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US 2003/0009038 A1Published application
Process for the preparation of 5-carboxyphthalide
AssigneeInfosint SA
InventorsLeone Dall'Asta, Umberto Casazza, Giovanni Cotticelli
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Abstract
There is described a process for the preparation of 5-carboxy phthalide, which comprises adding terephthalic acid to fuming sulfuric acid containing at least 20% of SO3, then adding formaldehyde to the mixture, heating the mixture at a temperature of 120-145° C. and isolating 5-carboxyphthalide from the reaction mixture.
Claims21
A process for the preparation of 5-carboxyphthalide of formula A
- 5
- which comprises adding formaldehyde and terephthalic acid of formula I
- 6
- to fuming sulfuric acid containing al least 20% of SO3, heating the mixture at 120-145° c and isolating the 5-carboxyphthalide thus obtained.
1 more element
Dependencies are inferred from the claim text.