摘要
本文仔细地研究了Mn(Ⅲ)-Co(Ⅲ)催化体系中不同离子在丙酸氧化中的功能:Mn(Ⅲ)离子首先与丙酸作用并被还原成Mn(Ⅱ)离子;Co(Ⅲ)离子可在反应体系中将Mn(Ⅱ)再氧化,而还原了的Co(Ⅱ)离子可为氧再生.这样建立起的氧化还原体系形成了催化循环.
The function of different ions in Mn ( Ⅲ ) -Co ( Ⅲ ) catalytic system during the oxidation of propionic acid were investigated by UV-VIS-spectroscopy as well as cyclic volt ammetry .The experimental results showed that the catalytic activity was low and the activity-duration was short when only single Mn ( acac)3 was used as catalyst in the oxidation of propionic acid.It seems that the reaction is stoichiometric but not catalytic; moreover, when Co ( acac ) 3 was used as catalyst alone, no catalytic activity was detected at all under the same reaction conditions.However,higher catalytic activity and longer activity-duration were observed when both Mn ( acac ) 3 and Co ( acac ) 3 were used as catalyst.It indicated that the combination of Mn(acac)3and Co ( acac ) 3 plays an important role in the oxidation of propionic acid.
The electron spectrum of Mn ( acac ) 3 -Co( acac)3 in reaction medium showed that Mn ( Ⅲ ) may be first reduced to Mn(Ⅱ) by the substrate, and then be reoxidized by Co ( Ⅲ ) under the reaction conditions. This inference was also confirmed by the results obtained by the cyclic voltammetry of Mn(acac)3-Co(acac)3in the reaction medium. The results obtained in this work demonstrated that a redox process could be established between Mn(Ⅲ)and Co ( Ⅲ ) during the reaction, which could offer a catalytic cycle for the oxidation of propionic acid.
出处
《分子催化》
EI
CAS
CSCD
1989年第3期211-217,共7页
Journal of Molecular Catalysis(China)
基金
国家自然科学基金资助项目
