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US 4,151,201 AGranted
Process for preparing 2-hydroxybenzoic aldehydes
AssigneeMontedison S.p.A.
InventorsGiuseppe Casnati, Giovanni Casiraghi, Giuseppe Puglia, Giovanni Sartori, Giuliana Terenghi
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Abstract
There is disclosed a catalytic process for preparing, from phenols and formaldehyde 2-hydroxybenzoic aldehydes some of which are new in the art and, more particularly, a high-selectivity process for preparing the aldehydes by direct synthesis from phenols having at least a free ortho position and formaldehyde, in the presence of a catalyst consisting of anhydrous stannous and/or stannic chloride and of an aprotic binder.
Claims8
Process for preparing 2-hydroxy-benzoic aldehydes having the general formula (I):
- ##STR3## wherein R, R.sup.1, R.sup.2 and R.sup.3, which can be the same or different, represent hydrogen atoms;
- alkyl, aryl, cycloalkyl, alkoxyl, hydroxyl, or acylamino groups, or halogen;
- characterized in that a phenol of general formula (II) ##STR4## wherein R, R.sup.1, R.sup.2 and R.sup.3 have the same meaning as in general formula (I), is condensed with formaldehyde at temperatures of from about 90.degree. to 150.degree. C., in a substantially stoichiometric molar ratio between phenol (II) and formaldehyde, in the presence of anhydrous stannous and/or stannic chloride, in ratios comprised between about 0.02 and 0.2 mole expressed as Sn for one mole of phenol (II), and of a binder selected from the group consisting of pyridine, alkylpyridines, acetylpyridines, hexamethylphosphotriamide, tetramethylethylenediamine, tetramethylpropylenediamine, quinolines, quinoxalines, anilines, substituted anilines and tertiary amines, in an aprotic solvent.
Dependencies are inferred from the claim text.