Production and characterization of biodiesel from trap grease

The feasibility of the production of biodiesel from trap grease containing 51.5% free fatty acids (FFAs) was investigated. The esterification of FFAs by an acid catalyst followed by the transesterification of triglycerides by an alkali catalyst was examined. The esterification of trap grease by sulfuric acid as a homogeneous catalyst or by Amberlyst-15 as a heterogeneous catalyst was optimized through a response surface methodology. After the two-step esterification of trap grease by sulfuric acid, the acid value decreased from 102.9 mg KOH/g to 2.75 mg KOH/g. Through the transesterification by potassium hydroxide, fatty acid methyl ester (FAME) content reached 92.4%. Following the esterification of trap grease by Amberlyst-15, the acid value decreased to 3.23 mg KOH/g. With the transesterification by potassium hydroxide, FAME content increased to 94.1%. After the distillation of the produced biodiesel, FAME content increased again, to 97.6%. The oxidation stability of the trap grease biodiesel was 0.17 h, and its cold filter plugging point was 4 °C. As the FAME content of the trap grease biodiesel satisfies the Korean Biodiesel Standard, the trap grease biodiesel seems to be applicable for use as an engine fuel after properties improvement.     

A Quantitative Method of Analysis for Sterol Glycosides in Biodiesel and FAME Using GC-FID

Sterol glycosides (SG) are known to cause filter blocking problems in biodiesel use. The extraction and quantitative analysis of SG is difficult due to its low problematic concentration and its compatibility with biodiesel. The purpose of this study is to develop a method to quantify SG in FAME and biodiesel using gas chromatography and other equipment found in laboratories performing routine biodiesel analyses. SG was isolated from FAME using n‐dodecane, acidification and cold soaking, followed by cold centrifugation at ?8 to ?15 °C. The solids obtained were further separated by phase partition with a Folch wash, followed by a final n‐dodecane rinse. This solution was analyzed by GC‐FID using the operating conditions outlined in ASTM D6584. A calibration curve for SG was produced and a first order fit gave a value of r² = 0.992. Reproducibility tests were performed on soybean FAME and B100 canola biodiesel samples spiked with SG. The recovery of SG by the new method was found to be 99 % for soy FAME with a standard deviation of 0.7 and 100 % for B100 canola with a standard deviation of 3.5 %. The reproducibility based on two standard deviations of the predicted concentration for all 12 spiked samples studied in this work was 2.4 ppm.     

Thermal and mechanical properties of sorbitol‐based epoxy resin cured with quercetin and the biocomposites with wood flour

After a bio‐based epoxy resin, sorbitol polyglycidyl ether (SPE) was mixed with a flavonoid, quercetin (QC) in tetrahydrofuran at an optimized epoxy/hydroxy ratio 1/1.2, the obtained SPE/QC solution was mixed with wood flour (WF), prepolymerized at 150°C, and subsequently compressed at 170°C for 3 h to give SPE‐QC/WF biocomposites (WF content:0, 20, 30, 40 wt %). The tan δ peak temperature of SPE‐QC without WF (85.5°C) was higher than that of SPE cured with conventional phenol novolac (81.0°C). In addition, diglycidyl ether of bisphenol A cured with QC had a higher tan δ peak temperature (145.1°C) than that cured with PN (90.8°C). The tan δ peak temperatures (106–113°C) of SPE‐QC/WF biocomposites were significantly higher than that of SPE‐QC. The tensile modulus of SPE‐QC/WF biocomposites increased with increasing WF content. A lower wavenumber shift of carbonyl stretching absorption peak in the FTIR spectrum of SPE‐QC/WF as compared with that of SPE‐QC suggested that hydroxy group of woody component forms hydrogen bonding with carbonyl group of quercetin moiety. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Separation of squalene from olive oil deodorizer distillate using supercritical fluids

In this study, an integrated strategy using supercritical fluids for extraction of squalene from olive oil deodorizer distillate (OODD), one of the most important by‐products of the olive oil refining process is presented. First, OODD was esterified in supercritical methanol, and then squalene was extracted from the sample consisting of 66% methyl ester using supercritical CO₂. The extraction conditions, i.e., pressure (88.2–121.8 bar), temperature (41.6–58.4°C) and extraction time (129.6–230.4 min), were optimized via RSM to achieve the highest squalene content. The optimal results were obtained at a temperature of 52.05°C, pressure of 104.8 bar and extraction time of 180 min. Consequently, two kinds of value‐added products such as biodiesel (up to 96% FAME, in extract) and olive squalene (up to 75%, in raffinate) were produced in shorter processing times when compared with distillation results of 70 h. Practical applications: Traditionally, squalene is extracted from liver oil of rare deep‐sea sharks. Here we present the recovery of vegetal squalene in high purity from OODD. Our approach also presents a simple, reliable, and mobile solution. Squalene is widely used in cosmetics as a protective agent and natural moisturizer and as an adjuvant in influenza vaccines.     

Response surface modeling and optimization of biodiesel production from Cynara cardunculus oil

Cardoon (Cynara cardunculus L.) is a perennial spontaneous thistle grown in Mediterranean countries and well adapted to marginal lands, recently considered as a non‐food energy crop. Their seeds contain 24% of oil (dry basis). In this study, modeling and optimization of the production of fatty acid methyl esters (FAME) from cardoon oil for biodiesel uses was performed at laboratory scale, via response surface methodology, following a central composite rotatable design. FAME were obtained by transesterification of crude cardoon oil with methanol in the presence of a catalyst (sodium methoxide) for 120 min. The temperature ranged from 26 to 94 °C, the amount of sodium methoxide varied between 0.12 and 2.5 wt‐% and the molar ratio methanol/oil from 0.95 : 1 to 11 : 1. The estimated yield of FAME (97%) was obtained after 30 min, at 52 °C, for a molar ratio of 6.4 : 1 and 1.4 wt‐% of catalyst. In laboratory‐scale model validation experiments, 94% of FAME yield was obtained after 30 min of reaction. Transesterification was performed in a 30‐L reactor, under previously optimized conditions: A yield of 88% FAME was obtained after 90 min of reaction time, due to mass transfer limitations. After purification, the biodiesel showed high quality according to DIN EN 14214 standard specifications.     

An Empirical Equation for Estimation of Kinematic Viscosity of Fatty Acid Methyl Esters and Biodiesel

Kinematic viscosity (µ) is an important physical property of fatty acid methyl esters (FAME) and biodiesel. In this work, the Martin's rule of free energy additivity is extended to cover the kinematic viscosity of saturated and unsaturated FAME commonly found in nature. The proposed model can also be extended to estimate kinematic viscosity of biodiesel. The kinematic viscosity of a FAME or a biodiesel can be easily estimated from its carbon number (z), number of double bonds (n_d) at different temperatures (T) without a prior knowledge of the viscosity of individual FAME. Both z_ave and n_d(ave) can be derived from its fatty acid composition. Thus, kinematic viscosity of biodiesel at temperatures between 20 and 100 °C and at atmospheric pressure can be estimated. The average absolute deviation (AAD) estimated at 20–100 °C for saturated, unsaturated FAME, biodiesels and biodiesel blends are 4.15, 3.25, 6.95 and 2.79 %, respectively. The biodiesels collected in this study (191 data points) have the z_ave and n_d(ave) between 14.10 and 17.96 and 0.21–1.54, respectively. The standard deviation was 0.249. The proposed model would be good for estimation of viscosity of biodiesel containing normal fatty acids, generally found in biodiesel feed stocks.     

The Enzymatic Synthesis and Characterization of Disolketal Iminodiacetic Acid (DSIDA)

Disolketal iminodiacetic acid (DSIDA) has been synthesized from the enzyme‐catalyzed condensation reaction between derivatives of iminodiacetic acid (IDA) and glycerol. According to all available literature, DSIDA is a novel diester that has never been synthesized. It is a precursor to water‐soluble polyhydric alcohols and helps to address the global need of the biodiesel industry to find new uses for glycerol. Reacting diMe‐IDA with solketal, a protected glycerol, produced DSIDA in yields as high as 96.4% under optimal reaction conditions of 70 °C and 200 Torr for 24 h. The reaction was monitored using ATR‐IR and a validated GC method. ATR‐IR monitored the disappearance of the primary solketal alcohol and the appearance of cyclic solketal ether bonds in the molecular backbone of the intermediates and product. Structural analysis of the intermediates and products was performed using two‐dimensional NMR, GC, GC–MS and elemental analysis. All spectral data was in agreement with the proposed structures for the chemical reaction. Thermal profiles were determined by TGA to be single‐stage decompositions above 160 °C.     

Wood‐derived phenol novolaks and their wood/epoxy biocomposites

Guaiacol novolak (GCN) and wood‐tar creosote novolak (WCN) were synthesized by the reactions of wood‐derived guaiacol and creosote with formalin, respectively, and used as hardeners of sorbitol polyglycidyl ether (SPE). Thermal and mechanical properties of the cured resins (SPE‐GCN and SPE‐WCN) and their biocomposites with wood flour (WF) were compared with those of the materials prepared by using a petroleum‐based phenol novolak (PN). Although tan δ peak temperatures of SPE‐GCN and SPE‐WCN were lower than that of SPE‐PN, that (58.5–70.8°C) of SPE‐GCN/WF(40–50 wt %) was higher than that (56.6–57.0°C) of SPE‐PN/WF(40–50 wt %). Tensile moduli of all the biocomposites increased by the addition of WF, while tensile strengths were rather reduced. When the biocomposites with the same WF content were compared, tensile modulus of SPE‐GCN/WF was higher than that of SPE‐PN/WF. The 5% weight loss temperatures (346–291°C) of SPE‐GCN and SPE‐GCN/WF were comparable to those (338–284°C) of SPE‐PN and SPE‐PN/WF. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41347.     

Two approaches in preparation for cogeneration α‐tocopherol and biodiesel from cottonseed

A two‐step process and a direct alkaline transesterification process in preparation for cogeneration α‐tocopherol and biodiesel (fatty acid methyl esters, FAME) from cottonseeds were studied in this article. The effects of some factors on recovery of α‐tocopherol and conversion of cottonseed oil (triacylglycerols, TAGs) to biodiesel in the two processes were systematically studied by single factor experiments and orthogonal design method. In the two‐step process, α‐tocopherol and biodiesel were produced from extraction with two‐phase solvent followed by base‐catalysed transesterification. Approximately 95.5% TAGs was converted into biodiesel, and 1.008 mg/g (wet basis) α‐tocopherol was detected on the condition: 1:3 petroleum ether/methanol volume rate, 40°C extraction temperature; 7:1 methanol/cottonseed oil molar ratio, 1.1% KOH (w/v) concentration in methanol and 60°C esterification temperature. And in the direct alkaline transesterification reaction, 98.3% conversion of TAGs and 0.986 mg/g content of α‐tocopherol could be achieved at 60°C in 2 h. Both of the two processes were feasible from the economic point of view for further utilisation of cottonseed. © 2011 Canadian Society for Chemical Engineering     

Comparisons of Biodiesel Produced from Unrefined Oils of Different Peanut Cultivars

Biodiesels were prepared according to standard procedures from unrefined oils of eight commercially available peanut cultivars and compared for differences in physical properties important to fuel performance. Dynamic viscosity, kinematic viscosity and density were measured from 100 to 15 °C, and differences (p < 0.05) in these physical properties occurred more frequently at lower temperatures when comparing the different cultivars. Unlike data for the oil feedstocks, no meaningful correlations among biodiesel fatty acid profiles and either fuel viscosity or density were observed. Low temperature crystallization of the peanut biodiesels was measured via differential scanning calorimetry. Increased concentrations of long chain saturated fatty acid methyl esters (FAME) were associated with an increased propensity for low temperature crystallization, and the single FAME category most associated with low temperature crystallization was C:24. Tempering at 10 °C followed by analysis of the soluble fractions (winterization), improved crystallization properties and confirmed the importance that long chain saturated FAMEs play in the final functionality of peanut biodiesel. Peanut data is also compared to data for canola and soy biodiesels, as these feedstocks are more common worldwide for biodiesel production. Overall, this work suggests that minimizing the concentration of long chain saturated FAMEs within peanut biodiesel, either through processing and/or breeding efforts would improve the low temperature performance of peanut biodiesel.     

Flow and crystallization of saturated fatty acid methyl esters and their binary mixtures

Demand for biodiesel has increased due to being a more environmentally-friendly fuel. Cold weather operation of biodiesel is challenging due to fatty acid methyl ester (FAME) content in biodiesel. Saturated FAMEs crystallize at relatively high temperatures, increase the viscosity of biodiesel, and can clog fuel lines. Here, several factors altered crystallization temperature (CT) of FAMEs, including composition, shear rate, and cooling rate. The crystallization of pure and binary mixtures of methyl palmitate, methyl myristate, and methyl stearate were studied under shear flow and static conditions. Static phase CTs of pure methyl palmitate, methyl myristate, and methyl stearate were 26, 14, and 35°C, respectively. In binary mixtures, CTs were depressed up to 7°C, which agreed with freezing point depression theory. Increasing shear rate up to 100 s⁻¹ decreased CT by 2°C compared to static conditions. Decreasing cooling rate from 1 to 0.1°C/min increased CT less than 2°C. Overall, FAME composition altered CT more than shear flow or cooling rate for pure and binary mixtures of three FAMEs.     

Preparation,characterization and thermal stability improvement of mesoporous sulfated zirconia for converting deodorizer distillate to methyl esters

This article reported a new procedure for synthesizing ordered mesoporous sulfated zirconia (m-SZ), an effective oxophosphate process for strengthening thermal stability of the as-synthesized m-SZ catalyst forming mesoporous phosphated sulfated zirconia (m-PSZ). The study also afforded a new reaction routine for synthesizing the m-SZ through condensation method using Zr(SO₄)₂ solution precursor in the incipient wetness impregnation method. The m-PSZ contained dense surface superacid sites being suitable for methanolysis of almost vegetable oils or animal fats producing methyl ester. The temperature of the condensation process was varied in the range of 70–100 °C, and the time periods were surveyed from 12 to 72 h for well self-assembling the mesoporous structure. The precipitation obtained from the condensations was calcined at 450 °C for 3 h after completely removing of the surface water overnight at 100 °C. The after calcination powder was the m-SZ catalyst. The H₃PO₄ was used as precursor for oxophosphate process producing the m-PSZ catalyst. The m-PSZ catalyst was applied to the methyl ester synthesis using deodorizer distillate collected from vegetable oil refinery in Vietnam as feedstock. The methanolysis was established at 130 °C for 4 h to obtain the refined methyl esters after passing through a purification process. The refined biodiesel characteristics were determined for its using in diesel engine, and the results showed almost positive values. Some techniques were used in the research such as XRD, TEM, BET, TG–DTA, NH₃–TPD and GC–MS.     

Determination of Double Bond Positions and Geometry of Methyl Linoleate Isomers with Dimethyl Disulfide Adducts by GC/MS

The dimethyl disulfide (DMDS) adduct method is one of the convenient and effective methods for determining double bond positions of unsaturated fatty acid methyl esters (FAME) except conjugated FAME. When analyzed using gas chromatography/electron ionization‐mass spectrometry (GC/EI‐MS), unsaturated FAME with DMDS added to the double bonds yields high intensity MS spectra of characteristic ions. The MS spectra of characteristic ions can then be used to easily confirm double bond positions. Here we explore the GC/EI‐MS analysis of the DMDS adducts of methyl linoleate geometrical isomers isolated by high performance liquid chromatography (HPLC) with a silver nitrate column. For C18:2‐c9, c12 and C18:2‐t9, t12, DMDS randomly formed adducts with double bonds at either carbon 9–10 or carbon 12–13, but not both at the same time due to steric hindrance. For C18:2‐c9, t12 and C18:2‐t9, c12, however, DMDS only formed adducts with the double bond in the cis configuration. Consequently, when analyzing fatty acids with methylene interrupted double bonds, with one double bond in the cis and one in the trans configuration, double bond positions cannot be completely confirmed.     

Enzymatic conversion of corn oil into biodiesel in a batch supercritical carbon dioxide reactor and kinetic modeling

Synthesis of fatty acid methyl esters (FAME) as biodiesel from corn oil was studied in a batch supercritical carbon dioxide (SC-CO₂) bioreactor using immobilized lipase (Novozym 435) as catalyst. Effects of reaction conditions on the contents of FAME, monoacylglycerols (MAG), diacylglycerols (DAG), and triacyglycerols (TAG) were investigated at various enzyme loads (5–15%), temperatures (40–60 °C), substrate mole ratios (corn oil:methanol; 1:3–1:9), pressures (10–30 MPa), and times (1–8 h). The highest FAME content (81.3%) was obtained at 15% enzyme load, 60 °C, 1:6 substrate mole ratio, and 10 MPa in 4 h. A reaction kinetic model was used to describe the system, and the activation energy of the system was calculated as 72.9 kJ/mol. Elimination of the use of organic solvents, chemical catalysts and wastewater as well as reasonably high yields make the enzymatic synthesis of biodiesel in SC-CO₂ a promising green alternative to conventional biodiesel process.     

Application of short path distillation for recovery of polyphenols from deodorizer distillate

During physical refining of oil derived from ‘high temperature short time’ (HTST) pretreated rapeseeds, polyphenols are separated from the oil during deodorization and accumulate together with other high‐value minor compounds in the so‐called deodorizer distillate. For recovery of these compounds single‐stage and multistage short path distillations were carried out in a laboratory scale apparatus at evaporation temperatures between 110 and 170°C and pressures between 0.006 and 0.01 mbar. In addition, the removal of traces of pesticides from rapeseed deodorizer distillate was investigated. It was observed that these compounds can be separated from deodorizer distillate by means of short path distillation very effectively. On the basis of these experiments, a recovery process for polyphenols was proposed involving short path distillation, acid catalyzed esterification with methanol, solvent crystallization and solvent extraction processes. The final product was a polyphenol enriched extract containing about 14% of polyphenols. A polyphenol recovery of 50% is considered to be reachable and fractions rich in tocopherols and sterols may be obtained as by‐products.     

Biodiesel (FAME) Productivity,Catalytic Efficiency and Thermal Stability of Lipozyme TL IM for Crude Palm Oil Transesterification with Methanol

Crude palm oil (CPO) transesterification with methanol at room temperature is an important factor for optimizing biodiesel processing costs with respect to energy input; in addition, good stability of expensive lipase activity was ensured and is reported in this study. The enzyme loading, agitation speed and reaction time at a constant operating temperature of 30 °C were studied to find favourable operational conditions using a factorial design. Statistical analysis was used to assist the enzymatic transesterification so that a reduced mass transfer effect was achieved to obtain high FAME yields. The combination of optimum enzyme loading of 6.67 wt% and 150 rpm agitation speed for the system at 30 °C gave 81.73% FAME yield at 4 h and a production rate of 85.86% FAME yield/h. The high viscosity of CPO observed at 30 °C compared to 40 °C hindered the achievement of 96.15% FAME yield at room temperature. It was found that an increase of 10 °C invariably deactivated the lipase, but was compensated by the enhanced FAME production rate with 96.15% FAME yield after only 4 h reaction time. Thus, 40 °C was considered the most suitable operating temperature for lipozyme TL IM to catalyze CPO transesterification.     

Lipase‐catalyzed transesterification to remove saturated MAG from biodiesel

Saturated MAG (SMG) are known to be present in FAME intended to be used as biodiesel. These SMG can strongly affect the properties of biofuels such as the cloud point (CP), and they have been implicated in engine failure due to filter plugging. It is shown here that lipase G from Penicillium camemberti can be efficiently used for the transesterification of SMG to fatty acid methyl ester and glycerol even in the presence of the bulk biodiesel. Thus, in samples of commercial biodiesel to which glycerol monostearate (GMS) and glycerol monopalmitate (GMP) had been added, their levels were enzymatically reduced from 2% (w/v) to 0.22% (w/v) for GMP and 0.14% (w/v) for GMS as confirmed by GC‐MS analysis. Practical applications: SMG present in biodiesel can have a pronounced negative effect on the CP, and/or filterability and in‐field performance of the fuel. The lipase‐catalyzed transesterification shown in this paper enables a significant reduction in the amount of SMG, leading to superior biodiesel quality.     

Method for determining the olefinic content of the saturated and aromatic fraction of petroleum distillates by hydroboration

This study was prompted by a perceived need for a reliable method for determining olefin content in petroleum distillate fractions. An improved analytical method for the determination of olefin content in naphtha and higher boiling distillate fractions is described. The procedure comprises quantitative addition of diborane that specifically converts the olefins in the saturated and aromatic portion of the petroleum to alcohols. The reaction mixture is chromatographed on alumina, and alcohols are eluted with dichloromethane. The procedure was applied to two hydrocarbon mixtures of 20 saturated, olefinic and aromatic hydrocarbons in the investigated boiling range. Naphtha (ibp–200 °C) and light gas oil (200–350 °C) fractions from the Lloydminster oil were also analysed. Results are compared with the standard FIA method, and a method utilizing both the FIA and proton magnetic resonance spectrometry.     

Preparation and properties of biocomposites composed of sorbitol‐based epoxy resin,pyrogallol–vanillin calixarene,and wood flour

The reaction of pyrogallol (PG) and vanillin (VN), both of which are derived from plant resources, in the presence of p‐toluenesulfonic acid gave PG–VN calixarene (PGVNC) mainly composed of guaiacyl pyrogallol[4]arene. After sorbitol polyglycidyl ether (SPE) was mixed with PGVNC in tetrahydrofuran at an optimized epoxy/hydroxy ratio 1/2.65, the obtained SPE/PGVNC solution was mixed with wood flour (WF), prepolymerized at 150°C, and subsequently compressed at 190°C for 3 h to give SPE–PGVNC/WF biocomposites with WF content 0–20 wt%. The tan δ peak temperature of SPE–PGVNC was 148.1°C, which was much higher than that of the SPE cured with petroleum‐based phenol novolac (SPE–PN) at an optimized epoxy/hydroxy ratio 1/1. Although tan δ peak temperature slightly decreased with increasing WF content, the storage moduli of the SPE–PGVNC/WF biocomposites in the rubbery state at more than 150°C were much higher than those of SPE–PGVNC and SPE–PN. Also, the tensile modulus and strength for SPE–PGVNC/WF increased with increasing WF content. Field emission‐scanning electron microscopy analysis of the biocomposites revealed that WF is tightly incorporated into the crosslinked epoxy resins. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Application of the immobilized bacterial recombinant lipase from <Emphasis Type="Italic">Geobacillus stearothermophilus</Emphasis> G3 for the production of fatty acid methyl esters

The heterogeneous BCL biocatalyst based on the recombinant extracellular lipase from the thermophilic bacteria Geobacillus stearothermophilus G3 with an activity of 23.6 U.A./g was prepared by covalent immobilization on aminated silica gel. The effect of the solvent, temperature (30–60°C), methanol : oil molar ratio (1 : 1 to 9 : 1), and the amounts of water (1–10%) and catalyst (0.25–25%) on the yield of fatty acid methyl esters (FAME) during the methanolysis of sunflower oil with BCL was studied. The maximum yield of FAME was 43%. The biocatalyst exhibits high operational stability: after 480 h of operation (20 cycles), it retains more than 50% of its original activity, making BCL a promising catalyst for application in manufacturing of FAME as feedstock for biodiesel production.