(19)

(11)

EP 1 037 956 A1

(12)

(43) Date of publication: 27.09.2000 Bulletin 2000/39 (21) Application number: 98962018.2 (22) Date of filing: 09.12.1998

(51) International Patent Classification (IPC)7: C10G 45/64, C10G 47/16 (86) International application number: PCT/US9826/112 (87) International publication number: WO 9929/810 (17.06.1999 Gazette 1999/24)

(84) Designated Contracting States: DE ES FI FR GB GR IT NL PT (30) Priority: 10.12.1997 US 988287 (71) Applicant: CHEVRON U.S.A. INC. San Ramon, CA 94583-4289 (US)	(72) Inventors: ROSENBAUM, John, M. Richmond, CA 94806 (US) HOWELL, Robert, L. Hercules, CA 94547 (US) (74) Representative: Nash, David Allan et al Haseltine Lake & Co.,Imperial House, 15-19 Kingsway London WC2B 6UD London WC2B 6UD (GB)