Imperial College London
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Dr Roberto Rinaldi FRSC

Faculty of Engineering, Department of Chemical Engineering

Reader in Applied Chemistry
 
 
 
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Contact

 

+44 (0)20 7594 1302r.rinaldi1 Website

 
 
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Location

 

523ACE ExtensionSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{de:2018:10.1039/c8cy00491a,
author = {de, Castro IBD and Graca, I and Rodriguez-Garcia, L and Kennema, M and Rinaldi, R and Meemken, F},
doi = {10.1039/c8cy00491a},
journal = {Catalysis Science and Technology},
pages = {3107--3114},
title = {Elucidating the reactivity of methoxyphenol positional isomers towards hydrogen-transfer reactions by ATR-IR spectroscopy of the liquid-solid interface of RANEY (R) Ni},
url = {http://dx.doi.org/10.1039/c8cy00491a},
volume = {8},
year = {2018}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - In the valorisation of lignin, the application of catalytic hydrogen transfer reactions (e.g. in catalytic upstream biorefining or lignin-first biorefining) has brought a renewed interest in the fundamental understanding of hydrogen-transfer processes in the defunctionalisation of lignin-derived phenolics. In this report, we address fundamental questions underlining the distinct reactivity patterns of positional isomers of guaiacol towards H-transfer reactions in the presence of RANEY® Ni and 2-PrOH (solvent and H-donor). We studied the relationship between reactivity patterns of 2-, 3- and 4-methoxyphenols and their interactions at the liquid–solid interface of RANEY® Ni as probed by attenuated total reflection infrared (ATR-IR) spectroscopy. Regarding the reactivity patterns, 2-methoxyphenol or guaiacol is predominantly converted into cyclohexanol through a sequence of reactions including demethoxylation of 2-methoxyphenol to phenol followed by hydrogenation of phenol to cyclohexanol. By contrast, for the conversion of the two non-lignin related positional isomers, the corresponding 3- and 4-methoxycyclohexanols are the major reaction products. The ATR-IR spectra of the liquid–solid interface of RANEY® Ni revealed that the adsorbed 2-methoxyphenol assumes a parallel orientation to the catalyst surface, which allows a strong interaction between the methoxy C–O bond and the surface. Conversely, the adsorption of 3- or 4-methoxyphenol leads to a tilted surface complex in which the methoxy C–O bond establishes no interaction with the catalyst. These observations are also corroborated by a smaller activation entropy found for the conversion of 2-methoxyphenol relative to those of the other two positional isomers.
AU  - de,Castro IBD
AU  - Graca,I
AU  - Rodriguez-Garcia,L
AU  - Kennema,M
AU  - Rinaldi,R
AU  - Meemken,F
DO  - 10.1039/c8cy00491a
EP  - 3114
PY  - 2018///
SN  - 2044-4753
SP  - 3107
TI  - Elucidating the reactivity of methoxyphenol positional isomers towards hydrogen-transfer reactions by ATR-IR spectroscopy of the liquid-solid interface of RANEY (R) Ni
T2  - Catalysis Science and Technology
UR  - http://dx.doi.org/10.1039/c8cy00491a
UR  - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000435659500011&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR  - http://hdl.handle.net/10044/1/65665
VL  - 8
ER  -
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