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US 6,204,394 B1Granted
Method for preparing oxy-diphthalic anhydrides
AssigneeManac Inc.
InventorsJunichi Sakata, Shinsuke Inoue, Shinichi Kadono
Life of this patent
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Abstract
Disclosed is a method for preparing oxy-diphthalic anhydrides, which comprises reacting a halo-phthalic anhydride represented by the formula (1): where Hal represents F, Cl, Br or I, with a carbonate salt selected from the group consisting of lithium carbonate, sodium carbonate, magnesium carbonate and calcium carbonate in a solvent to prepare oxy-diphthalic anhydrides represented by the formula (2):
Claims9
A method for preparing oxy-diphthalic anhydrides, which comprises reacting a halo-phthalic anhydride represented by the formula (1):
- where Hal represents F, Cl, Br or I, with a carbonate salt selected from the group consisting of lithium carbonate, sodium carbonate, magnesium carbonate and calcium carbonate in a solvent, in the presence of a phosphonium or sulfonium salt which acts as a phase transfer catalyst, and in the presence of an alkali-metal iodide or fluoride which acts as a co-catalyst, to prepare oxy-diphthalic anhydrides represented by the formula (2):
Dependencies are inferred from the claim text.