We present a rapid
method based on 2D thin layer chromatography
(TLC) for the simultaneous separation and quantification of organic,
lipophilic extractives occurring in lignocellulosic biorefineries.
The separation is based on alkaline followed by acidic elution for
a 2D separation of the different compound classes (sterols, fatty
alcohols, fatty acids, and resin acids). Staining with Nile Blue A
and subsequent scanning and image analysis of the plates provides
quantitative information on the concentration of each compound class.
Correlation coefficients between 0.92 (abietic acid, resin acid) and
0.98 (β-sitosterol, sterol) are determined in these experiments.
Besides the analysis of the composition, this procedure indicates
the relative polarity as the acidity or basicity of the constituents.
TLC results of an industrial lipophilic extractives sample correlate
with state-of-the-art GC × GC–MS measurements with differences
being in the range between 0.5 (fatty alcohols) and 6% (resin acids),
respectively.
Here, we investigate the electrochemical properties and stability of 1,1′-ferrocene-bisphosphonates in aqueous solutions. 31 P NMR spectroscopy enables to track decomposition at extreme pH conditions revealing partial disintegration of the ferrocene core in air and under an argon atmosphere. ESI-MS indicates the decomposition pathways to be different in aqueous H 3 PO 4 , phosphate buffer, or NaOH solutions. Cyclovoltammetry exhibits completely reversible redox chemistry of the evaluated bisphosphonates, sodium 1,1′-ferrocene-bis(phosphonate) (3) and sodium 1,1′-ferrocene-bis(methylphosphonate) (8), from pH 1.2 to pH 13. Both the compounds feature freely diffusing species as determined using the Randles-Sevcik analysis. The activation barriers determined by rotating disk electrode measurements revealed asymmetry for oxidation and reduction. The compounds are tested in a hybrid flow battery using anthraquinone-2-sulfonate as the counterside, yielding only moderate performance.
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