Tertiary phosphines, long-chain

In this chapter, we examine the various processes by taking a qualitative look at which parts need to be improved by further research in order to make them commercially attractive for the separation of lower volatility products and especially competitive with low pressure distillation. Once again we focus on the rhodium/tertiary phosphine catalysed hydroformylation of long chain alkenes, specifically 1-octene, since data concerning this reaction is provided in the preceding chapters. A summary of the best results obtained from each of the processes and the problems associated with their implementation appears in Table 9.1. A full economic analysis of each approach to the product separation problem is beyond the scope of this book, so any conclusions as to... 

Amphiphilic tertiary phosphines have their phosphorus donor atom located somewhere in the hydrophobic part of the molecule and should have at least one long alkyl or alkyl-aryl chain carrying a polar head group (Scheme 4. 10). Some of them, such as the sulfonated derivatives, are quite well soluble in water, others, such as Ph2P(CH) COOH (n = 3, 5, 7, 9, 11) are practically insoluble, however, can be easily solubilized with common surfactants (SDS, CTAB etc.). 

The Preparation, Characterization, and Properties of Highly Soluble Transition-Metal Complexes of Long-Chain Tertiary Phosphines... 

Tertiary phosphine groups with long alkyl chains bound directly to phosphorus or substituted at the para position of triphenylphosphine give rise to a range of interesting and potentially useful complexes. In particular these may be used to prepare polyolefin hydrogenation catalysts based on platinum(II) and palladium(II) complexes that are both more active and more selective towards reduction to monoolefins than previous catalysts based on these systems. The platinum(II) complexes are better than the palladium(II) complexes. Additionally the new phosphines are more effective than triphenylphosphine in promoting the oxidative addition of methyl iodide to trans- [Rh(PR3)2Cl(CO)]. 

Stelzer and co-workers reported a number of chiral water-soluble secondary phosphines [14], prepared by nucleophilic phosphination of primary phosphines with fluorinated aryl sulfonates in the superbasic medium DMSO/KOH. Further reaction with alkyl halides gives bidentate tertiary phosphines with P-chirality, but only racemic versions have been reported so far. Hanson et al. introduced so-called surface-active phosphines into asymmetric aqueous-phase catalysis. One of the main problems inherent to two-phase catalysis is the often very low miscibility of the substrates in the aqueous phase. Insertion of long alkyl chains between phosphorus atoms and phenyl groups in sulfonated phosphine ligands has been proven to increase reaction rates in the Rh-catalyzed hydroformylation of 1-octene [15], This concept was extended to a number of chiral ligands, i.e., the monoden-... 

Tertiary phosphine oxides, alkylmethyl sulphoxides, and alkylhydroxyethyl sulphoxides produced in the same way from trialkyl phosphines and thioethers, as well as N-alkyl-pyrrolidones (III) [51] and some long-chain imidazoline derivatives (IV) [52] should be... 

Cationic non-nitrogeneous surfactants may be synthesized essentially in the same way as the nitrogeneous compounds. So, tertiary long-chain phosphines or arsines are quatemised with conventional alkylating agents, such as alkyl halides or alkyl sulphates [101, 102]. However, heterogeneous chain compounds other than N-containing ones are not so beneficial especially from an economical viewpoint. 

A further example of practical catalyst development is the hydroformylation of long-chain a-olefins with various copper(i) complex catalysts [6]. Modification of the catalysts with tertiary phosphines and amines led to aldehydes as products in varying yields, with alcohols and alkanes as byproducts. It was foimd that defined copper complexes have only a low catalytic activity. Only after the introduction of tertiary amines as solvents and catalyst components were better results obtained. 

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