Patent ID: 7402708

Claim:
A method for producing an aqueous ortho-phthalaldehyde solution which comprises the steps of: (a) forming a precursor solution by introducing an acetal of the o-phthalaldehyde into water, (b) acidifying the precursor solution to a pH <7 by adding an acid to the precursor solution, (c) forming an aqueous ortho-phthalaldehyde solution consisting of ortho-phthalaldehyde, water and the eliminated corresponding alcohol by bringing the acidified precursor solution obtained according to step (b) to a temperature between 10° C. and 90° C. to thereby convert the acetal into o-phthalaldehyde by eliminating the corresponding alcohol, and (d) retaining the corresponding alcohol eliminated according to step (c) in the aqueous ortho-phthalaldehyde solution so as to aid in the dissolution of the converted o-phthalaldehyde therein.