Mechanism, kinetics and selectivity of a Williamson ether synthesis: elucidation under different reaction conditions

We show that platinum displays a self-adjusting surface that is active for the hydrogenation of acetone over a wide range of reaction conditions. Reaction kinetics measurements under steady-state and transient conditions at temperatures near 350 K, electronic structure calculations employing density-functional theory, and microkinetic modeling were employed to study this behavior over supported platinum catalysts. The importance of surface coverage effects was highlighted by evaluating the transient response of isopropanol formation following either removal of the reactant ketone from the feed, or its substitution with a similarly structured species. The extent to which adsorbed intermediates that lead to the formation of isopropanol were removed from the catalytic surface was observed to be higher following ketone substitution in comparison to its removal, indicating that surface species leading to isopropanol become more strongly adsorbed on the surface as the coverage decreases during the desorption experiment. This phenomenon occurs as a result of adsorbate–adsorbate repulsive interactions on the catalyst surface which adjust with respect to the reaction conditions. Reaction kinetics parameters obtained experimentally were in agreement with those predicted by microkinetic modeling when the binding energies, activation energies, and entropies of adsorbed species and transition states were expressed as a function of surface coverage of the most abundant surface intermediate (MASI, C3H6OH*). It is important that these effects of surface coverage be incorporated dynamically in the microkinetic model (e.g., using the Bragg–Williams approximation) to describe the experimental data over a wide range of acetone partial pressures.

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Oxidation of 1,2-Propanediol to Lactic Acid under Novel Supported Au Catalysts and Reaction Kinetics

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.850.41 ◽

2020 ◽

Vol 850 ◽

pp. 41-47

Author(s):

Svetlana Zhizhkuna ◽

Svetlana Chornaja ◽

Jevgenija Vladiko ◽

Reinis Drunka ◽

Dzidra Jankoviča ◽

...

Keyword(s):

Lactic Acid ◽

Reaction Kinetics ◽

Oxidation Process ◽

Gold Catalysts ◽

Reaction Conditions ◽

Oxidation Parameters

This work demonstrates that 5wt% gold catalysts supported on Al2O3 and TiO2 nanopowders as well as on TiO2 nanofibers are active in the 1,2-propanediol (1,2-PDO) oxidation to lactic acid. The influence of catalysts different parameters and reaction conditions on 1,2-PDO conversion and oxidation process selectivity was studied. The best result was achieved using 5wt%Au/TiO2 catalyst over the following oxidation parameters: c0(1,2-PDO) = 0.3 mol/L, n (1,2-PDO)/n (Au) = 4000 mol/mol, p (O2) = 6 bar, c0(NaOH) = 2 mol/L, t = 60 °C: 1,2-propanediol conversion was 98 % and lactic acid selectivity 89 %.

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Cotton Fabric-Supported Cationic Acrylate Polymer as an Efficient and Recyclable Catalyst for Williamson Ether Synthesis Reaction in Solid–Liquid–Liquid Phase Transfer Catalysis System

ACS Omega ◽

10.1021/acsomega.0c01981 ◽

2020 ◽

Vol 5 (34) ◽

pp. 21468-21475

Author(s):

Hui Peng ◽

Manjun Lei ◽

Lihui Yang ◽

Jie Sun ◽

Lei Yang ◽

...

Keyword(s):

Liquid Phase ◽

Cotton Fabric ◽

Phase Transfer Catalysis ◽

Phase Transfer ◽

Recyclable Catalyst ◽

Synthesis Reaction ◽

Solid Liquid ◽

Ether Synthesis ◽

Acrylate Polymer ◽

Williamson Ether Synthesis

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Cationic shield mediated electrodeposition stability in metal electrodes

Journal of Materials Chemistry A ◽

10.1039/c9ta06170c ◽

2019 ◽

Vol 7 (31) ◽

pp. 18442-18450 ◽

Cited By ~ 3

Author(s):

Feng Hao ◽

Ankit Verma ◽

Partha P. Mukherjee

Keyword(s):

Reaction Kinetics ◽

Diffusive Transport ◽

Metal Electrodes ◽

Mechanistic Understanding ◽

Coupled Reaction

Mechanistic understanding of coupled reaction kinetics, diffusive transport and electrostatic shield mediated electrodeposition stability is elucidated.

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Dimethyl sulfoxide as a solvent in the Williamson ether synthesis

Canadian Journal of Chemistry ◽

10.1139/v69-325 ◽

1969 ◽

Vol 47 (11) ◽

pp. 2015-2019 ◽

Cited By ~ 26

Author(s):

Russel G. Smith ◽

Alan Vanterpool ◽

H. Jean Kulak

Keyword(s):

Reaction Time ◽

Dimethyl Sulfoxide ◽

Butyl Alcohol ◽

Major Product ◽

Hydroxyl Groups ◽

Reaction Products ◽

Butyl Chloride ◽

Butyl Ether ◽

Ether Synthesis ◽

Williamson Ether Synthesis

Using the conventional Williamson ether synthesis, n-butyl ether was prepared from sodium hydroxide, n-butyl alcohol, and n-butyl chloride using excess of the alcohol as solvent in 61% yield after 14 h reaction time. However, when the excess alcohol was replaced by dimethyl sulfoxide, the yield of ether rose to 95% with 9.5 h reaction time. Other primary alkyl chlorides exhibited similar behavior to n-butyl chloride, but secondary alkyl chlorides and primary alkyl bromides gave little etherification, elimination being the major reaction. Unreactive halides, such as vinyl chloride, phenyl bromide, and 2,4-dinitrobromobenzene, were not etherified in dimethyl sulfoxide. The reaction products obtained from aliphatic dichlorides depended upon the relative positions of the chlorine atoms. Secondary alcohols reacted to give ethers, but tertiary alcohols were very unreactive. Polyols generally gave high yields of ethers, the major product being that in which all but one of the hydroxyl groups became etherified. Under forcing conditions, however, completely etherified polyols could be obtained.

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