1-Decene Wacker process

Water and a little 60% aq. HCIO4 (to prevent precipitation of Pd(0)) added via syringe to catalytic amounts of Pd(OAc)2, hydroquinone, and iron(II) phthalocyanine (as 62 carrier) in DMF, the mixture purged with O2, 1-decene added in 6 portions at 15 min intervals, and stirred at room temp, for 3 h under 1 atm O2 - 2-decanone. Y 73%. In contrast with the classical Wacker process (Synth. Meth. 19, 200), this catalytic route is much faster and free from chlorinated by-products the Fe-catalyst is readily removed by filtration. F.e.s. J.-E. Backvall, R.B. Hopkins, Tetrahedron Letters 29, 2885-8 (1988). 

Betzemeier et al. (1998) have used f-BuOOH, in the presence of a Pd(II) catalyst bearing perfluorinated ligands using a biphasic system of benzene and bromo perfluoro octane to convert a variety of olefins, such as styrene, p-substituted styrenes, vinyl naphthalene, 1-decene etc. to the corresponding ketone via a Wacker type process. Xia and Fell (1997) have used the Li salt of triphenylphosphine monosulphonic acid, which can be solubilized with methanol. A hydroformylation reaction is conducted and catalyst recovery is facilitated by removal of methanol when filtration or extraction with water can be practised. The aqueous solution can be evaporated and the solid salt can be dissolved in methanol and recycled. 

The metal-catalysed autoxidation of alkenes to produce ketones (Wacker reaction) is promoted by the presence of quaternary ammonium salts [14]. For example, using copper(II) chloride and palladium(II) chloride in benzene in the presence of cetyltrimethylammonium bromide, 1-decene is converted into 2-decanone (73%), 1,7-octadiene into 2,7-octadione (77%) and vinylcyclohexane into cyclo-hexylethanone (22%). Benzyltriethylammonium chloride and tetra-n-butylammo-nium hydrogen sulphate are ineffective catalysts. It has been suggested that the process is not micellar, although the catalysts have the characteristics of those which produce micelles. The Wacker reaction is also catalysed by rhodium and ruthenium salts in the presence of a quaternary ammonium salt. Generally, however, the yields are lower than those obtained using the palladium catalyst and, frequently, several oxidation products are obtained from each reaction [15]. 

Wacker oxidation of olefins to ketones catalyzed by palladium complexes is a well-known process which has been applied to numerous olefins [120]. However, selective oxidation of Cg-Cig a-olefins remains a challenge. Recently, Mortreux et al. have developed a new catalytic system for the quantitative and selective oxidation of higher a-olefins in an aqueous medium [121-123]. For example, 1-decene was oxidized to 2-decanone in 98% yield using PdS04/ H9PV6M06O40/CUSO4 as the catalyst in the presence of per(2,6-di-0-methyl)-j9-cyclodextrin, which probably played the role of a reverse phase transfer reagent [Eq. (22)]. 

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