scholarly journals Alkaline-Based Catalysts for Glycerol Polymerization Reaction: A Review

2020 ◽  
Author(s):  
Negisa Ebadipour ◽  
Sébastien Paul ◽  
Benjamin Katryniok ◽  
Franck Dumeignil
Keyword(s):  
Heterogeneous Catalysts ◽  
Antimicrobial Agents ◽  
Reaction Medium ◽  
Operating Conditions ◽  
Polymerization Reaction ◽  
High Catalytic Activity ◽  
Catalytic Systems ◽  
Glycerol Conversion ◽  
Advantages And Disadvantages ◽  
Wide Range

Polyglycerols (PGs) are biocompatible and highly functional polyols with a wide range of applications, such as emulsifiers, stabilizers, antimicrobial agents, in many industries including cosmetics, food, plastic and biomedical. The demand increase for biobased PGs encourages researchers to develop new catalytic systems for glycerol polymerization. This review focuses on alkaline homogeneous and heterogeneous catalysts. The performances of the alkaline catalysts are compared in terms of conversion and selectivity, and their respective advantages and disadvantages are commented. While homogeneous catalysts exhibit a high catalytic activity, they cannot be recycled and reused, whereas solid catalysts can be partially recycled. The key issue for heterogenous catalytic systems, which is unsolved so far, is linked to their instability due to partial dissolution in the reaction medium. Further, this paper also reviews the proposed mechanisms of glycerol polymerization over alkaline-based catalysts and discuss the various operating conditions with an impact on the performances. More particularly, temperature and amount of catalyst proved to have a significant influence on glycerol conversion and on its polymerization extent.

scholarly journals Alkaline-Based Catalysts for Glycerol Polymerization Reaction: A Review

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1021
Author(s):  
Negisa Ebadipour ◽  
Sébastien Paul ◽  
Benjamin Katryniok ◽  
Franck Dumeignil
Keyword(s):  
Heterogeneous Catalysts ◽  
Antimicrobial Agents ◽  
Reaction Medium ◽  
Operating Conditions ◽  
Polymerization Reaction ◽  
High Catalytic Activity ◽  
Catalytic Systems ◽  
Glycerol Conversion ◽  
Advantages And Disadvantages ◽  
Wide Range

Polyglycerols (PGs) are biocompatible and highly functional polyols with a wide range of applications, such as emulsifiers, stabilizers and antimicrobial agents, in many industries including cosmetics, food, plastic and biomedical. The demand increase for biobased PGs encourages researchers to develop new catalytic systems for glycerol polymerization. This review focuses on alkaline homogeneous and heterogeneous catalysts. The performances of the alkaline catalysts are compared in terms of conversion and selectivity, and their respective advantages and disadvantages are commented. While homogeneous catalysts exhibit a high catalytic activity, they cannot be recycled and reused, whereas solid catalysts can be partially recycled. The key issue for heterogenous catalytic systems, which is unsolved thus far, is linked to their instability due to partial dissolution in the reaction medium. Further, this paper also reviews the proposed mechanisms of glycerol polymerization over alkaline-based catalysts and discusses the various operating conditions with an impact on performance. More particularly, temperature and amount of catalyst are proven to have a significant influence on glycerol conversion and on its polymerization extent.

scholarly journals Ni@C Catalyzed Hydrogenation of Acetophenone to Phenylethanol under Industrial Mild Conditions in Flow Reactor

2021 ◽  
Author(s):  
Shanshan Lin ◽  
Jianguo liu ◽  
Longlong Ma
Keyword(s):  
Catalytic Hydrogenation ◽  
Conversion Rate ◽  
Heterogeneous Catalysts ◽  
High Efficiency ◽  
Flow Reactor ◽  
Hot Spot ◽  
Industrial Applications ◽  
High Catalytic Activity ◽  
Organic Substrates ◽  
Catalytic Systems

The catalytic hydrogenation of organic substrates containing many unsaturated functional groups is an important step in the industrial preparation of fine chemicals and has always been a hot spot in basic catalysis research. For example, the phenethyl alcohol obtained by the preferential hydrogenation of the C=O group of acetophenone is a valuable intermediate for the production of spices, flavors, and medicines. Furthermore, as the demand for 1-phenylethanol (PhE) continues to increase, the catalytic hydrogenation of acetophenone (AP) is becoming more and more important. The hydrogenation of acetophenone is a complex multi-step reaction. At present, relatively few catalytic systems are used in this reaction. The enantioselective hydrogenation on heterogeneous catalysts is due to its inherent operational and economic advantages, such as the atomic economy. It is one of the most ideal methods as it is easy to separate and recycle the catalyst. However, the traditional synthesis way in batch reactors usually takes a long time with an unsatisfying conversion which is not conducive to industrialization. Heterogeneous non-precious metal catalysts are advantageous for their implementation in flow reactor systems for industrial applications due to their ease of separation, low cost, and environmental protection. Herein, we report the first use of non-noble metal Ni-supported graphene-based catalysts for hydrogenation of acetophenone to phenylethanol with high efficiency in the flow reactor which can significantly improve mass and heat transfer. The conversion rate after optimizing the reaction conditions can be as high as 99.14% with a satisfactory conversion rate of 97.77%. This catalyst is magnetic and has good cyclability. After 48 hours of uninterrupted continuous experiments, the Ni-based catalyst still maintains high catalytic activity, the conversion rate still reaches 88.44%, and the catalyst structure remains intact and stable.

scholarly journals A Review on the Efficient Catalysts for Algae Transesterification to Biodiesel

2021 ◽  
Vol 13 (18) ◽  
pp. 10479
Author(s):  
Elena Ghedini ◽  
Somayeh Taghavi ◽  
Federica Menegazzo ◽  
Michela Signoretto
Keyword(s):  
Mass Transfer ◽  
Heterogeneous Catalysts ◽  
Fossil Fuel ◽  
Reaction System ◽  
Side Reaction ◽  
Biodiesel Production ◽  
Efficient Catalyst ◽  
Catalytic Systems ◽  
Mass Transfer Limitation ◽  
Advantages And Disadvantages

The depletion of fossil fuel resources and increasing environmental pollution led to a trend for using alternative, clean, green, and sustainable fuel and energy resources. To attain this aim, using biomass as an alternative resource for diesel production has been a hotspot among researchers. Biodiesel has several advantages, such as being lower toxic and more renewable, and eco-friendlier than diesel from fossil fuel resources. Several edible and non-edible bio-sources were used for the production of biodiesel from the transesterification process. Algal oil as a non-edible source is considered an abundant, low cost and green substrate for biodiesel production. Various factors such as reaction conditions and the type of catalyst affect the biodiesel production process. Different catalytic systems such as basic and acidic homogeneous and heterogeneous catalysts and biocatalysts were introduced for the process in the literature, and each proposed catalyst has its own advantages and disadvantages. For instance, in spite of the lower cost and better mass transfer of base and acid homogeneous catalysts, reaction system corrosion, non-reusability, and soap formation are serious challenges of these catalysts at an industrial scale. On the other hand, acid and base heterogenous catalysts overcame the issues of corrosion and recovery, but some matters such as mass transfer limitation, high cost, and weak performance in catalyzing both esterification of FFAs and transesterification of lipids must be taken into account. In addition, bio-catalysis as a high-cost process led to a purer product formation with less side reaction. Therefore, several significant factors should be considered for transesterification catalysts such as availability, cost, reusability, stability, mass transfer, and the possibility to manage both the transesterification of triglycerides and the esterification of FFAs, selecting a catalyst with predominant pros is viable. Here, a review of the biodiesel production from algal biomass focusing on the efficient catalyst of the process is presented.

Application of Heteropolyacid-Based Heterogeneous Catalysts for Conversion of Oleochemicals into Renewable Fuels and other Value-Added Products

2013 ◽  
Vol 757 ◽  
pp. 1-24 ◽  
Author(s):  
Ali Sabri Badday ◽  
Ahmad Zuhairi Abdullah ◽  
Keat Teong Lee
Keyword(s):  
Fatty Acids ◽  
Heterogeneous Catalysts ◽  
New Technologies ◽  
Reaction Medium ◽  
Value Added ◽  
Acid Sites ◽  
Esterification Reaction ◽  
High Water Content ◽  
Active Components ◽  
Wide Range

Oleochemicals offer viable choices to replace petrochemicals in a wide range of applications such as fuels, lubricants and surfactants. Many of the conversions require the use of suitable solid acids as the catalysts. The chemical and physical properties of the feedstock in oleochemical processes often result in difficulties and challenges that limit the success. Large amount of free fatty acids and high water content create barriers towards the successful use of broad range of oleochemicals as raw materials. To overcome this problem, efforts have been dedicated to the development of new technologies involving new types of catalyst. Solid acid catalysts based on heteropolyacids (HPAs) for various oleochemical conversions especially esterification reaction of fatty acids and transesterification of vegetable oils have been successfully developed. This type of catalyst already secured a tangible success in solving some problems associated with the earlier types of catalyst leading to higher productivity in the process while satisfying the needs of sustainable and environmental friendly industrial processes. Incorporation of HPAs active component into mesoporous supports can produce heterogeneous catalysts with high acid sites dispersion, stability to high temperature, recyclable and they usually demonstrate low leaching of active components in the reaction medium. This article reviews common oleochemical processes where various HPA catalysts already found successful application with some insight into the specific characteristics of the catalysts. Their advantages and drawbacks as well as specific process behaviors in few important oleochemical conversions of industrial importance will be discussed.

scholarly journals Recent Advances in Synthesis and Applications of MFe2O4 (M = Co, Cu, Mn, Ni, Zn) Nanoparticles

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1560
Author(s):  
Thomas Dippong ◽  
Erika Andrea Levei ◽  
Oana Cadar
Keyword(s):  
Antimicrobial Agents ◽  
Sol Gel ◽  
Dielectric Materials ◽  
High Coercivity ◽  
Synthesis Methods ◽  
Advantages And Disadvantages ◽  
Wide Range ◽  
Potential Applications ◽  
Co Precipitation ◽  
Zn Nanoparticles

In the last decade, research on the synthesis and characterization of nanosized ferrites has highly increased and a wide range of new applications for these materials have been identified. The ability to tailor the structure, chemical, optical, magnetic, and electrical properties of ferrites by selecting the synthesis parameters further enhanced their widespread use. The paper reviews the synthesis methods and applications of MFe2O4 (M = Co, Cu, Mn, Ni, Zn) nanoparticles, with emphasis on the advantages and disadvantages of each synthesis route and main applications. Along with the conventional methods like sol-gel, thermal decomposition, combustion, co-precipitation, hydrothermal, and solid-state synthesis, several unconventional methods, like sonochemical, microwave assisted combustion, spray pyrolysis, spray drying, laser pyrolysis, microemulsion, reverse micelle, and biosynthesis, are also presented. MFe2O4 (M = Co, Cu, Mn, Ni, Zn) nanosized ferrites present good magnetic (high coercivity, high anisotropy, high Curie temperature, moderate saturation magnetization), electrical (high electrical resistance, low eddy current losses), mechanical (significant mechanical hardness), and chemical (chemical stability, rich redox chemistry) properties that make them suitable for potential applications in the field of magnetic and dielectric materials, photoluminescence, catalysis, photocatalysis, water decontamination, pigments, corrosion protection, sensors, antimicrobial agents, and biomedicine.

scholarly journals Calcium Hydroxyapatite: A Highly Stable and Selective Solid Catalyst for Glycerol Polymerization

Catalysts ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1247
Author(s):  
Negisa Ebadipour ◽  
Sébastien Paul ◽  
Benjamin Katryniok ◽  
Franck Dumeignil
Keyword(s):  
Catalytic Activity ◽  
Calcium Hydroxyapatite ◽  
Polymerization Reaction ◽  
Solid Catalyst ◽  
High Catalytic Activity ◽  
Reaction Products ◽  
Icp Oes ◽  
Reaction Conditions ◽  
Glycerol Conversion ◽  
The Stability

Calcium-based catalysts are of high interest for glycerol polymerization due to their high catalytic activity and large availability. However, their poor stability under reaction conditions is an issue. In the present study, we investigated the stability and catalytic activity of Ca-hydroxyapatites (HAps) as one of the most abundant Ca-source in nature. A stochiometric, Ca-deficient and Ca-rich HAps were synthesized and tested as catalysts in the glycerol polymerization reaction. Deficient and stochiometric HAps exhibited a remarkable 100% selectivity to triglycerol at 15% of glycerol conversion at 245 °C after 8 h of reaction in the presence of 0.5 mol.% of catalyst. Moreover, under the same reaction conditions, Ca-rich HAp showed a high selectivity (88%) to di- and triglycerol at a glycerol conversion of 27%. Most importantly, these catalysts were unexpectedly stable towards leaching under the reaction conditions based on the ICP-OES results. However, based on the catalytic tests and characterization analysis performed by XRD, XPS, IR, TGA-DSC and ICP-OES, we found that HAps can be deactivated by the presence of the reaction products themselves, i.e., water and polymers.

scholarly journals Piperidinium and Pyrrolidinium Ionic Liquids as Precursors in the Synthesis of New Platinum Catalysts for Hydrosilylation

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 919 ◽  
Author(s):  
Magdalena Jankowska-Wajda ◽  
Olga Bartlewicz ◽  
Przemysław Pietras ◽  
Hieronim Maciejewski
Keyword(s):  
Ionic Liquids ◽  
Heterogeneous Catalysts ◽  
Glycidyl Ether ◽  
Reaction Medium ◽  
Platinum Complexes ◽  
Catalytic Performance ◽  
Attractive Alternative ◽  
High Catalytic Activity ◽  
Allyl Glycidyl Ether ◽  
Catalytic Cycles

Six new air-stable anionic platinum complexes were synthesized in simple reactions of piperidinium [BMPip]Cl or pyrrolidinium [BMPyrr]Cl ionic liquids with platinum compounds ([Pt(cod)Cl2] or K2[PtCl6]). All these compounds were subjected to isolation and spectrometric characterization using NMR and ESI-MS techniques. Furthermore, the determination of melting points and thermal stability of the above derivatives was performed with the use of thermogravimetric analysis. The catalytic performance of the synthesized complexes was tested in hydrosilylation of 1-octene and allyl glycidyl ether with 1,1,1,3,5,5,5-heptamethyltrisiloxane. The study has shown that they have high catalytic activity and are insoluble in the reaction medium which enabled them to isolate and reuse them in consecutive catalytic cycles. The most active complex [BMPip]2[PtCl6] makes it possible to conduct at least 10 catalytic runs without losing activity which makes it an attractive alternative not only to commonly used homogeneous catalysts, but also to heterogeneous catalysts for hydrosilylation processes. The activity of the studied catalysts is also affected by the kind of anion and, to some extent, the kind of cation.

On the Application of Roller Rigs for Studying Rail Vehicle Systems

2013 ◽  
Author(s):  
Sajjad Z. Meymand ◽  
Michael J. Craft ◽  
Mehdi Ahmadian
Keyword(s):  
Field Testing ◽  
Operating Conditions ◽  
Railway Vehicle ◽  
Railroad Industry ◽  
Railway Systems ◽  
Advantages And Disadvantages ◽  
Field Environment ◽  
Adhesion Wear ◽  
Wide Range ◽  
Vehicle Systems

The primary intent of this study is to highlight the advantages and disadvantages of using roller rigs for engineering issues of importance to the railroad industry. Roller rigs have been in existence for more than a century for studying railway vehicle behavior. In contrast to field testing, roller rigs offer a controlled laboratory environment that can provide a successful path for obtaining data on the mechanics and dynamics of railway systems for a variety of operating conditions. Their use, however, imposes discrepancies from the field environment due to the nature of the commonly-used roller design. This study describes different rig configurations, including scaled and full-scale rigs. It includes the potential advantages and limitations of various rigs for conducting a wide range of studies concerning the dynamic stability of railcars, wheel–rail adhesion, wear and fatigue mechanisms, braking systems, and locomotive power.

scholarly journals Multi-Dimensional Modeling of the CFR Engine for the Investigation of SI Natural Gas Combustion and Controlled End-Gas Autoignition

2020 ◽  
Author(s):  
Diego Bestel ◽  
Scott Bayliff ◽  
Anthony Marchese ◽  
Daniel Olsen ◽  
Bret Windom ◽  
...  
Keyword(s):  
Natural Gas ◽  
Chemical Reactivity ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Cfd Modeling ◽  
General Tendency ◽  
Natural Gas Engines ◽  
Advantages And Disadvantages ◽  
Crank Angle ◽  
Wide Range

Abstract Engine knock and misfire are barriers to pathways leading to high-efficiency Spark-Ignited (SI) Natural Gas engines. The general tendency to knock is highly dependent on engine operating conditions and the fuel reactivity. The problem is further complicated by low emission limits and the wide range of chemical reactivity in pipeline quality natural gas. Depending on the region and the source of the natural gas, its reactivity, described by its methane number (analogous to the octane number for liquid SI fuels) can span from 65–95. In order to realize diesel-like efficiencies, SI natural gas engines must be designed to operate at high BMEP near knock limits over a wide range of fuel reactivity. This requires a deep understanding regarding the combustion-engine interactions pertaining to flame propagation and end-gas autoignition (EGAI). However, EGAI, if controlled, provides an opportunity to increase SI natural gas engine efficiency by increasing combustion rate and the total burned fuel, mitigating the effects of the slow flame speeds of natural gas fuels which generally reduce BMEP and increase unburned hydrocarbon emissions. For this reason, in order to study EGAI phenomenon, the present work highlights multi-dimensional computational fluid dynamics (CFD) models of the Cooperative Fuel Research (CFR) engine. The CFR engine models are used to investigate fuel-engine interactions that lead to EGAI with natural gas, including effects of fuel reactivity, engine operating parameters, and exhaust gas recirculation (EGR). A Three-Pressure Analysis, performed with GT-Power, was used to estimate initial and boundary conditions for the three-dimensional CFD model. CONVERGE CFD v2.4 was used for the three-dimensional CFD modeling where the level set G-Equation model and SAGE detailed chemical kinetics solver were used. An assessment of the different modeling approaches is also provided to evaluate their limitations, advantages and disadvantages, and for which situations they are most applicable. Model validation was performed with experimental data taken with a CFR engine over varying compression ratio, CA50, EGR fraction, and IMEP and shows good agreement in Peak Cylinder Pressure (PCP), PCP crank angle, and the location of the 10%, 50%, and 90% mass fraction burned (CA10, CA50, and CA90, respectively). The models can predict the onset crank angle and pressure rise rate for light, medium, and heavy EGAI under a variety of fuel reactivities and engine operating conditions.

scholarly journals Calcium Hydroxyapatite: A Highly Stable and Selective Solid Catalyst for Glycerol Polymerization

2021 ◽  
Author(s):  
Negisa Ebadipour ◽  
Sébastien Paul ◽  
Benjamin Katryniok ◽  
Franck Dumeignil
Keyword(s):  
Catalytic Activity ◽  
Calcium Hydroxyapatite ◽  
Polymerization Reaction ◽  
Solid Catalyst ◽  
High Catalytic Activity ◽  
Reaction Products ◽  
Icp Oes ◽  
Reaction Conditions ◽  
Glycerol Conversion ◽  
The Stability

Abstract: Calcium-based catalysts are of a high interest for glycerol polymerization due to their high catalytic activity and large availability. However, their poor stability under reaction conditions is an issue. In the present study, we investigated the stability and catalytic activity of Ca-hydroxyapatites (HAps) as one of the most abundant Ca-source in nature. A stochiometric, a Ca-deficient and a Ca-rich HAps have been synthetized and tested as catalysts in the glycerol polymerization reaction. Deficient and stochiometric HAps exhibited a remarkable 100% selectivity to triglycerol at 15 % of glycerol conversion at 245 °C after 8 h of reaction in the presence 0.5 mol.% of catalyst. Moreover, under the same reaction conditions, Ca-rich HAp showed a high selectivity (88 %) to di- and triglycerol at a glycerol conversion of 27 %. Most importantly, these catalysts were unexpectedly stable towards leaching under the reaction conditions based on the ICP-OES results. However, based on the catalytic tests and characterization analysis performed by XRD, XPS, IR, TGA-DSC and ICP-OES, we found that HAps can be deactivated by the presence of the reaction products themselves, i.e., water and polymers.

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