scholarly journals Selective Hydrogenation of Phenol to Cyclohexanol over Ni/CNT in the Absence of External Hydrogen

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 846 ◽  
Author(s):  
Changzhou Chen ◽  
Peng Liu ◽  
Minghao Zhou ◽  
Brajendra K. Sharma ◽  
Jianchun Jiang
Keyword(s):  
Reaction Time ◽  
Physicochemical Properties ◽  
Efficient Method ◽  
Selective Hydrogenation ◽  
Transfer Hydrogenation ◽  
Impregnation Method ◽  
Complete Conversion ◽  
Phenol Derivatives ◽  
Successive Step ◽  
Icp Analysis

Transfer hydrogenation is a novel and efficient method to realize the hydrogenation in different chemical reactions and exploring a simple heterogeneous catalyst with high activity is crucial. Ni/CNT was synthesized through a traditional impregnation method, and the detailed physicochemical properties were performed by means of XRD, TEM, XPS, BET, and ICP analysis. Through the screening of loading amounts, solvents, reaction temperature, and reaction time, 20% Ni/CNT achieves an almost complete conversion of phenol after 60 min at 220 °C in the absence of external hydrogen. Furthermore, the catalytic system is carried out on a variety of phenol derivatives for the generation of corresponding cyclohexanols with good to excellent results. The mechanism suggests that the hydrogenation of phenol to cyclohexanone is the first step, while the hydrogenation of cyclohexanone for the generation of cyclohexanol takes place in a successive step. Moreover, Ni/CNT catalyst can be magnetically recovered and reused in the next test for succeeding four times.

Structural/Texture Evolution During Facile Substitution of Ni into ZSM-5 Nanostructure vs. its Impregnation Dispersion Used in Selective Transformation of Methanol to Ethylene and Propylene

2020 ◽  
Vol 23 ◽  
Author(s):  
Parisa Sadeghpour ◽  
Mohammad Haghighi ◽  
Mehrdad Esmaeili
Keyword(s):  
High Temperature ◽  
Physicochemical Properties ◽  
Active Sites ◽  
Catalytic Performance ◽  
Fixed Bed Reactor ◽  
Light Olefins ◽  
Isomorphous Substitution ◽  
Impregnation Method ◽  
Hydrothermal Temperature ◽  
X Ray

Aim and Objective: Effect of two different modification methods for introducing Ni into ZSM-5 framework was investigated under high temperature synthesis conditions. The nickel successfully introduced into the MFI structures at different crystallization conditions to enhance the physicochemical properties and catalytic performance. Materials and Methods: A series of impregnated Ni/ZSM-5 and isomorphous substituted NiZSM-5 nanostructure catalysts were prepared hydrothermally at different high temperatures and within short times. X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray (EDX), Brunner, Emmett and Teller-Barrett, Joyner and Halenda (BET-BJH), Fourier transform infrared (FTIR) and Temperature-programmed desorption of ammonia (TPDNH3) were applied to investigate the physicochemical properties. Results: Although all the catalysts showed pure silica MFI–type nanosheets and coffin-like morphology, using the isomorphous substitution for Ni incorporation into the ZSM-5 framework led to the formation of materials with lower crystallinity, higher pore volume and stronger acidity compared to using impregnation method. Moreover, it was found that raising the hydrothermal temperature increased the crystallinity and enhanced more uniform incorporation of Ni atoms in the crystalline structure of catalysts. TPD-NH3 analysis demonstrated that high crystallization temperature and short crystallization time of NiZSM-5(350-0.5) resulted in fewer weak acid sites and medium acid strength. The MTO catalytic performance was tested in a fixed bed reactor at 460ºC and GHSV=10500 cm3 /gcat.h. A slightly different reaction pathway was proposed for the production of light olefins over impregnated Ni/ZSM-5 catalysts based on the role of NiO species. The enhanced methanol conversion for isomorphous substituted NiZSM-5 catalysts could be related to the most accessible active sites located inside the pores. Conclusion: The impregnated Ni/ZSM-5 catalyst prepared at low hydrothermal temperature showed the best catalytic performance, while the isomorphous substituted NiZSM-5 prepared at high temperature was found to be the active molecular sieve regarding the stability performance.

scholarly journals Selective hydrogenation of 5-(hydroxymethyl)furfural to 5-methylfurfural over single atomic metals anchored on Nb2O5

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shaopeng Li ◽  
Minghua Dong ◽  
Junjuan Yang ◽  
Xiaomeng Cheng ◽  
Xiaojun Shen ◽  
...  
Keyword(s):  
Selective Hydrogenation ◽  
Function Theory ◽  
Density Function Theory ◽  
Reducing Agent ◽  
Dft Studies ◽  
Complete Conversion ◽  
Hydroxymethyl Furfural ◽  
Metal Atoms ◽  
Direct Hydrogenation ◽  
Reaction Result

Abstract5-Methylfurfural (MF) is a very useful chemical. Selective hydrogenation of biomass platform molecule 5-(hydroxymethyl)furfural (HMF) to MF using H2 as the reducing agent is very attractive, but challenging because hydrogenation of C=O bond in HMF is more favourable than C–OH both kinetically and thermodynamically, and this route has not been realized. In this work, we prepare isolated single atomic catalysts (SACs) Pt1/Nb2O5-Ov, Pd1/Nb2O5-Ov, and Au1/Nb2O5-Ov, in which single metal atoms are supported on oxygen defective Nb2O5 (Nb2O5-Ov). It is discovered that the SACs can efficiently catalyze the hydrogenation of HMF to MF using H2 as the reducing agent with MF selectivity of >99% at complete conversion, while the selectivities of the metal nanocatalysts supported on Nb2O5 are very poor. A combination of experimental and density function theory (DFT) studies show that the unique features of the SACs for the reaction result from the cooperation of the Nb and Pt sites near the interface in the Pt1/Nb2O5-Ov. The Pt atoms are responsible for the activation of H2 and the Nb sites activate C-OH in the reaction. This work opens the way for producing MF by direct hydrogenation of biomass-derived HMF using H2 as the reductant.

Transfer hydrogenation of biomass-derived levulinic acid to γ-valerolactone over supported Ni catalysts

RSC Advances ◽  
2016 ◽  
Vol 6 (64) ◽  
pp. 59753-59761 ◽  
Author(s):  
A. M. Hengne ◽  
B. S. Kadu ◽  
N. S. Biradar ◽  
R. C. Chikate ◽  
C. V. Rode
Keyword(s):  
Levulinic Acid ◽  
Transfer Hydrogenation ◽  
Complete Conversion ◽  
Catalytic Transfer Hydrogenation ◽  
Ni Catalysts ◽  
Catalytic Transfer ◽  
Supported Ni Catalysts ◽  
Supported Ni

A bifunctional Ni/MMT catalyst for catalytic transfer hydrogenation of levulinic acid to γ-valerolactone with complete conversion and selectivity.

scholarly journals Carboxylate-Functionalized P, N-Ligated Cobalt Catalysts for Alkene Hydrosilylation

2020 ◽  
Vol 17 ◽  
Author(s):  
Yangyang Ma ◽  
Jiayun Li ◽  
Ying Bai ◽  
Jiajian Peng
Keyword(s):  
Activation Energy ◽  
Reaction Time ◽  
Efficient Method ◽  
Cobalt Catalysts ◽  
Carboxyl Groups ◽  
Catalytic Hydrosilylation ◽  
P Ligands

: A series of N, P-ligands bearing carboxyl groups has been synthesized. These have been applied in conjunction with cobalt naphthenate in a facile, economic, and efficient method for the catalytic hydrosilylation of alkenes. In the presence of KOtBu as an additive, the reaction time and activation energy are greatly reduced.

Study on Catalytic Performance of Supported HPW/C Catalyst for Diethyl Adipate Synthesis

2012 ◽  
Vol 468-471 ◽  
pp. 1371-1374
Author(s):  
Ke Nian Wei ◽  
Bin Zhou ◽  
Jiang Quan Ma ◽  
Yan Wang
Keyword(s):  
Physical Chemistry ◽  
Reaction Time ◽  
Adipic Acid ◽  
Acid Content ◽  
Catalytic Performance ◽  
Impregnation Method ◽  
Reaction Conditions ◽  
Catalyst Amount ◽  
Reaction Performance ◽  
Optimal Reaction

HPW/C catalysts were prepared using impregnation method. The physical chemistry properties of the catalysts were characterized employing XRD and NH3-TPD.The effects of HPW loading, catalyst amount and reaction time on the catalyst performances were investigated. The results more acid content and active center contribute to the reaction performance. Under the optimal reaction conditions of 0.8g 29%(w) HPW/C as the catalyst, n(adipic acid): n(ethanol):n(toluene)=1:6:1,5h,the etherification rate was 97.3%.

Fast and Efficient Synthesis of Mono-(6-p-toluenesulfonyl)-β-cyclodextrin via Ultrasound Assisted Method

2015 ◽  
Vol 1083 ◽  
pp. 51-54 ◽  
Author(s):  
Wen Qian Zheng ◽  
Mei Xia Du ◽  
Feng Feng ◽  
Guo Lin Chen ◽  
Min Liao ◽  
...  
Keyword(s):  
Reaction Time ◽  
Efficient Method ◽  
Water Solution ◽  
Synthetic Methods ◽  
Efficient Synthesis ◽  
Alkaline Water ◽  
Novel Method ◽  
Ultrasound Assisted

The mono-(6-p-toluenesulfonyl)-β-cyclodextrin was firstly synthesized fast and efficiently by adopting ultrasound assisted method in alkaline water solution. The reaction time was only 40 min but with the yield of 31.1% under ultrasound condition. Compared with the conventional synthetic methods, the proposed novel method could shorten the reaction time and improve the yield. It is a simple, rapid and efficient method.

scholarly journals The Influence of Ce or Mn Doping on Cu-Based Catalysts for De-NOx with NH3-SCR

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Lei Jiang ◽  
Yixi Cai ◽  
Miaomiao Jin ◽  
Zengzan Zhu ◽  
Yinhuan Wang
Keyword(s):  
Low Temperature ◽  
Physicochemical Properties ◽  
Topological Structure ◽  
Zeolite Catalysts ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Performance Tests ◽  
Nh3 Scr ◽  
Temperature Window ◽  
Different Doses

In this study, the de-NOx performance of Cu-based zeolite catalysts supported on topological structure (SSZ-13, BEA, ZSM-5) and loaded with different doses of copper (from 2 to 6 wt.%) was investigated. The preparation of copper-based catalysts adopted the incipient wetness impregnation method. To analyze the physicochemical properties of the catalysts, advanced techniques like BET, XRD, NH3-TPD, H2-TPR, and DRS UV-Vis were used. The performance tests suggested the 4Cu/SSZ-13 catalyst exhibited higher low-temperature activity and wider temperature window. Furthermore, compared with Mn-Cu/SSZ-13, the Ce-Cu/SSZ-13 catalysts exhibited better de-NOx performance.

Physicochemical properties of a urea/zinc chloride eutectic mixture and its improved effect on the fast and high yield synthesis of indeno[2,1-c]quinolines

2020 ◽  
Vol 44 (19) ◽  
pp. 7987-7997
Author(s):  
Diana Peña-Solórzano ◽  
Vladimir V. Kouznetsov ◽  
Cristian Ochoa-Puentes
Keyword(s):  
Physicochemical Properties ◽  
Efficient Method ◽  
Zinc Chloride ◽  
Acidic Medium ◽  
Eutectic Mixture ◽  
Environmentally Friendly ◽  
High Yield

An environmentally friendly and efficient method for the synthesis of indeno[2,1-c]quinolines is developed using a urea/zinc chloride eutectic mixture as a green mildly acidic medium.

Efficient Copper-Catalyzed Synthesis of Substituted Pyrazoles at Room Temperature

Synlett ◽  
2018 ◽  
Vol 29 (20) ◽  
pp. 2689-2692 ◽  
Author(s):  
Haifeng Wang ◽  
Xiangli Sun ◽  
Shuangling Zhang ◽  
Guanglu Liu ◽  
Chunjie Wang ◽  
...  
Keyword(s):  
Reaction Time ◽  
Catalytic System ◽  
Efficient Method ◽  
Room Temperature ◽  
Copper Catalyst ◽  
Condensation Reaction ◽  
Reaction Conditions ◽  
Short Reaction Time ◽  
Acid Catalyzed ◽  
Substituted Pyrazoles

An efficient method for the synthesis of pyrazoles through a copper-catalyzed condensation reaction has been developed. The new catalytic system not only maintained a broad substrate scope but was also active under acid-free reaction conditions, overcoming the conventional requirement for an acid-catalyzed system. Furthermore, the copper catalyst enabled this reaction to be performed at room temperature and in a short reaction time.

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