釕羰基錯合物催化一氧化碳還原─氧化二氮之反應機構及動力學

The Kinetics and Mechanism for Catalytic Reduction of Nitrous Oxide by Carbon Monoxide in the Presence of Ruthenium Carbonyl

方偉平(Woei-Ping Fang)

《化學》 49卷4期 (1991/12) Pp. 261-266

https://doi.org/10.6623/chem.1991035

摘要

Ru_3(CO)_(12)在DMSO中，以KOAC為鹼，在100℃下可以迅速催化CO還原N_2O爲N_2和CO_2。其觸媒轉換率(turnover number)爲2.10 cycles/Rujhr。動力學的研究結果顯示反應速率與P_(N_2O)和[Ru_3(CO)_(12)]的一次方成正比。由艾靈圖形(Eyring plot)求得活化參數△H^≠、△S^≠和△G^≠分別爲16.3 kcal mol^(-1)、-28.0 cal K^(-1) mol^(-1)和26.7 Kcal mol^(-1)。在催化反應期間，Ru_3(CO)_(12)主要被還原爲Ru_4(CO)_(12)。Ru_4(CO)_(13)^(2-)與N_2O反應同時產生N_2和CO_2。在催化過程中Ru_4(CO)_(13)^(2-)是主要的金屬羰基陰離子，而且是活性觸媒。

並列摘要

Catalytic reduction of N_2O by CO to N_2 and CO_2 can be achieved rapidly at 100℃ in solutions containing Ru_3(CO)_(12) and a base. The average rate for the N_2O reduction of 2.10 turnovers per hour in dimethyl sulphoxide was obtained using potassium acetate as a base. Kinetics study shows that the rate has a first order dependency on P_(N2O) and [Ru_3(CO)_(12)]. The activation parameters ΔH^≠, ΔS^≠, ΔG^≠ obtained from the Eyring plot are 16.3kcal moll^(-1),-28.0calK^(-1) moll^(-1) and 26.7kcal moll^(-1) respectively. During the course of catalysis, Ru_3(CO)_(12) was mainly reduced to Ru_4(CO)_(13)^(2-). The reaction of Ru_4(CO)_(13)^(2-) with N_2O yielding N_2 and CO_2 simultaneously. In a catalytic cycle, Ru_4(CO)_13^(2-), is the primary ruthenium species and also the active species.