scholarly journals Mesoporous Activated Carbon Supported Ru Catalysts to Efficiently Convert Cellulose into Sorbitol by Hydrolytic Hydrogenation

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4394
Author(s):  
Fatima-Zahra Azar ◽  
M. Ángeles Lillo-Ródenas ◽  
M. Carmen Román-Martínez
Keyword(s):  
Carbon Materials ◽  
Activated Carbons ◽  
One Pot ◽  
Cellulose Conversion ◽  
Hydrolytic Hydrogenation ◽  
Ru Nanoparticles ◽  
Two Samples ◽  
Materials Used ◽  
The One ◽  
By Products

Catalysts consisting of Ru nanoparticles (1 wt%), supported on mesoporous activated carbons (ACs), were prepared and used in the one-pot hydrolytic hydrogenation of cellulose to obtain sorbitol. The carbon materials used as supports are a pristine commercial mesoporous AC (named SA), and two samples derived from it by sulfonation or oxidation treatments (named SASu and SAS, respectively). The catalysts have been thoroughly characterized regarding both surface chemistry and porosity, as well as Ru electronic state and particle size. The amount and type of surface functional groups in the carbon materials becomes modified as a result of the Ru incorporation process, while a high mesopore volume is preserved upon functionalization and Ru incorporation. The prepared catalysts have shown to be very active, with cellulose conversion close to 50% and selectivity to sorbitol above 75%. The support functionalization does not lead to an improvement of the catalysts’ behavior and, in fact, the Ru/SA catalyst is the most effective one, with about 50% yield to sorbitol, and a very low generation of by-products.

Carbon Materials as Adsorbents for the Removal of Pollutants from the Aqueous Phase

MRS Bulletin ◽  
2001 ◽  
Vol 26 (11) ◽  
pp. 890-894 ◽  
Author(s):  
Carlos Moreno-Castilla ◽  
José Rivera-Utrilla
Keyword(s):  
Water Treatment ◽  
Liquid Phase ◽  
Surface Chemistry ◽  
Surface Area ◽  
Carbon Materials ◽  
Activated Carbons ◽  
Raw Materials ◽  
World Production ◽  
Variable Surface ◽  
Materials Used

Activated carbons are the most important carbon materials used in water treatment. Their known world production is around 500,000 tons per year, of which about 80% is used for liquid-phase applications. These solids are manufactured in powder or granular form from a large variety of raw materials and are unique and versatile adsorbents due to their highly developed porosity, their large surface area (which in some cases can be up to 3000 m2/g), and their variable surface chemistry.

scholarly journals Adsorbents for Industrial Pollution Control

1997 ◽  
Vol 15 (10) ◽  
pp. 777-787 ◽  
Author(s):  
Mohammad S. El-Geundi
Keyword(s):  
Clay Minerals ◽  
Pollution Control ◽  
Industrial Pollution ◽  
Activated Carbons ◽  
Low Cost ◽  
Waste Materials ◽  
Adsorption Capacities ◽  
And Performance ◽  
Materials Used ◽  
By Products

Adsorbent materials used for treating industrial pollutants are reviewed. The article consists of two parts. The first part considers new trends in traditional adsorbents such as activated carbons and zeolites. New low-cost adsorbents such as waste materials and clay minerals are discussed in the second part. It has been reported that activated carbons can be obtained from agricultural by-products such as shells and stones of various fruit by a simple single-stage method. This method differs from the traditional processes for the production of activated carbons. On the other hand, natural zeolites have been used as low-cost adsorbents in industrial pollution control. The extent of their application is not only related to their low cost, but also to the improved properties and performance characteristics which they possess. Recently, a variety of agricultural and industrial waste materials and clay minerals have been evaluated as new adsorbents with an excellent potential for the removal of different pollutants from wastewater. The new low-cost adsorbents obtained were found to have large adsorption capacities and good mechanical properties.

scholarly journals Kinetic Modeling for the “One-Pot” Hydrogenolysis of Cellulose to Glycols over Ru@Fe3O4/Polymer Catalyst

Reactions ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 1-11
Author(s):  
Oleg Manaenkov ◽  
Yuriy Kosivtsov ◽  
Valentin Sapunov ◽  
Olga Kislitsa ◽  
Mikhail Sulman ◽  
...  
Keyword(s):  
Reaction Scheme ◽  
Hypercrosslinked Polystyrene ◽  
Formal Description ◽  
One Pot ◽  
Cellulose Conversion ◽  
Catalytic Systems ◽  
Polymer Catalyst ◽  
Magnetically Separable ◽  
The One ◽  
The Mathematical Model

Despite numerous works devoted to the cellulose hydrogenolysis process, only some of them describe reaction kinetics. This is explained by the complexity of the process and the simultaneous behavior of different reactions. In this work, we present the results of the kinetic study of glucose hydrogenolysis into ethylene- and propylene glycols in the presence of Ru@Fe3O4/HPS catalyst as a part of the process of catalytic conversion of cellulose into glycols. The structure of the Ru-containing magnetically separable Ru@Fe3O4/HPS catalysts supported on the polymeric matrix of hypercrosslinked polystyrene was studied to propose the reaction scheme. As a result of this study, a formal description of the glucose hydrogenolysis process into glycols was performed. Based on the data obtained, the mathematical model of the glucose hydrogenolysis kinetics in the presence of Ru@Fe3O4/HPS was developed and the parameter estimation was carried out. The synthesized catalyst was found to be characterized by the enhanced magnetic properties and higher catalytic activity in comparison with previously developed catalytic systems (i.e., on the base of SiO2). The summarized selectivity towards the glycols formation was found to be ca. 42% at 100% of the cellulose conversion in the presence of Ru@Fe3O4/HPS.

Comparative study of different catalysts for the direct conversion of cellulose to sorbitol

2015 ◽  
Vol 4 (2) ◽  
Author(s):  
Lucília S. Ribeiro ◽  
José J.M. Órfão ◽  
Manuel Fernando R. Pereira
Keyword(s):  
Direct Conversion ◽  
Single Step ◽  
Raw Material ◽  
Added Value ◽  
Supported Metal Catalysts ◽  
One Pot ◽  
Hydrolytic Hydrogenation ◽  
Renewable Raw Material ◽  
Pre Treatment ◽  
The One

AbstractThe catalytic conversion of lignocellulosic biomass to obtain high added value compounds and fuels is a rapidly developing field. Given the abundance of this renewable raw material and its reduced impact on the food chain, it is an attractive source for obtaining chemicals or fuels in the context of a sustainable economy. In this work, bi-functional catalysts were developed that were capable of performing in a single step the hydrolysis and hydrogenation of cellulose to produce compounds that may be used in the production of fine chemicals or easily converted into fuels (e.g., sorbitol). Different activated carbon (AC) supported metal catalysts were examined for the one-pot hydrolytic hydrogenation of cellulose. Among the prepared catalysts, 0.4% Ru/AC was shown to be the most active and selective for the conversion of cellulose into sorbitol. When microcrystalline cellulose was used, a conversion of 32% was reached after 5 h of reaction, with a selectivity to sorbitol of 30%. Moreover, ball-milled cellulose allowed attaining conversions over 50%, with selectivities to sorbitol of 45%. The results obtained showed that Ru/AC is effective for the hydrolytic hydrogenation of cellulose to sugar alcohols and that the conversion can be greatly improved by using the substrate after pre-treatment by ball-milling.

scholarly journals Impact of Design on the Activity of ZrO2 Catalysts in Cellulose Hydrolysis-Dehydration to Glucose and 5-Hydroxymethylfurfural

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1359
Author(s):  
Tatiana B. Medvedeva ◽  
Olga L. Ogorodnikova ◽  
Irina S. Yakovleva ◽  
Lyubov A. Isupova ◽  
Oxana P. Taran ◽  
...  
Keyword(s):  
Calcination Temperature ◽  
Sol Gel ◽  
Cellulose Hydrolysis ◽  
Microwave Treatment ◽  
Temperature Phase ◽  
One Pot ◽  
Cellulose Conversion ◽  
Co Catalyst ◽  
Pure Zro2 ◽  
The One

The one-pot hydrolysis-dehydration of activated microcrystalline cellulose was studied in pure hydrothermal water at 453 K over ZrO2 catalysts produced by thermodegradation, microwave treatment, mechanical activation, and sol–gel methods and spent without any co-catalyst. ZrO2 prepared by microwave treatment was more active compared to ones derived by other methods. The catalyst calcination temperature also impacted reactivity. The cellulose conversion increased simultaneously with acidity and SBET, which in turn were set by the preparation method and calcination temperature. Phase composition did not affect the activity. Yields of glucose and 5-HMF reaching 18 and 15%, respectively, were over the most promising ZrO2 prepared by microwave treatment at 593 K. To our knowledge, this ZrO2 sample provided the highest activity in terms of TOF values (15.1 mmol g−1 h−1) compared to the pure ZrO2 systems reported elsewhere. High stability of ZrO2 derived by microwave irradiation was shown in five reaction runs.

Spearman's Law of Diminishing Returns

2006 ◽  
Vol 27 (4) ◽  
pp. 199-207 ◽  
Author(s):  
Peter Hartmann
Keyword(s):  
Principal Axis ◽  
Age Groups ◽  
Principal Component ◽  
Longitudinal Survey ◽  
Male And Female ◽  
Two Samples ◽  
Diminishing Returns ◽  
The One ◽  
Armed Services ◽  
Principal Axis Factor

Spearman's Law of Diminishing Returns (SLODR) with regard to age was tested in two different databases from the National Longitudinal Survey of Youth. The first database consisted of 6,980 boys and girls aged 12–16 from the 1997 cohort ( NLSY 1997 ). The subjects were tested with a computer-administered adaptive format (CAT) of the Armed Services Vocational Aptitude Battery (ASVAB) consisting of 12 subtests. The second database consisted of 11,448 male and female subjects aged 15–24 from the 1979 cohort ( NLSY 1979 ). These subjects were tested with the older 10-subtest version of the ASVAB. The hypothesis was tested by dividing the sample into Young and Old age groups while keeping IQ fairly constant by a method similar to the one developed and employed by Deary et al. (1996) . The different age groups were subsequently factor-analyzed separately. The eigenvalue of the first principal component (PC1) and the first principal axis factor (PAF1), and the average intercorrelation of the subtests were used as estimates of the g saturation and compared across groups. There were no significant differences in the g saturation across age groups for any of the two samples, thereby pointing to no support for this aspect of Spearman's “Law of Diminishing Returns.”

A Series of Metal-Organic Frameworks for Selective CO2 Capture and Catalytic Oxidative Carboxylation of Olefins

2018 ◽  
Author(s):  
Huong T. D. Nguyen ◽  
Y B. N. Tran ◽  
Hung N. Nguyen ◽  
Tranh C. Nguyen ◽  
Felipe Gándara ◽  
...  
Keyword(s):  
Room Temperature ◽  
Gas Adsorption ◽  
New Materials ◽  
One Pot ◽  
Acid Gas ◽  
Naphthalene Diimide ◽  
Styrene Carbonate ◽  
Metal Organic ◽  
Adsorption Of Co ◽  
The One

<p>Three novel lanthanide metal˗organic frameworks (Ln-MOFs), namely MOF-590, -591, and -592 were constructed from a naphthalene diimide tetracarboxylic acid. Gas adsorption measurements of MOF-591 and -592 revealed good adsorption of CO<sub>2</sub> (low pressure, at room temperature) and moderate CO<sub>2</sub> selectivity over N<sub>2</sub> and CH<sub>4</sub>. Accordingly, breakthrough measurements were performed on a representative MOF-592, in which the separation of CO<sub>2</sub> from binary mixture containing N<sub>2</sub> and CO<sub>2</sub> was demonstrated without any loss in performance over three consecutive cycles. Moreover, MOF-590, MOF-591, and MOF-592 exhibited catalytic activity in the one-pot synthesis of styrene carbonate from styrene and CO<sub>2</sub> under mild conditions (1 atm CO<sub>2</sub>, 80 °C, and solvent-free). Among the new materials, MOF-590 revealed a remarkable efficiency with exceptional conversion (96%), selectivity (95%), and yield (91%). </p><br>

A Study on the Rearrangement of Dialkyl 1-Aryl-1-hydroxymethylphosphonates to Benzyl Phosphates

2020 ◽  
Vol 24 (4) ◽  
pp. 465-471 ◽  
Author(s):  
Zita Rádai ◽  
Réka Szabó ◽  
Áron Szigetvári ◽  
Nóra Zsuzsa Kiss ◽  
Zoltán Mucsi ◽  
...  
Keyword(s):  
Quantum Chemical ◽  
Room Temperature ◽  
Phase Transfer ◽  
One Pot ◽  
Substrate Dependence ◽  
Triethylbenzylammonium Chloride ◽  
One Step ◽  
The Pudovik Reaction ◽  
The One ◽  
Solid Liquid

The phospha-Brook rearrangement of dialkyl 1-aryl-1-hydroxymethylphosphonates (HPs) to the corresponding benzyl phosphates (BPs) has been elaborated under solid-liquid phase transfer catalytic conditions. The best procedure involved the use of triethylbenzylammonium chloride as the catalyst and Cs2CO3 as the base in acetonitrile as the solvent at room temperature. The substrate dependence of the rearrangement has been studied, and the mechanism of the transformation under discussion was explored by quantum chemical calculations. The key intermediate is an oxaphosphirane. The one-pot version starting with the Pudovik reaction has also been developed. The conditions of this tandem transformation were the same, as those for the one-step HP→BP conversion.

An Overview of the One-pot Synthesis of Imidazolines

2020 ◽  
Vol 24 (20) ◽  
pp. 2341-2355
Author(s):  
Thaipparambil Aneeja ◽  
Sankaran Radhika ◽  
Mohan Neetha ◽  
Gopinathan Anilkumar
Keyword(s):  
Asymmetric Catalysis ◽  
Organic Compounds ◽  
Ring Opening ◽  
Ecological Impact ◽  
Chiral Auxiliary ◽  
One Pot ◽  
One Pot Synthesis ◽  
The One ◽  
Synthetic Intermediate ◽  
Heterocyclic Moiety

One-pot syntheses are a simple, efficient and easy methodology, which are widely used for the synthesis of organic compounds. Imidazoline is a valuable heterocyclic moiety used as a synthetic intermediate, chiral auxiliary, chiral catalyst and a ligand for asymmetric catalysis. Imidazole is a fundamental unit of biomolecules that can be easily prepared from imidazolines. The one-pot method is an impressive approach to synthesize organic compounds as it minimizes the reaction time, separation procedures, and ecological impact. Many significant one-pot methods such as N-bromosuccinimide mediated reaction, ring-opening of tetrahydrofuran, triflic anhydrate mediated reaction, etc. were reported for imidazoline synthesis. This review describes an overview of the one-pot synthesis of imidazolines and covers literature up to 2020.

Synthesis and Kinetics of Highly Substituted Piperidines in the Presence of Tartaric Acid as a Catalyst

2018 ◽  
Vol 21 (4) ◽  
pp. 302-311
Author(s):  
Younes Ghalandarzehi ◽  
Mehdi Shahraki ◽  
Sayyed M. Habibi-Khorassani
Keyword(s):  
Ambient Temperature ◽  
Tartaric Acid ◽  
Aromatic Aldehydes ◽  
One Pot ◽  
Rate Determining Step ◽  
State Approximation ◽  
Solvent Free Conditions ◽  
Steady State Approximation ◽  
Absorbance Changes ◽  
The One

Aim & Scope: The synthesis of highly substituted piperidine from the one-pot reaction between aromatic aldehydes, anilines and β-ketoesters in the presence of tartaric acid as a catalyst has been investigated in both methanol and ethanol media at ambient temperature. Different conditions of temperature and solvent were employed for calculating the thermodynamic parameters and obtaining an experimental approach to the kinetics and mechanism. Experiments were carried out under different temperature and solvent conditions. Material and Methods: Products were characterized by comparison of physical data with authentic samples and spectroscopic data (IR and NMR). Rate constants are presented as an average of several kinetic runs (at least 6-10) and are reproducible within ± 3%. The overall rate of reaction is followed by monitoring the absorbance changes of the products versus time on a Varian (Model Cary Bio- 300) UV-vis spectrophotometer with a 10 mm light-path cell. Results: The best result was achieved in the presence of 0.075 g (0.1 M) of catalyst and 5 mL methanol at ambient temperature. When the reaction was carried out under solvent-free conditions, the product was obtained in a moderate yield (25%). Methanol was optimized as a desirable solvent in the synthesis of piperidine, nevertheless, ethanol in a kinetic investigation had none effect on the enhancement of the reaction rate than methanol. Based on the spectral data, the overall order of the reaction followed the second order kinetics. The results showed that the first step of the reaction mechanism is a rate determining step. Conclusion: The use of tartaric acid has many advantages such as mild reaction conditions, simple and readily available precursors and inexpensive catalyst. The proposed mechanism was confirmed by experimental results and a steady state approximation.

Sign in / Sign up

Export Citation Format

Share Document