligand.
The complex [P(2-py)3W(CO)(NO)2](BF4)2 (Ι) catalyzed a series of aldehydes trimerization at room temperature in a solvent-free condition to afford the corresponding 1,3,5-trioxanes in reasonably high yields. In addition, a noticeable increase in reaction rate and a slight decrease in product yields were observed when the I-catalyzed aldehyde trimerization reactions were carried out under microwave irradiation conditions. It should be noticed that several drops of the ionic liquid bmimPF6 (1-butyl-3-methyl imidazolium hexafluorophosphate) were required for conducting microwave. Also, and a significant rate enhancement was noticed when the similar reactions were performed at 400 psi of dinitrogen.
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