Low Cloud Point Research Articles

Biodegradable MAM-based amphiphilic block copolymers: Toward efficient and eco-friendly kinetic inhibitors for methane hydrate formation

The development of low dosage hydrate inhibitors holds significant implications for the oil and gas industry. Some commercially available inhibitors, such as Luvicap EG, are derived from the lactam-containing polymer PVCap, which exhibit limited biodegradability and possess low cloud point (30-40℃), thereby constraining their practical utility. The present study successfully synthesized a series of novel amphiphilic block copolymers based on methacrylamide (MAM) by introducing biodegradable hydrophobic esters (ε-caprolactone (CL), δ-valerolactone (VL), and glycolide (GA)) onto the main chain of poly (methyl acrylamide) (PMAM), serving as KHIs. The synthesized MAM-based polymers maintain water solubility within the range of 0–98 ℃ without thermal responsiveness, effectively preventing deposition issues associated with traditional KHIs. Additionally, all MAM-based polymers demonstrated good biodegradability. The dynamics experiments have shown that PMAM homopolymers did not possess KHI effect, while the MAM-based block copolymers, especially PMAM-b-PVL, exhibited excellent performance in inhibiting hydrate nucleation. At low concentrations, the KHI effect of PMAM-b-PVL was comparable to that of the commercial KHI Luvicap EG. The in-situ Raman spectroscopy experiment further revealed the inhibition mechanism of the amphiphilic polymers, which was achieved by forming effective arrangements at the gas–liquid interface and disrupting the water structure in the interfacial region, thereby impeding the formation of hydrate cages, especially large cages. The findings provided a promising and environmentally friendly solution for the management of hydrates in the oil and gas industry

Effect of biosurfactants on the self-assembly behavior and drug encapsulation for branched block copolymers

For the past few years, block copolymers have attracted extensive attention in the field of drug delivery. In this work, the hyperbranched PEO-PPO block copolymer H1304 having the same PEO segments and PPO segments as the commercially available 4-branched block copolymer Tetronic1304 was synthesized. Compared with T1304, H1304 was characterized by lower cloud point, smaller critical micelle concentration (CMC), larger micellar size and better drug solubilization capacity. The effect of three biosurfactants lecithin (PC), alkyl glycogen (APG), sodium deoxycholate (NaDC) on the aggregation behavior of H1304 and T1304 were researched. Meanwhile, the solubilization and in vitro release properties of hydrophobic anticancer drug podophyllotoxin were also evaluated. The addition of PC or APG to form a mixed micelle reduced the cloud point and CMC, optimized the drug carrier characteristics. NaDC exhibited different effects due to its unique disclike surface structure. NaDC formed back-to-back aggregates, which interfered the self-assembly process of block copolymer and in turn caused variation of the copolymer micellar properties. The study of mixed systems consisting of biosurfactants and block copolymers will help to change the performance of copolymers in various pharmaceutical fields and contribute to the application of copolymers as drug carriers in drug delivery systems.

Influence of glycol ether additive with low molecular weight on the interactions between CO2 and oil: Applications for enhanced shale oil recovery

The high-efficient development of shale oil is one of the urgent problems in the petroleum industry. The technology of CO2 enhanced oil recovery (EOR) has shown significant effects in developing shale oil. The effects of several glycol ether additives with low molecular weight on the interactions between CO2 and oil were investigated here. The solubility of glycol ether additive in CO2 was firstly characterized. Then, the effects of glycol ether additives on the interfacial tension (IFT) between CO2 and hexadecane and the volume expansion and extraction performance between CO2 and hexadecane under different pressures was investigated. The experimental results show that diethylene glycol dimethyl ether (DEG), triethylene glycol dimethyl ether (TEG), and tetraethylene glycol dimethyl ether (TTEG) all have low cloud point pressure and high affinity with CO2. Under the same mass fraction, DGE has the best effect to reduce the IFT between hexadecane and CO2 by more than 30.0%, while an overall reduction of 20.0%–30.0% for TEG and 10.0%–20.0% for TTEG. A new method to measure the extraction and expansion rates has been established and can calculate the swelling factor accurately. After adding 1.0% DEG, the expansion and extraction amounts of CO2 for hexadecane are respectively increased to 1.75 times and 2.25 times. The results show that glycol ether additives assisted CO2 have potential application for EOR. This study can provide theoretical guidance for the optimization of CO2 composite systems for oil displacement.

Properties That Potentially Limit High-Level Blends of Biomass-Based Diesel Fuel.

While today's biomass-based diesel fuels are used at relatively low blend levels in petroleum diesel, decarbonization of the heavy-duty trucking and off-road sectors is driving increasing use of higher level blends and the combination of hydroprocessing-derived renewable diesel (RD) with biodiesel (fatty acid methyl esters) to create a 100% renewable fuel. However, little data are available on the properties of biodiesel blends over 20 vol % into RD or conventional diesel, despite the potential for properties to fall well outside the normal range for diesel fuels. Here, we evaluate the properties of 20-80% blends of a soy-derived biodiesel into RD and petroleum diesel. Properties measured were flash point, cloud point, cetane number, surface tension, density, kinematic viscosity, distillation curve, lower heating value, water content, water solubility in the fuel, lubricity, and oxidation stability. Density and viscosity were measured over a wide temperature range. A key objective was to reveal properties that might limit blending of biodiesel and any differences between biodiesel blends into RD versus petroleum diesel and to understand research needed to advance the use of high-level blends and 100% renewable fuel. Properties that may limit blending include the cloud point, viscosity, distillation curve, and oxidation stability. Meeting cloud point requirements can be an issue for all distillate fuels. For biodiesel, reducing the blend level and use of lower cloud point hydrocarbon blendstocks, such as No. 1 diesel or kerosene, can be used in winter months. Alternatively, a heated fuel system that allows for starting the vehicle on conventional diesel before switching to pure biodiesel (B100) or a high-level blend has been successfully demonstrated in the literature. Some biodiesels can have kinematic viscosity above the upper limit for diesel fuels (4.1 mm2/s), which will limit the amount that can be blended. Biodiesel boils in a narrow range at the very high end of the No. 2 diesel range. Additional research is needed to understand how the high T90 of B100 and high-level blends and the very low distillation range of B100, some RD samples, and high-level biodiesel blends impact lube oil dilution, engine deposits, and diesel oxidation catalyst light-off. Blending with No. 1 diesel or kerosene or biodiesel-specific engine calibrations may mitigate these issues. Oxidation stability of higher level blends is poorly understood but may be addressed through the increased use of antioxidant additives. Finally, high-level biodiesel blends and B100 will have significantly higher density, viscosity, and surface tension compared to conventional diesel. In combination with the high boiling point, these properties may impact fuel spray atomization and evaporation, and additional research is needed in this area.

Comparison of Performance Properties of Muds Formulated With Synthesized C14 and C16 Esters of Lauric Acid

Drilling muds have relied on a range of base fluids, with mineral oil-based formulations dominating the landscape for decades. However, mineral oil-based muds contain a plethora of toxic aromatic compounds which are persistent in the environment. Hence, the objective of the paper was to synthesize and compare the performance properties of drilling muds formulated with C14 and C16 esters of lauric acid using appropriate standard procedures. Benchmarking of the esters with a reference synthetic base fluid indicated that the esters have suitable physicochemical properties for application as synthetic base drilling fluid. Their kinematic viscosities are within the API recommended range, ethyl laurate (EL) has a lower cloud point relative to the reference, and the two base fluids have higher flash point and electrical stabilities relative to the reference. The results obtained from comparing the rheology of muds prepared with ester products and that prepared with the reference fluid indicate that the muds prepared with ethyl, and n-butyl laurate have higher electrical stability than the mud prepared with the reference base fluid. The results also show that the muds prepared with the esters synthesized in this work displayed better rheology profiles than the mud prepared with the reference synthetic base fluid. However, ethyl laurate (EL) formulated mud had better thermal stability than n-butyl laurate (BL) at the temperature range studied. Through the investigation of these ester-based drilling muds, we showcased the potential of these esters to enhance drilling efficiency, minimize environmental impact, and optimize operational performance.

Liquid to solid phase transition detection by using a vibrating tube densimeter along with densities up to 137 MPa of beef tallow fatty acid alkyl esters

Phase behavior and thermophysical properties of biodiesel at high pressure and high temperature are limited in the literature. These are useful to develop models and to understand their behavior having in mind the use of biodiesel in engines. Liquid to solid phase transitions, by using a vibrating tube densimeter, along with densities of three beef tallow fatty acid alkyl esters were studied in this work. Measurements of the oscillating period for each biofuel were carried out in a modular array constituted by two vibrating tube densimeters coupled in series and connected to a single loading cell. The oscillating period was converted to density by the forced path mechanical calibration (FPMC) method. Experimental liquid density sets for three beef tallow biodiesel samples based on fatty acid alkyl esters (FAAEs) are reported for the first time for pressures up to 137 MPa. These biofuels, named fatty acid methyl esters (FAMEs), fatty acid ethyl esters (FAEEs) and fatty acid butyl esters (FABEs), were measured in the temperature range of 286–393 K. The detection procedure for the beginning of the high-pressure solidification was focused on the beef tallow FABEs sample based upon its lower cloud point (CPFABEs = 281.15 K) in comparison with the reported property for the other esters (CPFAEEs = 289.15 K, CPFAMEs = 291 K) with the same feedstock; therefore, the conditions for the metastable liquid to solid phase transition associated to the effect of high pressure was detailed for waste beef tallow butyl ester biodiesel by performing step-by-step compressions in the interval of 286.20–298.13 K and with the help of the vibrating tube densimeters. FABEs had the lower density in contrast with FAEEs and FAMEs, this one being the denser biofuel. Modeling of liquid density data was performed by the perturbed-chain statistical associating fluid theory (PC-SAFT) Equation of State and the Tammann-Tait equation with maximum absolute average deviations of 0.15 % and 0.05 %, respectively. Both models were applied for correlating the thermodynamic derived properties of the fluid phase: isobaric thermal expansivity and isothermal compressibility.

A sparse-dense hierarchical structured conductive elastomer composites for highly sensitive and stretchable strain sensor

Flexible strain sensor using conductive elastomer (CE) have fostered hope for the development of healthcare, human–machine interfaces, and soft robotics technologies. However, it is still challenging to obtain CE based strain sensor with excellent stretchability, wide strain range, high sensitivity coupled with outstanding stability via facile preparation process. Herein, combining the advantages of sparse and dense conductive network, a sparse-dense hierarchical structured conductive elastomer composites (CECs) based on natural rubber (NR) and modified MWCNTs (m-MWCNTs) is developed through facile one-pot synthesis. By means of the low cloud point of nonionic surfactant Triton x-100, the thick-sparse and thin-dense conductive layers as well as the excellent interface between hierarchical structure are formed by controlling the content of Triton x-100 and dispersed temperature. The severe slippage of sparse conductive network at small deformation and the avulsion of dense conductive network at large strain could synergistically enhance mechanical property and sensing performance of NR/m-MWCNTs CECs. Consequently, the designed stain sensor can achieve high sensitivity and linearity at a strain range of 0–200 % and 200–423 %, which are superior to most other state-of-the-art CECs strain sensors. Meanwhile, a wide range of detection (1 %-423 %), a fast response time (0.23 s), excellent repeatability, and stability are also obtained. Besides, our developed strain sensor was successfully applied in elbow pad and knee pad for monitoring human motion. In addition, NR/m-MWCNTs CECs exhibit the superior electric heating performance. The above satisfactory results reveal that our developed sparse-dense hierarchical CECs has the potential for applications in smart wearable electronics.

Performance evaluation of a diesel engine fueled with Chlorella Protothecoides microalgal biodiesel

The main objective of the current study is to determine the engine performance, combustion, and emission analysis of compression ignition engines fuelled with Chlorella Protothecoides microalgal biodiesel (CPMB). The biodiesel was derived from Chlorella Protothecoides microalgal oil (CPMO) through transesterification. Under the specified conditions, which included a methanol-to-oil molar ratio of 7.41 (vol/vol), a reaction time of 105.6 min, a reaction temperature of 65 °C, and a catalyst concentration of 1.024 (% wt/vol) and achieved a biodiesel yield of 98.1%. The fuel properties were determined using standard methods, revealing that the density and kinematic viscosity of CPMB were significantly higher than those of diesel. However, CPMB still exhibits satisfactory fuel properties that meet most biodiesel specifications. CPMB boasts a low cloud point (CP) and pour point (PP) of 0 and -3 °C, respectively, indicating its effective usability in cold climates. The oxidation stability of CPMB, determined by the modified Rancimat method, was found to be 4.6 h, satisfying ASTM specifications. The fuel tested in this study was 20% biodiesel with diesel, 100% biodiesel, and neat diesel. These fuels had been tested on a CI engine in which the engine speed and compression ratio were fixed at 1500 rpm and 18:1, respectively. Based on the results, it is found that the indicated thermal efficiency decreases up to 3.68% and 8.22% with B20 and B100 as compared to diesel. However, mechanical efficiency, volumetric efficiency, and indicated power were estimated to be higher at peak engine load conditions when correlated with neat diesel. Furthermore, the mean effective pressure for B20 and B100 was estimated to be decreasing while the mass fraction of fuel burnt and the rate of pressure rise increased compared to diesel at peak load conditions. For exhaust emission analysis, a significant reduction was recorded in CO and UHC emissions, while NOX emission increases at peak engine loads. From the above results, it is accomplished that the performance of B20 blends is nearly identical to diesel, and it can be recommended to be used in engines without any modification.

Betulin‐containing bioactive amphiphilic copolymers: Synthesis, characterization and self‐assembly

AbstractBetulin, a natural triterpene possessing a wide range of biological activities, has been modified via Steglich esterification to produce a methacrylate derivative capable of participating in radical polymerization. The modification is intended to increase the solubility of betulin, which is almost insoluble in water, by incorporating into the composition of an amphiphilic copolymer. The resulting solubility of betulin in water increased from 8·10−5 mg/mL to more than 10 mg/mL per betulin. For this, well‐defined biocompatible thermoresponsive copolymers with high betulin content have been synthesized through the conventional and RAFT copolymerizations of betulin methacrylate (BeMA) with methoxy oligo(ethylene glycol) methacrylate (MOEGMA). BeMA was more reactive in the BeMA‐MOEGMA pair; the resulting copolymers were slightly enriched with BeMA units (r1 = 1.70, r2 = 0.93). The copolymers exhibited LCST‐type behavior. LCST was tuned by balancing the hydrophobic betulin and hydrophilic OEG fragments. The molecular weight characteristics of polymers and their behavior in aqueous and organic solutions have been studied. Copolymers obtained by conventional polymerization had lower cloud points than RAFT copolymers of the same composition. The copolymers are characterized by low critical micelle concentrations that decrease as the BeMA fraction in the copolymers increases. RAFT copolymers were shown to form unimolecular micelles resistant to dissociation, which is promising for their use in targeted drug delivery.

Biodiesel production from high free fatty acid byproduct of bioethanol production process

Biodiesel is a reliable and promising replacement of fossil diesel. It is stable, less toxic and can be produced from sustainable resources, including a variety of raw materials. Currently, the most widely used are vegetable oils (edible and nonedible), due to their availability. The present paper considers the potential of obtaining fatty acid ethyl esters (FAEE) from corn oil, which is a byproduct of bioethanol production process. The ultimate outcome would definitely increase the profitability of the initial bioethanol production process. The biodiesel production process was implemented in two steps, due to the high content of free fatty acids of the obtained corn oil. The first step includes an acid-catalyzed esterification process and the second step comprises an alkali-catalyzed transesterification process to receive FAEE. Two different catalysts (sulfuric acid and p-toluene sulfonic acid) were utilized and compared each other in the esterification process, in order to cope with high acid number of the raw material. A comprehensive qualitative and quantitative analysis of both feedstock and biodiesel was performed using gas chromatography-mass spectrometry method. The obtained biodiesel was characterized by a significantly lower cloud point compared to the feedstock and high acid number.

Oxyvinylenelactam Polymers-A New Class of Lactam-Based Kinetic Hydrate Inhibitor Polymers.

The deployment of kinetic hydrate inhibitors (KHIs) is a chemical method for the prevention of gas hydrate plugging in gas, condensate, and oil production flow lines. Polymers made using the monomer N-vinylcaprolactam (VCap) are one of the most common KHI classes. Alternative classes of polymers containing caprolactam groups are rare. Here, we present a study on oxyvinylenelactam polymers and copolymers with pendant piperidone or caprolactam groups. Low-molecular-weight homo- and copolymers were obtained. The nonrotating vinylene groups impart rigidity to the polymer backbone. Poly(oxyvinylenecaprolactam) (POVCap) was insoluble in water, but poly(oxyvinylenepiperidone) (POVPip) and OVPip:OVCap copolymers with 60+ mol % OVPip were soluble with low cloud points. KHI screening tests were carried out using the slow constant cooling method in steel rocking cells. POVPip was water soluble with no cloud point up to 95 °C but showed a poor KHI performance. In contrast, OVPip:OVCap copolymers with about 60–70 mol % OVPip were also water soluble and showed a reasonable KHI performance, better than that of poly(N-vinylpyrrolidone) but not as good as that of poly(N-vinylcaprolactam). Surprisingly, several additives known to be good synergists for VCap-based polymers showed negligible synergy or were antagonistic with the 62:38 OVPip:OVCap copolymer with regard to lowering the onset temperature of hydrate formation. However, a blend with hexabutylguanidinium chloride showed a strong effect to delay the onset of rapid hydrate formation.

Chemical Conversion of Fischer–Tropsch Waxes and Plastic Waste Pyrolysis Condensate to Lubricating Oil and Potential Steam Cracker Feedstocks

The global economy and its production chains must move away from petroleum-based products, to achieve this goal, alternative carbon feedstocks need to be established. One area of concern is sustainable production of synthetic lubricants. A lubricating oil can be described as a high boiling point (>340 °C) liquid with solidification at least below room temperature. Historically, many lubricants have been produced from petroleum waxes via solvent or catalytic dewaxing. In this study, catalytic dewaxing was applied to potential climate neutral feedstocks. One lubricant was produced via Fischer–Tropsch (FT) synthesis and the other lubricant resulted from low temperature pyrolysis of agricultural waste plastics. The waxes were chosen because they each represented a sustainable alternative towards petroleum, i.e., FT waxes are contrivable from biomass and CO2 by means of gasification and Power-to-X technology. The pyrolysis of plastic is a promising process to complement existing recycling processes and to reduce environmental pollution. Changes in cloud point, viscosity, and yield were investigated. A bifunctional zeolite catalyst (SAPO-11) loaded with 0.3 wt% platinum was used. The plastic waste lubricants showed lower cloud points and increased temperature stability as compared with lubricants from FT waxes. There was a special focus on the composition of the naphtha, which accumulated during cracking. While the plastic waste produced higher amounts of naphtha, its composition was quite similar to those from FT waxes, with the notable exception of a higher naphthene content.

A hypothermia-sensitive micelle with controlled release of hydrogen sulfide for protection against anoxia/reoxygenation-induced cardiomyocyte injury

Hydrogen sulfide (H2S) provided a potential strategy to protect heart from ischemia-reperfusion injury (IRI). However, controllable and continuous H2S level for long periods of time remained challengeable in the aspect of maintaining viability of heart in cold storage. Hence, we investigated the protective efficiency of hypothermia-sensitive micelle with controlled release of H2S for cardiomyocyte through in vitro anoxia/reoxygenation (A/R) cardiomyocyte models. This micelle was fabricated through the self-assembly of an amphiphilic deblock copolymer methoxy poly(ethylene glycol)-poly(N-pyrrolidine-formyl-caprolactone-co-thiobenzamide-caprolactone) (mPEG-P(VPyCL-co-TBA-CL)). Benefiting from the reversible lower critical solution temperature (LCST)-type behavior with low cloud point (Tcp) of 13 °C, self-assembled micelle could control the release of H2S in response to temperature under the thiol-triggered condition. Noteworthily, with the disassembly of micelle at 4 °C, micelles enjoyed a controllable and continuous release profile of H2S. By mimicking the cold storage of the heart against IRI, released H2S from micelle was demonstrated to provide a significant protection for cardiomyocytes against A/R-induced injury. Taken together, we envisioned that this work offered a potential hypothermia-sensitive material with controlled release of H2S promising for heart preservation against IRI in cold storage.

Iso-oleic estolide products with superior cold flow properties

One of the drawbacks of using vegetable oils directly as a lubricant is poor low temperature performance, mainly pour and cloud points. Oleic estolides were developed to improve these properties as well as increase the oxidative stability of the oil. However, additional low temperature properties are desirable to increase the field of use of these materials. A new series of iso-oleic estolide free acids and 2-ethylhexyl (2-EH) esters capped with various fatty acids had superior physical properties and cold flow properties, compared to traditional oleic based estolides. The average pour point of the iso-oleic estolide 2-EH esters was − 41°C, compared to − 23°C of iso-oleic estolide free acids. The iso-oleic-octanoic and iso-oleic-decanoic estolide 2-EH esters had excellent pour points of − 60°C. The cold flow properties of iso-oleic estolides decrease with increasing the carbon number of the saturated capping fatty acid, while the viscosity index and oxidation stability were only slightly improved. Therefore, saturated mid-chain fatty acids are more suitable as the capping fatty acid for iso-oleic acid based estolides. Iso-oleic-coconut estolide 2-EH esters exhibited good physical properties, with pour points as low as − 45°C. The iso-oleic estolide free acids and 2-EH esters are a new kind of low-cost materials for bio-lubricants with excellent cold flow properties.

Influence of amino acids on the aggregation behavior and drug solubilization of branched block copolymers

Block copolymers and their related structure-performance relationships for controllable drug delivery have gained much attention recently. In this work, multibranched PEO-PPO copolymer M904 was synthesized, which had the same PEO and PPO segments with commercial 4-branched copolymer Tetronic 904 (T904). The effect of three amino acids alkaline lysine (Lys), neutral glycine (Gly) and acidic glutamic acid (Glu) on the aggregation behavior of M904 and T904 were investigated. The solubilization and in vitro release property of hydrophobic drug simvastatin (ST) were estimated. Compared to T904, lower cloud point, bigger critical aggregation concentration (CAC), smaller micropolarity, larger size aggregates, better drug solubilization capacity and drug released at a slower rate were features of multibranched copolymer M904. With the addition of Lys or Gly, cloud point, micropolarity and CAC decreased, while aggregates size and drug solubility raised, the rate of drug release slowed, and Lys had a greater effect than Gly. Glu showed opposite behavior, CAC and cloud point increased, and release rate became faster. Both the alteration of copolymer architecture and the addition of amino acids could regulate the copolymer performance, which would be beneficial to design drug formulations in pharmaceutical applications.

Oxidation Stability Improvement For Jatropha Biodiesel To Meet The International Standard For Automotive Applications

Biodiesel from Jatropha oil has several advantages compared to which from Palm oil, among others better cold flow properties (lower cloud point, pour point and CFPP). However, Jatropha biodiesel has an oxidation stability that is too low (2-3 hours) so that its application in the diesel engine is not acceptable. This paper reports the effect of addition of Palm bodiesel and commercial anti-oxidant on the oxidation stability of Jatropha biodiesel. The objective of this research is to find the formulation for Jatropha biodiesel which will meet the oxidation stability determined by World Wide Fuel Charter 2009 (WWFC) of min.10 hours. The required addition of BHT into Jatropha biodiesel is more than 10000 ppm to meet the WWFC specification. The addition of BHT will decrease to less than 10000 ppm if the Jatropha biodiesel was blended with Palm biodiesel as much as 60% v/v. Addition of antioxidant should be limited to a minimum value because there are also concerns about the negative effects of antioxidants on the engine components

Enhancement of physicochemical characteristics of palm olein and winged bean (Psophocarpus tetragonolobus) seed oil blends

Incorporation of oils from non-conventional sources into palm olein through the blending process generates a sustainable source of novel oleins with improved physicochemical and functional properties. The objective of this study was to evaluate the effects of blending winged bean (Psophocarpus tetragonolobus) seed oil (WBSO) and palm olein (POo) on the physicochemical properties of the blends. Blends of WBSO (25, 50 and 75% w/w) with POo were prepared and changes in fatty acid (FA) and triacylglycerol (TAG) compositions, iodine value (IV), cloud point and thermal behaviour were studied. Reductions in palmitic (C16:0) and oleic (C18:1) acids with concomitant increases in linoleic (C18:2) and behenic (C22:0) acids were observed as the amount of WBSO increased in the blends. Blending WBSO and POo at 75:25 increased the unsaturated FA content from 56% in palm olein to 64% in the blend, producing the highest IV of 70.5 g I2/100g. At higher WBSO ratios, triunsaturated and diunsaturated TAG species within the blends increased while disaturated TAG species decreased. The lowest cloud point (8.8 °C) was obtained in the oil blend containing 50% WBSO, while the cloud point further increased with increasing amount of WBSO in the blends. This was possibly attributed to increased trisaturated TAG with very long-chained saturated FA (C20 to C24) inherently present in WBSO within the blends. Thermal behaviour analysis by differential scanning calorimetry of the oil blends showed higher onset temperatures for crystallisation with increasing proportions of WBSO in POo, with melting thermograms correspondingly showing decreasing onset melting temperatures. These findings showed that blending WBSO with POo enhanced the physicochemical characteristics of the final oil blends, resulting in higher unsaturation levels and improved cloudiness resistance.

A Review on the Hydroisomerisasion of n-Parafins over Supported Metal Catalysts

Catalytic hydroisomerization of n-paraffin aims to produce branched paraffin isomers and suppress cracking reactions in the production of the low cloud point of biodiesel. The development of the type of metal and catalyst support, amount of metal loading, and reaction conditions are important to increase the catalyst activity. A high performace catalyst for hydroisomerization bears bifunctional characteristics with a high level of hydrogenation active sites and low acidity, maximizing the progress of hydroisomerization compared to the competitive cracking reaction. In addition, a catalyst support with smaller pore size can hinder large molecular structure isoparaffins to react on the acid site in the pore thus providing good selectivity for converting n-paraffin. Catalysts loaded with noble metals (Pt or Pd) showed significantly higher selectivity for hydroisomerization than non-noble transition metals such as Ni, Co, Mo and W. The reaction temperature and contact time are also important parameters in hydroisomerization of long chain paraffin, because long contact times and high temperatures tend to produce undesired byproducts of cracking. This review reports several examples of supported metal catalyst used in the hydroisomerization of long chain hydrocarbon n-paraffins under optimized reaction conditions, providing the best isomerization selectivity results with the lowest amount of byproducts. The role of various metals and their supports will be explained mainly for bifunctional catalysts.

Review of Kinetic Hydrate Inhibitors Based on Cyclic Amides and Effect of Various Synergists

This Review presents a comprehensive literature review of an important class of kinetic hydrate inhibitors (KHIs) that is based on cyclic amides (lactams). The major aspects of the KHIs, such as their synthesis, inhibition mechanism, toxicity, biodegradability, performance, and cloud point, are thoroughly discussed. Data for 70 KHIs made of homo/co/terpolymers from 330 experiments are collected and evaluated for performance. The effects of the inhibitor concentration, molecular weight, monomer ratio of the co/terpolymers, and 35 different synergist chemicals on various KHIs are also studied. In conclusion, the top 10 KHIs with the highest performances that had a cloud point above 70 °C are presented. The copolymer (1:1) N-vinylpyrrolidone/N-vinyl-caprolactam (VP/VCap) is found to have the highest induction time (IT) of 13 to 14 h at 0.25 wt % and at a cooling rate of 1 °C/h. Some KHIs like Inhibex BIO-800 and poly(N-vinyl azacyclooctanone) (PVACO) also have a very high ITs (17 and 13.5 h, respectively) at 0.25 wt % and at a cooling rate of 1 °C/h, but they have low cloud points (<25 °C). Guanidinium salts (n-Bu6GuanCl/n-Bu6GuanBr) and a phosphonium salt, (n-Pe)4PBr, are found to be the best synergists for the cyclic-amide-based KHIs. When used at 0.15 to 0.30 wt % along with the KHIs, they further increase the IT by 3–5 h.

Unusual Growth and Hydration Characteristics of Oil Solubilized Micelles in Aqueous Pluronic Systems.

Lipophile induced modulations of self-assembly characteristics in aqueous Pluronic systems merit attention because of wide-ranging uses of Pluronics as solubilizing agents of lipophilic substances. In this paper, we report unusual evolutions of structural and hydration properties in lavender essential oil (LO) solubilized Pluronic P85 aqueous micellar systems as a function of micellar volume fraction and temperature. Our DLS, SANS, and viscometry studies show that the spherical-to-wormlike micellar structural transition observed in 1% P85 solutions upon solubilization of LO quite unexpectedly gets suppressed with increased P85 concentration to ≥5%. Detailed SANS studies reveal that the core sizes of the oil solubilized micelles cannot attain the threshold value required for the onset of structural transition at higher copolymer concentrations due to their progressive shrinking with an increase in P85 concentration. Oil solubilized P85 solutions show two cloud points and very interestingly exhibit micellar growth upon cooling to their lower cloud points. Steady state fluorescence studies explain this based on increasing dehydration of micellar corona with a decrease in temperature, very much opposite to what is observed in pure aqueous Pluronic systems. The results give new insight into viscous flow properties and low temperature storage possibilities of oil solubilized aqueous Pluronic systems.