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

Journal Article · · Analytical Chemistry (Washington); (United States)
DOI:https://doi.org/10.1021/ac00186a017· OSTI ID:5383035
;  [1]
  1. National Institute for Petroleum and Energy Research, Bartlesville, OK (USA)

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-trifluoroethanol and (2) acylation of alcoholic and phenolic hydroxyls with trifluoroacetyl chloride. The aryl trifluoroacetates absorb at 1,800 cm{sup {minus}1}; the 2,2,2-trifluoroethyl esters absorb in the region 1,760-1,740 cm{sup {minus}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.

DOE Contract Number:
FC22-83FE60149
OSTI ID:
5383035
Journal Information:
Analytical Chemistry (Washington); (United States), Journal Name: Analytical Chemistry (Washington); (United States) Vol. 61:11; ISSN ANCHA; ISSN 0003-2700
Country of Publication:
United States
Language:
English