Low Cloud Point Research Articles

Low Fluorine Content CO2-philic Surfactants

The article addresses an important, and still unresolved question in the field of CO(2) science and technology: what is the minimum fluorine content necessary to obtain a CO(2)-philic surfactant? A previous publication (Langmuir 2002, 18, 3014) suggested there should be an ideal fluorination level: for optimization of possible process applications in CO(2), it is important to establish just how little F is needed to render a surfactant CO(2)-philic. Here, optimum chemical structures for water-in-CO(2) (w/c) microemulsion stabilization are identified through a systematic study of CO(2)-philic surfactant design based on dichain sulfosuccinates. High pressure small-angle neutron scattering (HP-SANS) measurements of reversed micelle formation in CO(2) show a clear relationship between F content and CO(2) compatibility of any given surfactant. Interestingly, high F content surfactants, having lower limiting aqueous surface tensions, γ(cmc), also have better performance in CO(2), as indicated by lower cloud point pressures, P(trans). The results have important implications for the rational design of CO(2)-philic surfactants helping to identify the most economic and efficient compounds for emerging CO(2) based fluid technologies.

Self-Assembly of Focal Point Oligo-catechol Ethylene Glycol Dendrons on Titanium Oxide Surfaces: Adsorption Kinetics, Surface Characterization, and Nonfouling Properties

This work covers the synthesis of second-generation, ethylene glycol dendrons covalently linked to a surface anchor that contains two, three, or four catechol groups, the molecular assembly in aqueous buffer on titanium oxide surfaces, and the evaluation of the resistance of the monomolecular adlayers against nonspecific protein adsorption in contact with full blood serum. The results were compared to those of a linear poly(ethylene glycol) (PEG) analogue with the same molecular weight. The adsorption kinetics as well as resulting surface coverages were monitored by ex situ spectroscopic ellipsometry (VASE), in situ optical waveguide lightmode spectroscopy (OWLS), and quartz crystal microbalance with dissipation (QCM-D) investigations. The expected compositions of the macromolecular films were verified by X-ray photoelectron spectroscopy (XPS). The results of the adsorption study, performed in a high ionic strength ("cloud-point") buffer at room temperature, demonstrate that the adsorption kinetics increase with increasing number of catechol binding moieties and exceed the values found for the linear PEG analogue. This is attributed to the comparatively smaller and more confined molecular volume of the dendritic macromolecules in solution, the improved presentation of the catechol anchor, and/or their much lower cloud-point in the chosen buffer (close to room temperature). Interestingly, in terms of mechanistic aspects of "nonfouling" surface properties, the dendron films were found to be much stiffer and considerably less hydrated in comparison to the linear PEG brush surface, closer in their physicochemical properties to oligo(ethylene glycol) alkanethiol self-assembled monolayers than to conventional brush surfaces. Despite these differences, both types of polymer architectures at saturation coverage proved to be highly resistant toward protein adsorption. Although associated with higher synthesis costs, dendritic macromolecules are considered to be an attractive alternative to linear polymers for surface (bio)functionalization in view of their spontaneous formation of ultrathin, confluent, and nonfouling monolayers at room temperature and their outstanding ability to present functional ligands (coupled to the termini of the dendritic structure) at high surface densities.

Optimizing Reaction Conditions for the Isomerization of Fatty Acids and Fatty Acid Methyl Esters to Their Branch Chain Products

AbstractIn order to improve the oxidative stability and cold flow properties of oleic acid or methyl oleate, branch chain isomerization was conducted using a beta zeolite catalyst. Reaction conditions of temperature (200–300 °C), pressure (0.1–3.0 MPa), and co‐catalyst (0–2 wt%) were optimized based on branch chain conversion and the cloud point of the ester following the isomerization reaction of oleic acid or methyl oleate. Fourier transform infrared spectroscopy (FTIR) and Gas Chromatograph equipped with Mass Spectrometry (GC/MS) analyses were used to analyze and quantify the isomerization product samples, while the cloud point of each sample was tested. The lowest and therefore, best cloud point measured was −15.2 °C at conditions of 200 °C, 3 MPa, and 2% co‐catalyst using methyl oleate as a starting material. The highest branch chain conversion achieved was 50% under conditions of 300 °C, 1.5 MPa and 0% co‐catalyst using oleic acid as a starting material. The use of oleic acid and methyl oleate is based on whether it is optimal to carry out the skeletal isomerization before or after the esterification reaction. Performing the isomerization reaction on the ester was preferred over the fatty acid based on the trans isomerization and cloud point results. Reducing the unbranched trans isomers was desirable in obtaining a low cloud point.

The feasibility of converting Cannabis sativa L. oil into biodiesel

Cannabis sativa Linn, known as industrial hemp, was utilized for biodiesel production in this study. Oil from hemp seed was converted to biodiesel through base-catalyzed transesterification. The conversion is greater than 99.5% while the product yield is 97%. Several ASTM tests for biodiesel quality were implemented on the biodiesel product, including acid number, sulfur content, flash point, kinematic viscosity, and free and total glycerin content. In addition, the biodiesel has a low cloud point (−5 °C) and kinematic viscosity (3.48 mm 2/s). This may be attributed to the high content of poly-unsaturated fatty acid of hemp seed oil and its unique 3:1 ratio of linoleic to α-linolenic acid.

Aqueous Solution Properties of the Acid-Labile Thermoresponsive Poly(meth)acrylamides with Pendent Cyclic Orthoester Groups

A series of poly(meth)acrylamide derivatives with pendent six-member cyclic orthoester groups, i.e., poly(N-(2-alkyloxy-1,3-dioxan-5-yl)methacrylamide)s and poly(N-(2-alkyloxy-1,3-dioxan-5-yl)acrylamide)s, have been synthesized and characterized. The difference between these polymers lies in the type of alkyl substitutes (R3), the stereochemical structures of the pendent cyclic orthoester groups (trans vs cis), and the main chain structures (polymethacrylamide vs polyacrylamide). Aqueous solution properties and pH-dependent hydrolysis behaviors of these polymers were studied by various methods including turbidimetry, fluorescence probe, DSC, 1H NMR, microscopy, and light scattering. The results show that these polymers except PtNPM can be dissolved in water at low temperature, and all of the water-soluble polymers are thermosensitive with different lower critical solution temperatures (LCSTs) and susceptible to hydrolysis in mildly acidic conditions. Both thermosensitive properties and acid-triggered hydrolysis behaviors of the polymers are closely related to the polymer structures. In general, polymethacrylamides display higher cloud points (CPs) than polyacrylamides. In addition, the polymers with larger R3 and trans configuration have a lower CP and greater magnitude of dehydration and exhibit a liquid−solid phase transition, while those with smaller R3 and cis configuration have a smaller magnitude of dehydration and undergo a liquid−liquid phase separation. In addition, a two-stage transition process is observed for the polymers with R3 being methyl. 1H NMR results reveal that the acid-triggered hydrolysis rate of the pendent orthoesters increases as R3 changed from methyl to isopropyl, and the configuration changed from cis to trans. The synergetic effect of R3 and stereochemical structure of the pendent groups on the hydrolysis products of the polymers were also observed

Modeling the Phase Behavior of PEO−PPO−PEO Surfactants in Carbon Dioxide Using the PC-SAFT Equation of State: Application to Dry Decontamination of Solid Substrates

The phase behavior of several commercially available poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) block copolymers (PEO−PPO−PEO or Pluronics L) in compressed carbon dioxide has been investigated within the framework of dry nuclear decontamination. For this purpose, cloud points have been measured in the pressure and temperature range from P = (10 to 40) MPa and from T = (293 to 338) K, respectively. To find a reliable method for surfactant selection, the perturbed-chain statistical association fluid theory (PC-SAFT) equation of state (EoS) has been applied to model the experimental data. The pure-component and the respective homopolymer + CO2 binary interaction parameters have been fitted to liquid densities and to homopolymer + CO2 binary equilibrium data. The phase behavior of Pluronics L copolymers as a function of concentration, molar mass, and copolymer composition has been predicted very accurately using a constant PEO−PPO binary interaction parameter kPEO-PPO = 0.007. The PC-SAFT model was also successfully applied to Pluronics R copolymers (PPO—PEO—PPO), although a different kPEO-PPO = −0.018 was required to match the experimental data. The model predictions have shown that Pluronics L copolymers with molar mass M < 2750 g·mol−1 and a PEO mass fraction in the copolymer of less than 30 % have sufficiently low cloud-point pressures and are therefore the most suitable for the decontamination process.

F-T jet fuel from Rentech

In present study, we investigated jet fuel production process, including the crude oil-based conventional process, unconventional oil sources-based process, Fischer–Tropsch synthesis (F–T) process and renewable jet fuel process and analyzed the details of each jet fuel production process. Among these jet fuel production technologies, the F–T synthesis and renewable jet fuel process supply alternative fuels with potential environmental benefit of reduced life cycle greenhouse gas (GHG) emissions and the economic benefits associated with increased fuel availability and lower fuel costs. The F–T synthesis has a major advantage with the possibility of accepting any carbon-based input, which makes it suitable for using a variety of sources such as coal, natural gas and 2nd generation biomass as feedstocks. The renewable jet fuel process such as Bio-Synfining™ (Syntroleum) and Ecofining™ (UOP) as well as C-L™ (Tianjin University) is a low capital cost process of producing high quality synthetic paraffinic kerosene (SPK) from bio-renewable feeds like vegetable oils/fats and waste cooking oils/fats, greases, energy plants of jatropha and algal. The SPK has superior fuel properties to other options available today, with higher cetane number, lower cloud point and lower emissions

Synthesis and characterization of hazelnut oil-based biodiesel

The demand for diesel fuel far exceeds the current and future biodiesel production capabilities of the vegetable oil and animal fat industries. New oilseed crops that do not compete with traditional food crop are needed to meet existing energy demands. Hybrid hazelnut oil is just such an attractive raw material for production of biodiesel. Hazelnut oil was extracted from hybrid hazelnuts and the crude oil was refined. Hazelnut oil-based biodiesel was prepared via the transesterification of the refined hazelnut oil with excess methanol using an alkaline catalyst. The effects of reaction temperature, time and catalyst concentration on the yield of diesel were examined, and selected physical and chemical properties of the biodiesel were evaluated. The biodiesel yield increased with increasing temperature from 25 to 65 °C and with increasing catalyst concentration from 0.1 to 0.7 wt%. The increase in yield with reaction time was nonlinear and characterized by an initial faster rate, followed by a slow rate. Hazelnut oil-based biodiesel had an average viscosity of 8.82 cP at 25 °C, which was slightly higher than that of the commercial soy-based diesel (7.92 cP at 25 °C). An approximate 12 °C higher onset oxidative temperature and a 10 °C lower cloud point of hazelnut oil biodiesel than those of its commercial soy counterpart indicated a better oxidative stability and flowability at low temperature. The average heat of combustion of hazelnut oil biodiesel was 40.23 kJ/g, and accounted for approximately 88% of energy content of diesel fuel. The fatty acid composition of hazelnut oil-based biodiesel was the same as the nature oil.

Stereochemical Effect of Trans/Cis Isomers on the Aqueous Solution Properties of Acid-Labile Thermoresponsive Polymers

Two acid-labile, thermoresponsive poly(methacrylamide)s with the pendant cyclic orthoester moieties of trans and cis configurations, PtNEM and PcNEM, were synthesized via free radical polymerization of the corresponding trans and cis isomers of N-(2-ethoxy-1,3-dioxan-5-yl)methacrylamide (NEM). The thermally induced phase transition/separation behaviors of both polymers as well as the aqueous solution properties below and above their phase transition temperatures were investigated by means of turbidimetry, DSC, 1H NMR, microscopy, fluorescence probe, and dynamic light scattering. Both PtNEM and PcNEM showed aggregation behaviors below their respective LCSTs, and the former formed more hydrophobic microdomains which had greater capability to solvate pyrene molecules compared with PcNEM. These two polymers exhibited thermally induced sensitive and reversible phase transitions in aqueous solution. PtNEM showed a little lower cloud point but much greater phase transition enthalpy compared to PcNEM. The results...

Synthesis and characterization of amphiphilic fluorinated pentablock copolymers based on Pluronic F127

AbstractThe synthesis and self‐assembly behavior of pentablock copolymers consisting of Pluronic F127 (PEO100‐PPO65‐PEO100) and poly(2, 2, 3, 3, 4, 4, 5, 5‐octafluoropentyl methacrylate) (POFPMA) is herein described. Using the difunctional potassium alcoholate of F127, K+O–‐(PEO100‐PPO65‐PEO100)‐O–K+, as the macroinitiator, the POFPMA‐F127‐POFPMA pentablock copolymers were synthesized via oxyanion‐initiated polymerization. The chain length of POFPMA can be controlled by the original molar ratio of macroinitiator to OFPMA monomer, that is, F‐monomer. The composition and chemical structure of POFPMA‐F127‐POFPMA pentablock copolymers have been characterized by FTIR, 1HNMR, and 19F NMR spectroscopy, and gel permeation chromatography techniques. The solution behavior of POFPMA‐F127‐POFPMA copolymers was investigated by the methods of surface tension, cloud point, transmission electron microscopy, and high performance particle sizer (HPPS). The results indicate that these Pluronic F127‐based block copolymers modified with fluorinated segments possess relatively high surface activity and low cloud points, depending on various factors, such as the length of fluorinated block, the concentration of the copolymers in aqueous solution, and the adscititious inorganic salt. TEM measurements showed that the pentablock copolymers can self‐assemble in aqueous solution to form various micellar morphologies. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3029–3041, 2008

Cloud Point Extraction of Polycyclic Aromatic Hydrocarbons in Aqueous Solution with Silicone Surfactants

Abstract Cloud point extraction (CPE) processes with two silicone surfactants, Dow Corning DC-190 and DC-193, were studied as preconcentration and treatment for the water polluted by three trace polycyclic aromatic hydrocarbons (PAHs): anthracene, phenanthrene and pyrene. For all cases, the volumes of surfactant-rich phase obtained by two silicone surfactants were very small, i.e. a lower water content in the surfactant-rich phase was obtained. For example, less than 3% of the initial solution was obtained in a 1% (by mass) surfactant solution, which was much smaller than that of TX-114 in the same surfactant concentration. And TX-114 is known as a high compact surfactant-rich phase among most nonionic surfactants, thus the comparison showed that an excellent enrichment was ensured in the analysis application by the CPE process with the silicone surfactants, and the lower water content obtained in the surfactant-rich phase is also important in the large scale water treatment. The influences of additives and phase separation methodology on the recovery of PAHs were discussed. Comparing with DC-193. DC-190 has a lower cloud point and a higher recovery (near 100%) of all the three PAHs in same surfactant concentration, which was required for application as a preconcentration process prior to HPLC system. However the DC-190 solution is hard to be phase separated only by heating, whereas DC-193 has a relative higher phase separating speed by heating, but a high cloud point (around 360K) limits its application. Due to the phase separation by heating is the only method of CPE suitable to the large scale water treatment, the mixtures of two silicone surfactants solutions were investigated in this study. A solution containing 1% of mixed DC-190 and DC-193 (in the ratio of 90:10) removed anthracene, phenanthrene and pyrene near 100% with a relative low cloud point and quick phase separating speed.

Low-Pressure Hydrocracking of Coal-Derived Fischer−Tropsch Waxes to Diesel

Coal-derived low-temperature Fischer−Tropsch (LTFT) wax was hydrocracked at pressures of 3.5−7.0 MPa using silica−alumina-supported sulfided NiW/NiMo and an unsulfided noble metal catalyst, modified with MoO3. A low-pressure operation at 3.5 MPa produced a highly isomerized diesel, having low cloud points (from −12 to −28 °C) combined with high cetane numbers (69−73). These properties together with the extremely low sulfur (<5 ppm) and aromatic (<0.5%) contents place coal/liquid (CTL) derived distillates as highly valuable blending components to achieve Eurograde diesel specifications. The upgrading of coal-based LTFT waxes through hydrocracking to high-quality diesel fuel blend components in combination with commercial-feasible coal-integrated gasification combined cycle (coal-IGCC) CO2 capture and storage schemes should make CTL technology more attractive.

Modified protein carbonyl assay detects oxidised membrane proteins: A new tool for assessing drug- and chemically-induced oxidative cell injury

Introduction: The carbonyl content of cell proteins is a useful indicator of oxidative protein damage during drug- and chemically-induced toxicities. Since a range of lipophilic carbonylating agents is produced during the membrane peroxidation that accompanies chemically-induced oxidative stress, integral membrane proteins seem especially vulnerable to adduction by these species. To develop tools for assessing such damage, this work refined a popular spectrophotometric assay so that hydrophobic and hydrophilic proteins are separated prior to carbonyl analysis. Methods: The low cloud point properties of Triton X114 were used to resolve mouse liver extracts into fractions comprising hydrophilic and hydrophobic proteins. Following phase separation, protein precipitation and removal of unwanted detergent was achieved via extraction with toluene containing 5% trichloroacetic acid. Carbonyl groups were derivatised using 2,4-dinitrophenylhydrazine and then quantified via spectrophotometry. Results: Postmitochondrial fractions from mouse liver were incubated with azo initiators that generate peroxyl radicals in respective phases of biphasic systems, namely the water-soluble initiator 2,2′-azobis(2-amidinopropane) hydrochloride (AAPH) and the lipophilic initiator 2,2′-azobis(2,4-dimethylvaleronitrile) (AMVN). Following resolution using Triton X114, the carbonyl content of hydrophilic proteins in controls was 1.5 ±0.1 nmol/mg protein, compared to 6.7 ± 0.57 nmol/mg protein in the corresponding hydrophobic proteins ( N = 3, p < 0.05). Exposure to AAPH for 2 h at 37 °C increased the carbonyl content of proteins in the hydrophilic and hydrophobic phases by 4.6- and 3.5-fold, respectively ( p < 0.05). AMVN produced a 3.3-fold increase in the carbonyl content of hydrophobic proteins ( p < 0.05) but did not alter that of aqueous phase proteins. Discussion: This method allows facile resolution of proteins into hydrophobic and hydrophilic fractions prior to carbonyl determination. This modified assay method may facilitate studies of the role of oxidative protein damage in drug- and chemically-induced toxic syndromes.

Substituent Distribution and Clouding Behavior of Hydroxypropyl Methyl Cellulose Analyzed Using Enzymatic Degradation

The distribution of substituents along the polymer backbone will have a strong influence on the properties of modified cellulose. Endoglucanases were used to degrade three different batches of hydroxypropyl methyl cellulose (HPMC) derivatives with similar chemical properties. The phase separation of the HPMCs as a function of temperature, i.e., the clouding behavior, was analyzed prior to degradation. The total amount of unsubstituted glucose was determined using total acid hydrolysis followed by high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The products after enzymatic degradation were analyzed with size-exclusion chromatography with online multiangle light scattering and refractive index detection and also with reducing end determination. To further characterize the formed products, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was employed for analysis of short-chained oligosaccharides. The different endoglucanases showed varying degradation capability of HPMC derivatives, depending on structure of the active site. The investigated HPMCs had different susceptibility to degradation by the endoglucanases. The results showed a difference in substituent distribution between HPMC batches, which could explain the differing clouding behaviors. The batch with the lowest cloud point was shown to contain a higher number of non-degradable, highly substituted regions.

Diesel-Selective Hydrocracking of an Iron-Based Fischer−Tropsch Wax Fraction (C15−C45) Using a MoO3-Modified Noble Metal Catalyst

Iron-based low-temperature Fischer−Tropsch wax, in the carbon number range of C15−C45, was hydrocracked using an unsulfided Pt/SiO2−Al2O3 catalyst, modified with MoO3. The selective production of diesel having a low cloud point (−18 °C) combined with a high cetane number (71) was achieved. A bench-scale trickle-bed reactor was used to study the effect of operating conditions on product selectivities and yield. The effect of pressure and hydrocarbon chain length on reactivity and diesel properties was studied in particular. Low-pressure operation (3.5 MPa) improved the isoparaffin to n-paraffin ratio for the carbon number range C15−C22 but did not affect the degree of isomerization significantly after C22. The higher pressure of 7.0 MPa suppressed the isomerization and the C23+ percent conversion and improved the diesel selectivity by inhibiting secondary cracking. Increasing the pressure resulted in an overall paraffin reactivity decrease. A maximum in paraffin reactivity at C33 was observed at low-pressure operation, while high-pressure operation resulted in two maxima at C21 and C33. The observed unexpected paraffin reactivity pattern was the consequence of competing concentration and reactivity effects.

Phase behavior of water-in-supercritical carbon dioxide microemulsion with sodium salt of bis(2,2,3,3,4,4,5,5-octafluoro-1-pentanol) sulfosuccinate

The fluorinated analogues of AOT surfactant, sodium salt of bis(2,2,3,3,4,4,5,5-octafluoro-1-pentanol) sulfosuccinate, which has CO 2-philic chains and a hydrophilic head group, was synthesized for forming water-in-CO 2 microemulsion. The cloud point of this surfactant was measured and the supercritical fluid-phase behavior of water-in-CO 2 microemulsion was investigated by using a variable-volume view cell apparatus. It was found that the phase behavior of microemulsion is affected by the concentrations of water and surfactant in CO 2, molar ratio of water to surfactant ( W o = [water]/[surfactant]), and the amount of CO 2. From this experiment, we found out another cloudy point which exists above the homogeneous microemulsion region. We defined this point as “upper cloud point” and general cloud point as “lower cloud point. The region which exists between these two cloud points was defined as “stable region of microemulsion”. Conditions for the formation of water-in-CO 2 microemulsion were obtained at temperatures up to 370.15 K.

Nonionic Surfactant and Temperature Effects on the Viscosity of Hydrophobically Modified Hydroxyethyl Cellulose Solutions

Nonionic surfactant and temperature effects on the viscosity of hydrophobically modified hydroxyethyl cellulose (HMHEC) solutions are investigated experimentally. Weak shear thickening at intermediate shear rates takes place for HMHEC at moderate concentrations and becomes more significant at lower temperatures. While this amphiphilic polymer in surfactant-free solution does not turn turbid by heating to 95 degrees C, its mixture with nonionic surfactant shows a lower cloud point temperature than does a pure surfactant solution. For some mixture cases, phase separation takes place at temperatures as low as 2 degrees C. The drop of cloud point temperature is attributed to an additional attractive interaction between mixed micelles via chain bridging. With increasing temperature, the viscosity of an HMHEC-surfactant mixture in aqueous solution first decreases but then rises considerably until around the cloud point. The observed viscosity increase can be explained by the interchain association because of micellar aggregation.

PALM OIL AND SUNFLOWER OIL: EFFECT OF BLEND COMPOSITION AND STIRRER TYPES DURING FRACTIONATION ON THE YIELD AND PHYSICOCHEMICAL PROPERTIES OF THE OLEINS

ABSTRACT The effect of blend composition of refined, bleached and deodorized (RBD) palm oil and sunflower oil and that of different types of stirrers during fractionation on the yield and physicochemical characteristics of the oleins was investigated. Blends of 80% palm oil with 20% sunflower oil, and 60% palm oil with 40% sunflower oil were fractionated at 21C, and the oil samples were agitated with stirrers 1, 2, 3 and 4. The results showed that the highest yield was obtained with 60% palm oil and 40% sunflower oil blend when stirrer 2 was used to agitate the sample. There was a significant difference in iodine value (IV) of samples agitated with stirrers 3 and 4. The difference was not significant when stirrers 1 and 2 were used. Blending palm oil with sunflower oil followed by fractionation produced oleins of much higher IV than either commercially available regular palm olein or superolein. The major fatty acids in the oleins obtained after fractionating blend of 80% palm oil and 20% sunflower oil were palmitic (31.8–33.2%), oleic (38.1–39.3%) and linoleic (21.6–24.1%) acids. With higher amount of sunflower oil of 40% in the oil blend, the amount of palmitic acid significantly decreased (25.1–26.3%). After fractionation, the blend containing 60% palm oil and 40% sunflower oil produced liquid fractions which were lower in dipalmitoyl‐oleoyl‐glycerol (POP), palmitoyl‐oleoyl‐stearoyl‐glycerol (POS), palmitoyl‐dioleoyl‐glycerol (POO) and dipalmitoyl‐linoleoyl‐glycerol (PLP) compared to the blend containing 80% palm oil and 20% sunflower oil. The blend with a higher level of sunflower oil at 40% produced oleins of much lower cloud point (3.5–3.7C) than the blend containing only 20% sunflower oil. The type of stirrer did not have any significant effect on the cloud point.

Micellization of sodium bis(2-ethylhexyl)sulfosuccinate in supercritical CO 2 with fluorinated co-surfactant and its solubilization of hydrophilic species

The solubilities of sodium bis(2-ethylhexyl)sulfosuccinate (AOT) in supercritical CO 2 (scCO 2) in the presence of ethanol, 1-pentanol and 2,2,3,3,4,4,5,5-octafluoro-1-pentanol (F-pentanol) at 38.0 °C and different pressures were determined. It was found that AOT (0.01–0.07 M) could be solubilized in scCO 2 with smaller amount of F-pentanol (0.20–0.30 M) compared with ethanol (1.00–1.40 M) and 1-pentanol (0.60–1.00 M), because F-pentanol has ‘CO 2-philic’ fluorinated alkane chain. The phase behavior studies for AOT (0.03 M)/F-pentanol (0.18–0.35 M)/scCO 2 system ranging in temperature from 38.0 to 52.2 °C and pressures up to 35.00 MPa indicated that the cloud point pressure of AOT decreased significantly with the addition of F-pentanol, and the lower temperature, the lower cloud point pressure of AOT especially at higher concentrations of F-pentanol. In addition, 0.016 M AOT/0.24 M F-pentanol/scCO 2 system could solubilize a significant amount of water ( W 0 total = 11.5 , and W 0 corr = 6.0 ) at moderate conditions, which implied the formation of water-in-CO 2 reverse microemulsions. Visual observation using a video camera on the solubilization of methyl orange (MO) further proved the existence of polar micro-water domains within the AOT W/C reverse microemulsions. Besides that, bio-macromolecules such as cytochrome c and lysozyme and 8-hydroxy-1,3,6-pyrenetrisulphonic acid trisodium salt (HPTS) characteristic of highly ionic property could be solubilized in the microemulsions, which was obviously reflected by the UV–vis spectra.

Physicochemical characteristics of palm oil and sunflower oil blends fractionated at different temperatures

This research was carried out to determine the effect of fractionation temperature on the physicochemical characteristics of refined, bleached and deodorized (RBD) palm oil and sunflower oil blends fractionated at different temperatures. Blends of 20% and 40% sunflower oil with 80% and 60% RBD palm oil, respectively, were fractionated at three different temperatures (15, 18 and 21 °C). The results showed that olein with higher iodine value was obtained at lower fractionation temperature. This was because, at lower fractionation temperature, more of the polyunsaturated fatty acid, namely linoleic acid (C18:2), went into the liquid fraction. On the other hand, more of the saturated fatty acid, namely palmitic acid (C16:0), went into the liquid fraction at higher fractionation temperature. Blending reduced the triacylglycerol composition, namely POP, POS, SOO and PLP, while OLO, PLL, OLL and LLL/LLnO increased. Lower fractionation temperature decreased the composition of monosaturated triacylglycerol and increased the composition of di- and polyunsaturated triacylglycerols. Lower fractionation temperature produced a liquid fraction with lower solid fat content and lower cloud point than did higher fractionation temperature.