Abstract: The present invention pertains to a process for separating monochloroacetic acid and dichloroacetic acid from one another via extractive distillation using (a) an extractive agent that is chemically stable and has a BF3 affinity of between 65 kJ/mole and 110 kJ/mole and (b) an organic solvent that is either an acid with a lowest pKa of between 3.0 and 6.

Abstract: The invention relates to a process for preparing monochloroacetic acid (MCA) comprising a chlorination step and a hydrogenation step and is characterized in that said process comprises the removal of aldehydes from a process stream by peroxidation using a peroxycarboxylic acid. A preferred peroxycarboxylic acid comprises peracetic acid. Preferably, the process is carried out at a temperature of 60-100° C., most preferably at atmospheric pressure. Preferably, an about equimolar amount of peroxycarboxylic acid is used relative to the molar amount of aldehydes present in the process stream. A practical choice for the process stream is the acetic acid recycle stream. The invention process provides a clear and colourless MCA end product.