Phosphorus-based catalysts

Organocatalytic asymmetric carbonyl reductions have been achieved with boranes in the presence of oxazaborolidine and phosphorus-based catalysts (Section 11.1), with borohydride reagents in the presence of phase-transfer catalysts (Section 11.2), and with hydrosilanes in the presence of chiral nucleophilic activators (Section 11.3). 

Borane Reduction Catalyzed by Oxazaborolidines and Phosphorus-based Catalysts... 

IR Data Characterizing Selected Phosphorus-Based Catalysts after Drying and Calcination... 

Fig. 37. Number of patents concerning phosphorus-based catalysts filed in Japan during the period 1977-1994.

Use Phosphorus-based catalyst in organic and latex-based fire-retardant intumescent paints, mastics, and polymers. 

Poly-N [Solutia]. (ammonium polyphosphate). TM for chemical used as a phosphorus-based catalyst in organic as well as latex-based products. 

Polymerizations using Phosphorus-Based Catalysts Phosphines and Phosphazenes 86... 

Table 4 Representative examples of the ROP catalyzed by phosphorus-based catalysts...

When a Br nsted base functions catalytically by sharing an electron pair with a proton, it is acting as a general base catalyst, but when it shares the electron with an atom other than the proton it is (by definition) acting as a nucleophile. This other atom (electrophilic site) is usually carbon, but in organic chemistry it might also be, for example, phosphorus or silicon, whereas in inorganic chemistry it could be the central metal ion in a coordination complex. Here we consider nucleophilic reactions at unsaturated carbon, primarily at carbonyl carbon. Nucleophilic reactions of carboxylic acid derivatives have been well studied. These acyl transfer reactions can be represented by... 

More recently there have been developed water- resistant phosphorus-based intumescence catalyst. This commercially available product, as an example Phos-Chek P/30 tradename from Monsanto, can be incorporated (with other water insoluble reagents) into water-resistant intumescent coatings of either the alkyd or latex-emulsion type. These intumescent coatings, formulated ac-... 

The key to the successful development of homogeneous catalysts has been the exploitation of the effects that ligands exert on the properties of metal complexes by tailoring the electronic and steric properties of a catalytically active metal complex, activities and selectivities can be altered considerably. This especially holds for phosphorus based ligands, which are the most commonly encountered ligands as.sociated with organometallic compounds. 

Apart from the hydrolysis step, the SCR-urea process is equivalent to that of stationary sources, and in fact the key idea behind the development of SCR-urea for diesel powered cars was the necessity to have a catalyst (1) active in the presence of 02, (2) active at very high space velocities ( 500.000 per hour based on the washcoat of a monolith) and low reaction temperatures (the temperature of the emissions in the typical diesel cycles used in testing are in the range of 120-200°C for over half of the time of the testing cycle), and (3) resistant to sulphur and phosphorus deactivation. V-Ti02-based catalysts for SCR-NH3 have these characteristics and for this reason their applications have also been developed for mobile sources. 

Rhodium complexes of phosphorus based ligands are of considerable importance as (pre-)catalysts in hydroformylation which has developed into one of the most important homogeneous catalytic processes [57]. A recent advantage in this field involved the use of phosphinines as ligands whose low-lying r -orbitals provide for similar r-acceptor qualities as for phosphites [13, 58]. 

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