Determination of volatile sulfur compounds in canola oil

A simple and sensitive method for the quantitative determination of volatile isothiocyanates in canola oil has been developed. The method is based on the specific absorbance of isothiocyanates in the infrared region. The results obtained were confirmed by gas liquid chromatography using a flame photometric detector. The various volatile isothiocyanates isolated from the oil were allyl isothiocyanate, 3-butenyl isothiocyanate, 4-pentenyl isothiocyanate and 2-phenethyl isothiocyanate. Their identities were confirmed by mass spectroscopy and by retention times. The recoveries of sulfur from volatile sulfur compounds by this method ranged from 93.6% to 101.1% when compared to the amount determined by gas liquid chromatography. The coefficients of variability of volatile sulfur compounds in canola oils ranged from 1.7% to 3.2%. The sulfur content represented by the volatile sulfur compounds comprised 21.7% of the sulfur determined by the Raney nickel method for crude oil, 36.6% for refined oil and 22.7% for refined, bleached and deodorized oil.     

Determination of total sulfur in canola oil

A rapid and sensitive chromatographic method for the determination of total sulfur in canola oil is described. All forms of sulfur in the oil are quantitatively converted to sulfate in an oxygen bomb. The sulfate is separated from other ions and measured using an ion chromatograph equipped with a conductivity detector. Standards containing different forms of sulfur were prepared and analyzed with this method. Recovery achieved on 11 compounds covering the concentration range from 9.3 to 143.5 mg/kg S ranged from 95.7% to 102.2%. The coefficient of variability of total sulfur in canola oils ranged from 1.0% to 2.9%. Values obtained on high sulfur content mustard oils when plotted vs the values determined by barium precipitation method showed a correlation coefficient of 0.997 and provided a slope of 1.0. This new method employing comparatively simple equipment requires less than 40 minutes for a complete analysis and is reliable for the determination of as little as 0.5 mg/kg S in canola oil.     

Removal of sulfur compounds from naphtha solutions using solid adsorbents

Two types of solid adsorbents, activated carbon and zeolite 13X, were used at 80°C to remove sulfur compounds from naphtha solutions. Adsorption isotherms have been determined in a pressure vessel. This investigation indicated that activated carbon is superior to zeolite 13X at such high temperatures. A new formula based on the Langmuir model has been found to fit the experimental data satisfactorily. Comparison of the findings of this study with those of a previous one conducted at ambient temperatures in this department indicates that such treatment generally gives better results at low temperature where almost complete recovery of the sulfur compounds can be performed by using zeolite 13X.     

Mechanics of oil expression from canola

A laboratory-scale oilseed screw press was used to investigate the effects of shaft speed and choke opening and of seed pretreatments, including moisture conditioning, flaking and preheating, on the canola pressing performance. Maximum pressure increased, and press throughput and residual oil (RO) in presscake both decreased, with a reduction in choke opening and with lowering of shaft speed. When either whole seed or flakes were preheated in the range 40–100C, the pressure and throughput increased, and RO decreased. Press throughput and oil output both achieved maxima at a 5.0% moisture content in seed, while the RO showed a continuous increase with increasing seed moisture contents. The observed effects of choke opening and shaft speed on pressure, throughput, RO and press temperature could be explained with the aid of a simple equation representing the axial flow within the press. The same equation also served to explain the changes in pressure and throughput corresponding to the various seed pretreatments, when changes in viscosity of the oilseed mass were postulated. It was inferred that any seed pretreatment which increased viscosity would also increase throughput of the press. A further examination of the individual components of viscosity might explain the changes in the residual oil content and facilitate the development of improved or novel pretreatments of oilseeds.     

Effect of the presence of sulfur during the hydrogenation of canola oil

Sulfur was added to refined and bleached canola oil before hydrogenation in the form of allyl isothiocyanate and the effects on hydrogenation rate and fatty acid composition were determined. The effect was more pronounced under selective conditions (200 C and 7 psi) than under nonselective conditions (160 C and 44 psi). Sulfur added at the level of 3 mg/kg under selective conditions stopped the hydrogenation at an iodine value (IV) of 81, with 5 mg/kg at IV 88. Under nonselective conditions, there was a decrease in reaction rate, but even with 10 mg/kg added S, the reaction could be made to reach IV 70. The amount of S bound to the commercial nickel catalyst was determined and in all cases was less than the amount that was bound to Raney nickel. Relatively more sulfur was bound at lower temperature (longer time) and higher pressure. Addition of 3 mg/kg of S or more resulted in considerably higher formation of trans isomers.     

Identification of sulfur compounds in rapeseed oil

Seven sulfur compounds were found in industrially extracted rapeseed oils. Four of these were identified as 3-butenyl-, 4-pentenyl-, and phenethyl isothiocyanate, and 5-vinyl-2-oxazolidinethione. These compounds are hydrolysis products from glucosinolates present in the seed. Contribution No. 481 from Department of Plant Science, University of Manitoba, Winnipeg, Manitoba, Canada, R3T 2N2. Presented in part at AOCS Meeting in Cincinnati, 197 5.     

Biobased epoxy resin from canola oil

Epoxidized canola oil (ECO)‐based thermoset epoxy resins were formulated with phthalic anhydride (PA) as the curing agent for different ratios of ECO to PA (1:1, 1:1.5, and 1:2 mol/mol) at curing temperatures of 155, 170, 185, and 200°C. The gelation process of the epoxy resins and the viscoelastic properties of the systems during curing were studied by rheometry, whereas the dynamic mechanical and thermal properties of the cured resins were studied by dynamic mechanical analysis (DMA) and differential scanning calorimetry. We found that the thermomechanical properties of the resins were not strongly dependent on the curing temperature of the resin, although elevated temperatures significantly accelerated the curing process. However, an increase in the curing agent (PA) amount significantly altered both the reaction rate and the thermomechanical properties of the final resin. Thus, in the ECO/PA system, the selection of the combination of the curing temperature and the molar ratios of the curing agent could be used to design thermoset resins with unique thermomechanical properties. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40142.     

络合萃取脱除FCC柴油中的碱性氮化物

采用AlCl3/甲醇作络合萃取剂,考察了其对FCC柴油中碱性氮化物的脱除效果.结果表明:采用AlCl3/甲醇作络合萃取剂,可有效脱除FCC柴油中的碱性氮化物,同时柴油的外观色度也得到了改善.甲醇与甲酸组成的复合溶剂可明显提高碱氮的脱除率和柴油收率,同时减少了络合剂的用量.在剂油比为1.0,甲酸与甲醇体积比为1:4,AlCl3用量为1.0 g/L时,反应3 min,静置15 min,柴油的脱氮率达96.6%,收率可达97.0%.     

Pigment removal from canola oil using chlorophyllase

Frost-damaged or prematurely harvested canola seed (rapeseed) may yield oil with a high chlorophyll content (50–60 μg/ml). Enzymatic hydrolysis of chlorophyll, added to buffer/surfactant, buffer/acetone or buffer/acetone/canola oil, to produce water-soluble chlorophyllide (green pigment) was studied using a crude chlorophyllase preparation (acetone-dried chloroplasts) from 15 to 20-day-old sugar beet seedlings. In buffer/surfactant, the optimum pH for enzyme activity was temperature dependent. At 30 C and 0.24% Triton X-100 (or 30% acetone), chlorophyllase showed maximum activity toward a crude chlorophyll preparation over the range of pH 8–10. At 60 C, the activity was more than twofold higher, with a sharp maximum at ∼pH 8. Mg²⁺ enhanced the activity with an optimal concentration of 50 mM. At pH 7.5, 50 C and in the presence of only 6% acetone, the enzyme showed high affinity for chlorophyll (Km=15μM or 13.5 μg/ml), suggesting that the natural chlorophyll concentrations found in green canola oils might facilitate high enzymatic efficiencies. The crude enzyme was stable in buffer/acetone at pH 7.5 and 50 C for at least two hr. With acetone concentrations as low as 6%, maximum enzyme activities in buffer and buffer/canola oil required intensive mixing (homogenization) of the various substrate, enzyme and liquid phases. In general, the rate and extent of chlorophyll hydrolysis were greater in buffer than in buffer/oil. In both reaction systems, chlorophyll hydrolysis slowed down with time due to accumulation of phytol, which proved to be a competitive inhibitor (K_i=11 μM or 3.3 μg/ml). The other hydrolysis product, chlorophyllide, did not affect enzymatic activity. Crude canola oil used in the reconstitution of green oil did not support enzymatic chlorophyll hydrolysis without prior degumming and desoaping. The optimum buffer/oil ratio of the reaction mixtures was above 2/1 (v/v).     

Removal of sulfur compounds from utility pipelined synthetic natural gas using modified activated carbons

Synthetic natural gas (SNG), which is produced from petroleum and distributed via pipeline in Honolulu by The Gas Company, was analyzed using a gas chromatograph equipped with a sulfur chemiluminescence detector (GC/SCD). Hydrogen sulfide (H₂S), methyl mercaptan (MM), ethyl mercaptan (EM), dimethylsulfide (DMS), dimethyl disulfide (DMDS), tetrahydrothiophene (THT), ethyl disulfide (EDS), and one unidentified compound (UN1) were detected. Among these sulfur compounds, THT is added as an odorant and was present in the highest concentration.A commercial activated carbon (Calgon OLC plus 12X30) was modified by oxidation and impregnation methods and the resulting materials were evaluated for their ability to adsorb sulfur compounds present in SNG. The evaluation results indicate that all of the modification methods can improve the retention of individual sulfur compounds or the total sulfur capacity compared with the untreated virgin carbon. It is also found that activated carbons impregnated with metal impurities have different selectivity for sulfur compounds. Cu and Zn loaded carbons had the highest capacity for H₂S removal, Fe loaded carbon was more efficient for DMS removal (the most difficult S compound to remove), and carbon oxidized by HNO₃ was the best for THT removal.Based on these findings, a composite sorbent consisting of Cu loaded and Fe loaded carbons was designed and tested. The test results indicate that the composite sorbent had improved performance in the removal of individual sulfur compound. A linear programming model was used to design a composite sorbent optimized to minimize the required sorbent mass based on a 1-kW scale fuel cell system service target. Validation tests showed that the optimized sorbent required less of the individual modified carbon components than when they were individually used for the same sulfur removal target.     

酸性离子液体脱除柴油中碱性氮化物

合成离子液体N-甲基吡咯烷酮磷酸二氢盐([Hnmp]H_2PO_4),用吡啶红外探针法测定其酸性。采用500μg/g的喹啉模型油考察其对油品中碱性氮化物的脱除性能。结果表明,在剂油质量比1∶7,反应温度为30℃,反应时间为30 min,静置时间120 min的条件下,模型油中碱性氮化物的脱除率可达到98.64%。在离子液体[Hnmp]H_2PO_4回收利用4次后,碱氮脱除率仍在96%以上。同时该离子液体也能有效脱除碱氮含量高达0.52%(质量分数)的抚顺页岩油柴油馏分中的氮化物,当剂油质量比为1∶1时,柴油馏分的碱氮脱除率可达94.25%。     

酸性离子液体脱除柴油中碱性氮化物

合成离子液体N-甲基吡咯烷酮磷酸二氢盐([Hnmp]H_2PO_4),用吡啶红外探针法测定其酸性。采用500μg/g的喹啉模型油考察其对油品中碱性氮化物的脱除性能。结果表明,在剂油质量比1∶7,反应温度为30℃,反应时间为30 min,静置时间120 min的条件下,模型油中碱性氮化物的脱除率可达到98.64%。在离子液体[Hnmp]H_2PO_4回收利用4次后,碱氮脱除率仍在96%以上。同时该离子液体也能有效脱除碱氮含量高达0.52%(质量分数)的抚顺页岩油柴油馏分中的氮化物,当剂油质量比为1∶1时,柴油馏分的碱氮脱除率可达94.25%。     

Biodiesel production from mixtures of canola oil and used cooking oil

Used cooking oil (UCO) was mixed with canola oil at various ratios in order to make use of used cooking oil for production of biodiesel and also lower the cost of biodiesel production. Methyl and ethyl esters were prepared by means of KOH-catalyzed transesterification from the mixtures of both the oils. Water content, acid value and viscosity of most esters met ASTM standard except for ethyl esters prepared from used cooking oil. Canola oil content of at least 60% in the used cooking oil/canola oil feedstock is required in order to produce ethyl ester satisfying ASTM specifications. Although ethanolysis was proved to be more challenging, ethyl esters showed reduced crystallization temperature (−45.0 to −54.4 °C) as compared to methyl esters (−35.3 to −43.0 °C). A somewhat better low-temperature property of ester was observed at higher used cooking oil to canola oil ratio in spite of similar fatty acid compositions of both oils.     

Kinetics of oil extraction from canola (rapeseed)

The extraction of oil from canola (rapeseed) using hexane as a solvent can be described by a two stage washing/diffusion model. Oil which is at the surface of the seed as a result of pressing or cooking is removed rapidly at the beginning of the extraction process by simple washing by the solvent. This is followed by a slow extraction of the oil from the seed by a diffusional process. This latter process appears to be controlled by two mechanisms: slow, unhindered diffusion of oil held in the ruptured cells in the seed; and very slow, hindered diffusion of oil held within unruptured cells in the seed. To evaluate this model, rapeseed was extracted with commercial hexane in a simple bench scale batch extractor and the effects of variables such as particle thickness, temperature, cooking, degree of agitation, and solvent-to-seed ratio were studied.     

Polymorphic behavior of high-melting glycerides from hydrogenated canola oil

Canola oil was hydrogenated with a commercial nickel catalyst at 175°C and 15 psi hydrogen pressure. Samples were taken during the reaction starting at 15 min and thereafter at ten-minute intervals. The reaction was stopped after two hours. The high-melting glycerides (HMG) were obtained by fractional crystallization at 15°C with acetone as solvent. The HMG were analyzed for fatty acid and triglyceride composition by gas liquid chromatography andtrans was determined by infrared spectroscopy. In the first 45 min of hydrogenation of canola oil, the 18:0 fatty acid increased at a low rate while thetrans fatty acid content increased at a much faster rate. The 16:0 and 18:0 content of the HMG was highest andtrans content the lowest during the period in which the triglyceride composition was the most diverse. The 54-carbon triglyceride content of the HMG increased from 64% to 78% during the two hours of hydrogenation. The short spacings for the HMG showed the presence ofβ crystals as well as several intermediate forms. The number of short-spacings increased with hydrogenation time. The differential scanning calorimetry (DSC) melting profile of the HMG showed one broad peak between 20 and 30°C and two peaks around 60°C and above. Crystallization temperatures of the HMG were in the range of 40–45°C. Presented at the 81st American Oil Chemists' Society Annual Meeting, April, 1990, Baltimore, Maryland.     

离子液体对燃油含硫化合物的萃取性能研究

在合成离子液体[Bmim]PF6的基础上,考察了萃取脱硫时间、温度、溶剂比等因素对含硫体系燃油脱硫率的影响。[Bmim]PF6萃取脱硫平衡速度很快,只需1min。[Bmim]PF6萃取脱硫适宜的操作温度为30～40℃,对噻吩类含硫化合物分配系数可达到0.4～0.5,通过4级萃取脱硫率可以达到80%以上。     

Rapid extraction of canola oil

The simultaneous size reduction and solvent extraction of canola seeds were studied using a laboratory blender and a small, pilot-scale Szego mill. The laboratory tests established that over 95% of the oil may be removed from the seed in a single contact stage. The effects of contact time and solvent-to-seed ratio were investigated. The extraction equilibrium favored the extraction of the oil at higher solvent-to-seed ratios. In all cases the extraction reached some 90% of the equilibrium value after 3 min. Runs in the Szego mill, which is a unique orbitalmill developed by one of us (O. Trass), confirmed that solvent grinding is an efficient extraction technique. In this equipment, contact times as short as 30 sec give significant extraction, with the system approaching equilibrium in one minute. The Szego mill appears to be suitable for the rapid extraction of edible oil seeds such as rapeseed.     

Scale-up of canola oil degumming

The chemical degumming of canola oil was optimized using citric acid and maleic anhydride as degumming agents. These chemicals were selected from a group of 54 degumming agents, reported previously. The effect of temperature, chemical addition level, water addition level and contact times was investigated. Best results were obtained at 40 C, using 10 min contact with the chemical, followed by the addition of 2% water and agitation for 20 min. Chemical degumming reduced the residual phosphorus level from 1049 mg/kg to 50 mg/kg using either maleic anhydride or citric acid. Refining tests gave excellent deodorized or hydrogenated products. The optimized reaction conditions were applied to 330 kg test batches of oil in the P.O.S. Pilot Plant. Results were identical to those obtained in the laboratory, indicating that the process may be scaled up readily for industrial application.     

Polymorphism of hydrogenated canola oil

The polymorphism of hydrogenated Canola oil was investigated using X-ray diffraction. The effects of hydrogenation conditions (selective: 200 C; 48 kPa hydrogen pressure, and nonselective: 160 C; 303 kPa) and degree of unsaturation on the transformation β′ → β are discussed. A densitometer was used to follow the changes in the relative density of the characteristic short spacings, in an attempt to present a semiquantitative measure of β′ « β transformation during storage. The samples studied were selectively and nonselectively hydrogenated Canola oils of iodine values (IV) 70 and 60, respectively. Among the 4 samples, the selectively hydrogenated sample with IV 70 was the most stable and the nonselectively hydrogenated sample with IV 60 the least stable.     

Removal of nitrogen compounds from shale oil by adsorption on to acid-treated shale ash

Basic nitrogen compounds occurring in shale oil can be selectively adsorbed by spent oil shale ash that has first been treated with either a mineral acid, e.g. HCl, or a Lewis acid, e.g. CuCl₂. For Rundle shale oil a reduction in the basic nitrogen level from 0.55 wt% to less than 0.05 wt%, and total nitrogen from 1.2 wt % to 0.5 wt%, has been achieved using an ash rich in clay minerals and low in carbonates. It has also been shown that pyridine, quinoline and 2,6-dimethylpyridine are all readily adsorbed by ash treated with several common transition metal chlorides. Selection of an appropriate Lewis acid, or mixture of acids should enable adsorption to be optimized when specific impurities are known to be present. Under appropriate conditions most of the reference basic nitrogen compounds can be adsorbed in less than 1 h.