An Efficient and Practical System for the Catalytic Oxidation of Alcohols, Aldehydes, and a,b-Unsaturated Carboxylic Acids
Joseph M. Grill, James W. Ogle, and Stephen A. Miller
J. Org. Chem. 2006, 71, 9291-9296
Standard procedure for the oxidation of primary alcohols under solvent free conditions was followed with phenylethylalcohol. Green NiCl2 sol turned nasty black as cold bleach was added. Reaction pulled from ice with a little salt at 2hrs. Reaction looked the same, black. Reaction left to stir at room temp for additional 2 hrs. At about the 3.3hr mark, shortly before it should be worked up, the researcher thought that because of the low room temp it might be a good idea to turn on the hot plate to get the temp up to 25. The researcher was surprised to find the flask was already warm. The researcher then decided to allow the reaction to stir until it returned to ambient temperature. The researcher was again surprised at the 5.5-6hr mark when the black opaque reaction mixture that was left had turned into a cloudy light green.
The doctors say that catalytic amounts of NiCl2 turns into nickel oxide hydroxide insoluble nanoparticles, Ni3O2(OH)2, with the addition of bleach which oxidizes the alcohol/aldehyde and is then re-oxidized by the excess bleach back to nickel oxide hydroxide.
6 NiCl2 + 4 NaOCl + 2 H2O -> Ni3O2(OH)2 + 4 NaCl + 2 HCl + 2 Cl2
Is this right?
Now these products, once there is no more bleach to re-oxidize then reformed the original NiCl2, giving the green color? Why isn't the reaction mix acidic?
The mix is neutral to litmus and has a chlorine and PAA ester smell. If one made the mix acid with HCl, then distilled, could the NiCl2 be recovered and the PAA + ester steam distilled at the same time? Does phenylacetic acid steam distill?
The workup the docs use sucks. Why bother with solvent free conditions to then go and use a shitload of solvents? Since it is neutral, base it and concentrate, remove ester(or perhaps steam distill it), acidify and crystallize PAA, vac to dryness to recover NiCl2, perhaps needing a non polar at that point to remove residual PAA from the NiCl2.
Be unkind. The researcher wants this thing perfect, because compared to all the other oxidations performed, this one is the best by a long shot, especially if the yield is 90%+.
Even more so if pool shock can be used and the concentration increased.
Joseph M. Grill, James W. Ogle, and Stephen A. Miller
J. Org. Chem. 2006, 71, 9291-9296
Standard procedure for the oxidation of primary alcohols under solvent free conditions was followed with phenylethylalcohol. Green NiCl2 sol turned nasty black as cold bleach was added. Reaction pulled from ice with a little salt at 2hrs. Reaction looked the same, black. Reaction left to stir at room temp for additional 2 hrs. At about the 3.3hr mark, shortly before it should be worked up, the researcher thought that because of the low room temp it might be a good idea to turn on the hot plate to get the temp up to 25. The researcher was surprised to find the flask was already warm. The researcher then decided to allow the reaction to stir until it returned to ambient temperature. The researcher was again surprised at the 5.5-6hr mark when the black opaque reaction mixture that was left had turned into a cloudy light green.
The doctors say that catalytic amounts of NiCl2 turns into nickel oxide hydroxide insoluble nanoparticles, Ni3O2(OH)2, with the addition of bleach which oxidizes the alcohol/aldehyde and is then re-oxidized by the excess bleach back to nickel oxide hydroxide.
6 NiCl2 + 4 NaOCl + 2 H2O -> Ni3O2(OH)2 + 4 NaCl + 2 HCl + 2 Cl2
Is this right?
Now these products, once there is no more bleach to re-oxidize then reformed the original NiCl2, giving the green color? Why isn't the reaction mix acidic?
The mix is neutral to litmus and has a chlorine and PAA ester smell. If one made the mix acid with HCl, then distilled, could the NiCl2 be recovered and the PAA + ester steam distilled at the same time? Does phenylacetic acid steam distill?
The workup the docs use sucks. Why bother with solvent free conditions to then go and use a shitload of solvents? Since it is neutral, base it and concentrate, remove ester(or perhaps steam distill it), acidify and crystallize PAA, vac to dryness to recover NiCl2, perhaps needing a non polar at that point to remove residual PAA from the NiCl2.
Be unkind. The researcher wants this thing perfect, because compared to all the other oxidations performed, this one is the best by a long shot, especially if the yield is 90%+.
Even more so if pool shock can be used and the concentration increased.