\u3cp\u3eThe invention pertains to a process for preparing acrylic acid and/or the ester of acrylic acid and lactic acid from a lactic acid oligomer or polymer, comprising the steps of - bringing a reaction mixture comprising the lactic acid oligomer or polymer to reaction conditions to form acrylic acid and/or the ester of acrylic acid and lactic acid, the reacting mixture comprising a halide source selected from a bromide source and/or a chloride source and optionally an acid selected from the group of acids with a pKa of at most 2.0 and compounds which under reaction conditions decompose under the formation of an acid with a pKa of at most 2.0, with the reaction mixture comprising less than 1 wt. % of water, and - keeping the reaction mixture under reaction conditions for a time sufficient to produce acrylic acid and/or the ester of acrylic acid and lactic acid. It has been found that the use of a bromide source and/or a chloride source in combination with the specified acid results in a process which can be operated to obtain a high yield, and is relatively easy to perform.\u3c/p\u3
