Selective Nickel-Catalyzed Conversion of Model and Lignin-Derived Phenolic Compounds to Cyclohexanone-Based Polymer Building Blocks

Valorization of lignin is essential for the economics of future lignocellulosic biorefineries. Lignin is converted into novel polymer building blocks through four steps: catalytic hydroprocessing of softwood to form 4‐alkylguaiacols, their conversion into 4‐alkylcyclohexanols, followed by dehydrogen...

Celý popis

Uložené v:
Podrobná bibliografia
Vydané v:ChemSusChem Ročník 8; číslo 10; s. 1805 - 1818
Hlavní autori: Schutyser, Wouter, Van den Bosch, Sander, Dijkmans, Jan, Turner, Stuart, Meledina, Maria, Van Tendeloo, Gustaaf, Debecker, Damien P., Sels, Bert F.
Médium: Journal Article
Jazyk:English
Vydavateľské údaje: Weinheim WILEY-VCH Verlag 22.05.2015
WILEY‐VCH Verlag
Wiley Subscription Services, Inc
Predmet:
biomass
Catalysis
Cerium - chemistry
Copper - chemistry
Cyclohexanones - chemistry
Guaiacol - chemistry
heterogeneous catalysis
lignin
Lignin - chemistry
nickel
Nickel - chemistry
Phenols - chemistry
Polymers - chemistry
synthesis design
Wood
Zirconium - chemistry
nickel
biomass
lignin
heterogeneous catalysis
synthesis design
ISSN:1864-5631, 1864-564X
On-line prístup:Získať plný text
Tagy: Pridať tag
Žiadne tagy, Buďte prvý, kto otaguje tento záznam!
Popis
Shrnutí:Valorization of lignin is essential for the economics of future lignocellulosic biorefineries. Lignin is converted into novel polymer building blocks through four steps: catalytic hydroprocessing of softwood to form 4‐alkylguaiacols, their conversion into 4‐alkylcyclohexanols, followed by dehydrogenation to form cyclohexanones, and Baeyer–Villiger oxidation to give caprolactones. The formation of alkylated cyclohexanols is one of the most difficult steps in the series. A liquid‐phase process in the presence of nickel on CeO2 or ZrO2 catalysts is demonstrated herein to give the highest cyclohexanol yields. The catalytic reaction with 4‐alkylguaiacols follows two parallel pathways with comparable rates: 1) ring hydrogenation with the formation of the corresponding alkylated 2‐methoxycyclohexanol, and 2) demethoxylation to form 4‐alkylphenol. Although subsequent phenol to cyclohexanol conversion is fast, the rate is limited for the removal of the methoxy group from 2‐methoxycyclohexanol. Overall, this last reaction is the rate‐limiting step and requires a sufficient temperature (>250 °C) to overcome the energy barrier. Substrate reactivity (with respect to the type of alkyl chain) and details of the catalyst properties (nickel loading and nickel particle size) on the reaction rates are reported in detail for the Ni/CeO2 catalyst. The best Ni/CeO2 catalyst reaches 4‐alkylcyclohexanol yields over 80 %, is even able to convert real softwood‐derived guaiacol mixtures and can be reused in subsequent experiments. A proof of principle of the projected cascade conversion of lignocellulose feedstock entirely into caprolactone is demonstrated by using Cu/ZrO2 for the dehydrogenation step to produce the resultant cyclohexanones (≈80 %) and tin‐containing beta zeolite to form 4‐alkyl‐ε‐caprolactones in high yields, according to a Baeyer–Villiger‐type oxidation with H2O2. In the Ni‐ck of time: The four‐step conversion of lignocellulose to caprolactones is demonstrated. One of the major challenges is the selective removal of the methoxy group from the guaiacols. Ni/CeO2 is a suitable catalyst for this reaction, yielding considerable amounts of cyclohexanols, which are prone to undergo dehydrogenation and Baeyer–Villager oxidation.
Bibliografia:istex:B2A746878AA2E58D2D433744F3A71AABE11E7A87
Research Foundation-Flanders (FWO)
Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen)
ark:/67375/WNG-2GK1XM82-H
ArticleID:CSSC201403375
ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 14
content type line 23
ISSN:1864-5631
1864-564X
DOI:10.1002/cssc.201403375