Non-shrinking, non-swelling, cellulose bodies for chromatography
OwnerIoannis Scarpa, Bozidar Stipanovicinventors
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Abstract
Disclosed are small particles of cellulose which are useful for liquid chromatography supports, and the like. Disclosed are methods for making small, substantially spherical bodies with a near complete absence of irregularities, holes, cracks, and the like. This is made possible by a new process wherein the coagulation of viscose is carried out before any regeneration is allowed to begin. This method is of general utility applying also to the production of rayon fiber and cellophane film.
Claims36
A chromatography support comprising spheroidal, rigid beads of regenerated cellulose, wherein said beads each have an integral nonporous outer skin, said skin demonstrating no holes, cracks or voids at a magnification of 6,000.times., and wherein said beads retain their structural integrity in aqueous solutions under operating chromatographic column pressures at least of 100 p.s.i., wherein said beads swell not more than 15% of their original volume when immersed in aqueous solutions, and wherein said beads are essentially non crystalline as determined by X-ray diffractometry.
A liquid-chromatography support comprising spheroidal cellulose beads:
- (a) wherein each said bead has an integral outer skin apparently non-porous at 6,000.times. magnification;
- (b) said skin being impervious to nitrogen under the B.E.T. method of measuring surface area;
- (c) said beads swelling not more than 15% of their original volume when immersed in an aqueous solution;
- and
- (d) said beads being essentially non crystalline as determined by X-ray diffractometry.
A method for producing a film of reconstituted cellulose, said film having a surface skin manifesting no holes, cracks or voids at a magnification of 6,000.times., said film swelling no more than 15% of its original volume in aqueous solutions, said film being essentially non crystalline as determined by X-ray diffractometry, said method comprising the steps of:
- (a) extruding said viscose through a die into a concentrated alcoholic salt solution to coagulate said viscose, said viscose thereby attaining the configuration of said film;
- (b) immersing said film in an excess of a solution of a dehydrating salt in an organic solvent, said organic solvent selected from the group consisting of alcohols, glycols, and esters and ethers of glycols, said film now comprising coagulated cellulose xanthate with surface skin rendered non-sticky;
- (c) washing residual impurities from said coagulated cellulose xanthate film, thereby preserving said non-sticky skin and preventing holes or cracks in said skin by immersing said film in a highly concentrated aqueous solution of at least 25% salt by weight, wherein said salt is selected from the group consisting of chlorides of calcium and magnesium;
- bromides of lithium, manganese, and calcium;
- iodides of lithium, magnesium, and calcium;
- nitrates of lithium and calcium;
- thiocyanates of lithium, sodium, potassium, and calcium;
- formates of sodium and potassium;
- acetates of lithium, potassium, magnesium, and sodium;
- propionates of sodium and potassium;
- lactate of sodium;
- and salicylates of lithium, sodium, and calcium;
- (d) washing residual salt and water from said film with alcohol prior to acid/alcohol regeneration of cellulose;
- (e) regenerating cellulose by immersion of said film in approximately 5% to 25% by weight acid solution, wherein said alcohol is selected from the group of alcohols miscible with water in all proportions, wherein said acid is selected from the group consisting of carboxylic acids, organic sulfonic acids, and inorganic acids;
- (f) washing said film with water;
- and
- (g) air drying said film.
A method for producing a filament of reconstituted cellulose, said filament having a surface skin manifesting no holes, cracks or voids at a magnification of 6,000.times., said filament swelling no more than 15% of its original volume in aqueous solutions, said filament being essentially non crystalline as determined by X-ray diffractometry, said method comprising the steps of:
- (a) at a temperature of less than 30.degree. C., extruding said viscose through a spinerette into a concentrated alcoholic salt solution to coagulate said viscose, said viscose attaining the configuration of said filament;
- (b) immersing said filament in an excess of a dehydrating salt solution in an organic solvent, said organic solvent selected from the group consisting of alcohols, glycols, and esters and ethers of glycols, whereby said filament comprises coagulated cellulose xanthate, said surface skin being non-sticky;
- (c) washing impurities from said coagulated cellulose xanthate filament, thereby preserving said non-sticky skin and preventing holes or cracks in said skin by immersion in a highly concentrated aqueous solution of at least 25% by weight salt, wherein said salt is selected from the group consisting of chlorides of calcium and magnesium;
- bromides of lithium, magnesium, and calcium;
- iodides of lithium, magnesium, and calcium;
- thiocyanates of lithium, sodium, potassium, and calcium;
- formates of sodium and potassium;
- acetates of lithium, potassium, magnesium, and sodium;
- propionates of sodium and potassium;
- lactate of sodium;
- and salicylates of lithium and calcium;
- (d) washing residual salt and water from said filament with alcohol prior to acid/alcohol regeneration of said cellulose;
- (e) regeneration of cellulose by immersion of said filament in 5% to 25% by weight acid solution, wherein said alcohol is selected from the group of alcohols miscible with water in all proportions, wherein said acid is selected from the group consisting of carboxylic acids, organic sulfonic acids, and inorganic acids;
- (f) washing said filament with water;
- and
- (g) air drying said filament.
A three-dimensional article comprised of cellulose, said cellulose being reconstituted from viscose, said article having a skin demonstrating no cracks, holes or voids with magnification of 6,000.times., said article having a length greater than its width, said article swelling no more than 15% in aqueous solutions and said article is essentially non crystalline as determined by X-ray diffractometry.
A liquid chromatography support comprising spheroidal cellulose beads:
- (a) having an integral outer skin apparently nonporous at 25,000.times. magnification;
- (b) said beads being impervious to nitrogen under the B.E.T. method of measuring surface area;
- (c) said beads swelling not more than 15% of their original volume when immersed in an aqueous solution;
- and
- (d) said beads are essentially non crystalline as determined by X-ray diffractometry.
A method for producing an article of manufacture, formed from reconstituted cellulose, characterized in that it swells no more than 15% of its original volume in aqueous solutions of pH less than 13, and having a surface skin which reveals no holes or voids at 6,000.times. magnification, said article of manufacture is essentially non crystalline as determined by X-ray diffractometry, said method comprising the following steps:
- (a) at a temperature less than 30.degree. C., extruding viscose through a die into a concentrated alcoholic salt solution to coagulate said viscose thereby attaining the configuration of said article;
- (b) immersing said article in a solution of a dehydrating salt in an organic solvent, said organic solvent selected from the group consisting of alcohols, glycols, and esters and ethers of glycols, said article then comprises coagulated cellulose xanthate with surface skin rendered non-sticky;
- (c) washing residual impurities from said coagulated cellulose xanthate article, thereby preserving said non-sticky skin and preventing holes and cracks in said skin by immersing said article in a highly concentrated aqueous solution of at least 25% salt by weight, wherein said salt is selected from the group consisting of chlorides of calcium and magnesium;
- bromides of lithium, magnesium, and calcium;
- iodides of lithium, magnesium, and calcium;
- nitrates of lithium and calcium;
- thiocyanates of lithium, sodium, potassium, and calcium;
- formates of sodium and potassium;
- acetates of lithium, potassium, magnesium, and sodium;
- propionates of sodium and potassium;
- lactate of sodium;
- and salicylates of lithium, sodium, and calcium;
- (d) washing residual salt and water from said article with alcohol prior to acid/alcohol regeneration of cellulose;
- (e) regenerating cellulose by immersion of said article in approximately 5% to 25% by weight acid/alcohol solution, wherein said alcohol is selected from the group of alcohols miscible with water in all proportions, wherein said acid is selected from the group consisting of carboxylic acids, organic sulfonic acids, and inorganic acids;
- (f) washing said article with water;
- and
- (g) air drying said article.
A method for producing regenerated cellulose beads from viscose, said beads having skins without holes and cracks discernable under 6,000.times. magnification, said beads swelling no more than approximately 15% in aqueous solutions, said beads being essentially non crystalline as determined by X-ray diffractometry, said method comprising the steps of:
- (a) at a temperature less than 30.degree. C., forming an emulsion of viscose with at least one emulsifying agent and a liquid carrier, wherein said carrier is an organic solvent immiscible with water, to produce small, individual viscose droplets;
- (b) blending said viscose emulsion into a dehydrating solution of a salt in a hydrophilic organic solvent, said solvent selected from the group consisting of alcohols, glycols, and esters and ethers of glycols, to coagulate said droplets as beads;
- (c) washing impurities from said coagulated cellulose xanthate beads using an aqueous solution of no less than 25% concentration by weight of salt, said salt selected from the group consisting of chlorides of calcium and magnesium;
- bromides of lithium, magnesium, and calcium;
- iodides of lithium, magnesium, and calcium;
- nitrates of lithium and calcium;
- thiocyanates of lithium, sodium, potassium, and calcium;
- formates of sodium and potassium;
- acetates of lithium, potassium, magnesium, and sodium;
- propionates of sodium and potassium;
- lactate of sodium;
- and salicylates of lithium, sodium, and calcium;
- (d) washing residual aqueous salt from said beads with an alcohol selected from the group of alcohols miscible with water in all proportions;
- and
- (e) regenerating cellulose in said beads by immersing said beads in an acidified alcohol solution, wherein said alcohol solution comprising acids selected from the group consisting of carboxylic acids, organic sulfonic acids and inorganic acids.
Dependencies are inferred from the claim text.