scholarly journals Selective valorization of lignin to phenol by direct transformation of Csp2–Csp3 and C–O bonds

2020 ◽  
Vol 6 (45) ◽  
pp. eabd1951
Author(s):  
Jiang Yan ◽  
Qinglei Meng ◽  
Xiaojun Shen ◽  
Bingfeng Chen ◽  
Yang Sun ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Aromatic Ring ◽  
Density Functional ◽  
Zeolite Catalyst ◽  
Reaction Pathway ◽  
Scale Up ◽  
Functional Theory ◽  
Direct Transformation ◽  
Mild Conditions ◽  
Bond Breakage

Phenol is an important commodity chemical in the industry, which is currently produced using fossil feedstocks. Here, we report a strategy to produce phenol from lignin by directly deconstructing Csp2–Csp3 and C–O bonds under mild conditions. It was found that zeolite catalyst could efficiently catalyze both the direct Csp2–Csp3 bond breakage to remove propyl structure and aliphatic β carbon–oxygen (Cβ–O) bond hydrolysis to form OH group on the aromatic ring. The yield of phenol could reach 10.9 weight % with a selectivity of 91.8%. In this unique route, water was the only reactant besides lignin. A scale-up experiment showed that 4.1 g of pure phenol could be obtained from 50.0 g of lignin. The reaction pathway was proposed by a combination of control experiments and density functional theory studies. This work opens the way for producing phenol from lignin by direct transformation of Csp2–Csp3 and C–O bonds in lignin.

Synthesis of novel N-functionalized 4-aryl-tetrahydrobiquinoline-2,5-(1H,3H)-diones via one-pot three-component reaction: a joint experimental and computational study

2018 ◽  
Vol 96 (12) ◽  
pp. 1071-1078
Author(s):  
Vahideh Zadsirjan ◽  
Sayyed Jalil Mahdizadeh ◽  
Majid M. Heravi ◽  
Masumeh Heydari
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Computational Study ◽  
Reaction Pathway ◽  
Deep Insight ◽  
One Pot ◽  
Functional Theory ◽  
Three Component Reaction ◽  
High Yields ◽  
Mechanism Of The Reaction

A novel series of N-functionalized 4-aryl-tetrahydrobiquinoline-2,5-(1H,3H)-diones were synthesized in high yields by a one-pot three-component reaction involving 2-chloroquinoline-3-carbaldehydes, Meldrum’s acid, and enaminones (dimedone-based enaminones) in the presence of K2CO3 in CH3CN under reflux condition. To gain a deep insight on the mechanism of the reaction, an extensive series of quantum mechanics calculations in the framework of density functional theory (DFT) were carried out for supporting the suggested reaction pathway.

scholarly journals Density Functional Theory Based Micro- and Macro-Kinetic Studies of Ni-Catalyzed Methanol Steam Reforming

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 349 ◽  
Author(s):  
Changming Ke ◽  
Zijing Lin
Keyword(s):  
Density Functional Theory ◽  
Steam Reforming ◽  
Density Functional ◽  
Reaction Pathway ◽  
Elementary Reaction ◽  
Main Reaction ◽  
Methanol Steam Reforming ◽  
Surface Species ◽  
Functional Theory ◽  
Microkinetic Model

The intrinsic mechanism of Ni-catalyzed methanol steam reforming (MSR) is examined by considering 54 elementary reaction steps involved in MSR over Ni(111). Density functional theory computations and transition state theory analyses are performed on the elementary reaction network. A microkinetic model is constructed by combining the quantum chemical results with a continuous stirring tank reactor model. MSR rates deduced from the microkinetic model agree with the available experimental data. The microkinetic model is used to identify the main reaction pathway, the rate determining step, and the coverages of surface species. An analytical expression of MSR rate is derived based on the dominant reaction pathway and the coverages of surface species. The analytical rate equation is easy to use and should be very helpful for the design and optimization of the operating conditions of MSR.

scholarly journals Graphdiyne based metal atomic catalysts for synthesizing ammonia

2020 ◽  
Author(s):  
Huidi Yu ◽  
Yurui Xue ◽  
Lan Hui ◽  
Chao Zhang ◽  
Yan Fang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Electron Transfer ◽  
Density Functional ◽  
Reaction Pathway ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Faradaic Efficiency ◽  
Nitrogen Reduction ◽  
Strongly Coupled ◽  
Neutral Media

Abstract Exploring new catalysts for nitrogen reduction at ambient pressures and temperatures with ultrahigh ammonia (NH3) yield and selectivity is still a giant challenge. In this work, atomic catalysts with separated Pd atoms on graphdiyne (Pd-GDY) have been synthesized and show fascinating electrocatalytic properties for nitrogen reduction. Outstandingly, the catalyst shows the highest average NH3 yield of 4.45 ± 0.30 mgNH3 mgPd−1 h−1, almost tens of orders larger than previously reported ones, and 100% reaction selectivity in neutral media. And Pd-GDY exhibits almost no decreases in the NH3 yield and Faradaic efficiency. Density functional theory calculations show that the reaction pathway prefers to perform at the (Pd, C1, C2) active area due to the strongly coupled (Pd, C1, C2) which elevates the selectivity via enhanced electron-transfer. By adjusting the p-d coupling accurately, the reduction of self-activated nitrogen is promoted by anchoring atom selection, and the side effects are minimized.

Negligible Ability of Oxygen and Peroxide Ion Activation by Al(III) Ion Is Essential for Al(III)-Induced Neurodegeneration

2001 ◽  
Vol 56 (9-10) ◽  
pp. 865-871 ◽  
Author(s):  
Yuzo Nishida
Keyword(s):  
Density Functional Theory ◽  
Tyrosine Hydroxylase ◽  
Aromatic Ring ◽  
Density Functional ◽  
Density Functional Theory Method ◽  
Oxygen Molecule ◽  
Theory Method ◽  
Functional Theory ◽  
Previous Proposal ◽  
Electron Donation

Abstract The electron densities of the atoms in Fe(II)-or Al(III)-tyrosine hydroxylase (THO) containing oxygen and pterin were calculated by the DFT (Density-functional theory) method. The results obtained are consistent with our previous proposal that oxygen activation in THO proceeds through the formation of an intermediate derived from Fe(II), oxygen, and pterin. Electron donation from substrate to the oxygen molecule is important to cleave the O-O bond, and to give the hydroxylated product. Based on these results, it was concluded that hydroxylation of the aromatic ring does not proceed in the Al(III)-containing THO, and a relationship exists between Al(III) ion and neurodegeneration.

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