Petroleum nonporphyrin metal compounds

Unlike metalloporphyrins, the nonporphyrinic metal compounds are poorly characterized with respect to molecular structure and properties. Examining the nature of the nickel and vanadium in these compounds is important from the standpoint that often most of the Ni and V in a petroleum is nonporphyrinic, as shown in Table II. Sugihara et al. (1970) suggested that the nonporphyrin metal compounds comprise a wide variety of coordinated complexes resulting from the reaction of inorganic forms of the metals with polar organic molecules. Larson and Beuther (1966) speculated that the nonporphyrinic metal complexes are simply... 

Some researchers have doubted whether nonporphyrin metal compounds exist at all in petroleum (Goulon et al., 1984 Berthe et al., 1984). This speculation is based on the similarities in spectral features of petroleum-bound metals and model-metal porphyrin compounds from selected petroleums under the examination of x-ray absorption, photoelectron, and laser desorption spectroscopies. Interpretation of spectra from these methods, however, is uncertain and difficult given the lack of sufficient data on model compounds, particularly nonporphyrin metals and in a petroleum environment or matrix. 

In Section II, the nature of the metal compounds in petroleum oils is discussed to establish a basic understanding of the targeted reactants. The chemical composition of the host petroleum and residuum is described, including a discussion of the two classes of metal compounds (1) metal-loporphyrins and (2) nonporphyrin metals. The troublesome asphaltenes will also be described. Comparison is made between the characteristics of vanadium and nickel complexes and their distribution in residua. 

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