Utilization of vegetable oils as an alternative source for diesel-type fuel: hydrocracking on reduced Ni/SiO2 and sulphided Ni-Mo/γ-Al2O3

Synthesis, characterization and use of Nb2O5 based catalysts in producing biofuels by transesterification, esterification and pyrolysis

“…The results show that all solids are active for the methanolysis reaction (see entries [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Nonetheless, the most active catalyst using comparable conditions is the Nb 2 O 5 /H 3 PO 4 .…”

“…It was proposed that the decomposition of the glyceridic fragment of the triglyceride achieves carboxylic acids, acrolein and ketenes. 6,11,20,26 At the employed reaction conditions, these oxygenated compounds are further decomposed affording esters, carboxylic acid and hydrocarbons. Thus, the carboxylic acids are decarboxylated or decarbonylated, producing, respectively, carbon dioxide and paraffins or carbon monoxide, olefins and water.…”

“…Thus, the carboxylic acids are decarboxylated or decarbonylated, producing, respectively, carbon dioxide and paraffins or carbon monoxide, olefins and water. 20 It is also recognized that several side and consecutives reactions take place, such us cracking of C-C bonds, cyclization, dehydrogenation, aromatization and radical oligo-polymerization. 6 When the pyrolysis is carried out thermally, the characterization of the products indicated that the reaction affords a complex mixture containing high amounts of inconvenient oxygenated compounds, such as aldehydes and carboxylic acids.…”

“…19,22 On the other hand, it was also reported that the products of soybean and babassu oils pyrolysis catalyzed by γ-alumina doped with nickel and molybdenium were completely deoxygenated when the reaction was carried out in the presence of hydrogen pressure. 20 The production of mono-alcohol fatty acid esters by transesterification of vegetable oils with short chain monoalcohols, generating glycerin as a by product, is well studied and established using homogeneous Brønsted acids or alkali catalysts, like alkali metal hydroxides or alkoxides and sulfuric acid. 6,8 However, these catalytic systems have some technological problems, being the acid system associated with corrosion and the basic one with emulsification.…”

“…For example, it has been reported the production of hydrocarbons from Tung oil in China during the Second World War. 11 Since then, numerous studies about the thermal [12][13][14][15][16][17][18] and catalytic [19][20][21][22][23][24][25][26][27][28][29] pyrolysis of triglycerides and Vol. 20, No.…”