Coupling of resorcinols in retorted kukersite semi-coke

J Habicht,U Mäeorg

doi:10.3176/proc.2014.1.10

J Habicht, U Mäeorg

Open Access

https://doi.org/10.3176/proc.2014.1.10

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Abstract

Coupling products of three major phenols appearing in the waste streams of shale oil production from kukersite oil shale were isolated and analysed using high-resolution mass spectrometry (HRMS). The pattern of water-soluble phenols in retorted kukersite semi-coke leachate changes quickly during weathering. The amount of phenols decreases, but the rate of disappearance is dissimilar for different constituents. Oxidation experiments with three major phenols (resorcinol, 5-methyl resorcinol, and 2,5-dimethylresorcinol) and their mixtures in pairs were performed in a reaction medium similar to semi-coke leachate. Reaction products were detected using silica gel thin layer chromatography (TLC) and isolated for further analysis by silica gel dry-column chromatography. The composition of primary reaction products was confirmed by nuclear magnetic resonance (NMR) spectroscopy. The primary coupling products of the studied resorcinols included the corresponding dimeric monoand diquinones. Further coupling brought about the formation of water-insoluble products, which is the reason for the disappearance of resorcinols from the leachate.

Highlights

Coupling products of three major phenols appearing in the waste streams of shale oil production from kukersite oil shale were isolated and analysed using high-resolution mass spectrometry (HRMS)
The composition of primary reaction products was confirmed by nuclear magnetic resonance (NMR) spectroscopy
Three resorcinols – 5-methylresorcinol, 2,5-dimethylresorcinol, and resorcinol – were the major phenols in the leachate of the fresh semi-coke sample collected after 24 hours

Summary

Introduction

Coupling products of three major phenols appearing in the waste streams of shale oil production from kukersite oil shale were isolated and analysed using high-resolution mass spectrometry (HRMS). The pattern of water-soluble phenols in retorted kukersite semi-coke leachate changes quickly during weathering. Oxidation experiments with three major phenols (resorcinol, 5-methyl resorcinol, and 2,5-dimethylresorcinol) and their mixtures in pairs were performed in a reaction medium similar to semi-coke leachate. The total amount of water-soluble phenols from high unit capacity generators for shale oil production from kukersite (Kiviter process) is over 5.5 kg per tonne of processed shale; for 5-methyl resorcinol it is more than 1.5 kg and for 2,5-dimethyl resorcinol more than 0.4 kg per tonne [1]. The environmental hazardousness of retorted oil shale has been largely attributed to phenols found in semi-coke, the watersoluble fraction of these compounds [3]. The share of polymers amongst the reaction products was found to be rather low, and the decomposition rate of phenols exceeded 40% in both experiments [6]

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