Ultrasound assisted selective catalytic transfer hydrogenation of soybean oil using 5% Pd/C as catalyst under ambient conditions in water

Abstract

Catalytic transfer hydrogenation (CTH) is an alternative approach that does not require the use of potentially dangerous hydrogen gas. Pd/C is the most favoured catalyst for the selective hydrogenation of soybean oil yielding lower extent of formation of stearic acid and trans-isomer, which have adverse health effects. The present work deals with intensification of catalytic transfer hydrogenation of soybean oil in the presence of 5wt.% Pd/C using ultrasound under ambient reaction conditions. The effect of important operating parameters such as ultrasound power, temperature, type of hydrogen donor, catalyst loading and donor concentration on the progress of reaction has been investigated. It was established that the maximum extent of hydrogenation as indicated by reduction in iodine value from 135 to 95 was observed under optimized conditions of irradiation power as 100W, 22kHz frequency, 90% duty cycle, ammonium formate concentration of 0.32mol/50ml water and 2% (w/w) Pd/C loading at ambient temperature and pressure in the presence of water as solvent. The approach also offered excellent selectivity with much lower trans-isomer formation as compared to the conventional approach of high pressure hydrogenation. Overall, the work has successfully demonstrated process intensification benefits due to the use of ultrasound for the Pd/C catalyzed transfer hydrogenation of soybean oil.

Catalytic Transfer Hydrogenation of Low-erucic-acid Rapeseed Oil over a Ni-Ag_0.15/SBA15 Catalyst

“…When the formate ion concentration is increased to 0.40 mol/50 mL, the final iodine value obtained at the end of the reaction is only marginally different from the formate ion concentration of 0.32 mol/50 mL 26 .…”

Ni-Ag Bimetallic Magnetic Catalyst Improves the Performance of the Catalytic Transfer Hydrogenated Soybean Oil

“…Use of 0.16 mol/50 mL H 2 O and 0.24 mol/50 mL H 2 O of ammonium formate resulted in a much slower reaction rate. An increase in the donor quantity to 0.32 mol/50 mL water resulted in the best results , but a further increase to 0.40 mol/50 mL water showed only a marginal difference in the final iodine values that were obtained at the end of the reaction 27 . When the concentration of ammonium formate is 0.40 mol/50 mL H 2 O, the final iodine value is 101 g I 2 /100g.…”

Microwave‐assisted catalytic transfer hydrogenation of fatty acid methyl esters using metal‐doped nickel‐boride ‐ cetyltrimethylammonium bromide amorphous alloy catalyst

“…These results could be attributed to that water offered a medium in the reaction to form the aqueous solution film of isopropyl alcohol on the surface of Ni-Cr-B-CTAB catalyst. 9 Thus, the hydrogen donor of isopropyl alcohol could have good contact with the catalyst and the reactant of FAMEs. However, the large dosage of water used in the CTH could lead to the increase of the thickness of the aqueous solution film, inhibiting the approach of FAME with the catalyst surface and affecting the hydrogenation of FAME.…”

“…Therefore, CTH can be implemented at mild reaction conditions with simple facilities and has great potential in the production of value-added hydrogenated products in recent years. 9 Mei et al 10 found that the oxidation stability and cetane number of the soybean methyl ester were improved significantly via CTH reaction using isopropanol as the hydrogen donor and Raney-Ni as the catalyst. Amin et al 11 reported the CTH of castor oil with glycerol and limonene as hydrogen donors in the presence of Pd/C catalyst at the reaction temperature of 178 C, and the results suggested that the melting point of hydrogenated castor oil increased.…”