Abstract:
Treatment of anion exchange materials containing hydroxyl containing moieties in the beta position relative to the quaternary center in the hydroxide form with glycidol substantially alters the selectivity of the anion exchange material. Furthermore, sequential treatments of first a hydroxide containing solution to put the anion exchange material in the hydroxide form followed by treatment with glycidol in an alternating sequence progressively changes selectivity in a predictable manner allowing facile manipulation of selectivity. Unique to the selectivities achievable with this chemistry is the ability to reverse the elution order of sulfate and carbonate. With all other known systems, carbonate elutes ahead of sulfate and sometimes compromises the ability to quantitate sulfate. With glycidol treatment, carbonate can be moved after sulfate which eliminates interference issues for samples containing significantly more carbonate than sulfate. This modification is useful for columns operated with a hydroxide or carbonate eluent system.
Abstract:
The present invention provides a technique which allows stable use of an ion-exchange resin for removing boron impurities over a long period of time in the purification step of a silane compound or a chlorosilane compound. In the present invention, a weakly basic ion-exchange resin used for the purification of a silane compound and a chlorosilane compound is cleaned with a gas containing hydrogen chloride. When this cleaning treatment is used for the initial activation of the weakly basic ion-exchange resin, a higher impurity-adsorbing capacity can be obtained. Further, use of the cleaning treatment for the regeneration of the weakly basic ion-exchange resin allows stable use of the ion-exchange resin for a long time. This allows reduction in the amount of the resin used in a long-term operation and reduction in the cost of used resin disposal.
Abstract:
The present invention provides a technique which allows stable use of an ion-exchange resin for removing boron impurities over a long period of time in the purification step of a silane compound or a chlorosilane compound. In the present invention, a weakly basic ion-exchange resin used for the purification of a silane compound and a chlorosilane compound is cleaned with a gas containing hydrogen chloride. When this cleaning treatment is used for the initial activation of the weakly basic ion-exchange resin, a higher impurity-adsorbing capacity can be obtained. Further, use of the cleaning treatment for the regeneration of the weakly basic ion-exchange resin allows stable use of the ion-exchange resin for a long time. This allows reduction in the amount of the resin used in a long-term operation and reduction in the cost of used resin disposal.
Abstract:
The present invention provides a technique which allows stable use of an ion-exchange resin for removing boron impurities over a long period of time in the purification step of a silane compound or a chlorosilane compound. In the present invention, a weakly basic ion-exchange resin used for the purification of a silane compound and a chlorosilane compound is cleaned with a gas containing hydrogen chloride. When this cleaning treatment is used for the initial activation of the weakly basic ion-exchange resin, a higher impurity-adsorbing capacity can be obtained. Further, use of the cleaning treatment for the regeneration of the weakly basic ion-exchange resin allows stable use of the ion-exchange resin for a long time. This allows reduction in the amount of the resin used in a long-term operation and reduction in the cost of used resin disposal.
Abstract:
A method for the removal of a substance carrying a negative charge and being present in an aqueous liquid (I). The method comprises the steps of: (i) contacting the liquid with a matrix carrying a plurality of ligands comprising a positively charged structure and a hydrophobic structure, and (ii) desorbing the substance. The characterizing feature is that (I) each of said ligands together with a spacer has the formula: -- SP---[Ar-R1-N+(R2R3R4)] where (A) [Ar-R1-N+(R2R3R4)] represents a ligand a) Ar is an aromatic ring, b) R1 is [(L)nR'1]m where n and m are integers selected amongst zero or 1; L is amino nitrogen, ether oxygen or thioether sulphur; R'1 is a linker selected among 1) hydrocarbon groups; 2) -C(=NH)-; c) R2-4 are selected among hydrogen and alkyls; (B) SP is a spacer providing a carbon or a heteroatom directly attached to Ar-R1-N+(R2R3R4); (C) --- represents that SP replaces a hydrogen in (Ar-R1-N+(R2R3R4); (D) -- represents binding to the matrix; and (II) desorption. There is also described (a) anion-exchangers having high breakthrough capacities, (b) a screening method and (c) a desalting protocol.
Abstract:
Cation exchange processes can be carried out by treating liquids containing ionic impurities with particles, optionally in emulsion in aqueous media, of cation exchange resin which comprise approximately spherical beads of crosslinked copolymer having diameters of 0.01 to 1.5 micrometers and bearing 0.7 to 1.5 cation exchange functional groups per monomer unit (see fig. 1). The particles may be removed from the treated liquid by flocculation. The particles or emulsions thereof may be made by emulsion polymerization followed by functionalization, in some cases after, in some cases at the same time as, and in some cases without, coagulation of the emulsion polymer to form coagulum particles of the copolymer beads which may, if necessary, be subsequently redispersed in liquids. Emulsions of the strong acid resins and particles of the weak acid resins in the free base form. both as such and in emulsions are also claimed.