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Ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) enables the direct characterization of complex mixtures without prior fractionation. High mass resolution can distinguish peaks separated by as little as 1.1 mDa), and high mass accuracy enables assignment of elemental compositions in mixtures that contain tens of thousands of individual components (crude oil). Negative electrospray ionization (ESI) is particularly useful for the speciation of the most acidic petroleum components that are implicated in oil production and processing problems. Here, we replace conventional ammonium hydroxide by tetramethylammonium hydroxide (TMAH, a much stronger base, with higher solubility in toluene) to more uniformly deprotonate acidic components of complex mixtures by negative ESI FTICR MS. The detailed compositional analysis of four crude oils (light to heavy, from different geographical locations) reveals that TMAH reagent accesses 1.5-6 times as many elemental compositions, spanning a much wider range of chemical classes than does NH4OH. For example, TMAH reagent produces abundant negative electrosprayed ions from less acidic and neutral species that are in low abundance or absent with NH4OH reagent. More importantly, the increased compositional coverage of TMAH-modified solvent systems maintains, or even surpasses, the compositional information for the most acidic species. The method is not limited to petroleum-derived materials and could be applied to the analysis of dissolved organic matter, coal, lipids, and other naturally occurring compositionally complex organic mixtures. [ABSTRACT FROM AUTHOR]

Aging refers to the deterioration of hydrocarbon fluids that manifests as changes in the physicochemical characteristics of the fluid upon exposure to ambient conditions. In order to understand the effect of aging of crude oils on asphaltene inhibitor product recommendation, simulated aging studies were performed on a crude oil from Wyoming with known asphaltene issues. The results clearly show that aging of crude oil affects the stability of the oil with respect to asphaltenes and caution must be exercised when recommending asphaltene inhibitor if the evaluations were performed on fluids after long-term storage. A real case study where ambient storage in the lab adversely affects the stability of the crude oil and renders asphaltene inhibitor ineffective further confirms results from simulated aging. [ABSTRACT FROM AUTHOR]

Alkylamino derivatives of different N-Heterocyclic systems like the azoles, azines and piperazines have been synthesized and characterized for structural information by FT-IR and 13C NMR spectroscopy. Accelerated stability tests have been done to evaluate their sediment inhibition and dispersant characteristics on distillate fuels containing high proportions of unstable components and results discussed. It is inferred that hydroxy, aminoalkyl azines and aminoalkyl azoles are not only effective stabilizers but also effectively disperse gum and sediments formed. It is concluded that contributions from different structural tautomers and other structural parameters like the number of nitrogen atoms constituting the ring and the nature and position of substituents on the ring determines the performance behavior of these compounds. [ABSTRACT FROM AUTHOR]

Different N-substituted derivatives of urea, thiourea and guanidine have been synthesised and characterised for structural information by FT-IR and 13C NMR spectroscopy. Accelerated stability tests have been done to evaluate their sediment inhibition and dispersant characteristics on distillate fuels containing high proportions of unstable components and results discussed. It is inferred that urea and guanidine derivatives not only inhibit the reactions responsible for sedimentation in the test fuel but also effectively disperse the gum and sediment formed. It is concluded that the nature of substituents on the central carbon atom and on the amino groups determines the performance behaviour of these compounds. [Copyright &y& Elsevier]

This paper summarizes the synthesis of some amino acid esters and their derivatives. The structural characteristics of these derivatives have been studied by IR, 1H and 13C NMR spectroscopy. Evaluation of their efficacy with respect to gum and sediment inhibition and dispersant characteristics in highly unstable distillate fuel blends has been carried out. The results of accelerated stability test have been discussed and it is inferred that while most of these derivatives are quite effective for stabilization of fuel, phenyl alanine dodecanoate and N-tert-dodecyl lysine dodecanoate are highly efficient in imparting stability and dispersant characteristics to the fuel employed for study. It has been concluded that structural parameters such as nature of substituents on the amino acid backbone and the type and length of alkyl chains profoundly influence the dispersant as well as stabilizing characteristics. [ABSTRACT FROM AUTHOR]

Nine different derivatives of alkyloxy alkylamino propanols were synthesised from epichlorohydrin, straight or branched chain primary and secondary alcohols and tertiary alkyl primary amines as well as straight chain primary amine. Their sedimentation inhibition characteristics in distillate fuels of various compositions were studied in comparison to tertiary alkyl primary amines as well as some known commercial additives of similar nature. It is inferred that the replacement of hydrogen in tertiary alkyl primary amines with a long chain hydroxy ether greatly improves the sediment inhibiting properties of tertiary alkyl primary amines, which were otherwise not found very effective in the fuels employed for present studies. Moreover it has been concluded that among these derivatives tertiary-dodecyl appears to be most optimum chain length for the amine moeity and eight C-atoms in the alkyl chain backbone of alcohol moiety is the most optimum for effective inhibition. Sedimentation values have been reduced from 10 mg/100 ml to 2.89 mg/100 ml for 3(3,7 dimethyl octyloxy)-1(t-dodecylamino)-Propan-2-ol employed as inhibitor. [ABSTRACT FROM AUTHOR]

Asphaltenes, among the most complex components of crude oil, vary in their molecular structure, composition, and self-assembly in porous media. This complexity makes them challenging in laboratory characterization methods. In the present work, a novel microfluidic device was designed to access in situ transient, high-fidelity information on asphaltene deposition and dissolution within porous media. The automated microfluidic device features three independent 4.5 μL packed-bed microreactors on the same chip. The deposition of asphaltenes was investigated at five different temperatures (ranging from 25–65 °C) in addition to dissociation with xylenes. Our findings demonstrate a decrease in the dispersity of asphaltene nanoaggregates in the porous media when the deposition temperature is increased. Furthermore, the direct quantification of the dissociation solvent was made possible by in situ Raman spectroscopy. The average occupancy of xylenes and xylene-free porous media (or unrecognized sites) was estimated to be 0.41 and 0.66, respectively. It was observed that asphaltenes deposited at higher deposition temperatures are more difficult to dissociate by xylenes than those deposited at lower temperatures. In order to develop efficient remediation treatments in energy production operations, the convoluted behaviours of asphaltenes in porous media must be understood on a molecular level. Automated microfluidic systems have the potential to streamline treatment designs, improve their efficiency, and enable the design of green chemistry in conventional energy production operations. [ABSTRACT FROM AUTHOR]