Preparation of macrocyclic polyetherimide oligomers from substituted bisphthalimides
AssigneeGeneral Electric Company
InventorDaniel J. Brunelle
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Abstract
Macrocyclic polyetherimide oligomer compositions are prepared by the reaction of an alkali metal salt of a dihydroxyaromatic compound, preferably of bisphenol A, with a substituted bis-phthalimide, typically a chloro-, fluoro- or nitro-substituted o- or m-phenylene bis-phthalimide. The reaction takes place in a substantially non-polar solvent such as o-dichlorobenzene and at temperatures in the range of about 180.degree.-225.degree. C. in the presence of a phase transfer catalyst which is stable at such temperatures, such as a guanidinium salt. The concentration of phase transfer catalyst is such as to maintain the alkali metal salt at high dilution in the solvent, and the substituted bis-phthalimide is preferably also maintained at high dilution by portionwise addition.
Claims15
A method for preparing a composition comprising macrocyclic polyetherimide oligomers which comprises gradually introducing, at a temperature in the range of about 180.degree.-225.degree. C., at least one substituted bis-phthalimide of the formula ##STR5## wherein R.sup.1 is a C.sub.6-20 divalent aromatic hydrocarbon or halogenated hydrocarbon radical, a C.sub.2-20 alkylene or cycloalkylene radical, a C.sub.2-8 bis(alkylene-terminated) polydiorganosiloxane radical or a divalent radical of the formula ##STR6## in which Q is --C.sub.2 H.sub.4 --,--O--, ##STR7## X.sup.1 is fluoro, chloro, bromo or nitro and m is 0 or 1, into a mixture of a solvent of low polarity and at least one alkali metal salt of a dihydroxy-substituted aromatic hydrocarbon in the presence of a phase transfer catalyst which is substantially stable at the temperatures employed;
- the molar ratio of said alkali metal salt to said substituted bis-phthalimide being in the range of about 1.05-1.1:1 and the proportion of said phase transfer catalyst being in the range of about 2-8 mole percent based on said alkali metal salt;
- and recovering said macrocyclic polyimide oligomers from said composition.
Dependencies are inferred from the claim text.