TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Conditions: The isomerization conditions comprise a temperature of 40-250 degreesC, a pressure of 110 kPa - 10 MPa, a liquid hourly space velocity of 0.5-5 liquid volumes of catalyst, and a mole ratio of hydrogen to isomerizable hydrocarbon feed of 0.01 - 5.The temperature is 40-160 degreesC.The mole ratio of hydrogen to hydrocarbons in the process reactor effluent is less than 0.05 - 1.0.The eta:gamma ratio of the alumina support is at least 9:1. EXAMPLE - Catalysts were prepared from a bayerite alumina source La Roche Versal B alumina (2000 g) was placed in a muller. The muller was started and nitric acid (70.7%, 103.2 g) and deionized water (268 g) added over a 5-minute period,followed by mixing for 20 minutes. Methocel (TM) (33.15 g) was added and mulling continued for 10 minutes and then extruded to produce cylindrical extrudates which were dried for 2 hours at 100 degreesC, heated to 260 degreesC in 10% moisture, and finally calcined at 575 degreesC in 5 mole% moisture for 30 minutes.    The extrudates were washed with 1 mass% ammonium nitrate to achieve a sodium level of 100 ppm, dried for 2 hours at 100 degreesC, heated to 205 degreesC, and calcined at 325 degreesC. The washed extrudates were then impregnated in a solution of 3.5 mass% nitric acid in a volume ratio of 9 parts solution to 10 parts base to obtain peptized base material having a platinum to base ratio of about 0.9. The resulting mixture was cold-rolled for about 1 hour and evaporated until dry. The composites were then oxidized at 475 degreesC for 2 hours and reduced in electrolytic hydrogen at 500 degreesC for about 2 hours, and found to contains approximately 0.25 mass% Pt and 1 mass% chloride. The chloride content was adjusted by contact with anhydrous HCl. Impregnation of active chloride to 6-8 mass % was accomplished by sublimating aluminum chloride with hydrogen and contacting for about 25 minutes at 470 degreesC followed by treatment with anhydrous HCl at 260 degreesC.    The catalysts prepared were designated A, C and E which contained Pt% level of 0.275 (6.7), 0.27 (6.92) and 0.263 (5.93) respectively. The values in parenthesis indicate the Cl% level for each of the catalysts.    The catalysts differ in methylcellulose addition (A: 2.5 mass%; C: 0 mass%; and E: 5 mass%. The base calcinations temperature for A, C and E were 575, 600 and 650 degreesC.    The catalysts were tested for relative performance in isomerization. The same feedstock was used for each of the catalyst tests, and was a blend of C5 and C6 hydrocarbons having the composition (mass%): n-pentane: 43; n-hexane: 47; methylcyclopentane +cyclohexane: 8 and n-heptane: 2.    The results were expressed as % of isopentane to total pentanes (iC5/C5) and 2,2-dimethylbutane to total hexanes 2,2-DMB) in the product. The percentages are sensitive tests of catalyst performance than octane number measurements.    For catalysts A, C and E the iC5/C5 were 56.83, 53.53 and 50.95 respectively.    For catalysts A, C and E the 2,2-DMB were 13.53, 12.46 respectively.