In situ ATR-IR spectroscopy: a powerful tool to elucidate the catalytic oxidation of veratryl alcohol in aqueous media

Kervinen, Kaisa; Allmendinger, Markus; Leskelä, Markku; Repo, Timo; Rieger, Bernhard

doi:10.1039/b305885a

Cited by 21 publications

(24 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…101 They are also unique fragmentation products which had only previously been observed in minute quantities. Consistent with the corresponding electron transfer reduction literature, [103][104][105][106][107][108][109] Stephenson and co-workers proposed a reaction mechanism in which the reaction is initiated by visible-light excitation of the Ir III photocatalyst (146) to generate an excited state, Ir III *. From this excited state, the photocatalyst is reductively quenched by the single-electron oxidation of DIPEA.…”

Section: Reviewmentioning

confidence: 60%

Transition-metal catalyzed valorization of lignin: the key to a sustainable carbon-neutral future

et al. 2016

View full text Add to dashboard Cite

The development of a sustainable, carbon-neutral biorefinery has emerged as a prominent scientific and engineering goal of the 21st century. As petroleum has become less accessible, biomass-based carbon sources have been investigated for utility in fuel production and commodity chemical manufacturing. One underutilized biomaterial is lignin; however, its highly crosslinked and randomly polymerized composition have rendered this biopolymer recalcitrant to existing chemical processing. More recently, insight into lignin's molecular structure has reinvigorated chemists to develop catalytic methods for lignin depolymerization. This review examines the development of transition-metal catalyzed reactions and the insights shared between the homogeneous and heterogeneous catalytic systems towards the ultimate goal of valorizing lignin to produce value-added products.

show abstract

Section: Reviewmentioning

confidence: 60%

Transition-metal catalyzed valorization of lignin: the key to a sustainable carbon-neutral future

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Attenuated total reflection (ATR)-IR spectroscopy has been described as a promising technique for monitoring chemical reactions on line. [23][24][25] Because most of the absorption comes from the first few layers that are in contact with the probe [26] rather than from the bulk, ATR-IR spectroscopy circumvents the interference caused by the strong water absorptions, [18] which allows the observation of the vibrations associated with the substrate and product functional groups. To the best of our knowledge, only ATR-IR spectroscopic studies of cellulose involved the determination of cellulose structural characteristics or cellulose-water interactions.…”

Section: Introductionmentioning

confidence: 99%

Solid Acid‐Catalyzed Cellulose Hydrolysis Monitored by In Situ ATR‐IR Spectroscopy

et al. 2012

View full text Add to dashboard Cite

The solid acid-catalyzed hydrolysis of cellulose was studied under elevated temperatures and autogenous pressures using in situ ATR-IR spectroscopy. Standards of cellulose and pure reaction products, which include glucose, fructose, hydroxymethylfurfural (HMF), levulinic acid (LA), formic acid, and other compounds, were measured in water under ambient and elevated temperatures. A combination of spectroscopic and HPLC analysis revealed that the cellulose hydrolysis proceeds first through the disruption of the glycosidic linkages of cellulose to form smaller cellulose molecules, which are readily observed by their distinctive C-O vibrational stretches. The continued disruption of the linkages in these oligomers eventually results in the formation and accumulation of monomeric glucose. The solid-acid catalyst accelerated the isomerization of glucose to fructose, which then rapidly reacted under hydrothermal conditions to form degradation products, which included HMF, LA, formic acid, and acetic acid. The formation of these species could be suppressed by decreasing the residence time of glucose in the reactor, reaction temperature, and contact with the metal reactor. The hydrolysis of regenerated cellulose proceeded faster and under milder conditions than microcrystalline cellulose, which resulted in increased glucose yield and selectivity.

show abstract

“…Schiff bases are an important class of catalysts in a variety of liquid‐phase organic reactions . Hence, we report on the observation of the formation of a cobalt salicylaldimine Schiff base on γ‐aminopropyl modified SiO 2 (APS‐SiO 2 ) using FTIR and XAS simultaneously in a single experiment and two independent cells (Scheme ).…”

Section: Methodsmentioning

confidence: 99%

Genesis of a Co–Salicylaldimine Complex on Silica Followed in Situ by FTIR and XAS

2017

View full text Add to dashboard Cite

Several strategies have been proposed to replace soluble metallorganic complexes in organic solvents by similar molecular entities immobilized on non-reactive solids. The characterization of these complexes at atomic and molecular level during synthesis is demanding but essential to guide rational design. In the present work, the formation of cobalt salicylaldimine complex on γ-aminopropyl modified silica (SiO ) was monitored in ethanol on-line by Fourier transform infrared spectroscopy (FTIR) and in situ X-ray absorption spectroscopy (XAS) simultaneously using two independent cells. The organic ligand was monitored by FTIR to follow the stepwise synthesis of the Co-salicylaldimine complex. The oxidation state of Co, obtained by XANES, was found to be +2, while different coordination environments were observed in the presence or absence of the pendant organic ligand produced in situ on SiO . EXAFS analysis inferred that the oxidation state and the local structure of the Co ion on the modified SiO surface was similar to that of a salen-complex with four Co-O/N bonds.

show abstract

In situ ATR-IR spectroscopy: a powerful tool to elucidate the catalytic oxidation of veratryl alcohol in aqueous media

Cited by 21 publications

References 22 publications

Transition-metal catalyzed valorization of lignin: the key to a sustainable carbon-neutral future

Transition-metal catalyzed valorization of lignin: the key to a sustainable carbon-neutral future

Solid Acid‐Catalyzed Cellulose Hydrolysis Monitored by In Situ ATR‐IR Spectroscopy

Genesis of a Co–Salicylaldimine Complex on Silica Followed in Situ by FTIR and XAS

Contact Info

Product

Resources

About