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Summary: Açai, a fruit typical of Amazonia in Brazil, is consumed due to beneficial health effects. Aqueous two‐phase systems (ATPS) based on ethanol (28% w/w) and ammonium sulfate (17.5% w/w) were employed in the partitioning of anthocyanins from açai. Experiments, applying 50 mL equilibrium cells and a 1‐L glass vessel reactor, evaluated anthocyanin partition feasibility on a laboratory scale‐up. The anthocyanin preferentially moved to the top (ethanol‐rich phase) and sugars to the bottom (ammonium sulfate‐rich phase). Scale‐up effects were compared with the equilibrium cell experiments with anthocyanin extraction yielding more than 64% w/w, the yield of sugars in the bottom phase (>61% w/w) and removal of sugars (97%), showing the feasibility for the scale‐up process. The anthocyanin profile from açai, ATPS partition on the bench scale and laboratory scale‐up evaluated by UPLC‐QTOF‐MS identified cyanidin, peonidin and pelargonidin derivatives. [ABSTRACT FROM AUTHOR]

• Density measurements were conducted for the mixture of 1-butanol and two biodiesels under high-pressure conditions (up to 100 MPa). • Excess volumes were calculated for the blend of 1-butanol + biodiesel. • Correlation with the Tammann-Tait equation was performed, and derived properties were calculated. • Thermodynamic modeling was carried out using the PC-SAFT equation of state. Biodiesel, derived from renewable sources, offers advantages like biodegradability and compatibility with diesel engines. However, high production costs and low-temperature viscosity issues must be addressed. This could be mitigated by blending biodiesel with medium-chain alcohols. This study aims to assess the volumetric properties of the 1-butanol + biodiesel system under high-pressure conditions (0.1 – 100 MPa) and various temperatures (293.15 – 373.15 K) using a DMA HPM device from Anton Paar. Integrating experimental and modeling approaches, we applied equations to obtain derived properties and correlate density data. Equations such as Tammann-Tait and PC-SAFT were applied to the experimental data, yielding maximum mean absolute percentage deviations (DMRA Max.) of 0.011 % and 0.439 %, respectively, indicating satisfactory fits to the experimental data. The excess volumes were calculated, revealing minimal deviation from ideal behavior, with a maximum deviation of 0.15 % of the total volume. This suggests that the volumetric behavior of the 1-butanol + methyl biodiesel system closely resembles that of an ideal solution. We used both equations to obtain derived properties, such as the compressibility (κ T) and the isobaric thermal expansivity (α P). It was observed that the PC-SAFT equation has some limitations in its prediction. From these results, a crossing point in isobaric thermal expansivity (α P) was observed; this could be attributed to increasing biodiesel content, potentially linked to the effects of intermolecular forces. [ABSTRACT FROM AUTHOR]

[Display omitted] • New high-pressure density data for three iodide anion-based ionic liquids. • Alkyl chain length affects ionic liquids' structural packing efficiency. • Intermolecular forces interactions provoke a crossing point in internal pressure. • Four group contribution estimation methods were used for density estimation. Ionic liquids (ILs) constitute a captivating class of materials that has garnered significant attention from research and industrial applications, being recognized as promising substitutes for organic solvents in industrial processes. Consequently, comprehensive experimental physicochemical characterization, explicitly focusing on density data complemented by computational tools, is imperative. In pursuit of this objective, the present study explores the density behavior, both experimentally and computationally, of three iodide-based ionic liquids under high-pressure and high-temperature (HPHT) conditions. Here, it was studied the alkyl chain impact on density for 1-propyl-3-methylimidazolium iodide ([C 3 C 1 Im][I]), 1-butyl-3-methylimidazolium iodide ([C 4 C 1 Im][I]), and 1-hexyl-3-methylimidazolium iodide ([C 6 C 1 Im][I]) ILs. The vibrating tube method was utilized to determine the density over a range of pressure (P = 0.20 to 100.00 MPa) and temperature (T = 298.15 to 398.15 K). The density of the ionic liquids (ILs) was found to be influenced by the length of the cation alkyl chain, exhibiting the following sequence of increasing density: [C 6 C 1 Im][I] < [C 4 C 1 Im][I] < [C 3 C 1 Im][I]. Tammann-Tait equation was used to correlate experimental density data, resulting in an average absolute relative deviation (% A A R D) less than 0.008 % for [C 6 C 1 Im][I] and [C 4 C 1 Im][I], and less than 0.025 % for [C 3 C 1 Im][I]. The ILs density values were used to determine the isothermal compressibility (κ T), the isobaric expansivity (α p), the thermal pressure coefficient (γ v) , and the internal pressure (P i). These results revealed the structural impact of the alkyl chain on packing efficiency and its relationship with its physicochemical properties. Furthermore, ionic liquid density was estimated by using four group contribution estimation methods. Among these methods, the one proposed by Paduszynski and Domanska provided the best density estimative with a maximum % A A R D of 1.09 %. [ABSTRACT FROM AUTHOR]

· New experimental data of saturation pressures for two surfactants + MetOH + CO 2. · PC-SAFT parameters evaluation for compounds with negligible vapor pressure. · A new set of binary interaction parameters is provided for the PC-SAFT equation. · PC-SAFT equation of state modeling for CO 2 solubility in nonionic surfactants. The use of surfactants for oil and gas purposes has been explored and extensively applied. However, such systems' thermodynamic and predictability behavior still needs further investigation. This work aims to describe the phase behavior of the systems composed of nonionic ethoxylated surfactants (nonylphenyl ethoxylated surfactants—IGEPAL CO-630 and CO-720) + carbon dioxide (CO 2) with additional methanol in wide ranges of temperature (T = 313 to 413 K), pressure (P = 0.8 to 54.8 MPa), and CO 2 molar compositions (up to 90.0 %). It was observed for all systems studied that CO 2 solubility was inversely proportional to temperature and the number of ethoxylated units for pure surfactants. The addition of methanol greatly increases the overall CO 2 solubility. The thermodynamic modeling through the PC-SAFT equation of state was also evaluated. Bubble pressure deviations of 13.63 % and 13.49 % were obtained for pure IGEPAL CO-630 and IGEPAL CO-720 + CO 2 , respectively, and 12.63 % for the ternary system (IGEPAL CO-720 + methanol + CO 2). A new set of binary interaction parameters was also provided for IGEPAL CO-630 and IGEPAL CO-720 + CO 2. [Display omitted] [ABSTRACT FROM AUTHOR]

Liquid–liquid equilibria (LLE) data play an importantrolein the project and design of separation processes. The aim of thiswork was to study the LLE data of the solubility (binodal) curvesand tie-lines for the glycerol (1) + ethanol (2) + coconut biodiesel(3) system at two different temperatures [(293.15 and 323.15) K],at atmospheric pressure. From the experimental data, it could be observedthat the relative mutual solubility of ethanol is higher in the glycerolphase than the biodiesel phase. A consistency analysis has been performedby using the Othmer–Tobias correlation. The experimental liquid–liquiddata were correlated by using two local composition models (NRTL andUNIQUAC) for the activity coefficient calculation. From these models,binary parameters have been determined. Distribution coefficientsand separation factors were measured to evaluate the extracting capabilityof the ethanol used as a solvent. [ABSTRACT FROM AUTHOR]

Abstract: This work presents the study done on the effect of welding heating cycle on AISI 316L austenitic stainless steel corrosion resistance in a medium containing Brazilian heavy petroleum. AISI 316L stainless steel plates were welded using three levels of welding heat input. Thermal treatments were carried out at two levels of temperatures (200 and 300°C). The period of treatment in all the trials was 30h. Scanning electronic microscopy (SEM) and analysis of X-rays dispersive energy (EDX) were used to characterize the samples. Weight loss was evaluated to determine the corrosion rate. The results show that welding heating cycle is sufficient to cause susceptibility to corrosion caused by heavy petroleum to the heat affected zone (HAZ) of the AISI 316L austenitic stainless steel. [Copyright &y& Elsevier]

This paper aims to conduct an experimental investigation of the fluid phase behavior of a highly opaque Brazilian pre-salt crude oil-CO 2 system, specifically focusing on the occurrence of highly dispersed liquid-liquid transitions. The study involves examining the phase behavior of five global mole compositions [ z C O 2 = (37.9, 50.0, 76.6, 80.6, and 84.2) mol%] by using conventional PVT techniques as light scattering, pressure-volume curve, and direct fluid observation through sapphire windows. When other techniques were ineffective, a high-pressure microscope coupled with a short-wave infrared apparatus (SWIR camera and light source) was used for complex fluid inspection. [Display omitted] • Experimental measurements LV, LL, and SLL phase equilibria are presented. • 4 isopleth phase diagrams for Brazilian pre-salt crude oil + CO 2 are present. • Liquid-liquid equilibrium undetected by NIR transmittance signal. • Fluid inspection using short wave infrared coupled in high pressure microscope. [ABSTRACT FROM AUTHOR]

• Experimental measurements VL phase equilibria are presented. • Dew pressure and liquid dropout data for methane + alcohol (methanol or ethanol). • Higher liquid dropout values for methane + ethanol system. • Thermodynamic modelling by using CPA equation of state. Hydrate inhibitor injection through gas-lift flow is used in production fields. The gas + inhibitor system's phase behavior provides essential information regarding monophasic regions and operational safety conditions. Methane is the main constituent of natural gas and is commonly used as a model component to represent gas reservoir fluids. However, pressure variation during a gas-lift injection can cause liquid dropout at valve injection. Therefore, phase behavior knowledge of methane + alcohol mixtures is potentially interesting in the oil and gas industry. In this work, dew pressure and liquid dropout data were experimental measured for methane + methanol (96.60 mol % CH 4) and methane + ethanol (96.50 mol % CH 4) systems in the temperature domain of 313.15 to 366.65 K and pressure up to 70 MPa. The CPA equation of state was used to correlate dew pressure and liquid dropout data for all systems, presenting a dew pressure absolute relative deviation of 6.89 and 5.22 % for methane + methanol (96.60 mol % CH4) and methane + ethanol (96.50 mol % CH4), respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

Asphaltene precipitation has been related with flow assurance problems in all the stages of crude oil production and processing. The destabilization of asphaltenes in crudes depends on temperature, pressure and composition variations. The latter variable was specifically studied in this work throughout compositional modifications of Brazilian dead oils, by adding three different paraffins on the crudes ( n- hexadecane, docosane and a commercial paraffinic pool). These paraffins were firstly added in a crude oil, here named P1 (16.5 °API, 6.34 wt % asphaltenes), and the resulting modified crudes were analyzed in terms of asphaltene yield and stability using n- heptane as precipitant. Asphaltenes precipitation onset was affected by the inclusion of all the paraffins tested in the same extension; at the maximum paraffin addition of 10 wt%, onset decreases by 5 ± 1 n- heptane wt %. Similar results were verified for other two different oils P2 (17.7 °API, 6.29 wt% asphaltenes) and P3 (16.7 °API, 1.55 wt% asphaltenes). The solids obtained from the different systems were analyzed by FT-IR spectroscopy, observing that the alkyl content of the asphaltenes was not affected by the inclusion of heavy paraffins. Precipitation behavior was evaluated by using literature reported thermodynamic models based on modifications of the Regular Solution Theory. This model reproduced qualitatively the experimental precipitation behavior and the asphaltene solvency affectation by paraffin addition in the crudes. [ABSTRACT FROM AUTHOR]

A pore-expanded mesoporous silica (SBA-15) was investigated for the immobilization of a recombinant Candida antarctica lipase B (LIPB). The influence of contact time and medium pH during adsorption, as well as thermal and solvent stability of the immobilized enzyme were evaluated. The best prepared biocatalyst was then evaluated in a model esterification reaction, the production of two flavour esters (e.g. methyl and ethyl butyrate) and in a model hydrolysis reaction, the ethyl hexanoate hydrolysis. The biocatalyst maintained high activity and operational stability even after five successive cycles of synthesis. A commercial C. antarctica lipase B was also immobilized on SBA-15 and evaluated under the same conditions, achieving similar volumetric productivities. In addition, the biocatalyst SBA-15-LIPB was tested in ethyl hexanoate hydrolysis. The influence of reactional medium pH was conducted (pH 5, 7 and 9.2) and the highest biocatalyst activity was at pH 5 (about 636.3 U/g enzyme ). SBA-15-LIPB and SBA-15-LIPB-GA (crosslinked biocatalyst) were reused for 5 cycles, retaining, after the third cycle, 56.6 and 76.80%, respectively, of its initial activity. The prepared biocatalysts were able to catalyze the model reactions (esterification and hydrolysis) with high activity and reasonable stability. [ABSTRACT FROM AUTHOR]

• The physicochemical properties of DES 1ChCl:2G were minimally affected with the addition of AgNO 3 due to the low concentration of 0.05 mol⋅L−1. • The reduction process of Ag+/Ag that have peak potentials around −0.05 V. • Ag+ ions strongly interact with the chloride anion in DES. The thermodynamic and electrochemical properties of the silver ions (Ag+) dissolved in choline chloride (ChCl) and glycerol (G) mixture at eutectic composition were investigated. In addition, a computational calculation was carried out using Molecular Dynamic (MD) and Density Functional Theory (DFT) methods to understand the prevailing interactions in the investigated system. Specific mass, speed of sound, viscosity, and refractive index were measured at temperatures between 293 and 343 K and 101.3 kPa. The electrochemical behavior of Ag+ ions was analyzed by cyclic voltammetry in the range of 313 and 343 K. Silver coatings were successfully electrodeposited on the gold (Au) surface without adding additives to the electroplating solution. Scanning Electron Microscopy (SEM) analyzed the surface morphologies of the electrodeposits. The computational calculation indicated that adding silver nitrate to the eutectic solvent provided a predominance of repulsive forces for 1ChCl:2G and had negligible influence on sound velocity and refractive index. Finally, MD simulations showed a strong interaction between the Ag+ ions with the Cl− ions. [ABSTRACT FROM AUTHOR]

This work aimed to study the production of a biosurfactant by a new strain of Bacillus subtilis ICA56 isolated from a Brazilian mangrove and to evaluate its functional properties and applicability for bioremediation. The use of agro-industrial wastes (glycerol, sunflower oil, cheese whey and cashew apple juice) as alternative substrates for biosurfactant production was tested as this may lead to a reduction in the cost of the bioprocess. Glycerol was the best carbon source yielding 1290 mg L −1 of crude biosurfactant. The critical micellar concentration of the crude biosurfactant produced by ICA56 was 25 mg L −1 and, at this concentration, it was able to reduce the surface tension of the water from 72 to 30 mN m −1 and to reduce the interfacial tension on a water/gasoline system from 15 to 3 mN m −1 . Furthermore, the crude biosurfactant retained its tensoative properties in a broad range of pH, temperature and salinity and it was not toxic to Artemia salina . In this work, model experiments were conducted to simulate the removal of hydrocarbons and heavy metals from contaminated environmental systems in the laboratory by the crude biosurfactant produced by ICA56. Results showed that it was very efficient, highlighting its potential for bioremediation. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DESs) have many advantages, making them a promising alternative in replacing ionic liquids and organic solvents. Besides, DESs have received much prominence due to their diverse applications: Electrodeposition of metals, organic synthesis, gas adsorption, and biodiesel production. Therefore, this work analyzed the effect of the temperature increase (298 K–353 K) on the behavior of the Co2+ ions in three eutectic solvents through electrochemical techniques and computational simulations. From the electrochemical analysis realized, the increase in temperature caused a reduction in specific mass and an increase in the diffusion coefficient. Besides, the activation energy values were of 15.3, 29.9, and 55.2 kJ mol−1 for 1ChCl:2 EG, 1ChCl:2U, and 1ChCl:2G, respectively. The computational simulations indicate that the increased temperature effect caused the replacement of HBD molecules by anions chloride around Co2+ ions for the SDW1 and SDW3 systems between the temperatures of 298 K–353 K, except for the SDW2 system that the replaced occurred in the interval of 313 K–353 K. Besides, the increase of temperature occasioned the increase of strength for Co–Cl interaction and weakened the interactions between the Co2+ ions with the oxygen of HBD molecules. [Display omitted] • Deep eutectic solvents (DESs) is a promising alternative in replacing ionic liquids and organic solvents. • The Cl− has a strong interaction with Co2+ ions independent of temperature in systems analyzed. • The Co–Cl interaction became stronger due to the increase of temperature in the SDW1, SDW2, and SDW3 systems. [ABSTRACT FROM AUTHOR]

Lecitase Ultra has been covalently immobilized on cyanogen bromide cross-linked 4% agarose (CNBr) beads, maintaining 70% of the initial activity. The activity of the immobilized enzyme was improved in the presence of Triton X-100, sodium dodecyl sulfate (SDS), and cetyltrimethyl ammonium bromide (CTAB) (e.g., up to 800% when using CTAB). However, CTAB and Triton X-100 presented a negative effect on enzyme stability even at low concentrations, and SDS cannot be used for a long time at 1% concentration. To maintain the hyperactivated conformation of the enzyme in the absence of detergent, ionic polymers were added during incubation of the immobilized enzyme in the presence of detergents. Coating the immobilized enzyme with polyethylenimine in aqueous buffer (PEI) produced a 3-fold increase in enzyme activity. However, in the presence of 0.1% SDS (v/v), this coating produced a 50-fold increase in enzyme activity. Using PEI and 0.01% (v/v) CTAB, the Lecitase activity decreased to 10%. Using irreversible inhibitors, it could be shown that the PEI/SDS-CNBr-Lecitase preparation allowed its catalytic Ser to be more accessible to the reaction medium than the unmodified CNBr-Lecitase. [ABSTRACT FROM AUTHOR]

Highlights: [•] LLE data has been studied in order to optimize biodiesel purification process. [•] LLE data were correlated with different activity coefficient models. [•] The influence of temperature plays a minor role on the purification process. [•] The use of methanol as extractor can accelerate the purification of biodiesel. [Copyright &y& Elsevier]

Asphaltenes and resins make a major contribution for the formation of stable water-in-oil emulsions during crude production, which could affect process operations and increase costs. The purpose of this investigation is to study the influence of these molecular substances from two different crude oil samples (regarding asphaltene stability) on the water-model oil interfacial tension, along with their effect on the emulsion stability. Asphaltene stability of these crude oils presented a marked difference when studied in our past work, with asphaltene precipitation onset that vary from 56 to 75 n- heptane wt %, despite their similar SARA composition. This difference on asphaltene stability was contrasted in this work with the chemical characterization, interfacial activity, and emulsion behavior of crude oil asphaltenes, resins, and their mixtures using toluene solutions. For each crude oil, resins and asphaltenes were extracted and characterized by XRD, SEM/EDS, FTIR, and elemental analysis, to better understand their molecular structure and surface-active species content. Then, it was prepared different model oil solutions in toluene, varying the content of asphaltenes and resins (500, 1,000, and 2000 mg/L). Additionally, it was prepared 2000 mg/L asphaltene/resin mixtures with different ratios (75:25 wt%, 50:50 wt%, and 25:75 wt%). Dynamic interfacial tension between the model oil and water was measured by intermediate of a Du Noüy ring method. Afterward, each model system was emulsified by adding water (at the same volumetric ratio) in a bottle test and stability was analyzed. For the sample with lower stable asphaltenes, a rapid stabilization of the dynamic interfacial tension (IFT) was observed, together with a decrease of IFT from 26.8 to 24.2 mN/m at the limit of asphaltene content studied. On the contrary, for the high stable asphaltenes sample, a transient dynamic IFT behavior was observed, until reach 12.0 mN/m (the lower operational equipment limit). Similar results were obtained for resins model solutions for both crude oils tested. For asphaltene obtained from the sample with lower asphaltene stability, the emulsions presented high stability (for a 24 h test). Besides for the high asphaltene stability sample and resins model oils, all emulsions prepared were unstable. Useful insights are given by the oil fractions chemical characterization, suggesting that smaller sized molecules from high stable crude oils have a predominant effect on IFT reduction, while larger molecules from less stable oils are responsible for the emulsion stability. • Interfacial activity of asphaltenes or resins extracted from crude oils with different stability was compared in model-oil/water systems. • Asphaltenes from lower stable crude oil present a faster stabilization of the dynamic interfacial tension (IFT). • Contrary, asphaltenes from high stable crude oil presented a wider transient dynamic IFT behavior with maximum decrease of IFT. • Resins presented longer stabilization times and lower IFT values. • Results suggest that smaller sized molecules have a predominant effect on IFT, while larger molecules are responsible for the emulsion stability. [ABSTRACT FROM AUTHOR]

Phase behavior of reservoir fluids is crucial for an efficient production development project. In this paper, a new dataset of phase transitions of Brazilian pre-salt crude oil mixed with methane systems is presented and phase behavior discussed under different analytical technics. A series of mixtures of a dead crude (API 28.0, 0.68 wt% of asphaltenes) with 65.0, 67.5, 70.0, 72.5, and 75.0 mol% of methane were studied by constant mass expansion in a PVT cell, coupled with a high-pressure microscopy (HPM). Pressure-volume data shows slight phase transition, with a not evident break due to difference on compressibility, specially by increasing methane molar content. For this reason, beside of visual observation, a near-infrared (NIR) transmittance was used for a proper identification of bubble point pressure. NIR transmittance also allow the detection of phase transitions above bubble point, that was confirmed by intermediate of by HPM analysis. A dispersion of fine particles was detected, and it was associated with asphaltenes onset, for the systems with high content of gas (72.5 and 75.0 mol% of methane). NIR transmittance along with micrographs taken during system pressurization confirm a low asphaltene hysteresis redissolution, with no flocs and mayor aggregates formation and rapid redissolution after system pressurization. This phenomenon could be related to the low content of asphaltenes on the crude oil sample. [ABSTRACT FROM AUTHOR]