TECHNOLOGY FOCUS - BIOLOGY - Preferred Components: The bioethanol is obtained from the fermentation of at least one biomass deriving from agricultural cultivations, such as corn, sorghum, barley, beetroot and/or sugar cane; or is obtained from fermentation of at least one lignocellulosic biomass selected from a) products of crops expressly cultivated for energy use (such as, miscanthus, foxtail millet, switchgrass, common cane), including waste products, residues and scraps, of the crops or of their processing; b) products of agricultural cultivations, forestation and silviculture, comprising wood, plants, residues and waste products of agricultural processing, of forestation and of silviculture; c) waste of agro-food products destined for human feeding or zootechnics; d) residues, not treated chemically, of the paper industry; and/or waste products coming from the differentiated collection of solid urban waste (such as urban waste of a vegetable origin, paper).    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The composition (C1) comprises (vol.%) at least one gas oil (30-68), at least one diethyl carbonate (2-10), and at least one hydrotreated vegetable oil (HVO) (30-60). The composition comprises methyl esters of fatty acids (FAME) ( less than or equal to 10%, preferably less than or equal to 7%); and additives ( not greater than 0.3 vol.%) such as flow improvers, lubricity improvers, cetane improvers, antifoam agents, detergents, antioxidants, anti-corrosion agents, antistatic additives and dyes. Preferred Method: The diethyl carbonate is obtained by transesterification of at least one dialkyl carbonate or at least one cyclic carbonate with bioethanol in the presence of at least one catalyst; by reaction of urea with bioethanol in presence of at least one catalyst; or oxidative carbonylation of bioethanol with carbon monoxide and oxygen in the presence of at least one catalyst. EXAMPLE - A gas oil composition comprising a gas oil (45 vol.%) (having a density at 15 degrees C of 844 kg/m3, flash point of 69 degrees C and a cetane number of 52); a hydrotreated vegetable oil (having a density at 15 degrees C of 779 kg/m3, a flash point of 78 degrees C and a cetane number of 77); and a diethyl carbonate (purity of 99.5%, 4 vol.%) was prepared. The composition showed a density at 15 degrees C of 821 kg/m3, flash point of 55 degrees C; and a cetane number of 59.