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用升温升压原位红外光谱法研究了低压一步法制备钴-膦络合物催化剂的反应机理。反应过程中的红外光谱变化表明,首先生成一种膦配位的钴盐,随后钴盐解离,并羰基化生成钴-膦羰基络合物和羧酸。由于羧酸和钴-膦羧基络合物可以构成可逆循环反应,因而阻止了催化剂的分解。在醛化反应条件下,催化剂的主要成份是Co_2/(CO)(PBu_3)_2和HCo(CO)_3PBu_3。考察了温度、压力、氢分压及钴和膦的原子比对反应的影响。
The reaction mechanism of cobalt-phosphine complex catalyst prepared by one-step low pressure was investigated by in situ infrared spectroscopy. Infrared spectroscopic changes during the reaction show that a phosphine-coordinated cobalt salt is first formed, followed by dissociation of the cobalt salt and carbonylation to form cobalt-phosphonocarbonyl complexes and carboxylic acids. Since the carboxylic acid and the cobalt-phosphine carboxylate complex can form a reversible cycle reaction, the decomposition of the catalyst is prevented. Under the hydroformylation reaction conditions, the main components of the catalyst are Co_2 / (CO) (PBu_3) _2 and HCo (CO) _3PBu_3. The effects of temperature, pressure, partial pressure of hydrogen and the atomic ratio of cobalt and phosphine on the reaction were investigated.