their preparationUS753774222 Dec 200326 May 2009Praxair Technology, Inc.multilayer adsorber beds, used for removing impurities including water, carbon dioxide, methane, carbon monoxide and nitrogen from a gas stream containing hydrogenUS76016638 Sep 200513 Oct 2009Sk Energy Co., Ltd.Solid acid catalyst for producing light olefins and process using the sameUS800775922 Mar 200630 Aug 2011Conopco In