scholarly journals Oxidation of Monoethylene Glycol to Glycolic Acid with Gold-Based Catalyst and Glycolic Acid Isolation by Electrodialysis

Reactions ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 47-58
Author(s):  
Sarah Tschirner ◽  
Eric Weingart ◽  
Linda Teevs ◽  
Ulf Prüße
Keyword(s):  
Glycolic Acid ◽  
Bimetallic Catalyst ◽  
Platinum Catalyst ◽  
Sodium Oxalate ◽  
Reaction Conditions ◽  
Batch Mode ◽  
Catalyst Composition ◽  
Reaction Solution ◽  
Alkaline Conditions ◽  
Monoethylene Glycol

In this work, a highly selective and active gold-based catalyst for the oxidation of high concentrated monoethylene glycol (MEG) in aqueous solution (3 M, 20 wt%) is described. High glycolic acid (GA) selectivity was achieved under mild reaction conditions. The optimization of the catalyst composition and of the reaction conditions for the oxidation of MEG in semi-batch mode under alkaline conditions led to a GA yield of >80% with a GA selectivity of about 90% in short reaction time. The bimetallic catalyst 0.1 wt% AuPt (9:1)/CeO2 showed very high activity (>2000 mmolMEG/gmetalmin) in the oxidation of MEG and, contrary to other studies, an extremely high educt to metal mole ratio of >25,000 was used. Additionally, the gold–platinum catalyst showed a high GA selectivity over more than 10 runs. A very efficient and highly selective process for the GA production from MEG under industrial relevant reaction conditions was established. In order to obtain a GA solution with high purity for the subsequent polymerization, the received reaction solution containing sodium glycolate, unreacted MEG and sodium oxalate is purified by a novel down-stream process via electrodialysis. The overall GA yield of the process exceeds 90% as unreacted MEG can be recycled.

A review of lignin hydrogen peroxide oxidation chemistry with emphasis on aromatic aldehydes and acids

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ajinkya More ◽  
Thomas Elder ◽  
Zhihua Jiang
Keyword(s):  
Hydrogen Peroxide ◽  
Oxidative Degradation ◽  
Reaction Medium ◽  
Dicarboxylic Acids ◽  
Aromatic Aldehydes ◽  
Product Distribution ◽  
Reaction Conditions ◽  
Alkaline Conditions ◽  
The Stability ◽  
Oxidation Chemistry

Abstract This review discusses the main factors that govern the oxidation processes of lignins into aromatic aldehydes and acids using hydrogen peroxide. Aromatic aldehydes and acids are produced in the oxidative degradation of lignin whereas mono and dicarboxylic acids are the main products. The stability of hydrogen peroxide under the reaction conditions is an important factor that needs to be addressed for selectively improving the yield of aromatic aldehydes. Hydrogen peroxide in the presence of heavy metal ions readily decomposes, leading to minor degradation of lignin. This degradation results in quinones which are highly reactive towards peroxide. Under these reaction conditions, the pH of the reaction medium defines the reaction mechanism and the product distribution. Under acidic conditions, hydrogen peroxide reacts electrophilically with electron rich aromatic and olefinic structures at comparatively higher temperatures. In contrast, under alkaline conditions it reacts nucleophilically with electron deficient carbonyl and conjugated carbonyl structures in lignin. The reaction pattern in the oxidation of lignin usually involves cleavage of the aromatic ring, the aliphatic side chain or other linkages which will be discussed in this review.

Intensification of the Production of 2-Ethyl-Hexyl Acrylate: Batch Kinetics and Reactive Distillation

2018 ◽  
Vol 16 (7) ◽  
Author(s):  
Vivek D. Talnikar ◽  
Onkar A. Deorukhkar ◽  
Amit Katariya ◽  
Yogesh S. Mahajan
Keyword(s):  
Kinetic Model ◽  
Acrylic Acid ◽  
Process Development ◽  
Reactive Distillation ◽  
Batch Reactor ◽  
Process Intensification ◽  
Complete Conversion ◽  
Reaction Conditions ◽  
Batch Mode ◽  
Batch Kinetics

Abstract The reaction of acrylic acid and 2-ethyl-1 hexanol was explored in this work with the intent of process intensification. In order to assess the effect of important parameters on the course of reaction, this work initially conducted batch reactor experiments. Reaction conditions in the batch reactor for a specific conversion (~ 30 %) were obtained. A kinetic model was then obtained through regression to arrive at a rate expression that is later used in process development. Experiments were performed in the reactive distillation (RD) environment in batch mode, which showed substantial increase in conversion (~ 80 %) indicating the applicability of RD. Further, this work performed simulation in the RD environment to assess process intensification. Simulations show that it is possible to obtain complete conversion of the acid.

Effects of bimetallic catalyst composition and growth parameters on the growth density and diameter of carbon nanotubes

2001 ◽  
Vol 18 (2) ◽  
pp. 208-214 ◽  
Author(s):  
A. K. M. Fazle Kibria ◽  
Young Hwan Mo ◽  
Min Hee Yun ◽  
Moon J. Kim ◽  
Kee Suk Nahm
Keyword(s):  
Carbon Nanotubes ◽  
Bimetallic Catalyst ◽  
Growth Parameters ◽  
Catalyst Composition

Glycerol aqueous phase reforming for hydrogen generation over Pt catalyst – Effect of catalyst composition and reaction conditions

Fuel ◽  
2008 ◽  
Vol 87 (17-18) ◽  
pp. 3483-3489 ◽  
Author(s):  
Nianjun Luo ◽  
Xianwen Fu ◽  
Fahai Cao ◽  
Tiancun Xiao ◽  
Peter P. Edwards
Keyword(s):  
Aqueous Phase ◽  
Hydrogen Generation ◽  
Pt Catalyst ◽  
Reaction Conditions ◽  
Aqueous Phase Reforming ◽  
Catalyst Composition ◽  
Catalyst Effect

scholarly journals BUTENEDIOLS PRODUCTION FROM ERYTHRITOL ON Rh PROMOTED CATALYST

2020 ◽  
Vol 50 (2) ◽  
pp. 89-94
Author(s):  
Emanuel Martín Virgilio ◽  
Cristina Liliana Padró ◽  
Maria Eugenia Sad
Keyword(s):  
Bimetallic Catalyst ◽  
Good Activity ◽  
Reaction Conditions ◽  
Total Conversion ◽  
Reaction Orders ◽  
Temperature Programmed ◽  
Lower Temperature ◽  
Low Activity ◽  
Monometallic Catalyst ◽  
Lower Carbon

The C-O hydrogenolysis of Erythritol to Butanodiols was studied in aqueous solution at 473 K and 25 bar of H2 using Rh/ReOx/TiO2 and the monometallic Rh/TiO2 and ReOx/TiO2 catalysts. The solids were characterized by temperature programmed reduction (TPR), TEM and XPS. TPR and XPS showed that ReOx species are close to Rh particles leading to reduction at lower temperature than Re on monometallic catalyst. However, some segregated Rhenium species were suspected by TPR profile for the bimetallic catalyst and detected by TEM.  Re/TiO2 exhibited low activity forming only products from dehydration and epimerization. Although Rh/TiO2 showed high activity (total conversion at 14 h), was more selective to C-C cleavage leading to lower carbon products. Rh/ReOx/TiO2, showed instead, a good activity and selectivity towards C-O hydrogenolysis route yielding 37.5% of Butanodiols. Activation energy and reaction orders on ERY (0.58) and H2 (0.53) were estimated from experiences made at different reaction conditions

scholarly journals Graphene encapsulated low-load nitrogen-doped bimetallic magnetic Pd/Fe@N/C catalyst for the reductive amination of nitroarene under mild conditions

2021 ◽  
Author(s):  
Jianguo liu ◽  
Shanshan Lin ◽  
Longlong Ma
Keyword(s):  
Noble Metals ◽  
Reductive Amination ◽  
Bimetallic Catalyst ◽  
Environmentally Friendly ◽  
Pharmaceutical Products ◽  
The Novel ◽  
Reaction Conditions ◽  
Mild Conditions ◽  
Doped Graphene ◽  
Catalytic Reactivity

Aniline is a group of important platform molecules and is widely used in the synthesis of other high-value chemicals and pharmaceutical products. How to produce high-value anilines as the high-value chemical intermediates more efficiently and more environmentally has always been a research topic in the industry. Catalytic hydrogenation is an environmentally friendly method for preparing halogenated anilines. Traditional noble metals catalysis face cost and noble metals residue problems. To improve the purity of the product and the activity and recyclability of the catalyst, we prepared a Pd/Fe magnetic bimetallic catalyst supported on N-doped carbon materials to reduce nitrobenzene to aniline under mild conditions. The loading of Pd was very low, which was 1/10 of the content of common commercial precious metal Pd/C and Pt/C catalysts, which was only 0.5%. And the prepared bimetallic Pd/Fe@N/C catalyst showed excellent catalytic reactivity with the conversion rate of nitrobenzene > 99%, and the selectivity of aniline 99% under mild reaction conditions of 0.8 MPa H2 and 40 °C. A variety of halogenated and aliphatic nitro compounds were well tolerated and had been transformed to the corresponding target amine products with excellent selectivity. In addition, the novel N-doped graphene-encapsulated bimetallic magnetic Pd/Fe@N/C catalyst not only had magnetic physical properties, which was easy to separate, recover, and used for the recycling of the catalyst without metal leaching but also catalyzed highly selective reductive amination of aromatics was a green, economical and environmentally friendly reaction with the only H2O as a by-product.

Modifying an ÄKTApurifier System for the Automated Acquisition of Samples for Kinetic Modeling of Batch Reactions

2019 ◽  
Vol 25 (2) ◽  
pp. 106-110
Author(s):  
Adrian Sanden ◽  
Sandra Haas ◽  
Jürgen Hubbuch
Keyword(s):  
Regression Coefficient ◽  
Exchange Chromatography ◽  
Individual Species ◽  
Time Step ◽  
Reaction Conditions ◽  
Time Intervals ◽  
Reaction Solution ◽  
Automatic Sampling ◽  
The Individual ◽  
Kinetics Of

Recording the data necessary to assess the kinetics of a reaction can be labor-intensive. In this technology brief, we show a method to automate this task by utilizing parts of an ÄKTApurifier chromatography system to automatically take samples from a reaction vessel at predefined time intervals and place them in 96-well plates and also enable correlating the samples with in-line spectral data of the reaction solution. Automatic sampling can reduce experimental bottlenecks by enabling overnight reactions or a higher degree of parallelization. To demonstrate the feasibility of the method, we performed batch-PEGylation of lysozyme with varying conditions by changing the molar excess of the PEG reagent. We used analytical cation-exchange chromatography to analyze the samples taken during the batch reaction, determining the concentrations of the individual species present at each time step. Subsequently, we fitted a kinetic model on these data. Fitting the model to four different reaction conditions simultaneously yielded a regression coefficient of R2 = 0.871.

Synthesis of Novel Geopolymer Supported Nano Bimetallic Catalysts and its Application for Isopropanol Dehydrogenation

2018 ◽  
Vol 777 ◽  
pp. 190-195 ◽  
Author(s):  
John Satmon ◽  
Zheng Feng Hu ◽  
Ming Qiao Zhu
Keyword(s):  
Bimetallic Catalysts ◽  
Reduction Method ◽  
Bimetallic Catalyst ◽  
Excellent Performance ◽  
Reaction Conditions ◽  
Tem Analysis ◽  
Wet Impregnation ◽  
Catalyst Amount ◽  
Isopropanol Dehydrogenation ◽  
Catalytic Stability

A novel geopolymer supported nanobimetallic catalyst for isopropanol dehydrogenation was prepared by modified wet impregnation and reduction method. XRD, SEM, EDX and TEM analysis confirmed formation of amorphous geopolymer from the polymerization of metakaolin and deposition of nanometals over the geopolymer support. The bimetallic catalyst containing 5wt. % Cu and 10wt. % Ni loading over geopolymer shows an excellent performance with 23.18% conversion of isopropanol and 88.24% selectivity to acetone under reaction conditions of 90 °C, 3 hours, and catalyst amount of 0.15g/5.0g of isopropanol. Moreover, the catalyst maintains its catalytic stability without noticeable loss of activity after five cycles.

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