Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Patent
1975-11-13
1977-08-16
Holler, Alan
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
252451, 423327, 423329, C08F 402, C08F 424, C08F 1000
Patent
active
040427706
ABSTRACT:
This invention relates to a process for the manufacture of olefin polymers by polymerization of monoolefins with the aid of a silicic xerogel/chromium trioxide catalyst obtained by (1) synthesizing a particulate silicic xerogel, (2) doping this xerogel with chromium trioxide or a chromium compound which converts to chromium trioxide under conditions of stage (3) and (3) maintaining the resulting product at an elevated temperature in a water-free oxygen-containing stream of gas. The characteristic feature of the process of the invention is that the silicic xerogel/chromium trioxide catalyst used is one obtained by (1) synthesizing the silicic xerogel in the first stage as follows: (1.1) taking an aqueous solution of a sodium silicate, (1.2) substituting substantially all of the sodium ions contained in said solution by hydrogen ions by means of an ion exchanger, (1.3) introducing a water-soluble aluminum salt into the resulting aqueous silicic acid solution, (1.4) adjusting the pH of the solution obtained in stage (1.3) to from 0.1 to 3.5, if necessary, (1.5) adjusting the solution obtained in (1.3) or (1.4) to a pH of from 4 to 12 by means of a nitrogen-base compound, (1.6) extracting the product forming the solid phase in stage (1.5) (silicic hydrogel) by means of an alkanol and/or alkanone until the organic liquid absorbs no more water and, finally, (1.7) drying the dehydrated gel saturated with organic liquid resulting from stage (1.6) (xerogel formation). This process makes it possible to obtain polymers having a satisfactory particle size distribution and a favorable melt index.
REFERENCES:
patent: 3652216 (1972-03-01), Krekeler et al.
patent: 3900457 (1975-08-01), Witt
patent: 3960826 (1976-06-01), Aboutboul et al.
Bachl Robert
Frielingsdorf Hans
Gonsior Leonhard
Gruber Wolfgang
Mueller-Tamm Heinz
BASF - Aktiengesellschaft
Holler Alan
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