1-decene biphasic systems

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. 

Besides ruthenium tetroxide, other ruthenium salts, such as ruthenium trichloride hydrate, may be used for oxidation of carbon-carbon double bonds. Addition of acetonitrile as a cosolvent to the carbon tetrachloride-water biphase system markedly improves the effectiveness and reliability of ruthenium-catalyzed oxidations. For example, RuCl3 H20 in conjunction with NaI04 in acetonitrile-CCl4-H20 oxidizes (Ej-S-decene to pentanoic acid in 88% yield. Ruthenium salts may also be employed for oxidations of primary alcohols to carboxylic acids, secondary alcohols to ketones, and 1,2-diols to carboxylic acids under mild conditions at room temperature, as exemplified below. However, in the absence of such readily oxidized functional groups, even aromatic rings are oxidized. 

Rhodium complexes modified with polyether phosphine oxides according to the Structure 30 were used as catalysts for the hydroformylation of 1-decene and oleyl alcohol in micellar aqueous-biphase systems [56, 57]. 

Purwanto and Delmas [10] proposed the addition of co-solvent (ethanol) to enhance the solubility of 1-octene in the aqueous phase so that the overall reaction rate was increased, and their kinetic study led to a rate model similar to that in homogeneous liquid systems consistently from the point of view of bulk reaction mechanism. Chaudhari et al. [11] reported the improvement of the hydroformylation rate by addition of a small amount of PPhj to the biphasic system to enrich the effective catalyst species at the liquid-liquid interface. Kalck et al. [12] tested two more approaches to improve the mass transfer rate of biphasic hydroformylation of 1-octene and 1-decene with catalyst precursor [Rh2(/i-S Bu)2(CO)2(TPPTS)3j use the phase-transfer agent /i-cyclodextrin to transport the substrate into the aqueous phase to react there (see Section 2.2.3.2.2), and the supported aqueous-phase (SAP) catalyst to increase the reaction area due to the high specific surface area of porous silica (see Section 2.6). The improved conversion and TOF gave informative suggestions for the reaction mechanisms. 

The catalytic potential of the MTO/UHP oxidation system has also been tested in the room-temperature ionic liquid [EMIM] [BF4], in which it is soluble [77]. In contrast, the olefin is poorly soluble in such solvenfs. Therefore, the whole system is biphasic. Excellent conversions and selectivities for the epoxides of a wide number of olefinic substrates were reached under these anhydrous conditions. The exception was 1-decene (data collected in Table 17), for which poor conversion (entry 9, Table 17) may result in phase transfer problems, since it is the least soluble substrate in the ionic liquid. 

Rh/tppts catalysts in the presence of cyclodextrins constitute CPTC systems which are active in the hydroformylation oT various water-insoluble olefins.566,567,570 For example, 1-decene was biphasically hydroformylated with... 

This multicomponent catalytic system also made it possible to oxidize in high yields a wide range of straight-chain higher a-alkenes [24], However, the oxidation rate and the ketone selectivity were strikingly dependent on the nature of the cyclodextrin and on the chain length of the alkene (Figure 2). The alkene optimal size and shape was reached with 1-decene. Attempts to oxidize internal alkenes in biphasic medium with cyclodextrins modified in this way failed due to the lack of accessibility of the double bond in the inclusion complex. 

As already mentioned, isomerization (double bond shift) is also a side reaction, which reduces the selectivity of the oxidation of higher olefins. High selectivity with respect to the formation of methylketones is obtained with a system consisting of t-butyl hydroperoxide as the oxidant, acetonitrile as the solvent, and P-cyclodextrine as a phase transfer catalyst in the oxidation of 1-dodecene [80] and of higher olefins C22-C20 [81]. Also, modified P-cyclodextrines increase the selectivity and activity of a PdSO /CuSO /phosphomolybdovanadic acid catalyst in biphasic oxidation of 1-decene to 2-decanone [82,83]. 

The Wacker reaction was chosen as a representative reaction since in this case the conversion of an alkene to a ketone or an aldehyde can be achieved in one step, which is of industrial relevance. The reaction was carried out in a biphasic water/ acetonitrile system at 50-60 °C in an oxygen atmosphere, using the copper/ polyaniline nanocomposite, as well as a bare copper nanocluster. In the system, copper is present in the zero-valent state supported by polyaniline. Although 2-decanone is the only product formed, the yield obtained is still relatively low. It has to be mentioned in this context that the reaction carried out in the presence of bare copper nanoclusters showed no evidence for the presence of 2-decanone, indicating that those copper nanoclusters alone do not bring about the oxidation of 1-decene. 

A particular advantage of SAP catalysis is that reaction with hydro-phobic substrates occurs at the aqueous/organic interface allowing water insoluble higher olefins to be hydroformylated using the RhH(CO)(tppts)3 system. In the biphasic hydroformylation using RhH(CO)(tppts)3 the reaction rates decrease in the order 1-hexene > 1-octene > 1-decene. In contrast, using the same catalyst in a silica supported aqueous phase similar activities and selectivities were obtained in the hydroformylation of these olefins. The low n/i ratio observed in... 

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