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US 5,334,739 AGranted
Process an alpha monoclinic crystalline modification of 2,2',2"-nitrilo[triethyl-tris-(3,3',5,5'-tetra-tert-butyl-1,1'-biphenyl- 2,2'-diyl)phosphite]
AssigneeCiba-Geigy Corporation
InventorsStephen D. Pastor, Sai P. Shum, Paul A. Odorisio
Life of this patent
Estimating the term…
Abstract
The alpha crystalline modification of 2,2',2"-nitrilo[triethyl-tris-(3,3',5,5'-tetra-tert-butyl-1,1'-biphenyl-2, 2'-diyl) O"phosphite] is obtained by crystallizing said compound from selected solvents, preferably from a mixture of an aromatic hydrocarbon solvent and a lower alkanol. The alpha crystalline form is an effective process stabilizer for polyolefins, particularly polypropylene.
Claims5
A process for the preparation of the alpha, monoclinic crystalline form of the compound 2,2',2"-nitrilo[triethyl-tris-(3,3',5,5'-tetra-tert-butyl-1,1'-biphenyl-2, 2'-diyl) phosphite]which comprises
- crystallizing or recrystallizing said compound from a mixture of benzene, toluene, o-xylene, m-xylene, p-xylene, 1,2,3-trimethylbenzene, 1,3,5-trimethylbenzene, 1,2,4-trimethylbenzene, 1,2,4,5-tetramethylbenzene, ethylbenzene, cumene, o-cymene, m-cymene, p-cymene, o-diisopropylbenzene or m-diisopropylbenzene and an alkanol of 1 to 3 carbon atoms;
- from methyl formate, ethyl formate, methyl acetate, ethyl acetate, n-butyl acetate, isobutyl acetate or amyl acetate;
- from diethyl ether, diisopropyl ether or methyl tert-butyl ether;
- or
- from a mixture of methylene chloride, chloroform, 1,2-dichloroethane or 1,1,2,2-tetrachloroethane and an alkanol of 1 to 3 carbon atoms.
2 more elements
Dependencies are inferred from the claim text.