Brazilian oil shales

The bibliography on Brazilian oil shales amounts today to approximately 850 papers. No more than 250 deal with chemistry and the number of documents discussing its geochemistry is rather small. Many conclusions can be drawn from this statement. For instance, that oil shales do not appear to have been considered, as yet, an important subject in the Brazilian Science and Society (the relevance of oil shales to the Brazilian Society has been widely discussed by Costa Neto (1)). If it is looked at from a technical view point, a question may be posed which were (or should be) the boun[Pg.20]

Before going into the discussion of the available data on the geochemistry of Brazilian oil shales, insights into the existing Brazilian oil shale reserves will be given, so that the reader can feel the importance of these organites to Brazil. 

More details on the geology, economics etc. of these reserves can be found in Bigarella (11) and Moreira (12). The Brazilian Oil Shale Bibliography (13) should be consulted for exaustive surveys. 

It is interesting to quote that the oldest known reference in the literature to Brazilian oil shales was made in 1865, by Archer (15) concerning "A new bituminous substance imported under the name of coal from Brazil". Also that in the celebrated series of papers published by Treibs (16), where be defined the organic origin of petroleum, the Brazilian oil shale from Marau was one of the materials he used to show the presence of porphyrins in orga-nites. 

This paper will not be restricted to a description of geochemical features of Brazilian oil shales, since, as it was mentioned before, they are rather scarce. It will be, indeed, more of a critical discussion of Geochemistry on (using) Brazilian oil shales. 

Molecular Composition of Brazilian oil shales. Oil shales may be considered as composed of two main (chemical) phases an inorganic phase, constituted of mineral species (crystaline and/or amorphous) and an organic phase that, in its turn, can be divided into two oth er (sub) phases the bitumen, the soluble (in organic solvents) frac tion and the kerogen defined as the insoluble organic matter of organic. 

Chemical Composition of the organic phase of Brazilian oil shales Bitumens... 

Two main approaches have been used toward the chemical characterization of kerogens of Brazilian oil shales ... 

This method was used to determine the content of various organic functional groups (amines, alcohols, phenols, aldehydes, ketones, carboxyl, insaturation, allylic/benzylic sites) in kerogens of Brazilian oil shales. The results (26) indicate the Tremembe Formation as being the most functi.onatTzed while Irati is the least. This is in accordance with the accepted trend that functionalizations correlates with maturity. 

Maturation is, nevertheless, a product of the effect of all these parameters combined on the organic matter of oil shales. We shall give now the values of some of the indexes used to define maturation in respect to Brazilian oil shales. 

The functionality of an oil shale is generally related (inversely) to its maturation One can see from the three Brazilian oil shales compared (26) in functional groups content that the Vale do Paraiba oil shale is the most functionalized corroborating the above results that say it to be the less mature. Although no nume ical correlations have yet been established in this respect, one can antecipate that indexes can be derived to correlate maturation with the decaying of functional groups. 

The literature on Brazilian oil shales is relatively small From the 850 documents registered at the library of the Pro j eto Xi toquimica today, covering all areas related to oil shales, abstracts were produced which allowed, through a KWIC/KWOC format that a data base were developed for Brazilian oil shales. 

This system contains, presently, four main files one that arranges chromologically the references of all documents containing an abstract. A second relating historical facts regarding Brazilian oil shales a third containing a geographical record of the places the oil shales were found and the fourth, a substance index, in which all substances isolated from Brazilian oil shales are described. All these files are produced in three main indexes a... 

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