The existing protocols for analyzing fatty acid methyl esters (FAMEs) using a one-step acetyl chloride (AC) catalyzed transesterification and extraction procedure cannot accurately determine the medium- and long-chain fatty acids... more
The existing protocols for analyzing fatty acid methyl esters (FAMEs) using a one-step acetyl chloride (AC) catalyzed transesterification and extraction procedure cannot accurately determine the medium- and long-chain fatty acids simultaneously in clinical (enteral, parenteral) formulations. For example: (1) addition of AC at room temperature generates an exothermic reaction that often results in loss of sample and possible injury to the analyst; (2) certain polyunsaturated fatty acids (PUFAs) are less stable at elevated temperatures during the transesterification and contribute to the over-estimation of the C16:0 and C18:1 fatty acids; and (3) the flame-ionization detector (FID) response varies depending on the carbon chain length of the fatty acids, that consequently impacts the underestimation of medium-chain fatty acid (C6–C10) recoveries. To overcome these deficiencies and accurately determine FAMEs, we have developed an improved one-step transesterification method that employs the addition of AC in tubes kept on a dry ice bath, the transesterification at room temperature, and the data analysis using relative response factors. Using this modified protocol, we determined the fatty acid composition of lipid emulsions (Omegaven® and Lipidem®) on a Shimadzu GC2010 gas chromatography (GC) system using a capillary GC column (Zebron ZB-WAX plus, 30 m, 0.25 mm ID, 0.25 μm). Our data suggest that the improved method can be easily used to accurately determine fatty acids (C6–C24) in functional foods and lipid emulsions.
In the present research oleic acid carbon dots have been optimized for high-thermal stability applications via suitable thermal-tuning in liquid as well as in anhydrous medium. The intended tuning of the nano-dimensional particles was... more
In the present research oleic acid carbon dots have been optimized for high-thermal stability applications via suitable thermal-tuning in liquid as well as in anhydrous medium. The intended tuning of the nano-dimensional particles was achieved by Fischer Esterification using suitable hydroxyl group-bearing moieties. The achieved external surface functionalization was fast, easy and cost-effective. The synthesized carbon dots were characterized using UV-Vis, Fluorescence, FT-IR, SEM, TGA and DSC techniques. The coalesce of the stated instrumentations derived a possible mechanistic approach and relationship regarding the thermal-tuning of the carbon dots for a deeper overview. The band-gap energy measurement revealed exclusive wide band-gap semiconductor characteristics of the investigated nanoparticles. Further, the fabrication of carbon dots on cotton fabric potentialized a new class of synthetic flame-retardant free high temperature resistant textiles, deemed essential for a greener future. The enhanced nature of these carbon dots with requisite alteration capabilities for temperatures as high as 800 °C could certainly improve the applicability of these particles in future electronic advancements.
Palm stearin (POs) and palm kernel olein (PKOo) blends were modified by enzymatic interesterification (IE) to achieve the physical properties of margarine fats. POs and PKOo are both products of the palm oil industry that presently have... more
Palm stearin (POs) and palm kernel olein (PKOo) blends were modified by enzymatic interesterification (IE) to achieve the physical properties of margarine fats. POs and PKOo are both products of the palm oil industry that presently have limited use. Rhizomucor miehei lipase (Lipozyme IM 60) was used to catalyze the interesterification of oil blends at 60°C. The progress of interesterification was monitored by following changes in triacylglyceride composition. At 60°C interesterification can be completed in 5 h. Degrees of hydrolysis obtained through IE for all blends were decreased from 2.9 to 2.0 by use of dry molecular sieves. The solid fat contents of POs/PKOo 30:70 and 70:30 interesterified blends were 9.6 and 18.1 at 20°C, and 0 and 4.1 at 35°C, respectively. The slip melting point (SMP) of POs/PKOo 30:70 was 40.0°C before interesterification and 29.9°C after IE. For POs/PKOs 70:30, SMP was 47.7 before and 37.5°C after IE. These thermal characteristics of interesterified POs/PKOo blend ratios from 30:70 to 70:30 were comparable to those of commercial margarines. Results showed that IE was effective in producing solid fats with less than 0.5% trans.
Production of ethanol, biogas, pectin and limonene from citrus wastes (CWs) by an integrated process was investigated. CWs were hydrolyzed by dilute-acid process in a pilot plant reactor equipped with an explosive drainage. Hydrolysis... more
Production of ethanol, biogas, pectin and limonene from citrus wastes (CWs) by an integrated process was investigated. CWs were hydrolyzed by dilute-acid process in a pilot plant reactor equipped with an explosive drainage. Hydrolysis variables including temperature and residence time were optimized by applying a central composite rotatable experimental design (CCRD). The best sugar yield (0.41 g/g of the total dry CWs) was obtained by dilute-acid hydrolysis at 150 °C and 6 min residence time. At this condition, high solubilization of pectin present in the CWs was obtained, and 77.6% of total pectin content of CWs could be recovered by solvent recovery. Degree of esterification and ash content of produced pectin were 63.7% and 4.23%, respectively. In addition, the limonene of the CWs was effectively removed through flashing of the hydrolyzates into an expansion tank. The sugars present in the hydrolyzates were converted to ethanol using baker’s yeast, while an ethanol yield of 0.43 g/g of the fermentable sugars was obtained. Then, the stillage and the remaining solid materials of the hydrolyzed CWs were anaerobically digested to obtain biogas. In summary, one ton of CWs with 20% dry weight resulted in 39.64 l ethanol, 45 m3 methane, 8.9 l limonene, and 38.8 kg pectin.
In the last few years, biodiesel has emerged as one of the most potential renewable energy to replace current petrol-derived diesel. It is a renewable, biodegradable and non-toxic fuel which can be easily produced through... more
In the last few years, biodiesel has emerged as one of the most potential renewable energy to replace current petrol-derived diesel. It is a renewable, biodegradable and non-toxic fuel which can be easily produced through transesterification reaction. However, current commercial usage of refined vegetable oils for biodiesel production is impractical and uneconomical due to high feedstock cost and priority as food resources. Low-grade oil, typically waste cooking oil can be a better alternative; however, the high free fatty acids (FFA) content in waste cooking oil has become the main drawback for this potential feedstock. Therefore, this review paper is aimed to give an overview on the current status of biodiesel production and the potential of waste cooking oil as an alternative feedstock. Advantages and limitations of using homogeneous, heterogeneous and enzymatic transesterification on oil with high FFA (mostly waste cooking oil) are discussed in detail. It was found that using heterogeneous acid catalyst and enzyme are the best option to produce biodiesel from oil with high FFA as compared to the current commercial homogeneous base-catalyzed process. However, these heterogeneous acid and enzyme catalyze system still suffers from serious mass transfer limitation problems and therefore are not favorable for industrial application. Nevertheless, towards the end of this review paper, a few latest technological developments that have the potential to overcome the mass transfer limitation problem such as oscillatory flow reactor (OFR), ultrasonication, microwave reactor and co-solvent are reviewed. With proper research focus and development, waste cooking oil can indeed become the next ideal feedstock for biodiesel.
Although currently microalgae biomass is not considered as a sustainable feedstock for biofuel production, future developments of microalgae cultivation and harvest could make the commercial application of such fast-growing photosynthetic... more
Although currently microalgae biomass is not considered as a sustainable feedstock for biofuel production, future developments of microalgae cultivation and harvest could make the commercial application of such fast-growing photosynthetic biomass economically and environmentally feasible. This article aims at reviewing thermochemical conversion of microalgae into bio-crude oil through pyrolysis and hydrothermal liquefaction technologies. Subsequently, possible solutions to overcome the constraints to achieve the sustainable conversion of microalgae biomass are discussed in detail. The drawbacks of bio-crude oil as a transportation fuel and the technologies required for its upgrading are highlighted. Currently, microalgae-derived bio-crude oil is inferior to biodiesel and diesel in terms of quality, thus cannot be used as a transportation or jet fuel. It requires catalytic upgrading steps and further processing, including durable and cost-effective catalysts with strong regenerative capabilities.
The reaction kinetics of esterification between n-butanol and acetic acid on acidic solid catalyst named SERALITE SRC-120 under atmospheric pressure was investigated in this work. Reaction experiments were carried out in a stirred batch... more
The reaction kinetics of esterification between n-butanol and acetic acid on acidic solid catalyst named SERALITE SRC-120 under atmospheric pressure was investigated in this work. Reaction experiments were carried out in a stirred batch reactor at temperature range of 353 to 356 K, under various catalyst loads and various starting reactants feed ratios. The experimental data were fitted to estimate the kinetic parameters for reaction mechanisms. The chemical equilibrium composition was measured and kinetic information was obtained at the same temperature range. The results show that the activation energy of n-butanol esterification reaction was found to be 622.28 KJ/mol. Finally the results of produced reaction mechanisms were compared with Experimental results to validate the reaction mechanism. Then it was conclude that the model results with the regressed kinetic parameters are in excellent agreement with the experimental results.
A solid acid catalyst was prepared by sulfonating pyrolyzed rice husk with concentrated sulfuric acid, and the physical and chemical properties of the catalyst were characterized in detail. The catalyst was then used to simultaneously... more
A solid acid catalyst was prepared by sulfonating pyrolyzed rice husk with concentrated sulfuric acid, and the physical and chemical properties of the catalyst were characterized in detail. The catalyst was then used to simultaneously catalyze esterification and transesterification to produce biodiesel from waste cooking oil (WCO). In the presence of the as-prepared catalyst, the free fatty acid (FFA) conversion reached 98.17% after 3h, and the fatty acid methyl ester (FAME) yield reached 87.57% after 15 h. By contrast, the typical solid acid catalyst Amberlyst-15 obtained only 95.25% and 45.17% FFA conversion and FAME yield, respectively. Thus, the prepared catalyst had a high catalytic activity for simultaneous esterification and transesterification. In addition, the catalyst had excellent stability, thereby having potential use as a heterogeneous catalyst for biodiesel production from WCO with a high FFA content.
Due to the diminution of conventional fuels, biodiesel has attracted acute attention due to its renewable and zero-emission features. However, cleaner production of biodiesel on an industrial scale requires a stable heterogeneous , low... more
Due to the diminution of conventional fuels, biodiesel has attracted acute attention due to its renewable and zero-emission features. However, cleaner production of biodiesel on an industrial scale requires a stable heterogeneous , low cost and recyclable catalyst. This study presents the preparation and application of copper and calcium-based metal organic frameworks (MOFs) as catalysts in the esterification and transesterification reactions for biodiesel production from waste cooking oil (WCO). The synthesized catalysts are characterized using XRD, SEM, TGA, FTIR and BET. The catalyst characterization indicates the formations of the cubical structure of MOFs with a crystallite size of < 50 nm and thermal stability below 600°C. The catalyst has been tested for WCO to biodiesel production and the biodiesel samples comply with the ASTM standards. Furthermore, the process parameters i.e catalyst loading (X 1), reaction temperature (X 2) and alcohol-oil ratio (X 3) are optimized employing response surface methodology (RSM) via central composite design (CCD). The second-order regression model is employed to investigate the dynamic interaction between the process parameters and biodiesel yield (Y BD %). The optimum process values are determined i.e catalyst loading = 1.0 g/100 mL, reaction temperature = 60°C and alcohol-oil ratio = 20 with optimum biodiesel yield of 84.5 (vol%). The experimental results and predicted results are in good agreement with percentage error less than ± 5%. The regenerated catalyst demonstrates a significant biodiesel yield up to 7% reduction for 3 cycles.
In this study, a two-step process was developed to produce biodiesel from Calophyllum inophyllum oil. Pre-treatment with phosphoric acid modified β-zeolite in acid catalyzed esterification process preceded by transesterification which was... more
In this study, a two-step process was developed to produce biodiesel from Calophyllum inophyllum oil. Pre-treatment with phosphoric acid modified β-zeolite in acid catalyzed esterification process preceded by transesterification which was done using conventional alkali catalyst potassium hydroxide (KOH). The objective of this study is to investigate the relationship between the reaction temperatures, reaction time and methanol to oil molar ratio in the pre-treatment step. Central Composite Design (CCD) and Response Surface Methodology (RSM) were utilized to determine the best operating condition for the pre-treatment step. Biodiesel produced by this process was tested for its fuel properties.
In this paper, a reactive distillation (RD) column was applied for synthesis n-butyl acetate from n-butanol and acetic acid. The Langmuir-Hinshelwood-Hougen-Watson (LHHW) kinetic model and an equilibrium stage model for separation were... more
In this paper, a reactive distillation (RD) column was applied for synthesis n-butyl acetate from n-butanol and acetic acid. The Langmuir-Hinshelwood-Hougen-Watson (LHHW) kinetic model and an equilibrium stage model for separation were employed to study the RD process. The results obtained from the equilibrium stage model agreed well with the experiments. The effects of operating variables on the n-butanol conversion and n-butyl acetate purity were further investigated. The optimal column configuration for the production of n-butyl acetate was designed with 5 rectifying stages, 8 reaction stages and 13 stripping stages by the simulation study. According to the simulation results, n-butanol conversion and n-butyl acetate purity all reached greater than 96%.
Biodiesel produced from triglycerides and/or free fatty acid (FFA) by transesterification and esterification has attracted immense attention during the past decades as a biodegradable, renewable and sustainable fuel. Currently, solid... more
Biodiesel produced from triglycerides and/or free fatty acid (FFA) by transesterification and esterification has attracted immense attention during the past decades as a biodegradable, renewable and sustainable fuel. Currently, solid superacid catalysts has proved more efficient and “green” approach due to avoidance of environmental and corrosion problems, and reduce product purification procedures. However, it is less viable economically because the reusability is low due to lack of hydrophilic/hydrophobic balance in reactions that involve the use of inedible feedstock with high water content. Therefore, this study gives a critical review on recent strategies towards efficient and a “greener” production of biodiesel via solid superacid catalysis. The strategies discussed include alkyl-bridged organosilica moieties functionalized hybrid catalysis to improve the hydrothermal stability of superacid catalysts; pre- and in situ water removal; process intensification via temperature profile reduction. The strategies enabled well-defined porosity and excellent hydrophobicity/hydrophilicity balance, which suppressed deactivation by water and glycerol.
Analysis of free and esterified sterols in edible oils by online reversed phase liquid chromatography–gas chromatography (RPLC–GC) using the through oven transfer adsorption desorption (TOTAD) interface a b s t r a c t An online reversed... more
Analysis of free and esterified sterols in edible oils by online reversed phase liquid chromatography–gas chromatography (RPLC–GC) using the through oven transfer adsorption desorption (TOTAD) interface a b s t r a c t An online reversed phase liquid chromatography–gas chromatography (RPLC–GC) method is proposed to quantify free, total and esterified sterols of edible oils. To determine free sterols the diluted oils are injected into the liquid chromatograph, where free sterols are separated from triglycerides and the sterol fraction is automatically transferred to the gas chromatograph to be analysed. To determine total sterols the samples were saponified with potassium hydroxide in ethanolic solution and the unsaponifiable frac-tion was extracted with diethyl ether. The extract was then analysed by RPLC–GC, avoiding the laborious thin layer chromatography step used in the Official European Union (EU) Method. The relative standard deviations (RSDs) from the absolute peak area varie...
The ethanolysis of fish oil in various reaction medium (tert-pentanol, n-hexane and solvent free system) catalyzed by the immobilized commercial lipase Lipozyme(®) 435 (Candida Antarctica) at atmospheric pressure has been studied in this... more
The ethanolysis of fish oil in various reaction medium (tert-pentanol, n-hexane and solvent free system) catalyzed by the immobilized commercial lipase Lipozyme(®) 435 (Candida Antarctica) at atmospheric pressure has been studied in this work. The effect of some kinetic parameters, such as the amount of lipase, temperature and the initial reactant molar ratio ethanol:oil on monoacyglyceride and ethyl ester yield has been analyzed. Experimental data were successfully correlated by a simple kinetic model based on the elementary reactions proposed in this work. At high initial reactant molar ratio the three elementary steps can be considered as irreversible. However the reaction rate constants ratio for the deacylation of monoglyceride to glycerol decreased by decreasing the molar ratio ethanol:oil. The reaction rates are slower in n-hexane as reaction medium compared to tert-pentanol and a solvent-free system, at the experimental conditions essayed in this work. In this last case, eth...