Cu2+ Montmorillonite K10 Clay Catalyst as a Green Catalyst for Production of Stearic Acid Methyl Ester: Optimization Using Response Surface Methodology (RSM)

Abstract

Clay catalyst has received much attention to replace the homogeneous catalysts in the esterification reaction to produce fatty acid methyl ester as the source of biodiesel as it is low cost, easily available, as well as environmental friendly. However, the use of unmodified clay, in particular montmorillonite K10 (MMT K10), for the esterification of fatty acids showed that the acid conversion was less than 60% and this is not preferable to the production of biodiesel. In this study, synthesis of stearic acid methyl ester using Cu 2+ -MMT K10 (Cu-MMT K10) was successfully optimized via response surface methodology (RSM) based on 3-variable of Box-Behnken design (BB). The parameters were; reaction time (5-180 minutes), reaction temperature (80-120 o C) and concentration of Cu 2+ in MMT K10 (0.25-1 M). The use of RSM in optimizing the conversion of stearic acid was successfully developed as the actual experimental conversion of stearic acid was found similar to the actual values under the optimum conditions. The model equation predicted that the following conditions would generate the maximum conversion of stearic acid (87.05 % reaction time of 62 minutes, a reaction temperature of 80 o C and catalyst used is 1.0 M Cu-MMT K10. This finding can be considered as green catalytic process as it worked at moderate reaction temperature using low cost clay catalyst with a short reaction time.

Potential of Fatty Acid Methyl Ester as Diesel Blends Produced from Free Fatty Acid in Waste Cooking Oil Catalyzed by Montmorillonite-Sulfonated Carbon

“…AB, AC, and BC represented the interaction effect for each variable, whereas the terms A 2 , B 2 , and C 2 were the quadratic effects. The positive and negative signs correspond to the synergistic and antagonistic effects on the FFA conversion, respectively (Almadani et al, 2018). The ANOVA of the model (95% confidence level) derived from Equation 3 is shown in Table 5.…”

Optimization of the catalytic production of methyl stearate by applying response surface Box–Behnken design: an intensified green option for high-cetane biofuel manufacture

“…Concerning MST production, it is well known that this alkyl ester can be synthesized via the esterication of stearic acid (SA) with methanol following homogeneous, heterogeneous, or enzymatic routes; however, the number of reports dealing with the synthesis of MST is scarce contrasting to what is found for other alkyl esters. Regarding the heterogeneous route for MST production, some catalysts including montmorillonite-based clays, [8][9][10][11] Amberlyst-15, 12 Nb 2 O 5 , 13 tin zirconium oxide, 14 amidoximated polyacrylonitrile ion exchange bres, 15 carbon-based catalyst 16 and sulfated ZrO 2 -SiO 2 (ref. 17) have been tested.…”

“…Among several studies on MST production are available in the scientific literature, a very small number of publications deal with the application of DoE are found: two report relatively simple 2 k factorial designs 9,28 and only one applies a Box–Behnken design for a heterogeneous reaction yet is limited to two factors. 10 The so-called response surface designs such Central Composite (CCD) and Box–Behnken (BBD) are suitable for investigating processes dealing with more than three factors require a reasonable number of experiments and can be used for optimization. 29 BBD includes experimental points positioned in the middle of the edges, thus providing a better description of non-linear effects compared to CCD.…”

Esterification of oleic acid with alcohols over Cu-MMT K10 and Fe-MMT K10 as acid catalysts

“…80 ºC and a short time to achieve maximum conversion [17]. Optimization of esterification reaction using response surface methodology (RSM) based on 3-variable of Box-Behnken design (BB) has proven that 1 M Cu-MMT K10 was able to covert 87.05% of stearic acid at 80 ºC within 60 minutes [18].…”