Union Carbide Corporation

Desh R Garg

Moez M Nagji

Joseph P Ausikaitis

Brent M Lok

John D Sherman

Chien C Chao

Henry Rastelli

Ronald J Ross

James S Ritscher

William C Miller

Craig H Barkhausen

Carl J Kjellson

In the process for removing organic impurity constituents from aqueous media by adsorbing same on an organophilic molecular sieve adsorbent, followed by regeneration of the adsorbent by contact with an oxidant, such as hydrogen peroxide, whereby the organic adsorbate is converted to innocuous materials, principally CO.sub.2 and H.sub.2 O, the efficiency of the regeneration operation is found to be substantially improved by decreasing the pH of the regenerating medium and/or increasing the number of Bronsted acid sites in the molecular sieve adsorbent.

Process for aqueous stream purification

Carbon dioxide is selectively adsorbed and separated from non-acidic gases such as nitrogen, hydrogen and methane using a pressure swing adsorption process in a fixed adsorption bed containing a faujasite type of zeolitic aluminosilicate containing at least 20 equivalent percent of at least one cation species selected from the group consisting of zinc, rare earth, hydrogen and ammonium and containing not more than 80 equivalent percent of alkali metal or alkaline earth metal cations.

Selective adsorption of CO.sub.2 on zeolites

In the process for preparing methyl tert.-alkyl ether comprising the steps of (a) contacting and reacting in the liquid phase a reaction mixture formed by combining a stream consisting essentially of C.sub.4 -C.sub.5 hydrocarbons and containing at least some proportion of isoalkylene and a stoichiometric excess of methanol, with respect to the isoalkylene, to form a reaction product comprising methyl tert.-alkyl ether, unreacted methanol and unreacted C.sub.4 -C.sub.5 hydrocarbons; (b) isolating the methyl tert.-alkyl ether from the reaction product; and (c) recovering the unreacted methanol from the residual portion of the reaction product; the improvement which comprises selectively adsorbing the methanol constituent of said residual reaction product in a bed of crystalline molecular sieve adsorbent and recovering same by desorption using as a purge-desorption stream, the C.sub.4 -C.sub.5 hydrocarbon stream used to prepare the initial reaction mixture.

Process for preparing ethers

A process for the removal of water and other polar compounds from an acidic stream containing water and at least one acid compound comprising contacting the acidic stream with an adsorbent comprising a chabazite-type zeolite wherein said adsorbent has a M.sub.2 O/Al.sub.2 O.sub.3 mole oxide ratio of at least 0.5 where 'M' is at least one cation selected from the group consisting of potassium, rubidium and cesium.

Drying process using chabazite-type adsorbents

Toxic or otherwise contaminating organic impurity constituents in aqueous media such as waste water streams from industrial processes or potable water supplies are removed and converted to harmless oxidation products by contacting such media with an organophilic molecular sieve whereby the organic species are concentrated as adsorbates, and thereafter contacting the adsorbate-loaded molecular sieve with an aqueous solution of a compound which has a standard oxidation potential of at least 0.25 volt in an amount and for a sufficient time to convert the organic materials to non-toxic products such as CO.sub.2.

Process for removing toxic organic materials from weak aqueous solutions

An efficient fixed-bed vapor-phase adsorption cycle for bulk separations wherein the heat front generated by the exothermic heat of adsorption is maintained in the bed either in or behind the mass transfer zone, and is subsequently used in the desorption/regeneration step. The cycle is especially useful in drying mixtures of water and compounds which form azeotropes with water as well as the azeotropes themselves, such as 190-proof ethanol.

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Hopewell Junction, NY, United States of America

Desh R Garg