Figure 1
Block diagram for the high-acidity fatty material processing.
Figure 2
Experimental set-up used in this work.
Figure 3
SEM images of zinc monoglycerolate: (A) batch #1, (B) batch #2, (C) batch #3, and (D) batch #4.
Figure 4
Comparison of the results obtained for the methyl esterification of lauric acid (Cat. ≈ 12 % and MR ≈ 6:1). Symbols represent experimental data obtained for reactions without catalyst (empty symbols) and using montmorillonite K10 (full symbols and asterisk), at T = 140 °C (triangles, E1 and E4), T = 160 °C (squares, E2 and E5) and T = 180 °C (asterisks and circles, E3 and E6). Dotted lines are a guide for the eye.
Figure 5
Comparison of results obtained for the methyl esterification of lauric acid using different molar ratios at T = 180 °C and Cat. ≈ 40 g L-1. Symbols represent experimental data obtained for reactions using MR = 3.05:1 (squares, E7), MR ≈ 5.97:1 (diamonds, E8), MR ≈ 11.94:1 (squares, E9) and MR ≈ 49.79:1 (triangles, E10). Dotted lines are a guide for the eye.
Figure 6
Comparison of (A, C) FAME and (B, D) TAG contents obtained for the methyl transesterification of soybean oil using zinc monoglycerolate as catalyst. The symbols represent experimental data obtained for reactions without catalyst (empty symbols) and using zinc monoglycerolate (full symbols). Reaction conditions were: T1 (Cat. = 2.02 %, MR = 50.18:1 and T = 140 °C), T3 (Cat. = 2.02 %, MR = 50.64:1 and T = 180 °C), T4 (Cat. = 0 %, MR = 49.22:1 and T = 140 °C) and T5 (Cat. = 0 %, MR = 48.55:1 and T = 180 °C). Dotted lines are a guide for the eye.
Figure 7
Temperature effect in the contents of both (A) FAME and (B) TAG obtained for the methyl transesterification of soybean oil using zinc monoglycerolate (Cat. ≈ 2 % and MR ≈ 50:1). The symbols represent experimental data obtained for reactions T1 (triangles, T = 140 °C), T2 (diamonds, T = 160 ºC), and T3 (squares, T = 180 °C). Dotted lines are a guide for the eye.
Figure 8
Monitoring of composition of the samples obtained from the processing of acid oil using the methanol route, performed in duplicate (A) and (B). The symbols represent experimental data obtained for esterification reactions using montmorillonite K10 (reactions E11 and E12, Cat. ≈ 36 g L-1, FFA0 ≈ 40 %, MR ≈ 6:1 and T = 160 °C) and for transesterification reactions using zinc monoglycerolate (reactions T6 and T7, Cat. ≈ 4 g L-1, MR ≈ 40:1 and T = 180 °C). Lines are a guide for the eye.
Figure 9
Analyses of zinc monoglycerolate recovered after the processing of high-acidity fatty materials, reactions T6 and T7 (Cat. ≈ 4 g·L-1, MR ≈ 40:1 and T = 180 °C). (A) Comparison of XRD analysis of zinc monoglycerolate before and after reactions (dashed lines are a guide for the eye); (B) Comparison of FTIR spectra of zinc monoglycerolate before and after reactions; thermal analysis curves (TGA/DTG) of zinc monoglycerolate after reactions (C) T6 and (D) T7 (continuous lines indicate thermogravimetric curves and dotted lines refer to the thermogravimetric derivatives).
Figure A.1
XRD analysis of zinc monoglycerolate (batches #1, #2, and #3).
Figure A.2
Thermal analysis curves (TGA/DTG) of zinc monoglycerolate (batch #4) used for transesterification of soybean oil. Continuous lines indicate thermogravimetric curves (black) and thermogravimetric derivatives (red).
Figure A.3
Heating ramps for (A) esterification reactions using FFA, (B) transesterification reactions using soybean oil and (C) esterification and transesterification reactions using acid oil. The symbols represent experimental data obtained for reactions E1: Cat. = 12.03 %, MR = 6.06:1, T = 140 °C; E2: Cat. = 12.01 %, MR = 6.18:1, T = 160 °C; E3: Cat. = 11.75 %, MR = 5.97:1, T = 180 °C; E4: Cat. = 0 %, MR = 6.01:1, T = 140 °C; E5: Cat. = 0 %, MR = 6.10:1, T = 160 °C; E6: Cat. = 0 %, MR = 6.01:1, T = 180 °C; E7: Cat. = 39.7 g L-1, MR = 3.05:1, T = 180 °C; E8: Cat. = 40.7 g L-1, MR = 5.97:1, T = 180 °C; E9: Cat. = 40.3 g L-1, MR = 11.94:1, T = 180 °C; E10: Cat. = 39.8 g L-1, MR = 49.79:1, T = 180 °C; T1: Cat. = 2.02 %, MR = 50.18:1, T = 140 °C; T2: Cat. = 2.00 %, MR = 49.88:1, T = 160 °C; T3: Cat. = 2.02 %, MR = 50.64:1, T = 180 °C; T4: Cat. = 0 %, MR = 49.22:1, T = 140 °C; T5: Cat. = 0 %, MR = 48.55:1, T = 180 °C; E11 and E12: Cat. ≈ 36 g L-1, FFA0 ≈ 40 %, MR ≈ 6:1, T = 160 °C; T6 and T7: Cat. ≈ 4 g L-1, MR ≈ 40:1 and T = 180 °C. Lines are a guide for the eye.
Figure A.4
Effects of both the presence of zinc monoglycerolate and the temperature in the transesterification of soybean oil with methanol. The symbols represent experimental data obtained for reactions (A) T1 (Cat. = 2.02 %, MR = 50.67:1 and T = 140 °C), (B) T2 (Cat. = 2.00 %, MR = 49.91:1 and T = 160 ºC), (C) T3 (Cat. = 2.02 %, MR = 50.21:1 and T = 180 °C), (D) T4 (Cat. = 0 %, MR = 49.25:1 and T = 140 °C) and (E) T5 (Cat. = 0 %, MR = 48.58:1 and T = 180 °C). Dotted lines are a guide for the eye.
Figure A.5
Comparison of XRD analysis for zinc monoglycerolate before the reactions (batch #1) and recovered after the reactions of methyl transesterification of soybean oil. Reaction conditions were: T1: Cat. = 2.02 %, MR = 50.67:1 and T = 140 °C, T2: Cat. = 2.00, MR = 49.91:1 and T = 160 ºC, and T3: Cat. = 2.02, MR = 50.21:1 and T = 180 °C.
Table 1
Reaction conditions used for the synthesis of zinc monoglycerolate.
Table 2
Experimental conditions employed in the methyl esterification of lauric acid catalyzed by montmorillonite K10.
Table 3
Experimental conditions employed to evaluate the effect of molar ratio on the methyl esterification of lauric acid catalyzed by montmorillonite K10.
Table 4
Experimental conditions for the transesterification of soybean oil with methanol using zinc monoglycerolate as catalyst.
Table 5
Experimental conditions employed for the simulation of the processing of acid oils using the methanol route.
Table 6
Performance comparison of various solid catalysts used in previous studies and in this work for the production of biodiesel.
Table A.1
Densities of the compounds used in this work as a function of temperature.