Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymerizing in two or more physically distinct zones
Patent
1977-12-02
1979-03-27
Holler, Alan
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymerizing in two or more physically distinct zones
526 67, 526 68, 526 70, 526 77, 526 82, 526 87, 526159, 526173, 5263402, C08F 448, C08F 242, C08F 3608
Patent
active
041466934
ABSTRACT:
Improved continuous process for synthesis of cis-1,4 poly(isoprene). In the commercial process for synthesis of cis-1,4 poly(isoprene) only a portion of the monomer charged is polymerized. The polymer, thus obtained, is separated from the unreacted monomer which in turn is recycled with solvent back into the system for conversion to additional polymer. Fresh monomer must be added from a separate feed to this recycle stream in sufficient quantity to replace or "make-up" for that which was converted to polymer. In the improved process of this invention, this "make-up" isoprene monomer is dried and then is introduced into the process subsequent to the initiation of polymerization of the isoprene monomer already present within the system, but prior to deactivation of the polymerization catalyst. Dehydration of "make-up" isoprene prior to its introduction into the process stream at the above juncture avoids deactivation of the still active catalyst with water. The still active catalyst is thus free to react with other impurities, thereby either removing them from the "make-up" isoprene, or substantially reducing their concentration. This improved process permits the use of a "make-up" isoprene feed having substantially higher levels of impurities (e.g. .alpha.-acetylenes and cyclopentadiene) than could previously be tolerated by the coordination catalyst. Thus, this process permits substantial savings with respect to both catalyst consumption and greatly simplifies purification procedures in preparation of the isoprene feed stock by eliminating the need to add materials for neutralization of these catalyst deactivating impurities.
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Faro John H.
Holler Alan
The B. F. Goodrich Company
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