Patent ID: 7629490

Claim:
Process for preparing cyclopropanecarboxylic acid comprising hydrolyzing methyl or ethyl cyclopropanecarboxylate in admixture with one or more alcohols, optionally, hydrochloric acid, wherein the concentration of the hydrochloric acid is from 4 to 20% in the aqueous phase, wherein a) the methyl or ethyl cyclopropanecarboxylate one or more alcohols, water, and, optionally, hydrochloric acid are fed, either separately or together, into an apparatus comprising a vessel connected to a 1st column provided with a condenser, where the alcohol or alcohols taken off via the top of the column wherein, step a) is carried out by one of the following variants: 1) the methyl or ethyl cyclopropanecarboxylate, one or more alcohols, water, and, optionally, hydrochloric acid are introduced either separately or together into the 1st column, or 2) the methyl or ethyl cyclopropanecarboxylate, one or more alcohols, water, and, optionally, hydrochloric acid are fed either separately or together into the vessel, or 3) the methyl or ethyl cyclopropanecarboxylate and, one or more alcohols are introduced into the 1st column and where the water and, optionally, hydrochloric acid are fed either separately or together into the vessel, b) the reaction mixture which goes either directly or in cases a) 1) and a) 3) either in its entirety or partly via the 1st column into the vessel is subsequently fed to a 2nd column provided with a condenser, wherein the cyclopropanecarboxylic acid is taken off from the bottom of the 2nd column while the remaining reaction mixture is recirculated to the vessel and, if no hydrochloric acid is used, at least one acidic solid being placed initially in the vessel.