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BerkutSimp
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You could maybe try weakly reducing ethanoic acid?
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imidazole
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I might try the ethylene glycol method, any ideas how to purify it from anything else produced?
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Boffis
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I have an old bottle that claims to be acetaldehyde from Aldrich Chemicals its 20 years old. It is not especially volatile so I suspect hat it has
polymerised, presumably to paraldehyde. In one thread, this one I think, Weolen states that paraldehyde is easily depolymerised. Does anyone know how
or have a ref to a procedure. I have a cold trap and access to dry ice so its distillation is not a big issue. Von Richter's Chemistry of Organic
compounds makes the same claim but without reference or details.
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Waffles SS
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I wonder why someone here don’t try vinyl acetate route?
Just add a few drops of sulfuric acid on vinyl acetate and then reflux solution.that is really simple and high yield method.
Vinyl acetate will be made from acetylene and acetic acid+ mercury salt.
[Edited on 4-5-2025 by Waffles SS]
Chemistry = Chem + is + Try
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Alchemica
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Oxidations with BiBr3-H2O2 and pure and supported V2O5-H2O2
Oxidation of benzylic and aliphatic alcohols to aldehydes by bismuth tribromide and aqueous 30% hydrogen peroxide has been reported by M.-k. Han et al
[1]
Bismuth tribromide can be produced by the direct oxidation of bismuth in bromine
2 Bi + 3 Br2 → 2 BiBr3
Bismuth tribromide was prepared by forming Br2 in petroleum ether by the action of Oxone/NaBr (moistened) as an aq.-organic bilayer, then
this organic layer containing Br2 was added to powdered bismuth metal and allowed to react. The unreacted bismuth was separated by
dissolving the BiBr3 in water and evaporating. It was sluggish in forming the BiBr3 by such an approach and yield was low
Treatment of benzylic alcohols with 5.0 molar equivalents of hydrogen peroxide and bismuth tribromide (10 mol%) for 10–40 minutes at 70 °C provided
the corresponding oxidized carbonyl compounds
General Experimental Procedure for the Oxidation of Alcohols: To a solution of the alcohol (1.0 mmol) and hydrogen peroxide (5.0 mmol, 30% aq) was
added BiBr3 (10 mol%). The reaction mixture was stirred at 70 °C for 10–40 min, and the reaction mixture was extracted with dichloromethane (2 × 5
mL). The combined organic layers were washed with saturated brine (2 × 5 mL) and dried with anhydrous MgSO4. After evaporation of the solvent, the
residue was purified by flash column chromatography (SiO2; CH2Cl2–hexane, 3:2) to afford the pure carbonyl compound
Some higher aliphatic primary alcohols eg 1-nonanol have been oxidised to the aldehyde in reasonable yield but not sure how it goes for ethanol.
I tried the oxidation for one of the model compounds, PhCH2OH. At the 10.8g scale, I found it rapidly over-oxidised the alcohol to the
carboxylic acid but I had troubles with temperature control, sometimes exceeding 70 deg. C with the mixture boiling
With ethanol (25g) and 0.5 g BiBr3 catalyst followed by addition of 50mL 50% H2O2, allowing the acetaldehyde to
distill over as formed, a poor yield of 3.4g was obtained
[1] Han, Mi-kyung & Kim, Sohwa & Kim, Sung Tae & Lee, Jong. (2015). Bismuth Tribromide Catalyzed Oxidation of Alcohols with Aqueous
Hydrogen Peroxide. Synlett. 26. 10.1055/s-0035-1560467. https://doi.org/10.1055/s-0035-1560467
Oxidations with Vanadium
Similar to ordenblitz, https://www.sciencemadness.org/whisper/viewthread.php?tid=55... I tried with 100ml 95% EtOH, 500mg V2O5 and 100mL 50%
H2O2, 40mL of distillate smelling strongly of acetaldehyde was collected. This seemed to be the best method I've found yet. The
reaction mixture alternated between bright orange and deep red.
 
Some supported V2O5 catalysts were prepared by calcining the catalyst support with ammonium metavanadate at high temperature
- V2O5/activated carbon: 1g ammonium metavanadate in water added to 10g activated carbon. Water evaporated and catalyst calcined
at 500 deg C in air. It’s possible the reducing environment of the carbon hindered V2O5 formation
- V2O5/3A molecular sieves: Based loosely on V5+ supported on ZSM-5 molecular sieve, https://doi.org/10.1016/j.tet.2025.134592
My thoughts were that the V2O5 on supports may offer some advantages, and the molecular sieve supported oxidant cleaved alkenes
to carbonyl compounds without over-oxidation, so may have merits
However, both actually yielded significantly less than the pure V2O5. Only ~5mL of distillate was obtained for the
V2O5-molecular sieves and 12 mL for activated carbon supported V2O5
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