Preparation of Tetrasubstituted Bis(3-indolyl)methanes from Indoles and Acetophenes Using 1,3-Dibromo-5,5-dimehtylhydantoin as an Efficient Catalyst

2022 ◽  
Vol 19 ◽  
Author(s):  
Zubiao Zheng ◽  
Daoxin Zha ◽  
Peng Cui ◽  
Caixia Ye ◽  
Lei Jin ◽  
...  
Keyword(s):  
Optimal Condition ◽  
Reaction Temperature ◽  
Efficient Catalyst ◽  
New Process

Abstract: A new process that could efficiently prepare tetrasubstituted bis(3-indolyl)methanes from various indoles and acetophenones with 1,3-Dibromo-5,5-dimehtylhydantoin(DBDMH) as a catalyst was reported. The effects of catalysts, solvents, and reaction temperature were investigated. Under the optimal condition, most of the tetrasubstituted bis(3-indolyl)methanes were obtained in 90–99% yields.

scholarly journals Supported Bimetallic AuPd Nanoparticles as Catalyst for the Solvent-Free Selective Hydrogenation of Nitroarenes

2018 ◽  
Author(s):  
Ruiyang Qu ◽  
Margherita Macino ◽  
Sarwat Iqbal ◽  
Xiang Gao ◽  
Qian He ◽  
...  
Keyword(s):  
Activation Energy ◽  
Reaction Temperature ◽  
Selective Hydrogenation ◽  
Energy Input ◽  
Solvent Free ◽  
Impregnation Method ◽  
Efficient Catalyst ◽  
Effective Catalyst ◽  
Chemoselective Hydrogenation ◽  
Solvent Free Conditions

Selective hydrogenation of nitrobenzene was carried out under solvent-free conditions using supported AuPd nanoparticles catalyst, prepared by modified impregnation method (MIm), as efficient catalyst. >99% yield of aniline (AN) was obtained after 15 hours at 90 °C, 3 bar H2 that can be used without any further purification or separation, therefore reducing cost and energy input. Supported AuPd nanoparticles catalyst, prepared by MIm, was found to be active and stable even after 4 recycle experiments whereas the same catalyst prepared by SIm deactivated during the recycle experiments. The most effective catalyst was tested for the chemoselective hydrogenation of 4-chloronitrobenzene (CNB) to 4-chloroaniline (CAN). The activation energy of CNB to CAN was found to be 25 kJ mol-1, while that of CNB to AN was found to be 31 kJ mol-1. Based on this, the yield of CAN was maximized (92%) by lowering the reaction temperature to 25 °C.

scholarly journals In situ Generated Ru(0)-HRO@Na-β From Hydrous Ruthenium Oxide (HRO)/Na-β: An Energy-Efficient Catalyst for Selective Hydrogenation of Sugars

2020 ◽  
Vol 8 ◽  
Author(s):  
Sreedhar Gundekari ◽  
Heena Desai ◽  
Krishnan Ravi ◽  
Joyee Mitra ◽  
Kannan Srinivasan
Keyword(s):  
Aqueous Medium ◽  
Reaction Temperature ◽  
Energy Efficient ◽  
Ruthenium Oxide ◽  
Green Process ◽  
Sugar Alcohols ◽  
Reaction Conditions ◽  
Efficient Catalyst ◽  
Hydrogenation Reactions

A green process for the hydrogenation of sugars to sugar alcohols was designed in aqueous medium using hydrous ruthenium oxide (HRO) as a pre-catalyst supported on Na-β zeolite. Under optimized reaction conditions, sugars such as xylose, glucose, and mannose converted completely to the corresponding sugar alcohols xylitol, sorbitol, and mannitol with 100% selectivity. The pre-catalyst (HRO) is converted in situ to active Ru(0) species during the reaction under H2, which is responsible for the hydrogenation. The catalyst was recyclable up to five cycles with no loss in activity. The reduction of HRO to the active Ru(0) species is dependent on the reaction temperature and H2 pressure. Ru(0) formation increased and consequently an increased hydrogenation of sugars was observed with an increase in reaction temperature and hydrogen pressure. Further, in situ generation of Ru(0) from HRO was assessed in different solvents such as water, methanol, and tetrahydrofuran; aqueous medium was found to be the most efficient in reducing HRO. This work further demonstrates the use of supported HRO as an efficient pre-catalyst for biomass-based hydrogenation reactions.

Decomposition of Ilmenite by Ammonium Hydroxide

2013 ◽  
Vol 813 ◽  
pp. 484-488
Author(s):  
Hai Bo Tang ◽  
Yu Min Liu
Keyword(s):  
Experimental Data ◽  
Reaction Temperature ◽  
Significant Influence ◽  
Hydrothermal Process ◽  
Ammonium Hydroxide ◽  
Core Model ◽  
Shrinking Core Model ◽  
Operating Variables ◽  
New Process ◽  
Shrinking Core

A new process was provided for decomposition of ilmenite by ammonium hydroxide under hydrothermal process. The significant effects of reaction temperature, NH4OH concentration, NH4OH-to-ilmenite mass ratios on titanium extraction were studied. The temperature showed significant influence on titanium extraction. The experimental data of the extraction rates under the relevant operating variables were well interpreted with the shrinking core model under chemically controlled process.

scholarly journals Supported Bimetallic AuPd Nanoparticles as a Catalyst for the Selective Hydrogenation of Nitroarenes

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 690 ◽  
Author(s):  
Ruiyang Qu ◽  
Margherita Macino ◽  
Sarwat Iqbal ◽  
Xiang Gao ◽  
Qian He ◽  
...  
Keyword(s):  
Activation Energy ◽  
Reaction Temperature ◽  
Selective Hydrogenation ◽  
Energy Input ◽  
Solvent Free ◽  
Impregnation Method ◽  
Efficient Catalyst ◽  
Effective Catalyst ◽  
Chemoselective Hydrogenation

The solvent-free selective hydrogenation of nitrobenzene was carried out using a supported AuPd nanoparticles catalyst, prepared by the modified impregnation method (MIm), as efficient catalyst >99% yield of aniline (AN) was obtained after 15 h at 90 °C, 3 bar H2 that can be used without any further purification or separation, therefore reducing cost and energy input. Supported AuPd nanoparticles catalyst, prepared by MIm, was found to be active and stable even after four recycle experiments, whereas the same catalyst prepared by SIm was deactivated during the recycle experiments. The most effective catalyst was tested for the chemoselective hydrogenation of 4-chloronitrobenzene (CNB) to 4-chloroaniline (CAN). The activation energy of CNB to CAN was found to be 25 kJ mol−1, while that of CNB to AN was found to be 31 kJ mol−1. Based on this, the yield of CAN was maximized (92%) by the lowering the reaction temperature to 25 °C.

scholarly journals Ionic liquids modified cobalt/ZSM-5 as a highly efficient catalyst for enhancing the selectivity towards KA oil in the aerobic oxidation of cyclohexane

2019 ◽  
Vol 17 (1) ◽  
pp. 639-646 ◽  
Author(s):  
Yun Hong ◽  
Yanxiong Fang ◽  
Dalei Sun ◽  
Xiantai Zhou
Keyword(s):  
Ionic Liquids ◽  
Heterogeneous Catalyst ◽  
Reaction Temperature ◽  
Aerobic Oxidation ◽  
Power Input ◽  
Homogeneous Catalyst ◽  
Complex Catalyst ◽  
Efficient Catalyst ◽  
Reaction Pressure ◽  
And Performance

AbstractThe industrial oxidation of cyclohexane is currently performed with very low conversion level, i.e. 4-6% conversion and poor selectivity for cyclohexanone and cyclohexanol (K-A oil), i.e.70-85%, at above 150oC reaction temperature and above 10atm reaction pressure using molecular oxygen oxidant and homogeneous catalyst. Several disadvantages are, however, associated with the process, such as, complex catalyst-product separation, high power input, and low safe operation. Therefore, the oxidation of cyclohexane using heterogeneous catalyst oxygen oxidant from air at mild conditions has received particular attention. Aerobic oxidation of cyclohexane over ionic liquids modified cobalt/ZSM-5 (IL-Co/ZSM-5) in absence of solvents was developed in this article. The prepared catalysts were characterized by XRD, FT-IR, N2 adsorption-desorption, SEM, TEM and XPS analyses. The influence of reaction parameters on the oxidation of cyclohexane was researched, such as the various catalysts, reaction temperature, reaction time, and the reaction pressure, on the process. Highly selective synthesis of KA oil was performed by aerobic oxidation of cyclohexane using ionic liquids modified cobalt/ZSM-5 (IL-Co/ZSM-5) as the catalyst in absence of solvents for the first time. A selectivity of up to 93.6% of KA oil with 9.2% conversion of cyclohexane was produced at 150℃ and 1.5 MPa after 3 h, with about 0.1 mol cyclohexane, C7mimHSO4-Co/ZSM-5 catalyst equal to 6.0 wt%, respectively. The induction period of oxidation was greatly shortened when the ionic liquid was supported on ZSM-5. The catalyst was easy to centrifuge and was reused after five cycles. It was found that both the characterization and performance of the catalysts revealed that both the presence of oxygen vacancies with incorporation of Co ions into the framework of ZSM-5 and the introduction of C7mimHSO4 into the ZSM-5 leads to the both satisfactory selectivity and robust stability of the C7mimHSO4-Co/ZSM-5 heterogeneous catalyst.

Preparation of Foaming Agent by Modification Protein from Pea Meal

2011 ◽  
Vol 396-398 ◽  
pp. 811-816
Author(s):  
Ji Chuan Huo ◽  
Yan Hong Yuan ◽  
Cheng Wang ◽  
Chang Dong Xie
Keyword(s):  
Response Surface Methodology ◽  
Optimum Condition ◽  
Optimal Condition ◽  
Response Surface ◽  
Reaction Temperature ◽  
Foam Stability ◽  
Raw Material ◽  
Foaming Agent ◽  
Modification Process ◽  
Protein Foam

Pea meal was used as raw material to prepare protein foam agent. The parameters containing concentration of Ca(OH)2, reaction temperature and time were investigated and optimized by the response surface methodology in the modification process of foam agent. The optimum condition was obtained that the concentration of Ca(OH)2 0.78%, reaction temperature 92°C and 4 hours for extraction time. Under the optimal condition, the maximum forecasting foam stability was 16.2h and the verified value was 16.16h which relative error was 0.25% through confirmative test.

Application of PFSC in Seawater Desalination Pretreatment

2014 ◽  
Vol 945-949 ◽  
pp. 3510-3513 ◽  
Author(s):  
Jun Cheng ◽  
Si Cheng ◽  
Xiao Fan Cao
Keyword(s):  
Optimal Condition ◽  
Ferric Chloride ◽  
Reaction Temperature ◽  
Ph Value ◽  
Experimental Results ◽  
Curing Temperature ◽  
Molar Ratio ◽  
Seawater Desalination ◽  
Turbidity Removal ◽  
Molar Ratios

The optimal condition of polysilicon ferric chloride (PFSC) flocculant was established by thinking of the factors , such as Si/Fe molar ratios,the reaction temperature and the pH value of the solution. When the molar ratio of Si and Fe = 1, pH value = 0.6, curing temperature at 30 ~40 °C, poly ferric chloride dosage of 0.75mg/L, the rate of turbidity removal of seawater is up to 96.5%. Experimental results show that poly ferric chloride seawater turbidity removal effect is obvious.

Preparation of Cement Water Reducer of Modified Lignosulfonate

2010 ◽  
Vol 168-170 ◽  
pp. 541-544 ◽  
Author(s):  
Xiu Wen Wu ◽  
Heng Zhang
Keyword(s):  
Cement Paste ◽  
Reaction Temperature ◽  
High Efficiency ◽  
Oxidizing Agent ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Synthesis Conditions ◽  
Water Reduction ◽  
Optimum Synthesis ◽  
New Process

In this paper, the cement water reduction agent from modified lignosulfonate was synthesizd using a new process consisting of pre-oxidation, hydroxymethylation and sulfonation. The optimum synthesis conditions were identified: the oxidizing agent dosage is 15%, reaction temperature is 80-90oC, the dosage of formaldehyde is 30%, reaction temperature is about 95oC, pH is about 9.5. Fluidity of cement paste can be measured under the conditions of the addition of 0.25%, and the water-cement ratio is 0.4%. The results showed the modified lignosulfonate prepared under the above conditions had the better slushing performance. The fluidity of cement paste can reach 178 mm that is close to the high efficiency water reduction agent requirements.

scholarly journals Cu–Fe Incorporated Graphene-Oxide Nanocomposite as Highly Efficient Catalyst in the Degradation of Dichlorodiphenyltrichloroethane (DDT) from Aqueous Solution

2020 ◽  
Vol 63 (11-14) ◽  
pp. 1314-1324 ◽  
Author(s):  
Giang H. Le ◽  
Tuan T. Nguyen ◽  
Manh B. Nguyen ◽  
Trang T. T. Quan ◽  
Trinh Duy Nguyen ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Graphene Oxide ◽  
Photocatalytic Degradation ◽  
Optimal Condition ◽  
Phase Structure ◽  
Oh Radicals ◽  
Xps Analysis ◽  
Efficient Catalyst ◽  
Structure And Morphology ◽  
Implantation Method

Abstract Fe/graphene oxide and Cu–Fe/graphene oxide nanocomposite were synthesized by the atomic implantation method to study the photocatalytic degradation of dichlorodiphenyltrichloroethane (DDT). The synthesized nanocomposites were characterized by the XRD, N2 isotherms, SEM with EDX, TEM and XPS analysis. Characterization results have reported that oxides of Cu and Fe were uniformly distributed on graphene oxide and exited in the form of Cu+ and Fe2+ ions in Cu–Fe/graphene oxide nanocomposite. The high photocatalytic DDT removal efficiency 99.7% was obtained for Cu–Fe/graphene oxide under the optimal condition of 0.2 g/L catalyst, 15 mg/L H2O2 and pH 5. It was attributed to the reduction of Fe3+ to Fe2+ by Cu+ ions and –OH radicals formation. However, it was dropped to 90.4% in the recycling study by leaching of iron and without a change in phase structure and morphology. Graphic Abstract

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