Catalytic hydrogenation of fatty acid methyl esters

Catalytic conversions in green aqueous media. Part 8: Partial and full hydrogenation of renewable methyl esters of vegetable oils

“…Indeed, the two bis-allylic positions in ␣-MLN (at C-11 and C-14) and one bis-allylic position in ML (at C-11) are more prone to auto-oxidation compared with simple-allylic positions. Partial hydrogenations of FAME to C18:1 esters avoid deterioration in low-temperature behaviour of biodiesel fuel such as on its pour point because [40,46,64]. Furthermore, partial hydrogenation reactions of biodiesel combat its NO x -effect: the increase of NO x emissions observed in most studies of biodiesel fuel.…”

“…Wadumesthrige et al [63] applied heterogeneous Pd/C catalysts in the hydrogenation of FAME and the obtained product mixture exhibited a higher oxidative stability and a higher cetane number with however poorer cold flow properties. Pozdeev et al [64] partially hydrogenated FAME of sunflower oil employing heterogeneous Pd/Al 2 O 3 catalytic systems and could improve the properties of the biodiesel fuel. Sonmez et al [65] partially hydrogenated sunflower oil using heterogeneous Pd/Rhbased scrap automobile catalyst to obtain high yield in trans-C18:1, elaidic acid.…”

“…However, problems associated with the use of 1st generation biodiesel remain inter alia its low oxidative stability and low-temperature behaviour as well as its higher NO x emissions [38][39][40][41][42][43][44][45][46][47][48][49][50][51][52]. Partial hydrogenation reactions of polyunsaturated FAME of vegetable oils to yield their monounsaturated (C18:1) counterparts [15,16,[53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][122][123][124][125][126][127][128][129][130][131] without increasing the content of the saturated part, i.e. methyl stearate (MS, Scheme 1) are useful reactions for upgrading 1st generation biodiesel [15,…”

“…Furthermore, such catalytic processes possess a great potential to produce 2nd generation biodiesel from highly unsaturated FAME of alternative, non-edible oil feedstocks which are originally not suitable for biodiesel production or give poor quality biodiesel but combine the advantage that they would not affect food production and the lignocellulosic biomass of such crops could be used as a solid biofuel and would lower the cost of both biofuel products [15,16,24]. Catalytic full hydrogenation reactions of polyunsaturated methyl esters of vegetable oils to methyl stearate are industrially interesting conversions for the production of surfactants and solid soaps [64,72,134,135] as well as for studying the full hydrogenation reaction of the corresponding edible oils to saturated fats which are further subjected to interesterification reactions with liquid vegetable oils to yield shortenings, margarines and other foodstuffs containing zero amounts of trans-fats 134,135]. In recent years, trans-fats have raised serious health concerns from reports that they are considered to be strongly correlated with a higher concentration of plasma LDL-cholesterol and consumption of trans-fats provides no apparent nutritional benefit and possesses a considerable potential for harm [73][74][75][76][77][78][79][80].…”

“…Catalytic partial hydrogenation processes of polyunsaturated methyl esters of vegetable oils into their monounsaturated C18:1 counterparts (Scheme 1) [15,16,[53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][122][123][124][125][126][127][128][129][130][131] are of great interest in the fields of production of high quality 1st generation biodiesel fuel [15,16,[53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69]…”