Kinetics and thermodynamics of synthesis of palm oil-based trimethylolpropane triester using microwave irradiation

Enhancement of reaction performance utilizing microwave irradiation has drawn so much interest due to its shorter reaction time and low catalyst loading. These advantages are particularly significant from kinetics and thermodynamics perspectives. This study aimed to investigate the kinetics and thermodynamics of microwave-assisted transesterification of palm oil-based methyl ester into biolubricant. The transesterification reaction of palm oil methyl ester (PME) and trimethylolpropane (TMP) was conducted at 110–130 °C for 90 min under vacuum condition. Sodium methoxide was employed as the catalyst at 0.6 wt% of reactants fixed at molar ratio of 4:1 (PME: TMP). The experimental data were fitted with the second-order reversible reaction kinetics mechanisms. The data were solved via Runge-Kutta 4,5 order using MATLAB software. Analysis on the data revealed that the reaction rate constants at temperatures of 110–140 ℃ were in the range of 0.01–0.63 [(w/w)(min)]⁻¹, with standard errors of 0.0026–0.0228 within 99.99% prediction interval. Microwave-assisted reaction obtained 17.0 kcal/mol of activation energy. This method reduced activation energy by 49% as compared to the conventional heating. Activation energy and time-periodic energy assessment showed that the reaction was endothermic. The reaction at 130 °C is the easiest to activate. The positive Gibbs free energy (ΔG > 0) found using Eyring-Polanyi equation indicated that the transesterification was non-spontaneous and endergonic.     

Computational simulation of palm kernel oil-based esters nano-emulsions aggregation as a potential parenteral drug delivery system

The self-assembled structure of palm kernel oil-based esters (PKOEs) nano-emulsions has shown a great potential used for parenteral drug delivery applications. Here, all-atom level molecular dynamics (MD) was applied to investigate the aggregation process of PKOEs nano-emulsion system. The system consisted of palm kernel oil-based esters (PKOEs) and dipalmitoylphosphatidylcholine (DPPC) in water. The ratio of all constituents was taken from the homogenous region of a ternary phase diagram determined experimentally. The molecules started to aggregate very rapidly from random configurations. A doughnut-like toroidal assembled structure formed at 50 ns with PKOEs surrounded by DPPC molecules. The structural and dynamical properties of the self-assembled doughnut-like toroidal aggregate were analyzed using the principle moment of inertia, eccentricity and radius of gyration. The aggregation structures were compact with the average radius of gyration of 4.10 (±0.02) nm over the last 5 ns. Additionally, both hydrophobic and hydrophilic interactions were involved in aggregation process with a total solvent accessible surface area of 551.72 (±5.88) nm².     

Synthesis and thermal properties of soybean oil-based waterborne polyurethane coatings

Waterborne polyurethane coatings were prepared by a polyaddition reaction using toluene diisocyanate (TDI), 2,2-di(hydroxy-methyl) propionic acid, soy-based polyols with different hydroxyl values, plus 2-hydroxyethyl methacrylate (HEMA) as chain termination agent, triethylamine as neutralization agent, and DBTDL as catalyst. Six soybean oil-based polyols were used in this study with hydroxyl values of 100, 115, 128, 140, 155, and 164 mg KOH g⁻¹, respectively. The molar ratio of polyol hydroxyl to DMPA was varied from 1.6 to 2.6. The storage stability of the waterborne polyurethane coatings was greater than 6 months. The thermal properties of the coating films were investigated by TG and DCS. The results show that the soy-based polyurethane films decomposed in three stages. The glass transition temperatures, T _g, of the soy-based polyurethane films increased with the hydroxyl number of the soy-based polyol.     

Treatment of acidic palm oil for fatty acid methyl esters production

Acidic crude palm oil (ACPO) produced from palm oil mills with an acid value of 18 mg g⁻¹ was considered to be a possible feedstock for biodiesel production. Due to its high acidity, conventional transesterification cannot be applied directly for biodiesel production. Methane sulphonic acid (MSA, CH₃SO₃H) is used to reduce the acidity prior to the alkaline transesterification reaction. The laboratory-scale experiments involved an MSA to ACPO dosage of 0.25–3.5 %, a molar ratio (methanol to ACPO) from 4: 1 to 20: 1, reaction temperature of 40–80°C, reaction time of 3–150 min, and stirrer speed of 100–500 min⁻¹. The optimum esterification reaction conditions were 1 % of catalyst to ACPO, with a molar ratio of methanol to ACPO of 8: 1, a stirring speed of 300 min⁻¹, for 30 min and at 60°C. Under these conditions, the FFA content was reduced from 18 mg g⁻¹ to less than 1 mg g⁻¹ and with a yield of 96 %. The biodiesel produced met the EN14214 standard specifications. MSA was recycled for three times without losing its activity. The biodiesel produced in a two-stage process has a low acid value (0.14 mg g⁻¹).     

Synthesis of benzophenone-containing fatty acids

Syntheses of new benzophenone-containing fatty acids (FABPs) 1, 5, and 6 and a new route to FABP 3 are described. Combined with the known 2 and 4, these FABPs comprise a set of photoactivatable fatty acid analogues with the crosslinking site at defined distances from the carboxylic acid hydroxyl group oxygen atoms ranging from 7.9 to 25.0 A.     

Synthesis and characterization of biodegradable palm palmitic acid based bioplastic

This study involves the quantitative analysis of high free fatty acid crude palm oil, the separation of palmitic acid and synthesis of palm palmitic acid-based bioplastic. Synthesis of dimethyl 2-tetradecylmalonate (DMTDM) using methyl palmitate (MP) with sodium hydride (NaH) in the presence of reactive solvent of dimethyl carbonate (DMC) was carried out. The reaction conditions comprise at a mole ratio of MP: DMC: NaH: dimethylformamide (DMF) (0.1:2:0.25:1) at 60 °C for 14 h with 88.3 ± 1.4% yield. FTIR spectra of DMTDM showed the ester carbonyl group at 1740 cm^–1. The polymerization of DMTDM with 1,6-hexandiol or 1,12-dodecandiol was carried out using titanium (IV) isopropoxide Ti(OiPr)₄ as the catalyst and reaction time of 24 h. The results showed that the poly(dodecyl 2-tetradecylmalonte) (PDTDM) exhibited good thermal properties compared to poly(hexyl 2-tetradecylmalonte) (PHTDM). The increase of the chain length of diol in PDTDM improved the thermal properties of polyester with glass transition, T_g of 13 ºC and melting point of 51 ºC with a molecular weight of 12508 Da and polydispersity index (PDI) of 1.4. In general, the synthetic polyesters can be used as internalplasticizer in bio-based industry.     

Influences of fatty acid moiety and esterification of polyglycerol fatty acid esters on the crystallization of palm mid fraction in oil-in-water emulsion

We examined the crystallization of palm mid fraction (PMF) in oil-in-water (O/W) emulsion, after adding polyglycerol fatty acid esters (PGFEs). We employed ultrasonic velocity measurements and DSC techniques, with special emphases on the influences of fatty acid moiety and esterification of PGFE. Twelve types of PGFEs were examined as additives. PGFEs have a large hydrophilic moiety composed of 10 glycerol molecules to which palmitic, stearic and behenic acids were esterified as the fatty acid moiety with different degrees of esterification. Crystallization temperature (T(c)) of PMF remarkably increased with increasing concentrations of the PGFEs as the chain length of the fatty acid moiety increased, and the PGFE became more hydrophobic in accordance with increasing degree of esterification. We observed that the heterogeneous nucleation of PMF in the O/W emulsion was activated at the oil-water interface, where the template effect of very hydrophobic long saturated fatty acid chains of the PGFE might play the main role of heterogeneous nucleation.     

Synthesis and plugging effect of inverse emulsion polymerization microspheres (OPME) for oil-based drilling fluids

It is difficult to seal oil-based drilling fluids in the large pore and micro-fracture formation, and there are few suitable materials for the oil phase with good sealing ability at present. In order to solve the problem of the lack of sealing ability of oil-based drilling fluids, acrylamide, 2-acrylamido-2-methylpropane sulfonic acid, and acryloyl morpholine were used as monomers, N'N-methylenebisacrylamide was used as a cross-linking agent, Span-80 and Tween-60 were used as emulsifiers, and 2,2′-azobis(2-methylpropionamidine) dihydrochloride was used as an initiator. Polymer microsphere emulsion OPME was synthesized by inverse emulsion polymerization. The structure of polymer microspheres was characterized by infrared spectroscopy, scanning electron microscopy, electron microscopy, H NMR, laser particle size analysis and thermogravimetric analysis. The optimal synthesis conditions were determined by the control variable method: the monomer ratio of acrylamide, 2-acrylamido-2-methylpropane sulfonic acid, and acryloyl morpholine was 45:20:15, the amount of emulsifier was 8%, and the reaction temperature was 55℃. The synthetic polymer microspheres were added to the oil-based drilling fluids to perform filtration and loss plugging at atmospheric pressure and high-temperature and high-pressure, as well as pore and artificial fracture core plugging evaluation. The evaluation results show that the permeability reduction rate of pore core can reach 82%, and that of fracture core can reach 100% by adding polymer microspheres with 3% dosage. Finally, the pressure transmission experiment proves that the addition of polymer microspheres can slow the pressure transmission and filtrate intrusion, and enhance the stability of wellbore. Therefore, polymer microspheres are a micron-level plugging agent with good compatibility and high performance with oil-based drilling fluids, and the 3% dosage can better seal the formation of large pores and micro-fractures, which has a good potential for field application.     

Enzymatic alcoholysis of palm and palm kernel oils

The use of lipases as biocatalysts in ester synthesis has been the object of growing interest, owing to the importance of esters as emulsifiers, intermediates to produce oleochemicals, and fuel alternatives. We consider in this report the application of lipases in the ethanolysis of palm and palm kernel oils to produce fatty-acid esters, using n-hexane assolvent. In order to maximize ester production, wea dopted a Taguchi design and built an empirical model. Using this procedure, we determined the optimal condition for each system and established the influence of process variables in the conversion.     

Mechanisms of foam destruction by oil-based antifoams

Oils and mixtures of oils with hydrophobic particles are widely used in various technologies and consumer products to control foaminess and foam stability. The aim of this review is to summarize our current understanding of the mechanisms of foam destruction by such substances, which are usually called antifoams or defoamers. The experimental results show that two types of antifoam can be distinguished (called for brevity "fast" and "slow") which differ in the modes of their action. Fast antifoams are able to rupture the foam films at the early stages of film thinning. As a result, fast antifoams destroy completely the foam in less than a minute, in a typical foam-stability test. Microscopic observations have shown that the fast antifoams rupture the foam films by the so-called "bridging" mechanisms, which involve the formation of oil bridges between the two surfaces of the foam film. The stability/instability of these oil bridges is explained by using the theory of capillarity. In contrast, the oily globules of the slow antifoams are unable to enter the surfaces of the foam films and are first expelled into the Plateau borders (PBs). Only after being compressed by the narrowing walls of the PBs (due to water drainage from the foam), are the globules of the slow antifoams able to enter the solution surface and to destroy the adjacent foam films. Typically, the process of foam destruction by slow antifoams requires much longer time, minutes or tens of minutes, and a residual foam of well-defined height is observed in the foam tests. The experiments show that there is no direct relation between the magnitudes of the entry, E, spreading, S, and bridging, B, coefficients, on one side, and the antifoam efficiency, on the other side. The only requirement for having active antifoam, with respect to the bridging mechanisms, is that B should be positive. On the other hand, the barrier preventing the emergence of pre-emulsified antifoam globules on the solution surface (so-called "entry barrier") is of crucial importance for the mode of foam destruction and for the antifoam efficiency. Measurements of the entry barrier with recently developed film trapping technique (FTT) showed that antifoams possessing low entry barriers act as fast antifoams, whereas high barriers correspond to slow or inactive antifoams, although E, S, and B coefficients could be strongly positive in the latter case. A good agreement between the magnitude of the entry barrier, measured by FTT, and the height of the residual foam, in the presence of slow antifoams, was experimentally established and theoretically explained. The importance of various factors, such as the size of antifoam globules, oil spreading, kinetics of surfactant adsorption, hydrophobicity of solid particles in mixed oil-solid antifoams, and the presence of amphiphilic additives (foam boosters), is discussed from the viewpoint of the mechanisms of antifoaming. The main experimental methods, used for studying the modes of antifoam action, are briefly described.     

Synthesis of a highly fluorinated fatty acid analog

A five-step synthesis of Z-11,11,12,12,13,13,14,14,15,15,16,16,17,17,18,18,18-heptadecafluoro-octadec-8-enoic acid is reported, starting from 1,8-octanediol and 1,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8-heptadecafluoro-10-iododecane. The key step is a Wittig reaction to form the C8-C9 double bond with a Z:E isomeric ratio of 10:1. The route should be generally applicable to the synthesis of highly fluorinated monounsaturated fatty acids.     

Monitoring of oil-based polyurethane synthesis by FTIR-ATR

Oil-based polyurethanes were synthesized from triglyceride oil-based hydroxyl containing material and toluene diisocyanate or hexamethylene diisocyanate for wound dressing applications. The reactions were carried out with or without catalyst at 90 °C. The amount of free isocyanate during the reaction was determined by a FTIR-ATR method, and the results were compared with those from a back-titration method. The data obtained were used for determination of kinetic parameters.     

Preparation of polylactic acid/epoxidized palm oil/fatty nitrogen compounds modified clay nanocomposites by melt blending

In this study, new biopolymer nanocomposites have been prepared. Fatty nitrogen compounds (FNCs); fatty amide (FA), fatty hydroxamic acid (FHA), and carbonyl difatty amide (CDFA), which were synthesized from palm oil, have been used as one of organic compounds to modify natural clay (sodium montmorillonite). The clay modification was carried out by stirring the clay particles in an aqueous solution of FA, FHA, and CDFA by which the clay layer distance increases from 1.23 to 2.71, 2.91 and 3.23 nm, respectively. The modified clay was then used in the preparation of the polylactic acid/epoxidized palm oil (PLA/EPO) blend nanocomposites. The interaction of the modifier in the clay layer was characterized by X-ray diffraction (XRD), and Fourier transform infrared (FTIR). Elemental analysis was used to estimate the presence of FNCs in the clay. The nanocomposites were synthesized by melt blending of the modified clay and PLA/EPO blend at the weight ratio of 80/20. The nanocomposites were then characterized using XRD, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and tensile properties measurements. The XRD and TEM results confirmed the production of nanocomposites. PLA/EPO modified clay nanocomposites show higher thermal stability and significant improvement of mechanical properties in comparison with those of the PLA/EPO blend.     

Assessment of surfactant adsorption in oil-based magnetic colloids

We describe in this paper different and complementary experimental methods for assessing the adsorption of surfactants on metal particles in oil-based suspensions. Two different kinds of particles are dispersed in mineral oil: iron microparticles and CoNi nanoparticles. The adsorption of oleic acid in the Fe/oil interface in diluted suspensions can be determined by obtaining the adsorption isotherm. In addition, we present a method based on the time evolution of the optical absorbance of suspensions, from which the existence of adsorption can be inferred. For concentrated suspensions, the used of optical methods is not recommended, since they are affected by a significant inaccuracy. We present here a useful alternative based on electromagnetic induction phenomena. The results obtained allow a more comprehensive knowledge of the aggregation process in concentrated suspensions. With the same purpose, a third group of experiments, based on rheological techniques, is carried out in Fe/oil and CoNi/oil concentrated suspensions. In these series of experiments, the effect of three surfactants (oleic acid, aluminum stearate and lecithin) is tested by measuring either the viscosity, or the magnetic field-induced yield stress of the suspensions. The combination of these series of experiments gives us valuable information about the most appropriate surfactant/carrier combination capable of imparting a high stability and a strong magnetorheological response in magnetic colloids.     

Synthesis of polyunsaturated fatty acid-containing glucuronosyl-diacylglycerol through direct glycosylation

We describe a total synthesis of a polyunsaturated fatty acid (PUFA)-containing glucuronosyldiacylglycerol (GlcADG), which is a surrogate glycolipid whose synthesis is remarkably upregulated in plant membranes under phosphorus-depleted conditions. Glycosylation between the glucuronide donor bearing 3,4-dimethoxybenzyl (DMPM) protecting groups and di-acylglycerol acceptor proceeded smoothly in the presence of gold(I) catalyst to provide the protected α-isomer of GlcADG as the major product.     

Vegetable oil-based flame retardant epoxy/clay nanocomposites

Flammability of epoxy appears to be one of the greatest threats and hence limits its advanced applications. The present investigation, therefore, reports on vegetable oil-based self-extinguishing epoxy/clay nanocomposites for the first time. These nanocomposites were prepared by the ex-situ technique using mechanical shearing and ultrasonication at different loadings (1, 2.5 and 5 wt%) of nano-clay. Monoglyceride of Mesua ferrea L. seed oil, bisphenol-A and tetrabromobisphenol-A based epoxy resin was used as the matrix. XRD, TEM, SEM, FTIR and rheological studies confirmed partially exfoliated nanocomposites formation. The study demonstrates two fold improvements of tensile strength and scratch hardness, three-fold increase in adhesive strength and 20 units increase in gloss value without any change in impact resistance through nanocomposite formation. TG studied confirmed the enhancement of thermal stability of the nanocomposite by 25 °C. The limiting oxygen index values and UL 94 test indicated the self-extinguishing characteristic of the nanocomposites.     

Zinc-filled oil-based preserving materials modified with carbon additives

Protective efficiency of preservation materials based on spent motor oil and unrefined rapeseed oil with a zinc filler and additions of micrographite or multilwalled carbon nanotubes was studied.     

Synthesis of hydroxy-substituted unsaturated fatty acids and the amino-acid insect-derivative volicitin

An efficient synthesis of N-(17S-hydroxylinolenoyl)-l-glutamine (volicitin), a chemical elicitor from the herbivore-pest beet armyworm is presented. The synthesis, which utilizes a copper-catalyzed acetylene coupling, links (S)-3,6-heptadiyne-2-ol with a C-8 propargylic iodine methyl ester to form the (S)-17-hydroxylinolenate skeleton. By substituting different heptadiyne-2-ol groups, a series of methylene interrupted polyacetylene analogues were generated.     

Synthesis of sulfur-substituted phosphatidylethanolamines and inhibition of protozoan cyclopropane fatty acid synthase

A phosphalidylethanolamine(it1) containing two 9- thiastearyl groups was prepared by chemical synthesis. This compound and its methyl sulfonium derivative were found to be inhibitors of the cyclopropane fatty acid synthase from parasitic protozoan Crithidia fasciculata.