Solid Phase Organic Silicate Host Compositions (21075)
A new class of solid organic host – silicon (polysilsesquioxane) matrix polymers have been created. Inorganic silicates, which provide mesoporous cavities, and organic shape / size template molecules are combined to create a novel family of materials capable of tailored separation, catalytic, and surface active functions including metal ion removal and organic molecule recovery.ADVANTAGES: The polymers offer a stable silicate - organic host matrix that can be readily modified by utilizing different host structures to bind target inorganic and organic species. The materials promise facile and cost effective guest recovery and resin regeneration. Potential applications include process separations, catalysis, chiral reactivity, product recovery and environmental treatment.
SUMMARY: Solid inorganic silicates including clays and zeolites provide separation and catalytic properties utilizing their naturally occurring mesoporous cavities. The use of organic templates allows such cavities to be created synthetically with designed shapes and sizes that can function as guest hosts. Well known organic hosts include the crown ethers, cyclodextrins (CD) and calixarenes (CX). CDs, cyclic oligomers of glucose, possess a hydrophilic exterior and hydrophobic interior, which can retain a variety of small molecules. CXs are cyclic
oligomers of aligned phenols connected by methylene units that can complex a variety of cations. Covalently combining the silicate framework with cyclodextrin and calixarene structures offers the potential for new heterogeneous guest host and catalytic materials.
Materials have been developed that link CDs and CXs via a covalent carbon bond to silicon possessing three Si-O bonds, which can be transformed into extended silicon matrices via sol-gel chemistry. A new class of solid organic host – silicon (polysilsesquioxane) matrix polymers have been created with this technology. A wide range of branched and cross-linked polymer networks with CD and CX organic hosts can be prepared. Polymer properties are readily varied by adjusting starting host ring size, silicon reagent and reaction parameters. Soluble and heterogeneous systems can be created at modest materials cost.
CD-based polymers exhibit nanopocket d spacings of 9.2 Å in powder X-ray patterns. Scanning electron and transmission electron microscopy reveal random polymer network packing. Polymer BET surface areas of 1-2 m2/g have been measured. Over 90% removal of 4-nitrophenol (10-4 M) from aqueous solution was observed with solid CD-based polymer. Treatment with ethanol regenerates the polymer, in contrast to activated carbon. CX-based polymers selectively remove Fe3+ cations (10-4 M) from aqueous solution in the presence of other inorganic cations. Hybrid polymers containing CD and CX hosts removed both 4-nitrophenol and Fe3+ cations in aqueous mixtures. Separation efficiency depends on the pH, polymer loading and contact time employed.
STATUS: Sample materials have been produced and characterized.
U.S. Patent No. 7,271,259
Type of Offer: Licensing
« More Chemistry Patents