Title

HPLC AS AN IMPORTANT TOOL FOR CHARACTERISATION OF TOLUENE SOLUBLE FRACTIONS OF PITCHES

HPLC AS AN IMPORTANT TOOL FOR CHARACTERISATION OF TOLUENE SOLUBLE FRACTIONS OF PITCHES

Authorship

SOLÉ, RUBÉN A.; MARTÍN, YOLANDA; GARCÍA, ROBERTO; MOINELO, SABINO R.

SOLÉ, RUBÉN A.

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MARTÍN, YOLANDA

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GARCÍA, ROBERTO

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MOINELO, SABINO R.

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DOI

10.5151/2594-357x-28Red-509-522

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Abstract

A new HPLC methodology for the characterisation of toluene soluble fractions of pitches was developed. Although a chromatographic system typical of GPC was used, results indicate that, for these structurally complex samples, separation does not follow the usual discrimination by molecular size. A differentiation between different classes of polyaromatic hydrocarbons is achieved instead. Data are reported on the analysis of individual standard PAHs, showing that four different elution ranges can be observed: three of cata-condensed compounds (Cata1, Cata2 and Cata3) and one of peri-condensed compounds (Peri). Similar linear responses for all the standards indicate that quantitative results can be obtained without using response factors. Results are reported proving the capacity of the HPLC methodology to distinguish between pitches of different origin and nature such as coal tar, petroleum, biomass and synthetic pitches. It is also effective for the study of the chemical reactions occurring during the heat treatment under vacuum of a coal tar soft pitch, at different temperatures. The increasing heat treatment temperature promotes a conversion of Cata3 compounds to peri-compounds, which subsequently react to yield compounds recovered in the β-resin and QI fractions, mainly through consecutive reactions

A new HPLC methodology for the characterisation of toluene soluble fractions of pitches was developed. Although a chromatographic system typical of GPC was used, results indicate that, for these structurally complex samples, separation does not follow the usual discrimination by molecular size. A differentiation between different classes of polyaromatic hydrocarbons is achieved instead. Data are reported on the analysis of individual standard PAHs, showing that four different elution ranges can be observed: three of cata-condensed compounds (Cata1, Cata2 and Cata3) and one of peri-condensed compounds (Peri). Similar linear responses for all the standards indicate that quantitative results can be obtained without using response factors. Results are reported proving the capacity of the HPLC methodology to distinguish between pitches of different origin and nature such as coal tar, petroleum, biomass and synthetic pitches. It is also effective for the study of the chemical reactions occurring during the heat treatment under vacuum of a coal tar soft pitch, at different temperatures. The increasing heat treatment temperature promotes a conversion of Cata3 compounds to peri-compounds, which subsequently react to yield compounds recovered in the β-resin and QI fractions, mainly through consecutive reactions

Keywords

Pitches, Chemical characterisation, HPLC

Pitches, Chemical characterisation, HPLC