Surface-modified chromatographic separation material
OwnerJoseph J. Pesek, Sally A. Swedberginventors
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Abstract
A method is provided for modifying a porous chromatographic material such as silica, alumina, thoria, titania or magnesia, which involves the steps of halogenating the surface hydroxyl groups of such material, and reacting the halogenated surface with a suitable alkylation reagent. The method gives a direct surface-to-carbon linkage in a high-yield reaction.
Claims13
A method for coupling an olefinically unsaturated surface-modifying group to the surface of a surface hydroxyl-containing silica material to give an acid- and base-stable surface-modified silica substantially free of contamination and capable of further functionalization through the olefinic bond present in the surface-modifying group, comprising the steps of, in sequence;
- (a) reacting the surface hydroxyl groups of the silica material with a halogenating agent in an anhydrous, aprotic solvent, thereby replacing the surface hydroxyl groups with halogenations so as to provide a halogenated silica material having a halogenated surface;
- (b) isolating the halogenated silica material from the solvent, thereby obtaining an isolated halogenated silica material;
- (c) washing the isolated halogenated silica material to remove excess halogenating agent thereby forming a washed halogenated silica material;
- (d) reacting the washed halogenated silica material with a reagent selected from the group consisting of olefinically unsaturated Grignard reagents of the formula CH.sub.2 .dbd.CH--(CH.sub.2).sub.n MgBr and olefinically unsaturated organolithium reagents of the formula CH.sub.2 .dbd.CH--(CH.sub.2).sub.n Li, in which n is an integer in the range of from one to sixteen inclusive, thereby giving rise to direct covalent carbon to silicon linkages and the formation of an acid- and base-stable surface-modified silica having surface Si--(CH.sub.2).sub.n --CH.dbd.CH.sub.2 moieties;
- and
- (e) washing the acid- and base-stable surface-modified silica in the sequence of
- (i) first washing the surface-modified silica with sodium hydroxide;
- (ii) then washing the sodium hydroxide-washed surface-modified silica with hydrochloric acid;
- and
- (iii) repeating steps (i) and (ii) at least once.
A method for coupling an olefinically unsaturated surface-modifying group to the surface of a surface hydroxyl-containing porous particulate silica material having a surface area of at least about 50 .sup.2 /g and a pore diameter of at least about 30 angstroms to give an acid- and base-stable surface-modified silica substantially free of contamination and capable of further functionalization through the olefinic bond present in the surface-modifying group, comprising the steps of, in sequence:
- (a) reacting the surface hydroxyl groups of the silica material with thionyl chloride in anhydrous toluene, thereby replacing the surface hydroxyl groups with chlorinations so as to provide a chlorinated silica material having a chlorinated surface;
- (b) isolating the chlorinated silica material from the toluene, thereby obtaining an isolated chlorinated silica material;
- (c) washing the isolated chlorinated silica material to remove excess thionyl chloride thereby forming a washed chlorinated silica material;
- (d) reacting the washed chlorinated silica material with an olefinically unsaturated Grignard reagent of the formula CH.sub.2 .dbd.CH--(CH.sub.2).sub.n MgBr in which n is an integer in the range of from one to sixteen inclusive, thereby giving rise to direct covalent carbon to silicon linkages and the formation of an acid- and base-stable surface-modified silica having surface Si--(CH.sub.2)hd n--CH.dbd.CH.sub.2 moieties;
- (e) washing the acid- and base-stable surface-modified silica in the sequence of
- (i) first washing the surface-modified silica with sodium hydroxide;
- (ii) then washing the sodium hydroxide washed surface-modified silica with hydrochloric acid;
- and
- (iii) repeating steps (i) and (ii) at least once, thereby forming a washed product;
- (f) washing the washed product of step (e.) with deionized water, thereby forming a water-washed product;
- (g) washing the water-washed product with alcohol, thereby forming an alcohol-washed product;
- and
- (h) drying the alcohol-washed product at a temperature of 110.degree. C. or higher.
A method for coupling an olefinically unsaturated surface-modifying group to the surface of a surface hydroxyl-containing porous particulate silica material having a surface area of at least about 50 M.sup.2 /g and a pore diameter of at least about 30 angstroms to give an acid- and base-stable surface-modified silica substantially free of contamination and capable of further functionalization through the olefinic bond present in the surface-modifying group, comprising the steps of, in sequence:
- (a) reacting the surface hydroxyl groups of the silica material with thionyl chloride in anhydrous toluene, thereby replacing the surface hydroxyl groups material having a chlorinated surface;
- (b) isolating the chlorinated silica material from the toluene, thereby obtaining an isolated chlorinated silica material;
- (c) washing the isolated chlorinated silica material to remove excess thionyl chloride thereby forming a washed chlorinated silica material;
- (d) reacting the washed chlorinated silica material with an olefinically unsaturated organolithium reagent of the formula CH.sub.2 .dbd.CH--(CH.sub.2).sub.n Li in which n is an integer in the range of from one to sixteen inclusive, thereby giving rise to direct covalent carbon to silicon linkages and the formation of an acid- and base-stable surface-modified silica having surface Si--(CH.sub.2).sub.n --CH.dbd.CH.sub.2 moieties;
- (e) washing the acid- and base-stable surface-modified silica in the sequence of
- (i) first washing the surface-modified silica with sodium hydroxide;
- (ii) then washing the sodium hydroxide-washed surface-modified silica with hydrochloric acid;
- and
- (iii) repeating steps (i) and (ii) at least once, thereby forming a washed product;
- (f) washing the washed product of step (e.) with deionized water, thereby forming a water-washed product;
- (g) washing the water-washed product with alcohol, thereby forming an alcohol-washed product;
- and
- (h) drying the alcohol-washed product at a temperature of 110.degree. C. or higher.
Dependencies are inferred from the claim text.