Abstract: The invention relates to a mixture of glycerol, mono-, di- and triacetylglycerolester in which the amount of tri-ester is less than 15 mol %, the amount of glycerol is less than 25 mol %, the amount of monoester is about 20 mol % or more, more preferred about 30 mol % or more and the amount of diester is about 20 mol % or more preferred about 40 mol % or more. The invention further relates to methods to prepare such glycerolacetylester mixtures, and to the use thereof in the preparation of unsaturated polyesters. Polyesters comprising said glycerolacetylester mixtures are made from a higher amount of raw materials than obtainable from renewable resources.