latter is the trademark of an ecological fuel produced from natural resources and used either alone or in combination with diesel fuel derived from petroleum in the compression ignition engines diesel engines from the chemical point of view biodiesel is a mixture of alkyl esters produced by means of the transesterification of vegetable oils such as soybean oil rape oil corn oil etc preferably rape oil by using either an acid or basic catalyst most of the alkyl esters are currently produced by a basic catalysis transesterification for example a vegetable oil is caused to react with an alkyl alcohol preferably methyl alcohol in the presence of a basic catalyst for example either sodium or potassium hydroxide preferably sodium hydroxide providing a mixture of alkyl esters glycerine and base the obtained mixture is then neutralized with a mineral acid for example hydrochloric acid sulphuric acid etc preferably hydrochloric acid and the alkyl esters biodiesel are separated from the remainder of the mixture the impure glycerine obtained as a secondary product is then added to the cement without further purification the raw glycerine being preferably obtained by the process described above is incorporated into the cement during the production process thereof it can be added either to the clinker during the conveyance thereof to the mill for the milling.