Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From heavy metal or aluminum reactant having at least one...
Patent
1998-03-09
1999-12-28
Marquis, Melvyn I.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From heavy metal or aluminum reactant having at least one...
528 14, 528 15, 528 17, 528 18, 528 19, 526 93, 526117, 526113, 526126, C08G 7900
Patent
active
060083093
DESCRIPTION:
BRIEF SUMMARY
The invention relates to monodisperse soluble organopolysiloxane particles which comprise a single molecule and carry chemically bonded metal compounds, and to their preparation and use. The organopolysiloxane particles have an average diameter of 5 to 200 nm and are therefore in the mesoscopic size range.
In homogeneously catalyzed reactions with known homogeneous catalysts, a reaction product which is solid or insoluble in the reaction medium may be deposited on the internal wall of the reactor during continuous operation. This process, called fouling, usually leads to an interruption in operation.
Complexing ligands fixed to organic supports, such as polystyrene, and inorganic supports, such as silica gel, and the metal complexes which can be prepared with these are described comprehensively in R. H. Grubbs, CHEMTECH, August 1977, page 512 et seq. and D. D. Whitehurst, CHEMTECH, January 1980, page 44 et seq. The aim of heterogenization of the catalytically active metal complexes here is to avoid the disadvantages of homogeneous catalysis and to combine the advantages of homogeneous catalysts, i.e. high selectivity and activity, with the advantages of heterogeneous catalysts, i.e. easy removal and recovery of the catalyst from a liquid reaction mixture and no fouling in the case of solid reaction products.
The silicon dioxide-based inorganic support materials used to date, such as pyrogenic silicic acid or ground and, where appropriate, thermally modified silica gels, have non-uniform particle size distributions and particle sizes from 0.001 mm to 3 mm. Another disadvantage of these support materials is their irregular particle structure and the restriction to a low metal complex density on the support surface. These particles are insoluble in organic solvents.
Processes based on the sol-gel process for the preparation of spherical silica gel particles having a particle diameter of 0.01 mm to 3 mm and a relatively freely adjustable covering density of the silica support with the catalytically active metal complex compound by cocondensation of amine- and phosphine-functionalized trialkoxysilanes, preferably with tetraethoxysilane, are described in DE-C 30 29 599 and DE-C 39 25 359, as well as in U.S. Pat. No. 5,187,134. The resulting catalyst systems are insoluble in all solvents.
The object was to provide soluble organopolysiloxane particles which carry chemically bonded metal compounds and have a monodisperse particle size distribution within a size range from 5 to 200 nm.
The invention relates to crosslinked organopolysiloxane particles which comprise a single molecule, carry chemically bonded metal compounds, have an average diameter of 5 to 200 nm and are soluble to the extent of at least 1% by weight in at least one of the solvents chosen from the group consisting of methylene chloride, pentane, acetone, ethanol and water, at least 80% of the particles having a diameter which deviates not more than 30% from the average diameter.
The organopolysiloxane particles typically have average molecular weights of at least 10.sup.5, in particular 5.times.10.sup.5, and preferably not more than 10.sup.10 g/mol, in particular 10.sup.9. The average diameters of the organopolysiloxane particles are preferably at least 10 and not more than 150 nm. Preferably, at least 80% of the particles have a diameter which deviates not more than 20%, in particular not more than 10%, from the average diameter. The organopolysiloxane particles are preferably spherical particles.
The organopolysiloxane particles are soluble in solvents and can therefore be employed as homogeneous catalysts, although the catalytically active complex is immobilized on the mesoscopic support system. Preferably, the solubility in a solvent is at least 2% by weight, in particular 10% by weight. The solvent in which the organopolysiloxane particles dissolve depends on the build-up of the organopolysiloxane particles, and in particular on the groups on the surface of the organopolysiloxane particles. There is a suitable solvent for all organopolysiloxane
REFERENCES:
patent: 5187134 (1993-02-01), Panster et al.
patent: 5241036 (1993-08-01), Hsiue et al.
patent: 5442025 (1995-08-01), Spes et al.
R. H. Grubbs, Chemtech, Aug. 1977, p. 512 et seq.
D. D. Whitehurst, Chemtech, Jan. 1980, p. 44 et seg.
Derwent Abstract corresponding to DE-C 3029599 (#82-11871E).
Derwent Absract corresponding to DE-C 3925359 (#91-037961).
M. Schmidt "Simultaneous Static and Dynamic Light Scattering: Applications to Polymer Structure Analysis", contained in: Dynamic Light Scattering: The Method and Some Applications, Brown, W. (Editor), Oxford University Press, Oxford, UK, 372-406 (1993).
Antonietti (Angew. Chemie 100 (1998) 1813-1817).
Derwent Abstract corresponding to EP 0638604 (#95-076322).
Derwent Abstract corresponding to EP 0744 432(#97-001220).
Baumann Frank
Deubzer Bernward
Manfred Schmidt
Michael Geck
Marquis Melvyn I.
Wacker-Chemie GmbH
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