The purpose of this review is to provide appropriate details concerning the applications of ionic liquids for the removal of pollutants from refinery feedstocks, like sulfur-, nitrogen- and ...fluor-containing compounds, aromatics, naphthenic acids and asphaltenes. Furthermore, critical considerations surrounding the problems and challenges associated with the application of these technologies in the petroleum industry are discussed.
Although research in renewables is growing at a tremendous rate, the world will still be greatly dependent on fossil fuels for at least the first half of this century. In the quest for more efficient ...and clean fuels, oil refining companies have turned their attention to processes such as reforming and alkylation technologies; in the latter process, isobutane is reacted with butenes and/or propylenes to produce, among others, branched isooctane, which is the main high-octane component of the gasoline pool. The main benefit of this process is the possibility to produce sulfur-free high-octane fuels, so important economic and environmental advantages are foreseen if investments in this area are realized. This Review analyzes and discusses the most recent progress on catalyst technologies, starting from the traditional sulfuric acid process and proceeding to newly emerging catalyst technologies such as solid acid and ionic liquid-based catalysts. We start with basic mechanistic analyses and conclude this Review with the new non-liquid acid-based commercial and emerging technologies for isobutane alkylation. Emphasis is given to the structure–activity relationships and the advantages and disadvantages present in every discussed catalyst material.
The research and application of green chemistry principles have led to the development of cleaner processes. In this sense, during the present century an ever-growing number of studies have been ...published describing the use of ionic liquids (ILs) as solvents, catalysts, or templates to develop more environmentally friendly and efficient chemical transformations for their use in both academia and industry. The conjugation of ILs and microwave irradiation as a non-conventional heating source has shown evident advantages when compared to conventional synthetic procedures for the generation of fast, efficient, and environmental friendly synthetic methodologies. This review focuses on the advances in the use of ILs in organic, polymers and materials syntheses under MW irradiation conditions.
The application of methanesulfonic acid (MSA) as a green catalyst for the production of alkylate gasoline was successfully attained in the liquid (batch pressure reactor) and gas phase (1 atm, glass ...reactor, with MSA supported on silica gel) using real refinery hydrocarbon mixtures containing isobutane and butenes. The product quality was monitored by gas and liquid chromatography, yielding octane (C8s) selectivity of up to 92% in the gas phase and 70% in the liquid phase. The reaction temperature and catalyst/hydrocarbon mass ratio were the most influential reaction parameters affecting the conversion and selectivity. The addition of a liquid co-catalyst to MSA negatively affects the quality of the alkylate product, as well as the conversion of butenes. The presence of the silica support, in the gas phase at continuous regime alkylations, allowed us to obtain alkylate gasoline with sustained high conversions and selectivity to C8s at a quality similar or even higher to that obtained with sulfuric acid as the commercial catalyst. Characterization of the supported MSA reveals strong dipole–dipole interactions, revealed through the protonation of the surface –OH groups.
•A comparative study of demulsification by microwave and oil bath heating.•Results were confirmed by steady state fluorescence spectrometry.•The effect of a demulsifier on the oil-in-water (O/W) ...emulsion stability was studied.•The effect of salt content on the O/W emulsion stability was evaluated.
Oil-in-water (O/W) emulsions are an innovate manner by which otherwise highly viscous heavy and extra-heavy crude oils can be transported from producing sites to transforming sites through pipelines. In spite of the important reduction in viscosity and pressure drops, water must be removed from the crude oil before further process or refining. Hence, the present study discusses the demulsification of an O/W emulsion prepared with Mexican heavy crude oil. A comparative study was carried out between microwave and oil bath heating with regard to water separation time. The effect of a chemical demulsifier and salt content of the O/W emulsion’s aqueous phase was also investigated. Microwave dielectric heating of O/W emulsions showed a greater degree of water separation in less time than conventional oil bath heating. Water separation of O/W emulsions increased with microwave power and salt content of the aqueous phase, and in the presence of a chemical demulsifier. Finally, the fluorescence emission spectra of the initial and treated O/W emulsions were in agreement with the water separation results and provide a quick and effective way to study the demulsification processes.
The low solubility of lignin in most common solvents remains a significant challenge to be solved for its use and recovery. In this work, 18 novel protic ionic liquids (ILs) containing ...aromatic-substituted imidazolium cations and methanesulfonate and p-toluenesulfonate anions were synthesized and evaluated for lignin dissolution under microwave irradiation. ILs containing methanesulfonate demonstrated good lignin dissolving capacities, which can facilitate its separation and structural modifications to carry out their recovery under relatively mild and environmentally friendly conditions (few minutes, 90 °C). DFT theoretical calculations provided additional insights into the high lignin dissolution observed for the best performing ILs.
This work reports the synthesis of a new low-dosage kinetic hydrate inhibitor (KHI) based on the ionic liquid C12PyBr (N-dodecyl pyridinium bromide), which was characterized and evaluated in order to ...determine its inhibition performance. By means of a microwave-assisted reaction scheme, a high-purity product was obtained and the commercial product Inhibex 101 (IC) was employed as a comparison reference at 0.1, 0.5,, and 1.0 wt % in aqueous solution to test the inhibition of methane hydrate formation. In this sense, it was discovered that, by using C12PyBr at 0.1 wt %, the formation of methane hydrates was inhibited at a subcooling of 11.2 K and at a concentration one order of magnitude lower than that used with Inhibex 101 to reach the same performance as KHI. This fact could be used as an attractive factor when establishing gas hydrate inhibition plans for offshore and deep-water scenarios.
Five imidazolium-type ionic liquids, containing both N1 unsaturated and N3 long alkyl saturated chains as cations and bromide as anion (IL1–IL5), were obtained by conventional and microwave ...synthesis. Compounds were tested in aqueous 1 M H2SO4 as corrosion inhibitors for carbon steel. Weight loss and polarization curves indicated that inhibition efficiency increased with concentration, which turns out to be dependent on alkyl chain size linked to N3 (IL4 > IL3 > IL1 > IL2 > IL5). The relatively high inhibitory properties (88–95%) displayed by IL4 within 25–40 °C were ascribed to a chemisorption process that involved the following: the adsorption of protonated imidazolium molecules on both the anodic and cathodic sites, the latter in competition with hydrogen ions to mitigate hydrogen evolution; and also the formation of π bond with iron by the CN group from imidazolium ring (this way inhibitor produced more than one center of adsorption action). Surface analysis indicated a considerable reduction of corrosion products after the addition of IL4.
Water/oil emulsions are formed in oil wells because of the presence of natural surfactants, such as asphaltenes and resins. These molecules strongly stabilize the water/oil interface and prevent ...coalescence of water droplets. Because water/oil phase separation is necessary before oil refining, surfactants are used to break water/oil emulsions. Herein, surface-active ionic liquids were synthesized and evaluated for the first time as demulsifier agents for water-in-crude oil emulsions of light, heavy, and ultra-heavy Mexican crude oil under conventional and microwave dielectric heating. The use of microwave irradiation accelerated and increased significantly the efficiency of demulsification of ultra-heavy crude oil emulsion.
In the present work, three new ionic liquids (ILs) were tested as corrosion inhibitors (CIs): 1,2-dimethyl-3-decylimidazole iodide (DDI), N-triethyl methylammonium acetate (TMA) and N-triethyl ...methylammonium laurate (TML). The tests were carried out in 1.0 M solutions of sulfuric acid (H2SO4) and hydrochloric acid (HCL) in order to inhibit the corrosion of API 5L X-52 steel. The corrosion inhibitors (CIs) were evaluated by Tafel polarization and polarization resistance (R P). The Tafel polarization results confirmed that DDI, TMA, and TML inhibited the steel corrosion and worked as mixed inhibitors in both corrosive media. In 1.0 M H2SO4, DDI featured the best inhibition efficiency (IE), which ranged from 57 to 95%, whereas TMA in 1.0 M HCl showed the best IE, which was within the 30–70% range. The IE obtained by R P in 1.0 M H2SO4 was increased as a function of time, while in 1.0 M HCl, it was inversely proportional. The adsorption displayed by DDI, TMA, and TML on the API 5L X52 steel surface was both physical and chemical, which was obtained from different adsorption isotherms.
