Insights into the catalytic activity and surface modification of MoO3 during the hydrodeoxygenation of lignin-derived model compounds into aromatic hydrocarbons under low hydrogen pressures

2014 ◽  
Vol 7 (8) ◽  
pp. 2660-2669 ◽  
Author(s):  
Teerawit Prasomsri ◽  
Manish Shetty ◽  
Karthick Murugappan ◽  
Yuriy Román-Leshkov

MoO3 is an effective catalyst for the hydrodeoxygenation (HDO) of lignin-derived oxygenates to generate high yields of aromatic hydrocarbons without ring-saturated products.

2020 ◽  
Vol 24 (14) ◽  
pp. 1610-1642 ◽  
Author(s):  
Ahmed El-Mekabaty ◽  
Hassan A. Etman ◽  
Ahmed Mosbah ◽  
Ahmed A. Fadda

Barbituric, thiobarbituric acids and their related analogs are reactive synthons for the synthesis of drugs and biologically, and pharmaceutically active pyrimidines. The present review aimed to summarize the recent advances in the synthesis of different alkylsubstituted, fused cycles, spiro-, and binary heterocycles incorporated pyrimidine skeleton based on barbituric derivatives. In this sequence, the eco-friendly techniques under catalytic conditions were used for the diverse types of multicomponent reactions under different conditions for the synthesis of various types of heterocycles. Nano-catalysts are efficient for the synthesis of these compounds in high yields and effective catalyst reusability. The compounds are potent antibacterial, cytotoxic, xanthine oxidase inhibitory activities, and attend as urease inhibitors. The projected mechanisms for the synthesis of pyranopyrimidines, benzochromenopyrimidines, chromeno-pyranopyrimidines, spiroxyindoles, oxospiro-tricyclic furopyrimidines, pyrimidine-based monoand bicyclic pyridines were discussed. The potent and diverse biological activities for instance, antioxidant, antibacterial, cytotoxic, and xanthine oxidase inhibitory activities, as well as urease inhibitors, are specified.


Holzforschung ◽  
2012 ◽  
Vol 66 (3) ◽  
Author(s):  
Takumi Shiraishi ◽  
Toshiyuki Takano ◽  
Hiroshi Kamitakahara ◽  
Fumiaki Nakatsubo

Abstract The direct anodic oxidation of non-phenolic lignin model compounds was investigated to understand their basic behaviors. The results of cyclic voltammetry (CV) studies of monomeric model, such as 1-(4-ethoxy-3-methoxyphenyl)ethanol, are interpreted as the oxidation for Cα-carbonylation did not proceed in the reaction without a catalyst, but a base promotes this reaction. Indeed, the bulk electrolyses of the monomeric lignin model compounds with 2,6-lutidine afforded the corresponding Cα-carbonyl compounds in high yields (60–80%). It is suggested that deprotonation at Cα-H in the ECEC mechanism (E=electron transfer and C=chemical step) is important for Cα-carbonylation. In the uncatalyzed bulk electrolysis of a β-O-4 model dimeric compound, 4-ethoxy-3-methoxyphenylglycerol-β-guaiacyl ether, the corresponding Cα-carbonyl compound was not detected but as a result of Cα-Cβcleavage 4-O-ethylvanillin was found in 40% yield. In the electrolysis reaction in the presence of 2,6-lutidine (as a sterically hindered light base), the reaction stopped for a short time unexpectedly. These results indicate the different electrochemical behavior of simple monomeric model compounds and dimeric β-O-4 models. The conclusion is that direct electrooxidation is unsuitable for Cα-carbonylation of lignin.


RSC Advances ◽  
2016 ◽  
Vol 6 (29) ◽  
pp. 24097-24102 ◽  
Author(s):  
Betül Çelik ◽  
Yunus Yıldız ◽  
Hakan Sert ◽  
Esma Erken ◽  
Yagmur Koşkun ◽  
...  

Monodispersed PdCo@PVP NPs showed record catalytic activity, giving the best catalytic performance yet with a very high turnover frequency.


2010 ◽  
Vol 150-151 ◽  
pp. 1710-1713
Author(s):  
Ying Jie Zhang ◽  
Yue Xiao Tian ◽  
Da Peng Li ◽  
Guo Rui Liu ◽  
Li Zhang ◽  
...  

A new Fenton-like catalyst was prepared to degrade Orange IV in water by catalytic decomposition of H2O2. The optimal preparation conditions were discussed. The catalytic activity of catalyst was evaluated by the degradation of Orange IV and the decomposition of H2O2. The results show that solid super acid (S2O82-/FexOy) soaked in (NH4)2S2O8 is the most effective catalyst among the synthesized iron oxides soaked in other oxidants. The optimal conditions for solid super acid preparation are calcined at 500 for 2 h in the air.


2018 ◽  
Vol 5 (6) ◽  
pp. 065516 ◽  
Author(s):  
K Sureshkumar ◽  
K Shanthi ◽  
N R Sasirekha ◽  
J Jegan ◽  
S J Sardhar Basha

2009 ◽  
Vol 2009 (8) ◽  
pp. 465-467
Author(s):  
Hongjun Zang ◽  
Yong Zhang ◽  
Meiling Wang ◽  
Bo-Wen Cheng

The ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate, [bmim]BF4, has been demonstrated to be an effective catalyst for synthesis of methylene dioximes. These reactions proceed with excellent yields under shorter reaction times than other reported methods. Furthermore, the ionic liquid [bmim]BF4 can be recycled and reused without loss of catalytic activity.


Synthesis ◽  
2019 ◽  
Vol 51 (09) ◽  
pp. 2014-2022 ◽  
Author(s):  
Jianhui Xia ◽  
Xue Huang ◽  
Mingzhong Cai

The heterogeneous cascade addition-oxidative cyclization of nitriles with 2-aminopyridines or amidines was achieved in 1,2-dichlorobenzene or DMSO at 120–130 °C by using a 1,10-phenanthroline-functionalized MCM-41-supported copper(I) complex [Phen-MCM-41-CuBr] as the catalyst and air as the oxidant. The approach was used to generate a wide variety of 1,2,4-triazole derivatives in mostly high yields. This heterogeneous copper(I) catalyst could be easily prepared in a two-step procedure from commercially or readily available and inexpensive reagents and it exhibited higher catalytic activity than the CuBr/1,10-Phen system. Phen-MCM-41-CuBr was also easy to recover and was recyclable up to eight times with almost consistent activity.


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