Determination of conjugated dienes in petroleum products by supercritical fluid chromatography and ultraviolet detection

• Published in: Journal of separation science Vol. 26; no. 15-16; pp. 1403 - 1406
• Main Author: Albuquerque, Flávio Cortiñas
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.10.2003; WILEY‐VCH Verlag; Wiley
• Subjects: Applied sciences; Conjugated dienes; Crude oil, natural gas and petroleum products; Energy; Exact sciences and technology; Fuels; Petroleum products; Prospecting and production of crude oil, natural gas, oil shales and tar sands; Supercritical fluid chromatography; Petroleum products; Chemical analysis; Ultraviolet detector; Conjugated dienes; Petroleum product; Dienic compound; Supercritical fluid chromatography
• ISSN: 1615-9306; 1615-9314
• DOI: 10.1002/jssc.200301469

A method for determining total conjugated dienes in petroleum products, such as catalytic or thermal cracking fractions, using supercritical fluid chromatography (SFC) is presented. The separation is carried out in one or two silica columns and with CO2 as mobile phase. The conditions of analysis are the same as used in group‐type analysis of diesel fuels by SFC (ASTM D 5186 standard method), except that UV detection at 240 nm is used. Hydrocarbons with two conjugated double bonds are the only substances eluting in the retention time range of the non‐aromatics that appreciably absorb UV radiation at this wavelength. This was confirmed by analyzing standards of olefins, isolated diolefins, and conjugated diolefins. Results are reported in mol L–1 of 1,3‐pentadiene. Several samples of different natures, such as fluid catalytic cracking liquid products and hydrotreated cracking naphthas, were successfully analyzed. The results correlate quite well with the respective diene values as determined by UOP method 326, although the slope and intercept were specific for each type of product.