scholarly journals Solid Acid Catalysts Based on Niobium and Zirconium Oxides for Hydrolysis-Dehydration of Cellulose Into Glucose and 5-Hydroxymethylfurfural. Impact of Preparation Technique on Catalytic Properties

2020 ◽  
pp. 283-296
Author(s):  
Nikolay V. Gromov ◽  
Irina S. Yakovleva ◽  
Lubov A. Isupova ◽  
Valentin N. Parmon ◽  
Oxana P. Taran
Keyword(s):  
Catalytic Properties ◽  
Total Yield ◽  
Preparation Technique ◽  
One Pot ◽  
Solid Catalysts ◽  
Zirconium Oxides ◽  
Component Systems ◽  
Two Component Systems ◽  
The One ◽  
The Impact

The impact of the preparation techniques of niobium oxide and two-component systems based on niobium and zirconium oxides on the catalytic properties was studied in the one-pot hydrolysisdehydration of cellulose into glucose and 5-hydroxymethylfurfural. Cellulose transformation was performed in an autoclave at 180 °С under argon atmosphere. The most promising methods for the preparation of solid catalysts were found to be microwave heating and mechanical activation. Glucose and 5-hydroxymethylfurfural can be produced with total yield equal to 20-21 % in the presence of catalysts prepared using these techniques

scholarly journals Production of lactic acid from cellulose using solid catalyst

2019 ◽  
Vol 268 ◽  
pp. 07006 ◽  
Author(s):  
Sujitra Doungsri ◽  
P. Rattanaphanee ◽  
Aatichat Wongkoblap
Keyword(s):  
Lactic Acid ◽  
Batch Reactor ◽  
Nitrogen Pressure ◽  
Reaction Pathways ◽  
Solid Catalyst ◽  
One Pot ◽  
Solid Catalysts ◽  
Platform Chemicals ◽  
Acid And Base ◽  
The One

Lactic acid (LA), one of the important biomass derived platform chemicals, has been used in food and chemical industries, especially in biodegradable polymer as polylactic acid (PLA). The aim of this work is to study the one-pot production of LA from cellulose by using different solid catalysts. The reaction was conducted in a high pressure batch reactor and the catalyst used in this study were ZrO2 and Al2O3. The reaction was carried out at temperature of 200oC for 6 hr. and under nitrogen pressure of 1 MP. It was found that the production yield of LA were 8.02% and 6.63%, when the ZrO2 and Al2O3 catalysts were used respectively. The result indicated that the ZrO2 may effect on the LA production because of the acid and base sites of the ZrO2. Therefore, the reaction pathways for conversion of cellulose into lactic acid have been investigated, and developed the new conditions to achieve the higher yield.

Fabrication of conducting polymer/noble metal composite nanorings and their enhanced catalytic properties

2015 ◽  
Vol 3 (1) ◽  
pp. 83-86 ◽  
Author(s):  
Liu Yang ◽  
Zhen Zhang ◽  
Guangdi Nie ◽  
Ce Wang ◽  
Xiaofeng Lu
Keyword(s):  
Conducting Polymer ◽  
Noble Metal ◽  
Catalytic Properties ◽  
Soft Template ◽  
Template Method ◽  
Metal Composite ◽  
One Pot ◽  
The One ◽  
Metal Nanocomposites

We have described a soft-template method that allows the one-pot fabrication of ring-like conducting polymer/noble metal nanocomposites.

A modified repair strategy for two-component systems with revealed and unrevealed faults

1987 ◽  
Vol 24 (01) ◽  
pp. 178-185
Author(s):  
Norman L. Johnson ◽  
Samuel Kotz
Keyword(s):  
Repair System ◽  
Two Component System ◽  
Initial State ◽  
Repair Strategy ◽  
Component Systems ◽  
Two Component ◽  
Two Component Systems ◽  
The Times ◽  
The One

Some consequences of a modified repair system for Phillips' (1981a, b) model for a two-component system are discussed. In the original model, both components are repaired whenever a revealed fault occurs; in the modified model only faulty components are repaired. Specifically (i) the distribution of time from the initial state up to discovery of an unrevealed fault, (ii) the expected proportion of time during which there exists an unrepaired fault, and (iii) the distribution of number of revealed faults up to and including the one which leads to a discovery of an unrevealed fault, are obtained. The theory is illustrated by examples, based on specific distributions for the times between repairs and occurrences of the two types of faults. A characterization of the exponential distribution is indicated.

scholarly journals Structural, Textural, and Catalytic Properties of Ni-CexZr1−xO2 Catalysts for Methane Dry Reforming Prepared by Continuous Synthesis in Supercritical Isopropanol

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3728
Author(s):  
Svetlana Pavlova ◽  
Marina Smirnova ◽  
Aleksei Bobin ◽  
Svetlana Cherepanova ◽  
Vasily Kaichev ◽  
...  
Keyword(s):  
Nickel Nanoparticles ◽  
Catalytic Properties ◽  
Dry Reforming ◽  
High Dispersion ◽  
Incipient Wetness Impregnation ◽  
One Pot ◽  
Methane Dry Reforming ◽  
Continuous Synthesis ◽  
The One ◽  
Supercritical Isopropanol

A series of 5%Ni-CexZr1−xO2 (x = 0.3, 0.5, 0.7) catalysts has been prepared via one-pot solvothermal continuous synthesis in supercritical isopropanol and incipient wetness impregnation of CexZr1−xO2 obtained by the same route. The textural, structural, red-ox, and catalytic properties in methane dry reforming (MDR) of Ni-modified Ce-Zr oxides synthesized by two routes have been compared. It was shown by XRD, TEM, and Raman spectroscopy that the method of Ni introduction does not affect the phase composition of the catalysts, but determines the dispersion of NiO. Despite a high dispersion of NiO and near-uniform distribution of Ni within Ce-Zr particles observed for the one-pot catalysts, they have shown a lower activity and stability in MDR as compared with impregnated ones. This is a result of a low Ni concentration in the surface layer due to segregation of Ce and decoration of nickel nanoparticles with support species.

A modified repair strategy for two-component systems with revealed and unrevealed faults

1987 ◽  
Vol 24 (1) ◽  
pp. 178-185 ◽  
Author(s):  
Norman L. Johnson ◽  
Samuel Kotz
Keyword(s):  
Repair System ◽  
Two Component System ◽  
Initial State ◽  
Repair Strategy ◽  
Component Systems ◽  
Two Component ◽  
Two Component Systems ◽  
The Times ◽  
The One

Some consequences of a modified repair system for Phillips' (1981a, b) model for a two-component system are discussed. In the original model, both components are repaired whenever a revealed fault occurs; in the modified model only faulty components are repaired. Specifically (i) the distribution of time from the initial state up to discovery of an unrevealed fault, (ii) the expected proportion of time during which there exists an unrepaired fault, and (iii) the distribution of number of revealed faults up to and including the one which leads to a discovery of an unrevealed fault, are obtained. The theory is illustrated by examples, based on specific distributions for the times between repairs and occurrences of the two types of faults. A characterization of the exponential distribution is indicated.

scholarly journals Synthesis of Poly(Trimethylene Carbonate) from Amine Group Initiation: Role of Urethane Bonds in the Crystallinity

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 280
Author(s):  
Thomas Brossier ◽  
Gael Volpi ◽  
Vincent Lapinte ◽  
Sebastien Blanquer
Keyword(s):  
Thermal Studies ◽  
Trimethylene Carbonate ◽  
X Ray Diffraction ◽  
One Pot ◽  
Free Process ◽  
One Step ◽  
The One ◽  
Natural Amino Acids ◽  
The Impact

Semi-crystalline poly(trimethylene carbonate) (PTMC) can be efficiently prepared by ring-opening polymerization (ROP) initiated by amine using various catalysts. More promising results were reached with the one-step process of stannous octanoate unlike the two-step one-pot reaction using TBD and MSA catalysts. The ROP-amine of TMC consists in a simple isocyanate free process to produce polycarbonate-urethanes, compatible with the large availability of amines ranging from mono- to multifunctional until natural amino acids. ROP-amine of TMC leads to urethane bonds monitored by FTIR spectroscopy. The relationship between the nature of amines and the crystallinity of PTMC was discussed through X-ray diffraction and thermal studies by DSC and TGA. The impact of the crystallinity was also demonstrated on the mechanical properties of semi-crystalline PTMC in comparison to amorphous PTMC, synthesized by ROP initiated by alcohol. The semi-crystalline PTMC synthesized by ROP-amine opens many perspectives.

Self-assembly directed synthesis of Au nanorices induced by polyaniline and their enhanced peroxidase-like catalytic properties

2017 ◽  
Vol 5 (30) ◽  
pp. 7465-7471 ◽  
Author(s):  
Wei Song ◽  
Maoqiang Chi ◽  
Mu Gao ◽  
Bing Zhao ◽  
Ce Wang ◽  
...  
Keyword(s):  
Self Assembly ◽  
Catalytic Properties ◽  
One Pot ◽  
One Pot Synthesis ◽  
Directed Synthesis ◽  
The One

We describe a self-assembly directed method that allows the one-pot synthesis of Au/polyaniline nanorices with enhanced peroxidase-like activity.

scholarly journals The Impact of 3-(trihydroxysilyl)-1-propanesulfonic Acid Treatment on the State of Vanadium Incorporated on SBA-15 Matrix

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 397
Author(s):  
Ardian Nurwita ◽  
Piotr Decyk ◽  
Maria Ziolek ◽  
Maciej Trejda
Keyword(s):  
The State ◽  
Bifunctional Catalysts ◽  
Active Centers ◽  
One Pot ◽  
Redox Sites ◽  
Before And After ◽  
Acidic Sites ◽  
The One ◽  
The Impact ◽  
Vanadium Species

Bifunctional catalysts—e.g., those with acidic and redox sites—are of particular importance, especially in the cascade processes, including the one-pot transformation of glycerol to acrylic acid. In this study, we explore one aspect of the preparation of a vanadium-containing catalyst, which can be further modified with 3-(trihydroxysilyl)-1-propanesulfonic acid (TPS). The state of vanadium species loaded on mesoporous ordered silica of SBA-15 type was investigated before and after treatment with TPS, which can also be applied for the generation of acidic centers. Two vanadium sources, i.e., ammonium metavanadate and vanadium(IV) oxide sulfate, were applied to generate redox sites on SBA-15. The structure of materials obtained was analyzed using N2 adsorption/desorption and XRD measurements. For the estimation of the amount of vanadium and characterization of its state, the following techniques were applied: ICP, UV-Vis, XPS, ESR and FTIR combined with pyridine adsorption. The treatment of vanadium containing SBA-15 with TPS was found to lead to the oxidation of V4+ to V5+ and the partial removal of vanadium species, leading to a decrease in the number of penta-coordinated vanadium species. These features should be taken into account in the design of bifunctional catalysts with vanadium-active centers and SO3H acidic sites coming from TPS.

Static and Dynamic Studies of Gasoline in View of its Octane Number and its Toxic Effect

2013 ◽  
Vol 12 (7) ◽  
pp. 451-459
Author(s):  
Ashraf Yehia El-Naggar ◽  
Mohamed A. Ebiad
Keyword(s):  
Toxic Effect ◽  
Aromatic Hydrocarbons ◽  
Octane Number ◽  
Liquid Fuel ◽  
Positive Impact ◽  
Hydrocarbon Composition ◽  
Different Temperatures ◽  
Different Seasons ◽  
The One ◽  
The Impact

Gasoline come primarily from petroleum cuts, it is the preferred liquid fuel in our lives. Two gasoline samples of octane numbers 91 and 95 from Saudi Arabia petrol stations were studied. This study was achieved at three different temperatures 20oC, 30oC and 50oC representing the change in temperatures of the different seasons of the year. Both the evaporated gases of light aromatic hydrocarbons (BTEX) of gasoline samples inside the tank were subjected to analyze qualitatively and quantitatively via capillary gas chromatography. The detailed hydrocarbon composition and the octane number of the studied gasoline samples were determined using detailed hydrocarbon analyzer. The idea of research is indicating the impact of light aromatic compounds in gasoline on the toxic effect of human and environment on the one hand, and on octane number of gasoline on the other hand. Although the value of octane number will be reduced but this will have a positive impact on the environment as a way to produce clean fuel.

The Development of Agritourism in the Podkarpackie Voivodeship in the Light of International and National Conditions

2017 ◽  
Vol 13 ◽  
pp. 244-261
Author(s):  
Mariola Tracz ◽  
Małgorzata Bajgier-Kowalska ◽  
Radosław Uliszak
Keyword(s):  
Development Strategy ◽  
Current State ◽  
Central Statistical ◽  
Central Statistical Office ◽  
Tourism Resources ◽  
The One ◽  
The Impact ◽  
District Offices ◽  
Socio Economic Factors

Podkarpackie Voivodeship is one of the regions of Poland in which the number of agritourism entities is very high. Therefore tourism plays a significant role in its development strategy. The aim of the paper is to identify the current state of agritourism and the changes that have occurred in the region in the years 2000–2016. Specific objectives are to determine the distribution of agritourism farms and their offer, together with a comprehensive analysis of the environmental and socio-economic factors, as well as the impact of the Slovak-Ukrainian border. The report was developed on the statistical materials from the Polish Central Statistical Office, Podkarpackie Agricultural Advisory Centre in Boguchwała and data collected from municipalities and district offices that is published on their websites, as well as through interviews with 100 owners of agritourism farms in the Podkarpackie Voivodeship. The research has shown, on the one hand, the decline in the number of farms in the region and, on the other hand, the increase in the diversity of the tourist offer of these entities. Distribution of agritourism farms is closely linked to the attractiveness of natural environment and quality of secondary tourism resources. Traditional agritourism has not yet fully used its countryside, as well as cross-border advantages of its location.

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