New biodiesel additives from glycerol and isoamylenes

Abstract

The etherifi cation of glycerol and isoamylenes was performed using several macromolecular ion-exchange resins in order to fi nd the best catalyst which would provide the maximum conversion of glycerol and higher selectivities to ethers. Some different organic solvents (tert-amyl alcohol, 1,4-dioxane, acetonitrile, n-hexane, dichloromethane, diisopropylamine and dimethylformamide) were used in the etherifi cation of glycerol. Reactions were carried out in a batch autoclave reactor at 1.5 MPa in the temperature range from 25 to 100 °C for 24 h of contact time. It was found that resins with a greater pore volume and greater pore diameter showed a better performance in solventless reactions, but when employing solvents their polarity was responsible for the distinct results obtained in the conversion of glycerol: relative abundance and composition of the polar and non-polar phases in the fi nal reaction mixture. The solubilization of glycerol and isoamylenes in the reaction mixture seems to be the main factor in the progress of the reaction, which is refl ected in the different amount of ethers primarily obtained in the non-polar phase. tert-Amyl alcohol showed the best results in terms of conversion of glycerol due to the total miscibility of both reactants but it must be employed at temperatures below 50 °C in order to avoid its dehydration reaction that reduces the catalyst activity.

Glycerol Isopropyl Ethers: Direct Synthesis from Alcohols and Synthesis by the Reduction of Solketal

“…For exam-ple, conversions over 2% Pd/BEA-25 and 2% Pd/Al-HMS(20) at 120 8Cw ere 64 and 60 %, respectively,a lthought he acidity of Al-HMS is lower by af actor of 5.5 (858 mmol g À1 in BEA-25 against 157 mmol g À1 in Al-HMS (20)). At the same time, the yield of reduction products on the HMS-based catalyst was higherb yafactor of almost two (38 %o n2 %Pd/Al-HMS (20) against 22 %on2%Pd/BEA- 25).…”

“…The direct synthesis is especially effective in the case of lower alcohols, whicha re miscible with glycerol; the process can be performed on ah eterogeneousc atalyst. Processes for the heterogeneous catalytic conversion of glycerol with ethanol, [2,[10][11][12] tert-butanol, [13][14][15][16] n-butanol, [17][18][19] and higher alcohols [7,20] werep roposed;t he use of olefins (isobuty-lene, [21][22][23] isoamylenes, [24,25] and 1-octene) [26,27] for glycerol alkylation was described. As harp decrease in the rate of conversion on going to higher alcohols, caused by the mutual immiscibility of reactants, is ad isadvantage of this method.…”

Combustion Mechanisms and Kinetics of Fuel Additives: A ReaxFF Molecular Simulation

“…Because of the low energy density and high viscosity, glycerol is not the ideal biofuel. However, glycerol can be modified to biodiesel additive by etherification with light olefins, such as triether TTAG (shown in Figure 1) synthesized by Izquierdo et al 18 According to the above research, it can be found that though numerous efforts have been made, the understanding of fuel additives remains on a macro scale, such as particle emissions, CO emissions, and so on. The mechanism and pathway of fuel additives are the intrinsic reason for their characteristics and should receive more attention, but few papers have been reported.…”