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  • A reactive analytical approach for the estimation of olefinic content in gasoline-range hydrocarbons by gas chromatography.

A reactive analytical approach for the estimation of olefinic content in gasoline-range hydrocarbons by gas chromatography.

Journal of chromatographic science (2002-08-31)
A K Punetha, U Shanker, K Narsimha, T S R Prasada Rao
ABSTRACT

The estimation of olefinic content in conversion processes such as the etherification of olefins in fluid catalytic cracking (FCC) gasoline is essentially required. Gas chromatography (GC) is the well-established method for the quantitative analysis of olefins in etherification processes. The current state-of-the-art GC methods employing highly specific long single capillary columns such as Petrocol-DH are being used for the analysis of gasoline-range hydrocarbons. However, the method needs many standard reference samples of respective components in a complex mixture of hydrocarbons, which limits the scope of the analytical method. The alternative approach followed by this investigation is based on the reactive method of the analysis of olefins in FCC light gasoline by subjecting them to hydrogenation and estimating the olefinic content by GC comparing the gas chromatograms of the original feed and hydrogenated product using a Petrocol-DH column. A decrease in the quantity and disappearances of the peaks are assumed as olefins, and their number and total composition is calculated. In this study the bromine number method is used to estimate the olefinic content for a comparison of results with the adopted proposed methodology. The adopted methodology quantitates olefinic content in FCC light gasoline, which is comparable with reported literature values and the bromine number method. With the availability of standard reference samples of some important major reactive olefins, the adopted methodology can also give component-wise analysis as well as total olefinic content in a single step in processes such as etherification. The methodology can be also useful in reactions in which the conversion of total olefinic content is needed such as hydration, esterification, and alkylation of olefins in a complex mixture of hydrocarbons apart from the etherification of olefins in FCC gasoline.

MATERIALS
Product Number
Brand
Product Description

Supelco
Metal Packed GC Column (General Configuration), phase 3% Petrocol B, matrix 80/100 SUPELCOPORT support, L × O.D. × I.D. 1.7 ft (0.52 m) × 1/8 in. × 2.1 mm
Supelco
Petrocol® DH 50.2 Capillary GC Column, L × I.D. 50 m × 0.20 mm, df 0.50 μm
Supelco
Petrocol® EX2887 Capillary GC Column, L × I.D. 5.0 m × 0.53 mm, df 0.10 μm
Supelco
ASTM® D2887/D5307 Column Resolution Test Mix, certified reference material, 1 % (w/w) each component in octane
Supelco
Petrocol® DH 150 Capillary GC Column, L × I.D. 150 m × 0.25 mm, df 1.00 μm
Supelco
Petrocol® DH Capillary GC Column, L × I.D. 100 m × 0.25 mm, df 0.50 μm