(19)

(11)

EP 0 871 536 A1

(12)

(43) Date of publication: 21.10.1998 Bulletin 1998/43 (21) Application number: 96924419.0 (22) Date of filing: 10.07.1996

(51) International Patent Classification (IPC):  B01J 35/ 00( . ) F01N 3/ 28( . ) B01J 35/ 04( . ) F01N 7/ 04( . ) (86) International application number: PCT/US1996/011514 (87) International publication number: WO 1997/002884 (30.01.1997 Gazette 1997/06)

(84) Designated Contracting States: AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE Designated Extension States: AL LT LV SI (30) Priority: 12.07.1995 US 19950501755 12.07.1995 US 19950501333 22.12.1995 US 19950577619 22.12.1995 US 19950580101 (71) Applicant: Engelhard Corporation Iselin, NJ 08830-0770 (US)	(72) Inventors: SHELLER, David, Thomas Garrettsville, OH 44231 (US) WHITTENBERGER, William, A. Leavittsburg, OH 44430 (US) KUBSH, Joseph, E. Silver Spring, MD 20901 (US) (74) Representative: Fisher, Adrian John  CARPMAELS & RANSFORD 43 Bloomsbury Square London WC1A 2RA London WC1A 2RA (GB)