Thermostability and polymorphism of theobroma oil and palm kernel oil as suppository bases

Thermal stability of pharmaceutical ingredients is an important aspect. In this study, we adopted differential scanning calorimetry (DSC) to investigate thermal stability of suppository bases, theobroma oil (cocoa butter) and a palm kernel oil (PKO) blend. The study shows theobroma oil possesses six polymorphic forms whilst the palm kernel oil blend has three. Upon rescanning, the PKO blend does not show changes in the enthalpy of fusion and the melting point with time, whilst the theobroma oil shows significant reduction, and only regained its thermal stable state after 10 days. This indicates that PKO blend possesses better thermal stability.     

Spray-dried oil powder with ultrahigh oil content

We report a new facile route to the production of solid oil powders with an oil weight content of as high as 90% or beyond. The proposed method starts from a standard protein-stabilized oil-in-water emulsion in which a protein monolayer absorbed at the oil-water interface is successively cross linked by a thermal treatment. The emulsion is then spray dried as for ordinary emulsions, however without the addition of hydrocolloids typically needed when spray drying liquid oil dispersions. This leads to a final solid oil powder in which the total mass is constituted of oil, proteins, and eventual buffer salts and in which the elasticity of the cross-linked protein monolayer is alone sufficient to stabilize the powder and to limit any oil leakage. To best illustrate the potential in food applications and to preserve the food-grade nature of the constituents, we have used thermal denaturation at 80 °C for 15 min to cross link a β-lactoglobulin-stabilized olive oil-in-water emulsion and to produce the corresponding solid oil powder. Because of the simplicity and flexibility of the proposed pathway, the present method can be used inexpensively to convert any type of hydrophobic liquid into the corresponding solid powder and is then particularly suitable for cosmetic, pharmaceutical, medical, biotechnological, and food applications.     

Thermal characterisation of Australian oil shales

There has been a significant research effort on the development of an oil industry based on Australian oil shales. However, to date the research has been based mainly on the processing aspects of oil shale. The thermal analyses of oil shales, while having been the subject of many studies, have been limited to some extent by instrumentation and analytical techniques. This paper reports on thermal analysis studies utilising traditional thermogravimetry/differential thermal analysis (TG/DTA) and differential scanning calorimetry (DSC). The application of modern thermal analysis techniques such as high resolution TG (HRTG) and modulated differential scanning calorimetry (MDSC) is also examined and compared to the traditional methods.     

Thermal analysis of coals,oil shales and oil sands

Instances where differential scanning calorimetry and thermogravimetry have been applied to the study of coals, oil shales and oil sands are reviewed. Work carried out in this laboratory and model studies culled from the literature are used as examples to illustrate a particular application. The topics covered include characterization, assay, thermal stability determination and simulation of processing conditions.     

Monitoring of thermal behavior and decomposition products of soybean oil

The thermal degradation and corresponding decomposition products of fresh and heat-treated soybean oil were investigated by synchronous thermal analyzer combined with Fourier transform infrared spectrometry and quadrupole mass spectrometry (STA–FTIR–QMS). Two longtime heat-treated soybean oil samples were aforehand prepared by consistently heating the fresh soybean oil for 50 and 100 h, respectively. N₂ and simulative air (N₂/O₂ = 4:1, volume) were used as the thermal reaction gas atmosphere. The results showed that one stage of mass loss appeared in analysis of the all oil samples under N₂ atmosphere condition and longtime heat pre-treatment had no effect on the thermal behavior of the soybean oil under N₂ atmosphere condition. However, four stages occurred in analysis of both untreated and heat-treated oil samples under the simulative air atmosphere condition. Longtime heat pre-treatment influenced the thermal behavior of the soybean oil in certain extent, which was reflected in the different mass loss values of the four stages. According to the infrared absorption profiles and MS spectra of the released compounds in vapor phase, H₂O, CO, CO₂, hydrocarbons (such as CH₄), and hydroxyl, carbonyl, and carboxyl-contained compounds have been confirmed. Therefore, STA–FTIR–QMS can be suggested as a promising technique for investigating of thermal degradation and monitoring the decomposition products of the evolving substances in edible oils.     

Water content of a Brazilian refinery oil sludge and its influence on pyrolysis enthalpy by thermal analysis

Residual oil sludges represent an environmental problem in the oil industry and need a proper destination in order to allow sustainable industrial processes when exploring natural resources. In the present paper, the influence of the water content on the oil sludge pyrolysis process was studied by thermal analysis. A method using thermogravimetry on calcined mass basis was developed to estimate the water content of oil sludges. The water present in the sludge vaporizes during the first thermal processing stage, interfering in the initial process of the organic components pyrolysis and increasing the total oil sludge pyrolysis enthalpy. By quantitative differential thermal analysis (DTA) it can be seen that the water content of the sludge may significantly affect the thermal balance of its industrial pyrolysis process.     

Evaluation of the thermal stability of biodiesel blends of castor oil and passion fruit

The diversity of raw materials and technological routes employed in the biodiesel production has resulted in products with different chemical properties. This non-uniformity in the biodiesel composition may influence to the fuel quality. The aim of this study was to evaluate biodiesel blends of passion fruit and castor oil in different proportions and their thermal stability. Biodiesel blends of passion fruit and castor oil presented parameters in the standards of the Petroleum, Natural Gas and Biofuels National Agency. The TG curves indicated that castor oil biodiesel was more stable. Passion fruit biodiesel has a high content of oleic and linoleic acids, which are more susceptible to oxidation. Biodiesel blend of passion fruit and castor oil 1:1 increased the thermal stability in relation to passion fruit biodiesel. Biodiesel blend of passion fruit and castor oil 1:2 presented higher thermal stability, because castor oil has a high content of ricinoleic acid.     

Thermal degradation of flame-retardant compounds derived from castor oil

Castor oil is a non-edible plant oil produced in a large quantity annually. It is a triglyceride of primarily (approximately 90%) ricinoleic acid. The acid residues contain both a hydroxyl group and a double bond which permit ready functionalization. The hydroxyl group may be converted to phosphorus esters of varied structure while the unsaturation readily undergoes addition of bromine. Derivatives of castor oil containing phosphorus, bromine, or phosphorus and bromine have been prepared and fully characterized using spectroscopic and thermal methods. The thermal stability and mode of degradation for these compounds have been assessed using thermogravimetry and infrared spectroscopy. The primary mode of degradation for the phosphorus esters is elimination of the corresponding phosphorus acid (phosphates more readily than phosphonates). Brominated castor oil undergoes thermally induced dehydrobromination at relatively modest temperatures and this promotes dehydration (at temperatures well below that required for dehydration of unmodified castor oil). Brominated phosphorus esters of castor oil undergo degradation initiated by dehydrobromination.

     

爱沙尼亚油页岩及其热解产物的电子顺磁共振研究

采用电子顺磁共振（EPR）技术,系统地研究了热解温度对样品自由基浓度、g因子和线宽的影响。结果表明,油页岩干酪根及其制备的热解产物沥青、焦油和半焦的自由基浓度为2.29×10¹⁴-9.16×10¹⁴。当热解温度低于380℃时,主要发生干酪根的热解聚,当热解温度超过380℃,主要为中间产物热沥青的分解阶段,表现为热沥青的自由基浓度N_g和g因子值高于半焦。对EPR谱图线宽分析可知,当温度高于380℃时,焦油的线宽明显大于半焦和热沥青,说明液体内部自由基中自旋粒子间以及自旋粒子与环境的相互作用要比固体剧烈的多。温度低于380℃时,半焦和热沥青由于热解反应的进行,自由基自旋粒子之间及其与环境的相互作用增强,线宽随着温度的升高而增加。温度高于380℃时,半焦和热沥青的EPR曲线线宽降低,表明随着温度的升高自由基自旋粒子的相互作用减弱。     

Development of biobased polyurethane‐imides from maleinized cottonseed oil and castor oil

An eco‐friendly coating system, which is largely biobased, has been developed from castor and cottonseed oil. Cottonseed oil was functionalized with maleic anhydride by “ene” reaction to give maleinized cottonseed oil (MACSO); the anhydride groups were reacted with isocyanates to yield –NCO terminated polyurethane prepolymer. The prepolymer was further chain extended with hydroxyl groups of castor oil to give polyurethane‐imides (PUIs). The cross‐linked films thus obtained had good mechanical properties, and the imide groups in the backbone improved the corrosion resistance of PUIs as revealed by potentiodynamic polarization study. With increasing content of MACSO, thermal stability, glass transition temperatures (T_g), tensile strength, and corrosion resistance of resulting PUIs significantly increased.     

Characterization of Pentaclethra macroloba oil

The Pracaxi oil—(Pentaclethra macroloba) contains high concentrations of fatty acids with emollient action that contribute to skin hydration. The use of this oil is supported by the utilization of natural resources thus enabling regional development and social contribution. The objective of this study was to characterize the P. macroloba oil by thermogravimetry (TG, DTG, and DTA), gas chromatography, Fourier transform infrared spectroscopy (FT-IR), and oxidation stability—Rancimat, aiming at the quality control of plant raw material. Three samples of crude oil sold by Amazon Oil Industry (Ananindeua, Pará, Brazil) were studied. The analysis of these oil samples showed different fatty acids, especially the behenic, oleic, linoleic, and lignoceric acids totalizing approximately 96 % of the grease composition and in smaller percentage arachidic, lauric, myristic, palmitic, and linolenic acids were found. The major acids have wide medicinal use. According to the TG/DTG curve, thermal stability was observed up to 220 °C, indicating a greater mass loss related to the dehydration and elimination of volatile substances. The thermal decomposition process occurred in the range of 430–450° C according to the DTG curve. The absorption spectrum in the infrared region (FT-IR) showed well-defined bands confirming the presence of functional groups present in the oil. Tests in a Rancimat have shown an induction period between 8 and 10 h demonstrating that the samples are in agreement with the standards required by ANP No. 14/2012 which requires at least 6 h of testing.     

Thermal analysis of soybean oil based polyols

Soybean oil based polyols (5-OH polyol, 10-OH polyol and 15-OH polyol) were synthetised from epoxidized soybean oil. The melting peak of polyols and the relationship between melting peak and the number-average functionality of hydroxyl in polyols were investigated by differential scanning calorimetry (DSC). The thermal decomposition of polyols and some of their thermal properties by thermogravimetry (TG) and derivative thermogravimetry (DTG) were also studied. The thermal stability of polyols in a nitrogen atmosphere was very close hence they had a same baseplate of triglyceride for polyols. The extrapolated onset temperature of polyols in their thermal mass loss, first step had a decreasing order: 5-OH polyol>10-OH polyol>15-OH polyol due to the difficulty in forming multiple elements ring of them had the same order. The thermal behavior of polyols under non-isothermal conditions using Friedman’s differential isoconversional method with different heating rates indicated that the 5-OH polyol had the lowest activation energy in thermal decomposition amongst these polyols according to the same fractional mass loss because of the weakest intramolecular oligomerization. The 15-OH polyol was prior to reach the mass loss region because the six-member ring is more stable than the three-member ring from 10-OH polyol and more easily formed.     

Thermo-oxidative reactions of Nigerian oil sand bitumen

The thermal behavior of the Nigerian oil sand bitumen in an oxidizing environment was studied using non-isothermal thermogravimetric analysis (TGA) and differential thermal analysis (DTA). This condition can occur during in situ thermal recovery. The kinetics of the reactions was also determined by Arrhenius plot method.Three regions of weight loss corresponding to low-temperature oxidation, fuel deposition and high temperature oxidation were identified. Increasing the heating rate caused a shift in the reaction regions and peak temperatures to higher temperatures. No effect of gas flow rate was observed on the reactions. The oil sands have lower peak temperatures and activation energies compared with their corresponding bitumen extracts, suggesting a catalytic effect of sand on the reactions. The DTA revealed the exothermic nature of the reactions. The exothermicity increased with increasing heating rate.The results of this study showed that the heating rate and the presence of sand have significant effect on the thermo-oxidative reactions of the bitumen.     

Thermophysical properties of oil shale minerals

The thermal diffusivity values of eight minerals that are commonly associated with oil shales of the Green River formation have been measured by the laser flash technique. Data are presented in the temperature range 25–500°C for quartz, dolomite, calcite, plagioclase, analcite, pyrite, potassium feldspar and low albite. A comparison of the thermal conductivities of some of these minerals, calculated from experimentally measured thermal diffusivity and density, with the experimental values reported in the literature reveals good agreement. Trends in the variation of thermal diffusivity with temperature and anisotropic effects in thermophysical parameters are discussed from the point of view of grain boundary effects in these polycrystalline mineral aggregates.     

Thermal stability during pyrolysis of sunflower oil produced in the northeast of Brazil

This study aims to analyze thermal stability and make a rheological assessment of sunflower oil produced in the Northeast of Brazil, resulting from the pyrolysis process. Oil samples were submitted to thermal degradation and the reaction was evaluated by the thermogravimetric technique, at temperatures between 30 and 900?°C. Apparent activation energy was determined using the model-free kinetics theory. The coaxial cylinder system at operating temperature of 40?°C was used to obtain rheological parameters. Oil was characterized by gas chromatography. The lipid profile of the oil exhibited good quality. The activation energy of the sunflower oil was 201.2?kJ?mol^?1. Results showed the influence of physical?Cchemical characteristics of vegetable oil on the thermal decomposition process. Rheological analyses confirmed Newtonian rheological behavior. The high potential of the ??Catissol?? variety produced in Northeast Brazil as raw material for biofuel production using pyrolysis was also demonstrated.     

Analyzing the calcination of sulfur-rich calcareous oil shales using FT-IR spectroscopy and applying curve-fitting technique

The thermal processes during progressive calcination of sulfur-rich calcareous oil shales were analyzed using FT-IR spectroscopy and applying curve-fitting technique. The spectroscopic analysis is advantageous in the analysis of amorphous and short-range ordered thermal phases lacking of XRD peaks. The raw calcareous oil shales are composed of organic matter, kaolinite, smectite, calcite, and apatite (francolite). The principal thermal phases are metakaolinite, meta-smectite, free lime, anhydrite, gehlenite, and ellestadite. The thermal reactions observed with increase temperatures includes decomposition of organic matter followed by release of sulfur gas; dehydroxylation of kaolinite; and smectite at 500–600 °C; and thermal transformation to metakaolinite and meta-smectite; decarbonation of microcrystalline calcite to free lime at 600 °C; reaction of the sulfur gas with the free lime; formation of anhydrite at 600 °C; reaction of apatite and formation of ellestadite at 800 °C; reaction of the metakaolinite; the meta-smectite with the free lime; formation of gehlenite at 900 °C. Owingto the sulfatization process, a great part of the sulfur content of the raw oil shales is retained in the calcined ashes and the release of sulfur gas to the atmosphere decreases. Thus, the combustion of calcareous oil shales for energy source has less pollution effect than that of the clayey oil shales. FT-IR spectroscopy and spectral analysis seems to be useful methods for phase analysis of oil shales in combustion industry.     

Dynamic kinetic calculation of castor oil biodiesel

Diesel oil has an important role in the field of urban traffic as well as in the transportation of products. However, the amount of the non-renewable sources is continuously decreasing. This fact and the environmental requirements brought the necessity to search for other, renewable sources. This paper aimed the dynamic kinetic calculation of thermal decomposition of castor oil, methanol biodiesel and ethanol biodiesel using Coats–Redfern, Madhusudanan and Ozawa methods. On the base of the thermogravimetric curves the following thermal stability order could be established: castor oil>ethanol biodiesel>methanol biodiesel. Kinetic data presented coherent results. Methanol biodiesel presented lower activation energy than ethanol biodiesel, suggesting that methanol biodiesel has a better quality for combustion.     

Effect of contact surfaces on the thermal and photooxidation of dehydrated castor oil

The effect of stainless steel, glass, zirconium and titanium enamel surfaces on the thermal and photooxidative toughening mechanism of dehydrated castor oil films deposited on these surfaces was investigated using different analytical and spectroscopic methods. The conjugated and non-conjugated double bonds were identified and quantified using both Raman spectroscopy and 1D and 2D NMR spectroscopy. The disappearance of the double bonds in thermally oxidised oil-on-surface films was shown to be concomitant with the formation of hydroperoxides (determined by iodometric titration). The type of the surface had a major effect on the rate of thermal oxidation of the oil, but all of the surfaces examined had resulted in a significantly higher rate of oxidation compared to that of the neat oil. The highest effect was exhibited by the stainless steel surface followed by zirconium enamel, titanium enamel and glass. The rate of thermal oxidation of the oil-on-steel surface (at 100 °C, based on peroxide values) was more than five times faster than that of oil-on-glass and more than 21 times faster than the neat oil when compared under similar thermal oxidative conditions. The rate of photooxidation at 60 °C of oil-on-steel films was found to be about one and half times faster than their rate of thermal oxidation at the same temperature. Results from absorbance reflectance infrared microscopy with line scans taken across the depth of thermally oxidised oil-on-steel films suggest that the thermal oxidative toughening mechanism of the oil occurs by two different reaction pathways with the film outermost layers, i.e. furthest away from the steel surface, oxidising through a traditional free radical oxidation process involving the formation of various oxygenated products formed from the decomposition of allylic hydroperoxides, whereas, in the deeper layers closer to the steel surface, crosslinking reactions predominate.     

Synchronous fluorescence and excitation emission characteristics of transformer oil ageing

This paper describes the evaluation of synchronous fluorescence spectroscopy (SFS) and excitation emission matrix fluorescence (EEMF) spectroscopy as means of monitoring transformer oil degradation. When accelerated thermal ageing method is used, the onset of degradation of transformer oil on 17th day and transformer oil with polypropylene and cellulosic paper on 23rd and 27th days is sensitively reflected in the SFS and EEMF fluorescence spectral characteristics.     

Thermal dissolution of Estonian oil shale

The thermal dissolution of Estonian oil shale, kukersite and thermobitumen (TBO) formed, in the presence of solvents (benzene, ethanol, water and oil shale petrol) in autoclaves was studied. In all the solvents, except subcritical water, the total yield of benzene-soluble products, TBO, has a maximum (about 90%) at an optimum residence time and thereafter decreases due to coke formation. The formation of TBO from kukersite in supercritical water, ethanol and oil shale petrol is accelerated in comparison with low-temperature pyrolysis of kukersite without any solvent. The tests carried out with TBO without the mineral matter indicate deceleration of the coke formation in comparison with the initial kukersite.