Commercial Hexane Research Articles

Pressurized liquid extraction of soybean oil using intermittent process with ethanol and hexane as solvent: Extraction yield and physicochemical parameters comparison

AbstractThis research demonstrates pressurized liquid extraction (PLE) in an intermittent process in obtaining soybean oil using less solvent than conventional extraction. Temperature (T), solvent rinse volume (VS), contact time between the solvent and the matrix (St) in each cycle and number of cycles (C) were screened. Yield, fatty acids profile (FAs), and triacylglycerols were evaluated. After preliminary testing, T and St were tested for yield while VS, C, and P were fixed at 60% of total volume of the fixed bed extractor, 3 cycles, and 10.34 MPa respectively. The highest oil recoveries were 94.40% (85°C, 13 min, with hexane) and 86.16% (80°C, 12 min, with ethanol). The mass ratio of solvent/feeds resulted in a yield increase of 1.47% (hexane) and 3.99% (ethanol). The concentration of β‐sitosterol (≤182.78 mg/100 g of oil, hexane; ≤71.64 mg/100 g of oil, ethanol) and the fatty acid profile were not affected by the different solvents or process. The main fatty acids were linoleic (≤51.12%, ethanol; ≤40.31%, hexane) and oleic (≤24.98%, ethanol; ≤26.62%, hexane). The main triacylglycerols identified were LLO, LLL, and OOL. The results indicate that soybean oil can be obtained by a new process that uses a safe and renewable solvent, indicating that PLE in an intermittent process can replace conventional extraction without changing the main characteristics of the oil, with good yield using less solvent.Practical applicationsThe practical application of this research is related to the possibility of demonstrating the feasibility of PLE in obtaining soybean oil using pressurized ethanol. The solvent used in most oilseed extraction plants is commercial hexane, a toxic and non‐renewable solvent. The experiments were carried out with pressurized hexane to demonstrate the economy of solvents and compare with the results obtained when pressurized ethanol was used as a solvent. The ethanol study aimed to show high extraction yields, even using a polar solvent in soybean oil extraction. High yields and oil characterization showed that it is possible to use a green and clean technology to obtain vegetable oils.

Synthesis of Tantalum Carbide Using Purified Hexane by Titanium Powder.

Hexane is a safe, efficient, and cost-effective alternative to other commercial hydrocarbons for gaseous carburization; however, commercial hexane is not sufficiently pure. Titanium powder can remove oxygen-containing impurities from commercial hexane; however, research on the use of titanium powder remains limited. We investigated the purification of hexane using titanium, copper, and aluminum powders and used the purified hexane for the gaseous carburization of tantalum. Ti exhibited lower activation energy for oxidation (1.55 kJ/mol) than Cu (91.09 kJ/mol) and Al (150.25 kJ/mol) and a significantly higher oxidation rate (0.0269 g/h) in hexane at room temperature than Cu (0.0018 g/h) and Al (0.0001 g/h). The carbon content in tantalum carburized using the purified hexane was comparable to that carburized using unpurified hexane (approximately 6.22%); however, its oxygen content was significantly lower (1.39%), which indicates that the produced tantalum carbide has a higher purity. X-ray diffraction results revealed that the oxidation products of tantalum, such as Ta2O, TaO2, Ta0.8O2, and Ta2O5, were absent in the sample carburized using the purified hexane. Therefore, Ti powder can effectively remove oxygen-containing impurities from commercial hexane and facilitate its use as an effective carburizing medium for the synthesis of high-purity tantalum carbide.

On the behaviour of the temperature field around pool fires in controlled experiment and numerical modelling

This paper attempts to evaluate how the Fire Dynamics Simulator (FDS) correlates with experimental flame heights and temperature profiles around a small scale pool fire. Experimental studies were conducted in a 6 cm diameter burner inside an exhaustion hood with three liquid fuels largely used in industry: commercial hexane, hydrous ethanol and type C gasoline. The simulated fuels were defined as mixture of molecules from FDS fuel library. The burning rates were prescribed in the calculation routine and compared with the results when the burning rate is predicted by the simulator. FDS predicts flame heights with errors below 16% when the burning rate is prescribed as boundary condition. Good agreement with experimental data is observed for a given number of probe locations. However, FDS struggled to describe the temperature profile around the flame area in the region close to the pool rim, between X/D=0.25 and X/D=0.75, and with heights below 5.0 diameters.

ESTUDO DA UTILIZAÇÃO DE SOLVENTE ALTERNATIVO NO PROCESSO DE EXTRAÇÃO DO ÓLEO DE SOJA

A extração do óleo de soja é feita quase que exclusivamente pelo método de extração com hexano comercial. Com o intuito de avaliar novos solventes como alternativa deste processo tradicional de extração, foi realizado um estudo de extração do óleo de soja empregando-se misturas de etanol, acetato de etila e isopropanol como solvente. Como resultado, verificou-se que a mistura contendo 85% de etanol, 13% isopropanol e 2% acetato de etila apresentou o melhor rendimento (0,185g óleo/g soja). Apesar do óleo bruto obtido apresentar índices de acidez e saponificação fora das especificações da ANVISA para óleo bruto, o refino deste óleo possibilitou a obtenção de um óleo refinado com algumas de suas propriedades próxima das exigidas pela ANVISA para óleos refinados, dentre elas o índice acidez: 0,7% (exigido <0,6%). A inclusão da etapa de “winterization” no processo de refino pode contribuir com a melhoria das demais propriedades do óleo obtido pela extração com solvente alternativo

Deacidification and solvent recovery of soybean oil by nanofiltration membranes

Four tailor-made flat composite membranes of poly(vinylideneflouride) (PVDF) as a support and polydimethylsiloxane (PDMS) or cellulose acetate (CA) as coating layer, and a commercially available composite membrane (Solsep 030306) were used to remove hexane and free fatty acid (FFA) from crude soybean oil–hexane mixture. The effects of transmembrane pressure (Δp=10–20bar), temperature (T=30–50°C) and feed oil concentration (Cf=10–35 w/w%) on membrane selectivity and permeation flux were determined. The PVDF-12% siloxane composite nanofiltration membrane achieved the best results, being stable in commercial hexane and having promising permselectivity properties to separate soybean oil/hexane miscella. Improved separation performance was obtained at Cf=25%, Δp=20bar, and T=30°C, achieving a permeate flux of 20.3Lm−2h−1, 80% oil retention, 58% FFA removal.

Separation of Sunflower Oil from Hexane by Use of Composite Polymeric Membranes

AbstractVegetable oil extraction, as performed today by the oilseed‐crushing industry, usually involves solvent extraction with commercial hexane. After this step, the vegetable oil–hexane mixture (miscella) must be treated to separate its components by distillation. If solvent‐resistant membranes with good permeation properties can be obtained, membrane separation may replace, or be used in combination with, conventional evaporation. Two tailor‐made flat composite membranes, poly(vinylidene fluoride) (PVDF–Si and PVDF–CA) and a commercially available composite membrane (MPF‐50), were used to separate a crude sunflower oil–hexane mixture. The effects of temperature, cross‐flow velocity (v), transmembrane pressure (Δp), and feed oil concentration (Cf) on membrane selectivity and permeation flux were determined. The PVDF–Si membrane achieved the best results, being stable in commercial hexane and having promising permselectivity properties for separation of vegetable oil–hexane miscella. Improved separation performance was obtained at Cf = 25%, Δp = 7.8 bar, T = 30 °C, and v = 0.8 m s−1; a limiting permeate flux of 12 Lm−2 h−1 and 46.2% oil retention were achieved. Low membrane fouling was observed under all the experimental conditions studied.

Solvent extraction of jojoba oil from pre-pressed jojoba meal

The solvent extraction process of jojoba oil from the meal cake obtained after the mechanical pressing of jojoba seeds was studied. Commercial hexane and petroleum ether were used as solvents and the extraction was carried out at temperatures ranging from 30 to 55 °C using solvent-to-solid ratios, R between 2 and 15 L/kg. The equilibrium compositions of the solvent and solid phases were determined. Based on the equilibrium data, the partition coefficient or distribution ratio, D of the oil between both phases was estimated. Also, the number of extraction stages necessary to achieve a certain degree of oil recovery has been determined using different hexane-to-meal ratios. Jojoba oil was also tested for its physical and chemical properties including chemical composition, percentage fatty acid, peroxide value, flash point, fire point, pour point, refractive index, saponification and iodine values. The stability of jojoba oil during storage at room temperature and during heat treatment was also studied.

Recovery of phytosterols from sunflower oil deodorizer distillates

AbstractPhytosterols are usually recovered by crystallization from the deodorizer distillate (DD) of vegetable oils. In this work, the impact of the principal process variables (viz., solvents and cosolvents, cooling rate, crystallization temperature, and ripening time) on the quality and yield of the recovered phytosterols was studied by using a sunflower oil DD “enriched” (i.e., preconcentrated) via transesterification with ethanol (EDD) as a feedstock and commercial hexane as solvent (S), with S/EDD mass ratios of 3 to 5. Water (0 to 4.5 wt%) and ethanol (0 to 10 wt%) were used as cosovents, with crystallization temperatures between 0 and −20°C and crystallization times from 4 to 96 h. The cooling rate was either −20°C/h or “brisk chilling” from 40 to −5°C. The nature and composition of the EDD solvent and cosolvent composite arose as the most important process variable, strongly influencing both the percentage of sterol yield and the purity of the crystals, as well as their filterability and washability. Water‐saturated hexane sufficed to give good crystallization, yet the beneficial effect of adding water as the single cosolvent was enhanced by adding small and precise amounts of ethanol. A recovery of sterols as high as 84% (with 36% purity) was achieved by using a single‐stage batch crystallization of the S/EDD mixture (S/EDD=mass ratio 4).

Direct sampling of orujo oil for determining residual hexane by using a chemsensor

AbstractHexane is used to extract edible oils from oleaginous seeds. The detection of hexane in orujo oil is mandatory, as its presence in the final product may negatively affect human health. Headspace‐GC is the technique of choice for determining residual solvent in foods. In the present work, a new instrument based on the headspace principle and mass spectrometric detection without chromatographic separation, ChemSensor, is proposed for the direct screening of orujo oil to determine residual hexane. This instrument provided an overall response, corresponding to the volatiles profile, including that of hexane, which could not be directly discriminated. By selecting them/zvalues corresponding ton‐hexane (major component of commercial hexane), the selectivity of the method was good enough to determine residual hexane in the range of 2.0–65 μg mL−1(corresponding to 2.3–75.6 mg of hexane per kg of oil) with high precision. The detection limit achieved (0.7 mg per kg of oil) was lower than the maximum residual limit established by the European Union (5 mg per kg of oil). Two multivariate techniques, partial least squares and principal components regression (PCR), were compared with univariate regression; PCR provided the best results.

Studies on the extraction of wheat germ oil by commercial hexane

Extraction of an edible oil from wheat germ, an important byproduct of wheat milling industry in Egypt, using commercial hexane was studied. The extraction was carried out in a single and in two successive stages using different solvent-to-solid ratios from 2 to 6 m 3 / ton. The results showed that a good oil recovery (about 75%) can be achieved using 4 m 3 hexane for each ton germ extracted in a single stage. This amount of solvent can be reduced to 2.5 m 3 / ton if the process is carried out in two successive stages. The study has shown also that the amount of oil recovered from wheat germ is not significantly affected by heating the extraction mixture during the extraction process. The developments of free acids and peroxides in the oil during the storage period of wheat germ prior to extraction and during the hot extraction process were also investigated.

Modeling and simulation of an oilseed meal desolventizing process

Most oilseed crushing industries use solvent extraction with commercial hexane to produce crude oils. Desolventization with steam in a desolventizer-toaster (DT) is used to remove the residual solvent from oilseed meals. In this study, a mathematical model is developed to simulate the desolventizing process and analyze the influence of operating variables in continuous equipment. Mass transfer phenomena are outlined to take into account different retention and transport mechanisms. Solvent diffusion through pores from the solid to the vapor phase is analyzed and the contribution of axial dispersion along the bed is evaluated. The final equations describing solvent flow in meal particles and through the desolventizer are solved by numerical techniques. The influence of processing variables such as desolventizing temperature and residence time as well as the effect of some process parameters, like particle size, oil content and void fraction in the bed, on the meal residual solvent is simulated by the model.

Urinary 2,5 hexanedione as a biomarker of n-hexane exposure

n-Hexane is a saturated aliphatic hydrocarbon widely used in industry. In most cases it is used as a mixture with hexane isomers and various others solvents in the form of commercial hexane. n-Hexane is metabolized oxidatively to a number of compounds, including 2,5-hexanedione (2,5-HD), which is eliminated through the urine and is implicated in the neurotoxic effect of this solvent. The main objective of this study was to evaluate urinary 2,5-HD as a biomarker of n-hexane exposure. The study was carried out in seven industrial units. Post-shift urine samples from 111 workers who handled commercial hexane were collected and analysed for 2,5-HD by capillary gas chromatography. Air sampling was performed in the breathing zones of the workers, and the air samples were analysed using validated methods. Monitoring individual exposures showed that n-hexane exposure varied from 5 to 70 p.p.m. (mean±SD = 15.24±2.98 p.p.m.). Significant correlation was observed between exposure to n-hexane and urinary 2,5-HD levels, with high correlation coefficients (ρ= 0.81, p = 0.000), suggesting that urinary 2,5-HD is a good biomarker of occupational exposure to n-hexane. Urinary 2,5-HD is recommended as a better tool than air monitoring in the assessment of health risk, namely the early detection of n-hexane neurotoxicity.

Fractionation of commercial hexane and use of its fractions as extracting solvent of cottonseed oil

The problem of producing off-graded cottonseed oil using locally produced commercial hexane as extracting solvent has explored this research. It was aimed in this work to investigate whether this problem can be solved by controlling the boiling range of the extracting solvent. Four different hexane fractions of different boiling ranges were prepared from commercial hexane. The boiling range of commercial hexane was 62-68oC while the boiling ranges of the four fractions were 62- 64, 64-65, 65-66 and 66-68oC. Commercial hexane and the prepared four hexane fractions were then used to extract cottonseed oil from a fixed seed sample. The five crude oil samples were then refined and bleached and their colours were measured. The results have shown that the heaviest hexane fraction ( b.r 66-68oC) produced the lightest coloured oils. The colour index of the bleached oil using this heavy cut was 190 compared to 350 using the original commercial hexane. However, the production of a commercial hexane cut having a narrow boiling range will be costly. Therefore, this research has been extended to investigate the suitability of a heavy petroleum cut which has a boiling range as wide as that of commercial hexane to extract cottonseed oil. The boiling range of this cut was 66-72oC. The obtained results proved that the extraction of cottonseed oil using that heavy petroleum fraction produces much lighter oil than the use of conventional hexane solvent.

Chronic inhalation carcinogenicity study of commercial hexane solvent in F-344 rats and B6C3F1 mice.

The carcinogenic and chronic toxicity potential of commercial hexane solvent was evaluated in F-344 rats and B6C3F1 mice (50/sex/concentration/species) exposed by inhalation for 6 h/day, 5 days/week for 2 years. Target hexane vapor concentrations were 0, 900, 3000, and 9000 ppm. There were no significant differences in survivorship between control and hexane-exposed groups, and clinical observations were generally unremarkable. Small, but statistically significant decreases in body weight gain were seen in rats of both sexes in the mid- and high-exposure groups and in high-expsoure female mice. The only noteworthy histopathological finding in rats was epithelial cell hyperplasia in the nasoturbinates and larynx of exposed groups. This response was judged to be indicative of upper respiratory tract tissue irritation. No significant differences in tumor incidence between control and hexane-exposed rats were found. In mice, uterine tissue from the high-exposure females exhibited a significant decrease in the severity of cystic endometrial hyperplasia compared to controls. An increase in the combined incidence of hepatocellular adenomas and carcinomas was observed in high-exposure female mice. The incidence of liver tumors was not increased in the mid- or low-exposure female mice or in male mice exposed to hexane. An increased incidence of pituitary adenomas was observed in female, but not male mice. This finding was not believed to have been treatment-related because the incidence in the control group was unusually low, and the incidence in exposed groups was not dose-related and was within the historical control range. No other neoplastic changes judged to be treatment-related were observed in tissues from male or female mice. In conclusion, chronic exposure to commercial hexane solvent at concentrations up to 9000 ppm was not carcinogenic to F-344 rats or to male B6C3F1 mice, but did result in an increased incidence of liver tumors in female mice.

Multicomponent condensation in a shell and tube condenser – A comprehensive dataset

The purpose of this paper is to provide a database suitable for the validation of computer codes for condenser design purposes. It is too extensive to publish in full but copies of all data tables are available direct from the author. The test condenser is of industrial scale, (0.483 m diameter and 2.438 m between tubeplates), and design, (TEMA E), and should therefore be of particular relevance for this purpose. The important condition that all the individual resistances to heat and mass transfer should be controlling in some part of the dataset is fulfilled, by covering condensation of steam and steam–air mixtures, methanol and isopropanol and their mixtures with water, and hydrocarbon mixtures, commercial hexane and methylcyclohexane-toluene. Care is taken to ensure that the condenser is operating in a loaded condition with an appreciable vent flow to a knockout condenser. Data are reported at atmospheric pressure and at reduced pressures down to approximately 0.1 bar. Further the work includes measurements of the pressure and temperature profiles not only in condensation but with single-phase flow of air and two-phase flow of air–water mixtures in the stratified and spray flow regimes. The data have been analysed by standard methods available in the literature and specific conclusions are reached with respect to the performance of these methods. A particular feature is the application of rigorous models to predict multicomponent mass transfer. Care has been taken to describe the measurement techniques, their reliability and that of the dataset itself in consequence. The conclusions of the work are related to current industrial design practice and some needs for modification of current design methods are noted.

Isolation and Characterization of Defatted Canola Meal Protein

Protein was extracted and isolated from canola oil processing waste. Canola is an increasingly important oilseed crop worldwide. More than 99% of protein was extracted from crude commercial hexane defatted canola meal when a 5% w/v suspension in 0.4% w/v NaOH was agitated for 60 min at room temperature in baffled flasks on an orbital shaker at 180−200 rpm. Protein recovery was 87.5% upon precipitation with acetic acid. The major proteins in canola seed were glutelins (91.8% soluble in 0.4% w/v NaOH) and globulins (50.9% soluble in 5% w/v NaCl) as measured by separate extractions. Canola proteins had poor solubility between pH 2 and 10 for all dispersion solutions. Solubility of protein isolates was 60% or less. Extraction and precipitation procedure did not produce lysinoalanine. Amino acid profile of isolates indicated high nutritional quality for use in products for 10−12-year-olds and adults. Keywords: Canola meal; canola meal protein; protein quality

Evaluation of the State of Oxidation of Crude Olive-Pomace Oils. Influence of Olive-Pomace Drying and Oil Extraction with Solvent

The aim of this investigation was to follow the progress of oxidation during the phases of the industrial process of olive-pomace drying and the subsequent step of crude pomace oil extraction with solvent. Silica-gel column chromatography and high-performance size-exclusion chromatography were the analytical techniques utilized to this purpose. The data obtained showed that most of the oxidation occurs during industrial drying of the pomace with a mean increase of 35% in the oxidized triglycerides while no statistically significant increase was observed for triglyceride oligopolymers. The subsequent extraction of oil with solvent and the removal of the last traces of commercial hexane for the preparation of crude olive-pomace oil did not seem to entail any substantial increase in oxidation. There was a change in the state of oxidation given that there was an increase in triglyceride oligopolymers, which on average reached 0.32%, and in secondary oxidation products (mean p-anisidine value = 15.31). Hydroly...

A bioresource solvent for extraction of castor oil

Extraction of castor oil from castor seeds was carried out using a bioresource solvent and compared with the extraction capacity of a commercial solvent. The solvents used were feint, a liquid industrial waste from the distillery and commercial hexane. Results of the chemical and physical properties of the extracted oils indicate that feint could serve as an effective substitute solvent for commercial hexane in the extraction of castor oil intended for alkyd resin production. The extraction coefficients for enhanced oil removal from the seed meal and the enthalpy changes accompanying the extraction process were determined. The solvent power of the solvents was temperature dependent.

Alternative hydrocarbon solvents for cottonseed extraction

AbstractHexane has been used for decades to extract edible oil from cottonseed. However, due to increased regulations affecting hexane because of the 1990 Clean Air Act and potential health risks, the oil‐extraction industry urgently needs alternative hydrocarbon solvents to replace hexane. Five solvents,n‐heptane, isohexane, neohexane, cyclohexane, and cylopentane, were compared with commercial hexane using a benchscale extractor. The extractions were done with a solvent to cottonseed flake ratio of 5.5 to 1 (w/w) and a miscella recycle flow rate of 36 mL/min/sq cm (9 gal/min/sq ft) at a temperature of 10 to 45°C below the boiling point of the solvent. After a 10‐min single‐stage extraction, commercial hexane removed 100% of the oil from the flakes at 55°C; heptane extracted 100% at 75°C and 95.9% at 55°C; isohexane extracted 93.1% at 45°C; while cyclopentane, cyclohexane, and neohexane removed 93.3, 89.4, and 89.6% at 35, 55, and 35°C, respectively. Each solvent removed gossypol from cottonseed flakes at a different rate, with cyclopentane being most and neohexane least effective. Based on the bench‐scale extraction results and the availability of these candidate solvents, heptane and isohexane are the alternative hydrocarbon solvents most likely to replace hexane.

Two-generation reproduction study on commercial hexane solvent.

The reproductive effects of inhalation exposure to commercial hexane vapors were evaluated in Sprague-Dawley rats. Males and females were exposed to commercial hexane vapor at target concentrations of 0, 900, 3000 or 9000 ppm for 6 h a day, 5 or 7 days a week, over two generations. In addition to pre-breed exposures of 10 weeks' duration, exposures continued through mating, gestation and lactation. At both the F0 breed to produce F1 litters and the F1 breed to produce F2 litters, reproductive parameters were unaffected by commercial hexane exposure. The mating, fertility and gestational indices, as well as litter size and postnatal survival, were not significantly different between exposure groups. However, reductions in body weight and body weight gain were observed in both F1 and F2 litters exposed to 9000 ppm. Effects on body weight were not observed in offspring exposed to the two lower concentrations of commercial hexane. Histopathological examination of selected tissues revealed hyaline droplet nephropathy in adult F0 and F1 males exposed to 9000 ppm. This finding was anticipated and is not believed to be relevant for the assessment of human health effects. No other treatment-related histopathological lesions were observed. Thus, exposure of rats to commercial hexane for two generations resulted in reduced body weight gains at 9000 ppm but no adverse effects on reproduction. These findings suggest that occupational exposure to commercial hexane vapors at currently recommended threshold limit value concentrations (i.e. TLV for n-hexane is 50 ppm and TLV for other hexane isomers is 500 ppm) should not pose a reproductive hazard.