Oxidative valorisation of lignin into valuable phenolics: Effect of acidic and basic catalysts and reaction parameters

2021 ◽  
pp. 125513
Author(s):  
Avnish Kumar ◽  
Bijoy Biswas ◽  
Ramandeep Kaur ◽  
Bhavya B. Krishna ◽  
Thallada Bhaskar
Keyword(s):  
Reaction Parameters ◽  
Basic Catalysts

Surfactant involved in Copper Sulfide Nanocrystallites Synthesis

2009 ◽  
Vol 59 (12) ◽  
Author(s):  
Claudia Maria Simonescu ◽  
Valentin Serban Teodorescu ◽  
Camelia Capatina
Keyword(s):  
Copper Sulfide ◽  
X Ray Diffraction ◽  
Reaction Parameters ◽  
Reaction Conditions ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Shape Of Nanoparticles ◽  
Tem Transmission Electron Microscopy ◽  
Shape And Size

This paper presents the obtaining of copper sulfide CuS (covelite) from Cu(CH3COO)2.H2O and thioacetamide (TAA) system. The reaction was conducted in presence or absence of sodium-bis(2-ethylhexyl) sulfosuccinate (Na-AOT). The effects of various reaction parameters on the size and on the shape of nanoparticles have been examined. CuS obtained was characterized by X ray diffraction, IR spectroscopy, TEM � transmission electron microscopy and SAED selected area electron diffraction. The influence of surfactant to the shape and size of CuS (covellite) nanocrystals was established. The size of the nanocrystals varied from 10-60 nm depending on the reaction conditions such as quantity of surfactant.

Synthesis and Evaluation of Levulinic Ester as Biodiesel Additives

2020 ◽  
Vol 71 (8) ◽  
pp. 21-26
Author(s):  
Elena-Emilia Oprescu ◽  
Cristina-Emanuela Enascuta ◽  
Elena Radu ◽  
Vasile Lavric
Keyword(s):  
Maximum Yield ◽  
Strength Distribution ◽  
Point Of View ◽  
Reaction Parameters ◽  
X Ray ◽  
Ethyl Levulinate ◽  
Ft Ir ◽  
Ir Analysis ◽  
Biodiesel Blend ◽  
Acid Strength Distribution

In this study, the SO42-/TiO2-La2O3-Fe2O3 catalyst was prepared and tested in the conversion of fructose to ethyl levulinate . The catalyst was characterized from the point of view of the textural analysis, FT-IR analysis, acid strength distribution, X-ray powder diffraction and pyridine adsorption IR spectra. The influence of the reaction parameters on the ethyl levulinate yield was study. The maximum yield of 37.95% in levulinate esters was obtained at 180 �C, 2 g catalyst and 4 h reaction time. The effect of ethyl levulinate addition to diesel-biodiesel blend in different rates, i.e, 0.5, 1, 2.5, 5 (w.t %) on density, kinematic viscosity and flash point was evaluated and compared with the European specification.

Simple theoretical models of elimination reactions on polar catalysts; Dehydration reactivity of secondary alcohols on acidic and basic catalysts

1985 ◽  
Vol 50 (4) ◽  
pp. 920-929 ◽  
Author(s):  
Jiří Sedláček
Keyword(s):  
Experimental Data ◽  
Quantum Chemical ◽  
Theoretical Models ◽  
Aliphatic Alcohols ◽  
Secondary Alcohols ◽  
Carbonium Ion ◽  
Dehydration Reactions ◽  
Aromatic Alcohols ◽  
Basic Catalysts ◽  
Simple Models

CNDO/2 calculations for simple models of adsorption and dehydration reactions of secondary aliphatic and aromatic alcohols on polar catalysts are presented. The models involve selected stages of elimination mechanisms of various types (E1, E2 and E1cB elimination). Calculated quantum chemical quantities were correlated with reported experimental data. It is shown that reactivities for the series of substituted phenylethanols correlate very well with the ease of carbonium ion formation. In the case of aliphatic alcohols, calculated quantities correlate generally with the reactivities on SiO2 and are in anticorrelation with the reactivities on Al2O3.NaOH.

Radiation Induced Graft Copolymerization of Vinyl Acetate and Isopropenyl Acetate Onto Isotactic Polypropylene

1996 ◽  
Vol 61 (2) ◽  
pp. 259-267 ◽  
Author(s):  
Bhupendra N. Misra ◽  
G. S. Chauhan ◽  
Inderjeet Kaur
Keyword(s):  
Vinyl Acetate ◽  
Isotactic Polypropylene ◽  
Graft Copolymerization ◽  
Optimum Conditions ◽  
Reaction Parameters ◽  
Maximum Percentage ◽  
Radiation Induced ◽  
Isopropenyl Acetate

Radiation-induced graft copolymerization of vinyl acetate (VAC) and isopropenyl acetate (PAC) onto isotactic polypropylene (IPP) has been studied. The percentage of grafting was calculated for various reaction parameters, and the optimum conditions for attaining the maximum percentage of grafting were determined. Maximal achieved extents of grafting are 39% and 29% for VAC and PAC, respectively. The reactivity of the two monomers with respect to grafting is discussed.

scholarly journals Screening a Strain of Klebsiella sp. O852 and the Optimization of Fermentation Conditions for Trans-Dihydrocarvone Production

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2432
Author(s):  
Li Chen ◽  
Lu-Lu Zhang ◽  
Jing-Nan Ren ◽  
Xiao Li ◽  
Gang Fan ◽  
...  
Keyword(s):  
Ethanol Concentration ◽  
Flavor Compounds ◽  
Accession Number ◽  
Reaction Parameters ◽  
Isolation And Characterization ◽  
Biotransformation Process ◽  
Pharmaceutical Industries ◽  
Final Ethanol Concentration ◽  
Optimization Of Fermentation

Flavors and fragrances have high commercial value in the food, cosmetic, chemical and pharmaceutical industries. It is interesting to investigate the isolation and characterization of new microorganisms with the ability to produce flavor compounds. In this study, a new strain of Klebsiella sp. O852 (accession number CCTCC M2020509) was isolated from decayed navel orange (Citrus sinensis (L.) Osbeck), which was proved to be capable of converting limonene to trans-dihydrocarvone. Besides, the optimization of various reaction parameters to enhance the trans-dihydrocarvone production in shake flask was performed for Klebsiella sp. O852. The results showed that the yield of trans-dihydrocarvone reached up to 1 058 mg/L when Klebsiella sp. O852 was incubated using LB-M medium for 4 h at 36 °C and 150 rpm, and the biotransformation process was monitored for 36 h after adding 1680 mg/L limonene/ethanol (final ethanol concentration of 0.8% (v/v)). The content of trans-dihydrocarvone increased 16 times after optimization. This study provided a basis and reference for producing trans-dihydrocarvone by biotransformation.

scholarly journals Achieving selectivity in porphyrin bromination through a DoE-driven optimization under continuous flow conditions

2020 ◽  
Author(s):  
Paolo Zardi ◽  
Michele Maggini ◽  
Tommaso Carofiglio
Keyword(s):  
Reaction Time ◽  
Design Of Experiment ◽  
Continuous Flow ◽  
Optimization Process ◽  
Porphyrin Ring ◽  
Flow Conditions ◽  
Reaction Parameters ◽  
Synthetic Procedure ◽  
Relevant Factors ◽  
Post Functionalization

AbstractThe post-functionalization of porphyrins through the bromination in β position of the pyrrolic rings is a relevant transformation because the resulting bromoderivatives are useful synthons to covalently link a variety of chemical architectures to a porphyrin ring. However, single bromination of porphyrins is a challenging reaction for the abundancy of reactive β-pyrrolic positions in the aromatic macrocycle. We herein report a synthetic procedure for the efficient preparation of 2-bromo-5,10,15,20-tetraphenylporphyrin (1) under continuous flow conditions. The use of flow technology allows to reach an accurate control over critical reaction parameters such as temperature and reaction time. Furthermore, by performing the optimization process through a statistical DoE (Design of Experiment) approach, these parameters could be properly adjusted with a limited number of experiments. This process led us to a better understanding of the relevant factors that govern porphyrins monobromination and to obtain compound 1 with an unprecedent 80% yield.

Electrochemical Preparation of CuZn Metallic Foams for Removing Water Contaminants

2019 ◽  
Vol 19 (11) ◽  
pp. 7374-7380
Author(s):  
G. Vourlias
Keyword(s):  
Grain Size ◽  
Water Treatment ◽  
Metallic Foams ◽  
Reaction Parameters ◽  
Water Contaminants ◽  
Electrochemical Preparation ◽  
Precipitation Procedure ◽  
Cuzn Alloy ◽  
Deposition Mode ◽  
Cu And Zn

This study is focused on the preparation of metal (Cu, Zn) nanopowders by an electrochemical reduction/precipitation procedure, which provides the primary components for the development of CuZn alloy metallic foams. This well-controlledmethod allows straight forward control of the reaction parameters and the restriction of oxidation effects, while resulting in stable and small grain size metal nanopowders. Whether precipitation of Cu and Zn is held separately or in alternating deposition mode, the characteristics of synthesized nanopowders assist easier mixing, alloying and realization of metallic foams suitable for water treatment applications. CuZn alloy foams developed with this technique presented equivalent efficiency and lower corrosion and leaching rates compared to those prepared with commercial powder methods.

Sign in / Sign up

Export Citation Format

Share Document