Rigorous modeling of solubility of normal alkanes in supercritical CO2

In this contribution, ANFIS approaches are developed for the prediction of normal alkane solubility in supercritical carbon dioxide. Regarding the economic and environmental benefits of carbon dioxide injection, it introduced as a well-known procedure of EOR. With this in mind that solubility of normal alkanes followed by CO₂ injection affected by various operational condition, in this article functionality of solubility of normal alkanes in supercritical carbon dioxide from operational condition was investigated using Adaptive Neuro Fuzzy Interface System (ANFIS). Results demonstrate that the model is precise. The model shows an overall R² and AARD% estimations of 0.9921 and 0.89%, respectively.     

An approach to characterisation of producibility and lubricity of reacted films under boundary lubrication

Boundary oil films can be transformed into reacted films during an extremely short period of time under certain conditions of reactive dynamics. A comprehensive index R is introduced to characterise the producibility and lubricity of the reacted films. Index R, which is calculated using maximum and minimum friction coefficients in the formation process of the reacted films as well as from the reacting and maintaining periods of the films, is correlated to conditions of reactive dynamics, such as temperature, pressure, and velocity.     

Extracted waxes from a lubricant oil base stock and their relation to composition and flow properties

The phase transition temperatures and associated enthalpies of extracted waxes from an IN range lubricant oil base stock and its fractions in the boiling range 247–546°C, were determined by DSC. X‐ray diffractograms of these samples, showing the variation in intensity with angle 2θ at 5°C and 24°C, were also obtained. The thermal parameters of the extracted waxes were correlated with the composition and flow properties of the base oil sample. The crystallisation behaviour of these waxes conforms to the hydrocarbon type component analysis of the base stock and its fractions, obtained by mass spectroscopy. The key n‐alkanes present in the extracted waxes, and that would be necessary in tailoring a suitable pour‐point depressant for the base oil, have also been predicted.     

Utilizing Terminal Oxidants to Achieve P450‐Catalyzed Oxidation of Methane

Terminal oxidant‐supported P450 reactions alleviate the need for substrate binding to initiate catalysis by chemically generating “compound I.” This allows investigation of the innate substrate range of the enzyme active site. Using iodosylbenzene as the oxidant, CYP153A6, a medium‐chain terminal alkane hydroxylase, exhibits methanol formation in the presence of methane demonstrating that P450‐mediated methane hydroxylation is possible.     

The hydrocarbon/water interfacial behaviour of alkyl aryl sulphonates

The interfacial tension and solubilisation characteristics of the alkane/water interfaces of a series of alkyl aryl sulphonates synthesised with 1‐butanol as a co‐surfactant have been studied. It was observed that there is a narrow range of carbon numbers of these sulphonates at which maximum solubilisation of a particular alkane occurred. This range shifted progressively to a higher value, with a corresponding increase in the carbon number of the n‐alkane. The extent of solubilisation of the alkane is highly dependent on the structure of the hydrocarbon portion of the sulphonate. Unexpectedly, an ultra‐low interfacial tension seems not to be an important prerequisite for the solubilisation of hydrocarbon in the aqueous surfactant phase. The free energy decrease required for solubilisation seems to be far more dependent on the energetic interactions connected with entropy parameters. The conformational aspects of the hydrocarbon portion of sulphonate molecules, as a consequence, seem to play a decisive role in molecular interactions, leading to solubilisation of a large quantity of a particular hydrocarbon in aqueous solution of a given sulphonate. The present work aims at understanding the selection criteria for sulphonates in applications involving solubilisation and ultra‐low interfacial tension at the hydrocarbon/water interface, such as those in insecticidal/pharmaceutical formulations, fire‐resistant hydraulic fluids and enhanced oil recovery.     

介孔Pt/SAPO-11的制备工艺优化及其催化油酸脱羧制备航空煤油性能评价北大核心CSCD

为提高SAPO-11分子筛在催化油酸脱羧制备航空煤油主要成分C8~C17烷烃的催化反应效果,以聚环氧乙烷-聚环氧丙烷-聚环氧乙烷三嵌段共聚物(P123)和十二烷基三甲基溴化铵(DTAB)为介孔双模板剂,采用原位合成法制备了介孔Pt/SAPO-11分子筛催化剂,探究不同晶化温度、晶化时间和煅烧温度对介孔Pt/SAPO-11结晶度、孔结构、形貌特征的影响,并考察其催化油酸脱羧制备C8~C17烷烃效果。结果表明:在晶化温度190℃、晶化时间36 h、煅烧温度650℃、煅烧时间5 h时,合成的介孔Pt/SAPO-11具有较大的比表面积、较高结晶度、较合适孔径和较好的形貌特征;在油酸脱羧制备C8~C17烷烃的反应中,在反应温度340℃、剂油比1∶10、反应时间6 h时,C8~C17烷烃收率可达78.3%。     

“Magic Numbers” in Self-Faceting of Alcohol-Doped Emulsion Droplets

Oil-in-water emulsion droplets spontaneously adopt, below some temperature T_d, counterintuitive faceted and complex non-spherical shapes while remaining liquid. This transition is driven by a crystalline monolayer formed at the droplets' surface. Here, we show that ppm-level doping of the droplet's bulk by long-chain alcohols allows tuning T_d by >50 °C, implying formation of drastically different interfacial structures. Furthermore, “magic” alcohol chain lengths maximize T_d. This we show to arise from self-assembly of mixed alcohol:alkane interfacial structures of stacked alkane layers, co-crystallized with hydrogen-bonded alcohol dimers. These structures are accounted for theoretically and resolved by direct cryogenic transmission electron microscopy (cryoTEM), confirming the proposed structures. The discovered tunability of key properties of commonly-used emulsions by minute concentrations of specific bulk additives should benefit these emulsions' technological applicability.