59348-19-5Relevant academic research and scientific papers
Breaking the Limit of Lignin Monomer Production via Cleavage of Interunit Carbon–Carbon Linkages
Dong, Lin,Lin, Longfei,Han, Xue,Si, Xiaoqin,Liu, Xiaohui,Guo, Yong,Lu, Fang,Rudi?, Svemir,Parker, Stewart F.,Yang, Sihai,Wang, Yanqin
, p. 1521 - 1536 (2019)
Conversion of lignin into monocyclic hydrocarbons as commodity chemicals and drop-in fuels is a highly desirable target for biorefineries. However, this is severely hindered by the presence of stable interunit carbon–carbon linkages in native lignin and those formed during lignin extraction. Herein, we report a new multifunctional catalyst, Ru/NbOPO4, that achieves the first example of catalytic cleavage of both interunit C–C and C–O bonds in one-pot lignin conversions to yield 124%–153% of monocyclic hydrocarbons, which is 1.2–1.5 times the yields obtained from the established nitrobenzene oxidation method. This catalyst also exhibits high stability and selectivity (up to 68%) to monocyclic arenes over repeated cycles. The mechanism of the activation and cleavage of 5–5 C–C bonds in biphenyl, as a lignin model adopting the most robust C–C linkages, has been revealed via in situ inelastic neutron scattering coupled with modeling. This study breaks the conventional theoretical limit on lignin monomer production. The conversion of lignin into monocyclic hydrocarbons as commodity chemicals and drop-in fuels is essential for the future of biorefineries. State-of-the-art lignin depolymerization is primarily achieved via cleavage of interunit C–O bonds to form low-molecular-weight feedstocks. However, these processes can hardly cleave interunit C–C bonds in lignin, and thus, the yields of lignin monomers are heavily restricted. Here, we report a multifunctional catalyst, Ru/NbOPO4, that achieves the first example of catalytic cleavage of both interunit C–C and C–O bonds in lignin in one-pot reactions to yield 153% of monocyclic C6–C9 hydrocarbons from Kraft lignin, which is 1.5 times the theoretical yield obtained from the established nitrobenzene oxidation (NBO) method. Thus, significantly, this study successfully breaks the conventional limit on lignin monomer production. Lignin, containing a large volume of aromatic functionalities, is the most energy-dense fraction of renewable biomass. Particularly, conversion of lignin into monocyclic hydrocarbons as commodity chemicals is a highly desirable target. However, this is severally hindered by the presence of stable interunit carbon–carbon linkages in native lignin and those formed during lignin extraction. Here, we report a multifunctional Ru/NbOPO4 catalyst that achieves the first example of catalytic cleavage of both interunit C–C and C–O bonds in lignin in one-pot reactions.
Acid-catalyzed Reactions of Aromatic Hydrocarbons with Alkanes and Cycloalkanes. X. Alkylations with Cyclohexane
Miethchen, Ralf,Steege, Sigrid,Kroeger, Carl-Friedrich
, p. 823 - 834 (2007/10/02)
The complex reaction mixtures of the nonconventional alkylation of benzene with cyclohexane in the presence of Lewis/proton acids and promotors were investigated by gas-liquid chromatography and mass spectrometry.Four representative groups of hydrocarbons were found including cycloalkylbenzenes, substituted indanes or tetralines (C12H16), C1-C6-alkylbenzenes and isomeric biscycloalkyls (C12H22).Their formation is interpreted as a competition between alkylation, (without or with isomerization), ringfission with cycloalkylation or fragmentation, and self-alkylation; phenylcycloalkylcations and phenylalkylcations are the intermediates.
