The production methodology was based on the specialist literature [18, (link)19] (link) and is briefly discussed in this text.
The pilot module comprised a 2 L encased glass reactor, a thermostated bath (TECNAL, TE184), and a mechanical stirrer (TECNAL, TE2003). The pilot modulo was agitated continuously and maintained at 323.15 K. After stabilizing the experimental conditions, the reactor was filled with potassium hydroxide (1 wt%) and alcohol. The reaction was conducted at an oil-alcohol molar ratio of 1:10 (oil-alcohol) for 30 min. After the completion of the reaction, the product was collected and centrifuged to separate the biodiesel-and glycerol-rich phases.
FAEEs and FAMEs were washed repeatedly with distilled water until the pH reached 7.0, with a progressive reduction in washing water volume. Initially, a water-biodiesel ratio of 1:10 at 343.15 K was employed to remove the catalyst, ethanol, and mono-and diacylglycerols. The pH was adjusted by adding sulfuric acid solution at a specific mass ratio of sulfuric acid to biodiesel. After each wash, phase separation was achieved via centrifugation, and the pH of the biodiesel-rich phase was verified. Subsequent washes with sterile water were conducted until a pH of 7.0 was reached. The purified biodiesel was then dried with manganese sulfate (MnSO 4 ) and filtered, and the yield of the transesterification/esterification reaction was determined with gas chromatography to quantify the total esters [18] (link).
A GC-2010/Shimadzu instrument (Shimadzu, San Jose, CA, USA) equipped with a split/splitless injection system was used, operating at 523.15 K, with a split ratio of 100:1, sample injection volume of 1.0 µL, and flame ionization detector (FID) operating at 523.15 K. A polar capillary column ZB-WAX plus/Phenomenex (Torrance, CA, USA) was employed, measuring 30 m in length, 0.32 mm in internal diameter, with a film thickness of 0.25 µm. High-purity hydrogen gas (99.95% LINDE) was used as the carrier gas. The temperature program for the oven and column was as follows: 433.15-498.15 K at 15 K/min, then 433.15-498.15 K at 3 K/min, resulting in a total analysis time of 11 min. The fatty acid composition was determined by identifying fatty acids by comparing retention times with those of standard ester mixtures (tricaprylin). Equation (1) was used to integrate the peak areas via normalization to quantify the fatty acids. The chemical composition of the major fatty acids was determined via gas chromatography (GC) using the European Standard EN14103 [20] (see Table 1).
where m tricaprylin , f tricaprylin , and A tricaprylin represent the mass, response factor, and peak area of the internal standard, respectively; A B is the sum of the peak areas of FAMEs or FAEEs; and m s is the mass of the sample. The average molar masses of sesame FAEEs and FAMEs were calculated based on the fatty acids listed in Table 1, yielding values of 307.738 and 293.714 g/mol for FAEEs and FAMEs, respectively. To estimate the molar mass of the esters formed, we assumed that each fatty acid was completely converted into its respective ester during the transesterification reaction. Based on this assumption, we utilized the methodology described by Halvorsen et al. [21] (link) to estimate the molecular weights of the produced esters.
The pilot module comprised a 2 L encased glass reactor, a thermostated bath (TECNAL, TE184), and a mechanical stirrer (TECNAL, TE2003). The pilot modulo was agitated continuously and maintained at 323.15 K. After stabilizing the experimental conditions, the reactor was filled with potassium hydroxide (1 wt%) and alcohol. The reaction was conducted at an oil-alcohol molar ratio of 1:10 (oil-alcohol) for 30 min. After the completion of the reaction, the product was collected and centrifuged to separate the biodiesel-and glycerol-rich phases.
FAEEs and FAMEs were washed repeatedly with distilled water until the pH reached 7.0, with a progressive reduction in washing water volume. Initially, a water-biodiesel ratio of 1:10 at 343.15 K was employed to remove the catalyst, ethanol, and mono-and diacylglycerols. The pH was adjusted by adding sulfuric acid solution at a specific mass ratio of sulfuric acid to biodiesel. After each wash, phase separation was achieved via centrifugation, and the pH of the biodiesel-rich phase was verified. Subsequent washes with sterile water were conducted until a pH of 7.0 was reached. The purified biodiesel was then dried with manganese sulfate (MnSO 4 ) and filtered, and the yield of the transesterification/esterification reaction was determined with gas chromatography to quantify the total esters [18] (link).
A GC-2010/Shimadzu instrument (Shimadzu, San Jose, CA, USA) equipped with a split/splitless injection system was used, operating at 523.15 K, with a split ratio of 100:1, sample injection volume of 1.0 µL, and flame ionization detector (FID) operating at 523.15 K. A polar capillary column ZB-WAX plus/Phenomenex (Torrance, CA, USA) was employed, measuring 30 m in length, 0.32 mm in internal diameter, with a film thickness of 0.25 µm. High-purity hydrogen gas (99.95% LINDE) was used as the carrier gas. The temperature program for the oven and column was as follows: 433.15-498.15 K at 15 K/min, then 433.15-498.15 K at 3 K/min, resulting in a total analysis time of 11 min. The fatty acid composition was determined by identifying fatty acids by comparing retention times with those of standard ester mixtures (tricaprylin). Equation (1) was used to integrate the peak areas via normalization to quantify the fatty acids. The chemical composition of the major fatty acids was determined via gas chromatography (GC) using the European Standard EN14103 [20] (see Table 1).
where m tricaprylin , f tricaprylin , and A tricaprylin represent the mass, response factor, and peak area of the internal standard, respectively; A B is the sum of the peak areas of FAMEs or FAEEs; and m s is the mass of the sample. The average molar masses of sesame FAEEs and FAMEs were calculated based on the fatty acids listed in Table 1, yielding values of 307.738 and 293.714 g/mol for FAEEs and FAMEs, respectively. To estimate the molar mass of the esters formed, we assumed that each fatty acid was completely converted into its respective ester during the transesterification reaction. Based on this assumption, we utilized the methodology described by Halvorsen et al. [21] (link) to estimate the molecular weights of the produced esters.
