Ultrasound-assisted transesterification of soybean oil using low power and high frequency and no external heating source.
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ABSTRACT:
SUBMITTER: Oliveira PA
PROVIDER: S-EPMC8384912 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Biodiesel, a mixture of fatty acid methyl esters (FAME), is bio-renewable, non-toxic, biodegradable, and is an attractive alternative to petroleum diesel. This work studied the sonochemical transesterification of Lesquerella fendleri oil (LFO) using inexpensive solid Lewis acid (LA) catalysts with an aim to reduce environmental pollution and dependance on non-renewable fuel sources. Due to the presence of hydroxy fatty acid methyl esters (HFAME) in LFO (∼60%), in addition to producing biofuel it can also be used to generate chemically important estolides and cyclic lactones. AlCl3, SnCl2, and Sn(CH3COO)2 showed catalytic activity using direct immersion ultrasound (DI-US) among a list of LA catalysts investigated, with AlCl3 being the best catalyst. Ultrasound increased the reaction rate by facilitating carbocation formation of glyceridic carbons. Experiments were carried out at room temperature in a solvent range from 3:1 to 18:1 methanol-to-oil molar ratio and catalyst loading from 1 wt% to 6 wt% over 10 to 60 min sonication time at 48% ultrasound amplitude (roughly 17 W/cm2). Complete conversion (>99%) was achieved in 40 min with 5 wt% AlCl3 catalyst. A statistical regression analysis with STATA 14.0 software was performed to optimize process parameters. Chemical characterizations of the compounds were performed with nuclear magnetic resonance (NMR) spectroscopy (1H NMR & 13C NMR), and % conversion of FAMEs was calculated from the 1H NMR spectra. The fatty acid profile was determined by GC-FID and GC-MS analysis. FT-IR spectroscopic analysis and thermogravimetric analysis (TGA) were performed to investigate the infrared absorption pattern of the compound and the volatility difference between Lesquerella fendleri biodiesel and oil under nitrogen atmosphere. Results indicate that this is a fast, green, energy-efficient, sustainable, and industrially applicable method for biodiesel production from LFO.
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Project description:In this study, biodiesel production from microalgal oil by microwave-assisted transesterification was carried out to investigate its efficiency. Transesterification reactions were performed by using Chlorella protothecoides oil as feedstock, methanol, and potassium hydroxide as the catalyst. Methanol:oil ratio, reaction time and catalyst:oil ratio were investigated as process parameters affected methyl ester yield. 9:1 methanol/oil molar ratio, 1.5% KOH catalyst/oil ratio and 10 min were optimum values for the highest fatty acid methyl ester yield.
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Project description:In this investigation, we report the synthesis of biodiesel using benzimidazolium-based brønsted acid ionic liquid (BBAIL) catalyst under the influence of ultrasonication. The prepared BBAIL catalyst was characterized by Fourier transform infrared and NMR spectroscopy techniques, and its acidity was determined by the Hammett method with 4-nitroaniline as the indicator. Ultrasonicator horn (22 kHz, 500 W) was used in this work with an on-off cycle of 50-20 s at 70% amplitude. The highest biodiesel yield of 96% was achieved by ultrasonication when 1:10 molar ratio of castor oil to methyl alcohol was used at 50 °C temperature with 9 mol % of the catalyst in just 90 min, which is about 10 times lesser than the process without ultrasonication. At similar conditions, 96% biodiesel yield was obtained in 14 h without ultrasonication. In summary, ultrasonication proved to be an efficient way to improve biodiesel synthesis in less time and BBAIL showed excellent activity toward the conversion of glycerides to synthesize biodiesel. Other important highlights are easy separation of the catalyst and recyclability up to three cycles with small decrease in its activity.
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Project description:The optimization of wheat starch esterification (acetylation) with a high degree of substitution was performed through response surface methodology (RSM) via various concentrations of reagents (acetic anhydride), pHs, and temperatures under various ultrasonication frequencies (25, 40, and 25 + 40 kHz). According to RSM methodology, optimized samples were selected by achieving high degrees of substitution at various frequencies, temperatures, and pHs. Solubility, swelling, X-ray, RVA, DSC, freeze-thaw stability, texture, and SEM analysis of the optimized samples were performed at three frequencies. X-ray pattern exhibited a more significant reduction in the crystallinity percentage of esterified starch at frequency 25 + 40 kHz compared with 25 kHz, 40 kHz, and native starch. According to DSC analysis, To, Tp, Tc, and enthalpy of gelatinization (?H gel) were lower in AC at frequency 25 + 40 kHz compared with AC at frequency 25 and 40 kHz and N starches. According to morphology analysis, in acetylated starches at 25 and 40 kHz, the surfaces and small granules underwent more damage, whereas in 25 + 40 kHz, large granules were more affected than small granules. Upon acetylation, freeze-thaw stability and textural properties of the starch significantly increased and decreased, respectively. The peak and final viscosity of acetylated starch increased (25 + 40 kHz ? 25 kHz ? 40 kHz ? N starch).
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Project description:Arabinoxylans (AX) are polysaccharides with antioxidant activity and emulsifying properties, which make them an attractive alternative for its potential application as a natural antioxidant in oils. Therefore, this work aimed to investigate the effect of ultrasonic treatment of AX on their antioxidant capacity and its ability to improve the oxidative stability of soybean oil. For this purpose, AX were exposed to ultrasonic treatment at 25% (100 W, AX-1) and 50% (200 W, AX-2) power and an operating frequency of 20 KHz during 15 min, and their macromolecular properties (weight average molecular weight (Mw), polydispersity index and intrinsic viscosity) were evaluated. The antioxidant capacity of AX was determined by the DPPH assay and Rancimat test. Results showed that ultrasonic treatment did not affect the molecular identity of the polysaccharide but modified its Mw distribution. AX-1 showed the highest antioxidant activity (75% inhibition) at 533 µg/mL by the DPPH method compared to AX and AX-2. AX at 0.25% (w/v) and AX-1 at 0.01% (w/v) exerted the highest protective effects on oxidative stability of soybean oil with induction periods of 7.69 and 5.54 h, respectively. The results indicate that AX could be a good alternative for the potential application as a natural antioxidant in oils.
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Project description:The aim of this work was to evaluate the technologies effect of cold extraction by centrifugation (CE) and ultrasound-assisted (US-CE) methods without adding water, on the avocado oil yield, nutritional composition, physicochemical characteristics, oxidative stability (oxidation temperature and time, besides activation energy) and accelerated shelf life regarding hexane extraction (control). The US-CE improved the physicochemical properties such as acidity, peroxides, and iodine indexes regarding CE and Control. US-CE improved the yield, nutritional quality of fatty acids, oxidative stability, shelf life, and ω-6/ω-3 ratio regarding CE. Furthermore, US-CE improved the ratio yield/time extraction of the oil and increased the oxidation temperature regarding control. The main advantage of oils extracted using CE and US-CE concerning control was higher oxidative stability. The most representative polyunsaturated fatty acids identified in all treatments were γ-linolenic and conjugated α-linolenic acids. α-linolenic acid was only detected in US-CE and control.Supplementary informationThe online version contains supplementary material available at 10.1007/s10068-021-00940-w.
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Project description:In this paper, the effects of ultrasound with different frequency modes on the sprouting rate, sprouting vigor, metabolism-related enzyme activity and late nutrient accumulation in soybean were investigated, and the mechanism of dual-frequency ultrasound promoting bean sprout development was explored. The results showed that, compared with control, the sprouting time was shortened by 24 h after dual-frequency ultrasound treatment (20/60 kHz), and the longest shoot was 7.82 cm at 96 h. Meanwhile, ultrasonic treatment significantly enhanced the activities of protease, amylase, lipase and peroxidase (p < 0.05), particularly the phenylalanine ammonia-lyase increased by 20.50%, which not only accelerated the seed metabolism, but also led to the accumulation of phenolics (p < 0.05), as well as more potent antioxidant activity at later stages of sprouting. In addition, the seed coat exhibited remarkable cracks and holes after ultrasonication, resulting in accelerated water absorption. Moreover, the immobilized water in seeds increased significantly, which was beneficial to seed metabolism and later sprouting. These findings confirmed that dual-frequency ultrasound pretreatment has a great potential to be used for seed sprouting and promoting the accumulation of nutrients in bean sprouts by accelerating water absorption and increasing enzyme activity.
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