Inclusion resins of cyclodextrin and methods of use

Abstract

Abstract Congo red is removed from an aqueous solution thereof by immersing in the solution an inclusion resin made by cross-linking cyclodextrin with epichlorohydrin. The congo red is absorbed on the resin.ALSO:A water-insoluble inclusion resin, having the property of forming inclusion complexes with organic and inorganic substances, is based on cyclodextrin. The resin may be made by cross-linking alpha-, beta- or gamma-cyclodextrins with e.g. epichlorohydrin, dichlorohydrin, diepoxybutane, diepoxy-propyl ether, ethylene glycol diepoxy-propyl ether or formaldehyde, or by embedding the cyclodextrin in a water-insoluble polymer such as polyamide, polyvinyl acetal, epoxy resin, nitrocellulose, acetyl cellulose, ethyl cellulose, polyacrylamide, polymethacrylamide, polyacrylate or polymethacrylate. Cross-linking may be effected in acid or alkaline, aqueous or non-aqueous media depending upon the reagents and the properties desired in the product, and may be carried out under an inert gas. Embedding the cyclodextrin may be carried out by dispersing it in a solution of polymer, and then removing the solvent, or by polymerizing a monomer containing dispersed cyclodextrin. The inclusion resin may be subjected to further modification. For example, the resin may be oxidized, with conversion of secondary hydroxyl groups to aldehyde groups, and the oxidized resin then treated with hydroxylamine to form oxime-type products, or reduced by sodium borohydride or lithium aluminium hydride, or further oxidized to form carboxyl groups. In examples (1) cyclodextrin is cross-linked by epichlorohydrin; (2) cyclodextrin is cross-linked by formaldehyde; (3) a dispersion of cyclodextrin in an acetone solution of acetyl cellulose is evaporated. In further examples, the inclusion resins are used to remove Congo red, o-nitrophenol, and benzaldehyde from aqueous solutions thereof, and to separate mixtures of inorganic and organic compounds. Example 11 relates to the oxidation ofcyclodextrin cross-linked by epichlorohydrin by periodate to form a dialdehyde derivative.ALSO:An inclusion resin made by cross-linking cyclodextrin with epichlorohydrin is used to separate (1) o-nitrophenol and p-nitrophenol; (2) phenylalanine and tryptophane; (3) p-nitrophenol, or o-nitrophenol or benzaldehyde from aqueous solutions thereof. Mixtures (1) and (2) are eluted from a column of the inclusion resin, one component being preferentially absorbed, while the organic compounds (3) are absorbed on powdered resin immersed in the aqueous solutions.

Inventors

• 👤 Jurg Solms

Bibliographic Details