| 摘要 |
1483246 Hydration catalysts NATIONAL DISTILLERS & CHEMICAL CORP 17 Dec 1974 [17 Dec 1973] 54427/74 Heading B1E [Also in Divisions C1 and C2] A silica xerogel, which is impregnated with phosphuric acid and utilised as a catalyst in the hydration of olefins e.g. ethylene, propylene or butylene by contacting the olefine and water vapour with catalyst, has the properties. Particle size: -3 + 20 mesh, Bulk density: 0.38 to 0.48 g/cc, Total Pore Volume: 0.80 to 1.3 ml/g with from 19-100 percent of the pores being micropores (diameter #600Š) B.E.T. Surface Area: 20-500 M<SP>2</SP>/g Dry Brush Strength: 4.4-15 lbs (averaged over 50 particles) Chemical Composition: 99 percent SiO 2 , 0.01-0.03 percent Fe 2 O 3 , 0.02-0.09 percent Na 2 O, <0.4 percent Al 2 O 3 (on a dry weight basis). The gel is prepared by steaming a silica xerogel starting material with water vapour at a total pressure of 40-1500 psi in which the partial pressure of water vapour is 40-225 psi at a temperature of at least 135‹C and below 200‹C, the starting xerogel material having the properties of particle size to pass through 3 mesh and be retained on 20 mesh, having a bulk density of from 0.38 to 0.48 g/cc, a total pore volume of from 0.80 to 2.2 ml/g with over 95% of the pores being micropores having an average pore diameter in the range of 100 to 200Š, a BET surface area of from 200 to 500 m<SP>2</SP>/g, and a dry crush strength averaged over 50 particles of from 2.2 to 5 pounds and containing on a dry weight basis over 99% SiO 2 , from 0.01 to 0.03% Fe 2 O 3 , from 0.02 to 0.09% Na 2 O and less than 0.4% Al 2 O 3 . The treated silica gel may then be impregnated with phosphoric acid e.g. aqueous acid of 40-70 percent by weight concentration. Ethylene may be present during the steaming. |
