70110-65-5Relevant academic research and scientific papers
Cleavage∕cross-coupling strategy for converting β-O-4 linkage lignin model compounds into high valued benzyl amines via dual C–O bond cleavage
Jia, Le,Li, Chao-Jun,Zeng, Huiying
, (2021/10/29)
Lignin is the most recalcitrant of the three components of lignocellulosic biomass. The strength and stability of the linkages have long been a great challenge for the degradation and valorization of lignin biomass to obtain bio-fuels and commercial chemicals. Up to now, the selective cleavage of C–O linkages of lignin to afford chemicals contains only C, H and O atoms. Our group has developed a cleavage/cross-coupling strategy for converting 4-O-5 linkage lignin model compounds into high value-added compounds. Herein, we present a palladium-catalyzed cleavage/cross-coupling of the β-O-4 lignin model compounds with amines via dual C–O bond cleavage for the preparation of benzyl amine compounds and phenols.
Cobalt Nanoparticles-Catalyzed Widely Applicable Successive C?C Bond Cleavage in Alcohols to Access Esters
Dai, Wen,Gao, Shuang,Li, Guosong,Luo, Huihui,Lv, Ying,Shang, Sensen,Wang, Lianyue
supporting information, p. 19268 - 19274 (2020/08/26)
Selective cleavage and functionalization of C?C bonds have important applications in organic synthesis and biomass utilization. However, functionalization of C?C bonds by controlled cleavage remains difficult and challenging because they are inert. Herein, we describe an unprecedented efficient protocol for the breaking of successive C?C bonds in alcohols to form esters with one or multiple carbon atoms less using heterogeneous cobalt nanoparticles as catalyst with dioxygen as the oxidant. A wide range of alcohols including inactive long-chain alkyl aryl alcohols undergo smoothly successive cleavage of adjacent ?(C?C)n? bonds to afford the corresponding esters. The catalyst was used for seven times without any decrease in activity. Characterization and control experiments disclose that cobalt nanoparticles are responsible for the successive cleavage of C?C bonds to achieve excellent catalytic activity, while the presence of Co-Nx has just the opposite effect. Preliminary mechanistic studies reveal that a tandem sequence reaction is involved in this process.
One-pot synthesis of β-O-4 lignin models: Via the insertion of stable 2-diazo-1,3-dicarbonyls into O-H bonds
Burtoloso, Antonio C. B.,De Oliveira, Gabriela P.,Dias, Rafael Mafra P.
, p. 4815 - 4823 (2020/07/13)
Because lignin is a macromolecule that is a sustainable source of aromatic compounds, model substrates are commonly used to increase our understanding of its complex structure. However, few methods have been described for the synthesis of these models. Herein, we describe a new route towards the synthesis of β-O-4 lignin models by intermolecular O-H insertion reactions with simple and stable diazocarbonyls. The benefits of this developed method were shorter reaction times and high yields, as well as mild and environmentally friendly conditions. This journal is
Au-Pd alloy cooperates with covalent triazine frameworks for the catalytic oxidative cleavage of β-O-4 linkages
Zhao, Li,Shi, Song,Zhu, Guozhi,Liu, Meng,Gao, Jin,Xu, Jie
, p. 6707 - 6716 (2019/12/26)
To design highly efficient catalysts for the cleavage of the C-O/C-C bond is the key task in the depolymerization of lignin. Bimetallic alloy catalysts Au-Pd-CTFs were developed to be effective in the oxidative cleavage of β-O-4 lignin model compounds with O2. Au-Pd nanoparticles with an Au/Pd molar ratio between 1?:?1 and 1?:?1.5 showed the highest cleavage efficiency. The kinetics of the reaction process revealed that a synergistic effect between Au and Pd played a crucial role in the oxidation of Cα-OH into CαO, which was the rate-determining step for the whole oxidative cleavage process. Further insight revealed that the cooperative effect between Au-Pd nanoparticles and the support covalent triazine frameworks (CTFs) facilitated the cleavage of the formed β-O-4 ketone compound to the corresponding aromatics. In addition, Au-Pd-CTF catalysts also showed efficiency in the oxidative transformation of the organosolv lignin. This catalytic system will provide guidance in the oxidative cleavage of β-O-4 linkages in lignin.
Selective Cα Alcohol Oxidation of Lignin Substrates Featuring a β-O-4 Linkage by a Dinuclear Oxovanadium Catalyst via Two-Electron Redox Processes
Tsai, Yan-Ting,Chen, Chih-Yao,Hsieh, Yi-Ju,Tsai, Ming-Li
supporting information, p. 4637 - 4646 (2019/11/16)
Developing highly efficient catalyst systems to transform lignin biomass into value-added chemical feedstocks is imperative for utilizing lignin as renewable alternatives to fossil fuels. Recently, the pre-activated strategy involving the selective oxidat
Transition-metal-free conversion of lignin model compounds to high-value aromatics: Scope and chemoselectivity
Lee, Tae Woo,Yang, Jung Woon
supporting information, p. 3761 - 3771 (2018/08/21)
An efficient and straightforward reaction protocol for the conversion of lignin model compounds was developed based on a simple system consisting of a base, oxygen, and a green solvent under mild conditions in the absence of metals. This protocol was successfully applied to the cleavage of both 'β-O-4' dimeric and trimeric compounds, and a controlled selective degradation was achieved depending on the bond type. The feasibility of this method to provide aromatic compounds in high yields from lignin by a sequential oxidative dehomologation reaction was clearly demonstrated.
Chemoselective oxidant-free dehydrogenation of alcohols in lignin using Cp?Ir catalysts
Zhu, Rui,Wang, Bing,Cui, Minshu,Deng, Jin,Li, Xinglong,Ma, Yingbo,Fu, Yao
supporting information, p. 2029 - 2036 (2016/04/19)
A remarkably effective method of chemoselective dehydrogenation of alcohols in lignin has been developed with an iridium catalyst. An additional operation of Zn/NH4Cl via a two-step one pot process could further promote the cleavage of the C-O bond in β-O-4 units in lignin. And this reaction system was also applicable to native lignin as the molecular weight of native lignin decreased obviously as detected by gel permeation chromatography (GPC). Additionally, this is the first to date generation of the by-product H2 from native lignin and the by-product was straightforwardly captured by 1-decene. A probable mechanistic pathway was also proposed with the help of density functional theory (DFT) calculations.
Lignin Depolymerization with Nitrate-Intercalated Hydrotalcite Catalysts
Kruger, Jacob S.,Cleveland, Nicholas S.,Zhang, Shuting,Katahira, Rui,Black, Brenna A.,Chupka, Gina M.,Lammens, Tijs,Hamilton, Phillip G.,Biddy, Mary J.,Beckham, Gregg T.
, p. 1316 - 1328 (2016/02/18)
Hydrotalcites (HTCs) exhibit multiple adjustable parameters to tune catalytic activity, including interlayer anion composition, metal hydroxide layer composition, and catalyst preparation methods. Here, we report the influence of several of these parameters on β-O-4 bond scission in a lignin model dimer, 2-phenoxy-1-phenethanol (PE), to yield phenol and acetophenone. We find that the presence of both basic and NO3- anions in the interlayer increases the catalyst activity by 2-3-fold. In contrast, other anions or transition metals do not enhance catalytic activity in comparison to blank HTC. The catalyst is not active for C-C bond cleavage on lignin model dimers and has no effect on dimers without an α-OH group. Most importantly, the catalyst is highly active in the depolymerization of two process-relevant lignin substrates, producing a significant amount of low-molecular-weight aromatic species. The catalyst can be recycled until the NO3- anions are depleted, after which the activity can be restored by replenishing the NO3- reservoir and regenerating the hydrated HTC structure. These results demonstrate a route to selective lignin depolymerization in a heterogeneous system with an inexpensive, earth-abundant, commercially relevant, and easily regenerated catalyst.
