Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
405 words
A process for the manufacture of an olefin polymer by polymerization of one or more α-monoolefins of 2 to 8 carbon atoms at from 60° to 160° C. and at an olefin pressure of from 0.5 to 40 bars, by means of a silicic acid xerogel/chromium trioxide catalyst which is obtained when 1. a finely divided silicic acid xerogel is first manufactured by (1.1) employing a silicic acid hydrogel containing from 10 to 25 percent by weight of solids (calculated as silicon dioxide), (1.2) extracting at least 60% of the water contained in the hydrogel from the latter by means of an organic liquid selected from the alkanols of 1 to 4 carbon atoms and the alkanones of 3 to 5 carbon atoms, (1.3) drying the resulting dehydrated get until there is no further loss in weight in the course of 30 minutes at 180° C. under 10 mm Hg and (1.4) reducing the resulting xerogel to particles having a diameter of from 20 to 2,000 μm, 2. this xerogel is then charged with chromium from a solution, of from 0.05 to 5 percent strength by weight, of chromium trioxide in an alkanone of 3 to 5 carbon atoms or from a solution, of from 0.05 to 15 percent strength by weight, of a chromium compound which under the conditions of stage (3) is converted to chromium trioxide, in an alkanol of 1 to 4 carbon atoms - the solvent in each case not containing more than 20 percent by weight of water - whilst evaporating the solvent, and 3. the resulting product is finally kept at from 400° to 1,100° C. for from 10 to 1,000 minutes in an anhydrous stream of gas containing oxygen in a concentration of more than 10 percent by volume, in which process a catalyst is employed which is manufactured under such conditions that in stage (1) the starting material is a silicic acid hydrogel (1.1) which is substantially spherical, has a particle diameter of from 1 to 8 mm and is obtained by A. introducing a solution of sodium waterglass or potassium waterglass both longitudinally and tangentially into a vortical stream of an aqueous inorganic acid, B. spraying droplets of the resulting silicic acid hydrosol into a gaseous medium, C. allowing the sprayed hydrosol to solidify to a hydrogel in the gaseous medium and D. freeing the resulting substantially spherical hydrogel from salts by washing, without prior aging.
Claim 2
Dependent Claim
405 words
A process for the manufacture of an olefin polymer by polymerization of one or more α-monoolefins of 2 to 8 carbon atoms at from 60° to 160° C. and at an olefin pressure of from 0.5 to 40 bars, by means of a silicic acid xerogel/chromium trioxide catalyst which is obtained when 1. a finely divided silicic acid xerogel is first manufactured by (1.1) employing a silicic acid hydrogel containing from 10 to 25 percent by weight of solids (calculated as silicon dioxide), (1.2) extracting at least 60% of the water contained in the hydrogel from the latter by means of an organic liquid selected from the alkanols of 1 to 4 carbon atoms and the alkanones of 3 to 5 carbon atoms, (1.3) drying the resulting dehydrated get until there is no further loss in weight in the course of 30 minutes at 180° C. under 10 mm Hg and (1.4) reducing the resulting xerogel to particles having a diameter of from 20 to 2,000 μm, 2. this xerogel is then charged with chromium from a solution, of from 0.05 to 5 percent strength by weight, of chromium trioxide in an alkanone of 3 to 5 carbon atoms or from a solution, of from 0.05 to 15 percent strength by weight, of a chromium compound which under the conditions of stage (3) is converted to chromium trioxide, in an alkanol of 1 to 4 carbon atoms - the solvent in each case not containing more than 20 percent by weight of water - whilst evaporating the solvent, and 3. the resulting product is finally kept at from 400° to 1,100° C. for from 10 to 1,000 minutes in an anhydrous stream of gas containing oxygen in a concentration of more than 10 percent by volume, in which process a catalyst is employed which is manufactured under such conditions that in stage (1) the starting material is a silicic acid hydrogel (1.1) which is substantially spherical, has a particle diameter of from 1 to 8 mm and is obtained by A. introducing a solution of sodium waterglass or potassium waterglass both longitudinally and tangentially into a vortical stream of an aqueous inorganic acid, B. spraying droplets of the resulting silicic acid hydrosol into a gaseous medium, C. allowing the sprayed hydrosol to solidify to a hydrogel in the gaseous medium and D. freeing the resulting substantially spherical hydrogel from salts by washing, without prior aging.
Claim 3
Dependent Claim
26 words
A process as claimed in claim 1 wherein the silicic acid hydrogel contains from 14 to 20 percent by weight of solids calculated as silicon dioxide.
Claim 4
Dependent Claim
21 words
A process as claimed in claim 1 wherein the silicic acid hydrogel has a particle diameter of 2 to 6 mm.
Claim 5
Dependent Claim
23 words
A process as claimed in claim 1 wherein at least 90% by weight of the water contained in the hydrogel is extracted therefrom.
Claim 6
Dependent Claim
18 words
A process as claimed in claim 1 wherein acetone is employed as the extracting material in step (1.2).
Claim 7
Dependent Claim
23 words
A process as claimed in claim 1 wherein the xerogel is reduced to particles having a diameter of from 40 to 300 μm.
Claim 8
Dependent Claim
30 words
A process as claimed in claim 1 wherein the solvent for the chromium trioxide or chromium compound in stage (2) contains not more than 5 percent by weight of water.