COMPLEXES OF PLATINUM METALS .7. HOMOGENEOUS RUTHENIUM AND OSMIUM CATALYSTS FOR DEHYDROGENATION OF PRIMARY AND SECONDARY ALCOHOLS
COMPLEXES OF PLATINUM METALS .7. HOMOGENEOUS RUTHENIUM AND OSMIUM CATALYSTS FOR DEHYDROGENATION OF PRIMARY AND SECONDARY ALCOHOLS
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DOI：
10.1021/ic50167a029
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发表时间：
1977-01-01
影响因子：
4.6
通讯作者：
ROBINSON, SD
中科院分区：
文献类型：
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作者：
DOBSON, A;ROBINSON, SD
钌和锇配合物 [M (ÓCORp) 2 (CO)(PPh3) 2](Rp= CF3、C2F5 或 CsFs) 分别是伯醇和仲醇脱氢生成醛和酮的催化剂。添加少量游离酸（RpCOOH）可促进催化作用，而醛或酮的积累以及添加大量酸则抑制催化作用。在酸 RpCOOH 存在下，氢化物配合物 [MH (OCORp)(CO)(PPh3) 2] 也起到催化剂的作用。催化过程提出的机理涉及催化剂 [M-(OCORf) 2 (CO)(PPI13) 2] 溶剂解形成醇盐 [M (O Aik)(OCORp)(CO)(PPh3) 2]，随后进行 ß 消除生成醛（或酮）并形成氢化物 [MH (OCORp)(CO)(PPh3) 2]。酸对氢化物的攻击释放出氢气并再生催化剂。已观察到多种伯醇、仲醇和环醇都会发生脱氢反应。已记录动力学数据；初始消除氢气的速率随着醇沸点的增加而增加，对于伯醇，在最佳条件下，催化剂[Ru (OCOCF3) 2 (CO)(PPh3) 2]的初始消除速率范围为7.50 X10-3 mol s-1（催化剂摩尔数）-1（乙醇）至2.27 mol s-1（催化剂摩尔数）-1（苯甲醇）。对于标准条件下给定的醇，催化剂效率按 Ru> Os 和 CF3~ C2F5> CsFs 的顺序降低。
Ruthenium and osmium complexes [M (ÓCORp) 2 (CO)(PPh3) 2](Rp= CF3, C2F5, or CsFs) are catalysts for the dehydrogenation of primary and secondary alcohols to aldehydes and ketones, respectively. The catalysis is promoted by the addition of smallamounts of free acid (RpCOOH) and is inhibited by the accumulation of aldehyde or ketone and by the addition of large amounts of acid. In the presence of acid, RpCOOH, the hydride complexes [MH (OCORp)(CO)(PPh3) 2] also function as catalysts. The mechanism proposed for the catalytic process involves solvolysis of the catalysts [M-(OCORf) 2 (CO)(PPI13) 2] to form alkoxides [M (O Aik)(OCORp)(CO)(PPh3) 2] which subsequently undergo a ß elimination to generate aldehyde (or ketone) and form the hydrides [MH (OCORp)(CO)(PPh3) 2]. Acid attack on the hydrides liberates dihydrogen and regenerates the catalysts. Dehydrogenation has been observed to occur with an extensive range of primary, secondary, and cyclic alcohols. Kinetic data have been recorded; the initial rate of dihydrogen elimination increases with increasing boiling point of the alcohol and for the primary alcohols ranges from 7.50 X10-3 mol s-1 (mol of catalyst)-1 (ethanol) to 2.27 mol s-1 (mol of catalyst)-1 (benzyl alcohol) for the catalyst [Ru (OCOCF3) 2 (CO)(PPh3) 2] under optimum conditions. Catalyst efficiency decreases in the sense Ru> Os and CF3~ C2F5> CsFs for a given alcohol under standard conditions.