Around the 1930s and 1940s, Arthur Imhausen developed and implemented an industrial process in Germany for producing edible fats by oxidizing synthetic paraffin wax made from coal. The products were fractionally distilled and the edible fats were obtained from the - fraction which were reacted with glycerol such as that synthesized from propylene. Margarine made from them was found to be nutritious and of agreeable taste, and it was incorporated into diets contributing as much as 700 calories per day. The process required at least 60 kg of coal per kg of synthetic butter. That industrial process was discontinued after WWII due to its inefficiency.