Determination of total hydroxyls and carboxyls in petroleum and syncrudes after chemical derivatization by infrared spectroscopy

Abstract

Oxygen-containing functional groups (hydroxyl and carboxyl) In fuels or crude oils, or fractions thereof, are determined by IR spectroscopy. The approach Is based on chemical derivatization followed by measurement of IR bands of the corresponding derivatives. The chemical derivatization procedure Involves two steps: (1) esterification of carboxylic acids with 2,2,2-trlfluoroethanol and (2) acylation of alcoholic and phenolic hydroxyls with trifluoroacetyl chloride. The aryl trlfluoroacetates absorb at 1800 cm'1; the 2,2,2-trlfluoroethyl esters absorb In the region 1760-1740 cm'1. Variation of molar absorptivity of the derivatives as a function of structure Is determined by using pure compounds and well-defined fractions from actual fuel samples. The overall accuracy, precision, sensitivity, and range of applicability to petroleum and related sample types are discussed.

Characterization of Athabasca Bitumen Heavy Vacuum Gas Oil Distillation Cuts by Negative/Positive Electrospray Ionization and Automated Liquid Injection Field Desorption Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

“…Organic acids in petroleum have been characterized extensively by a variety of techniques, including Fourier transform infrared spectroscopy, – 13 C nuclear magnetic resonance spectroscopy (NMR), , gas chromatography (GC) based methods such as GC-MS – and GC×GC, and mass spectrometry with various ionization sources including fast-atom bombardment (FAB), – chemical ionization (CI), , and electrospray ionization (ESI). ,,,– Recently a number of investigations have focused on the naphthenic acids in Alberta bitumens. – Although Athabasca bitumen has a high total acid number (TAN = 3.5−5.0 mg KOH/g oil), its corrosivity in oil sand processing plants has not been reported. In a recent investigation by the members of Canadian Crude Quality Technical Association (CCQTA), the corrosivity of the gas oil fraction of a selected Athabasca bitumen was found to be lower than that for a known corrosive gas oil based on the spinning cage technique .…”

Characterization of Acidic Species in Athabasca Bitumen and Bitumen Heavy Vacuum Gas Oil by Negative-Ion ESI FT−ICR MS with and without Acid−Ion Exchange Resin Prefractionation

“…Techniques used to characterize petroleum acids include Fourier transform infrared spectroscopy, – 13 C nuclear magnetic resonance, , two-dimensional gas chromatography, hyphenated mass spectrometric techniques, such as GC−MS, – LC−MS, and liquid-secondary ion mass spectrometry . Ionization techniques for mass spectrometry have included fast atom bombardment (FAB), – chemical ionization, atmospheric pressure chemical ionization (APCI), , electrospray ionization (ESI), ,,, field desorption ionization, and atmospheric pressure photoionization …”

Effect of Thermal Treatment on Acidic Organic Species from Athabasca Bitumen Heavy Vacuum Gas Oil, Analyzed by Negative-Ion Electrospray Fourier Transform Ion Cyclotron Resonance (FT-ICR) Mass Spectrometry

“…Corrosive feeds in that distillation range contain low-molecular-weight ( m / z 160−350), low double-bond equivalents (DBEs or rings plus double bonds) organic acids , based on negative-ion fast-atom bombardment mass spectrometry. In addition, petroleum acids as a whole have been characterized by a number of methods, including Fourier transform infrared (FTIR) spectroscopy, − 13 C nuclear magnetic resonance (NMR), − two-dimensional gas chromatography, gas chromatography−mass spectrometry, ,− and liquid-secondary ion mass spectrometry . Various ionization sources have also been used, such as fast atom bombardment, ,, chemical ionization, , atmospheric pressure chemical ionization, , and electrospray ionization (ESI). ,,− In the late 1990s, Blum, Olmstead, and co-workers pointed out that naphthenic acids can be thermally decomposed to yield a lower TAN product and reduce viscosity by what they termed “heat soak-induced naphthenic acid decomposition”. , However, the class, type, and carbon number reactivity of the naphthenic acids were not addressed.…”