TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The pressure in the reactive distillation column is ambient pressure to 20 bar, preferably 2-6 bar and the temperature in the reaction section is 100-220 degrees C, preferably 130-180 degrees C. The product stream containing the ester formed is subjected to a distillation step to remove unreacted first alcohol, which may be recycled to the distillation unit. The top stream product is subjected to a liquid-liquid phase separation by decantation, where the organic phase containing the first and the second alcohol is separated and recycled to the distillation unit and the water phase is separated and sent to waste water treatment or/and first alcohol recovery. The third supply stream enters the decanter of the reactive distillation column on level control. The outlet from the reactive distillation column is submitted to transesterification of glycerides to fatty acid esters in the presence of a solid base catalyst, at a pressure of 5-10 bar above the bubble point pressure of the reaction mixture at the reaction temperature. The transesterification of glycerides to fatty acid esters takes place in a multi-segment tubular reactor, where the length to diameter ratios is 100:1-1500:1, preferably 100:1-600:1. The reaction is carried out in at least two steps with intermediate removal of glycerol. The tubular reactor is placed in a fired furnace. Preferred Components: The carboxylic acid is a fatty acid, preferably a fatty acid comprising 10-18C fatty acids or its mixtures, and the first supply feed is a fatty acid rich feedstock, preferably a feedstock comprising 10-18C fatty acids and triglycerides of 10-18C fatty acids. The first alcohol is methanol, ethanol and/or propanols, preferably methanol and ethanol. The second alcohol is monoalkyl- alcohols with 4-10C, preferably 2-ethyl-hexanol. The fatty acids are present at 1-100 wt.% in a first supply stream, which comprises lipid material derived from waste fats, as frying and cooking fats and oils, edible and nonedible vegetable oils, animal fats, tall oil, and/or algae oil, including recycled fats and oils. The molar ratio of the first alcohol to the carboxylic acid supplied to the column is 1:1-10:1, preferably 1:1-2:1, where the molar ratio of the second alcohol to the carboxylic acid supplied to the column is 0.1:1-1:1, preferably 0.1:1-0.3:1. The reaction section comprises a solid acid catalyst, optionally in combination with a solid base catalyst, located below the solid acid catalyst. EXAMPLE - A bottom product from the reactive distillation section was mixed with first alcohol such that the molar ratio of alcohol/triglycerides was 3-30, preferably 9-12. The resulting mixture was submitted to pressure raise by the pump, which was 5-10 bar higher than the corresponding bubble pressure value. Then the resulting mixture entered the tubular reactor hosted in the furnace, where the mixture was brought to reaction temperature. The tubular reactor contained a solid base catalyst. The reaction temperature depended on the nature of the catalyst e.g. the solid base catalyst was a hydrotalcite. In this case, the reaction temperature was 150-250 degrees C, preferably 180-210 degrees C. The determination of the appropriate reaction temperature was within the scope of the skilled person. The outlet mixture was sent to the heat exchanger for temperature reduction in counter-current with the cold feed for the second reactor and worked up to give a glycerol phase. The liquid phase was cooled to a suitable temperature, typically around 40 degrees C, and worked up to give biodiesel.