Process for production of polytetramethylene-ether-glycol-diester using halloysite catalyst
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United States of America Patent
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Mar 27, 2001
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app pub date -
Jul 15, 1999
filing date -
Jan 17, 1997
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Abstract
An improved process for Polytetramethylene-Ether-Glycol-Diesters of the formula R--CO--O(CH.sub.2 --CH.sub.2 --CH.sub.2 --CH.sub.2 --O)n-COR.sup.1, in which R and R.sup.1 are identical or different and are alkyl radicals or derivatives thereof, by polymerization of tetrahydrofuran in the presence of a heterogeneous polymerization catalyst and in the presence of a carboxylic anhydride. The use of aluminum silicate catalyst composed of acid-activated and calcinated natural halloysite instead of the known catalytic silicates as bentonite, zeolite or kaolinite. The new catalyst with a very long lifetime produces polymers having more uniform properties and narrow molecular weight distribution even with a relative impure monomer.
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