scholarly journals OXIDATION OF ALCOHOLS OVER CERIUM-OXIDE CATALYST: CORRELATION BETWEEN THE ACTIVATION ENERGY OF THE REACTION AND THE CHEMICAL SHIFT δ (R13 COH)

2019 ◽  
Vol 85 (8) ◽  
pp. 66-72
Author(s):  
Volodymyr Brei
Keyword(s):  
Activation Energy ◽  
Chemical Shift ◽  
Hydrate Formation ◽  
Alcohol Oxidation ◽  
Sweep Rate ◽  
Electronic Density ◽  
Catalyst Sample ◽  
Mass Spec ◽  
Oxidation Of Alcohols ◽  
Aldehydes And Ketones

The oxidation of thirteen alcohols over sup-ported CeO2/Al2O3 catalyst with 10 wt.% of CeO2 have been studied using a desorption mass-spec-trometry technique. A catalyst sample 4–6 mg in quartz cuvette was evacuated at 100 0C, cooled to room temperature, and then adsorption of a alco-hol was provided. After vacuumation of alcohol excess, the TPR profiles of products of alcohol oxidation were recorded at sweep rate 2 a.u.m./sec and heating rate of 15 0C/min using MX-7304A monopole mass- spectrometer. Identification of formed aldehydes and ketones was provided on the bases of their characteristic ions in obtained mass-spectra, namely, acetaldehyde (m/e = 29, 44); pro-panal (29, 58); acetone (43, 58); butanal (44, 43); methyl propanal (43, 41, 72), 2-butanon (43, 72); methoxyacetone (45, 43); cyclohexanone (55); ace-tophenone (105, 77); benzaldehyde (77, 106). It was shown that the oxidation of several alcohols pro-ceeds in a wide temperature interval from 130 to 280 0C. So, peak of formaldehyde formation from me-thanol adsorbed on CeO2/Al2O3 is observed at 280 0C whereas peaks of methyl glyoxal and water formation from adsorbed hydroxyacetone are re-corded at 135 0 C. The linear correlation between activation energy of reaction and chemical shift δ (R13COH) of studied alcohols was found as Ea= 183 –1.4δ (kJ/mol). Respectively, the maximum oxi-dation rate, for instance, for methanol (50 ppm) is observed at 280 0C, for ethanol (58 ppm) at 215 0C, for n-butanol (62 ppm) at 200 0C, for n-propanol (64 ppm) at 190 0C, for 2-butanol (69 ppm) at 160 0C, for hydroxyacetone (69 ppm) at 135 0C, and for 1-phenylethanol (70 ppm) at 130 0C. Thus, ability of alcohols to oxidation decreases with increase of their electronic density on carbon atom of alcohol group in following order: 1-phenyl ethanol ≈ hyd-roxyacetone ≈ cyclohexanol > allyl alcohol ≈ 2-bu-anol ≈ i-butanol ≈ i-propanol > methoxypropanol-2 ≈ n-propanol ≈ n-butanol ≈ benzyl alcohol ≈ ethanol >> methanol. On an example of ethanol, the scheme of alcohol oxidation on ceria that assumes the addition of atomic oxygen to C–H bond of alcoho-lic group with intermediate acetaldehyde hydrate formation is discussed.

Ag–CoO nanocomposites for gas-phase oxidation of alcohols to aldehydes and ketones: intensified O2 activation at Ag–CoO interfacial sites

2020 ◽  
Vol 10 (24) ◽  
pp. 8445-8457
Author(s):  
Kun Liu ◽  
Yichen Zhao ◽  
Jiale Wang ◽  
Qingsong Xue ◽  
Guofeng Zhao
Keyword(s):  
Gas Phase ◽  
Active Sites ◽  
Active Oxygen Species ◽  
Alcohol Oxidation ◽  
Oxygen Species ◽  
Oxidation Of Alcohols ◽  
Phase Oxidation ◽  
Aldehydes And Ketones ◽  
Catalytic Active Sites ◽  
Gas Phase Oxidation

The fabrication of qualified catalysts is a key issue to implement gas-phase aerobic alcohol oxidation, but necessarily requires understanding the structures of catalytic active sites and the supply of active oxygen species.

Iron/ABNO-Catalyzed Aerobic Oxidation of Alcohols to Aldehydes and Ketones under Ambient Atmosphere

2016 ◽  
Vol 81 (5) ◽  
pp. 2189-2193 ◽  
Author(s):  
Lianyue Wang ◽  
SenSen Shang ◽  
Guosong Li ◽  
Lanhui Ren ◽  
Ying Lv ◽  
...  
Keyword(s):  
Aerobic Oxidation ◽  
Ambient Atmosphere ◽  
Oxidation Of Alcohols ◽  
Aldehydes And Ketones

scholarly journals A Study of Catalytic Oxidation of a Library of C2 to C4 Alcohols in the Presence of Nanogold

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 442
Author(s):  
Maciej Kapkowski ◽  
Anna Niemczyk-Wojdyla ◽  
Piotr Bartczak ◽  
Monika Pyrkosz Bulska ◽  
Kamila Gajcy ◽  
...  
Keyword(s):  
Organic Chemistry ◽  
Green Chemistry ◽  
Alcohol Oxidation ◽  
Catalytic Performance ◽  
Toxic Chemicals ◽  
Wide Scope ◽  
Catalytic Potential ◽  
Green Oxidation ◽  
Oxidation Of Alcohols ◽  
Different Levels

The classical stoichiometric oxidation of alcohols is an important tool in contemporary organic chemistry. However, it still requires huge modifications in order to comply with the principles of green chemistry. The use of toxic chemicals, hazardous organic solvents, and the large amounts of toxic wastes that result from the reactions are a few examples of the problems that must be solved. Nanogold alone or conjugated with palladium were supported on different carriers (SiO2, C) and investigated in order to evaluate their catalytic potential for environmentally friendly alcohol oxidation under solvent-free and base-free conditions in the presence H2O2 as a clean oxidant. We tested different levels of Au loading (0.1–1.2% wt.) and different active catalytic site forms (monometallic Au or bimetallic Au–Pd sites). This provided new insights on how the structure of the Au-dispersions affected their catalytic performance. Importantly, the examination of the catalytic performance of the resulting catalysts was oriented toward a broad scope of alcohols, including those that are the most resistant to oxidation—the primary aliphatic alcohols. Surprisingly, the studies proved that Au/SiO2 at a level of Au loading as low as 0.1% wt. appeared to be efficient and prospective catalytic system for the green oxidation of alcohol. Most importantly, the results revealed that 0.1% Au/SiO2 might be the catalyst of choice with a wide scope of utility in the green oxidation of various structurally different alcohols as well as the non-activated aliphatic ones.

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