The Hive > Novel Discourse

New method for P2P

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bio:
This is fantastic yield increase from 60-94% using 1 to 1 molar ratio. I will try it in a few days. The twodogs procedure uses 2.2 mole MEK to 1 mole PhCHO.

What was not stated in the synthesis part was the temp used when HCL gasing. There is a footnote to this article saying they followed this procedure.,,,,,,,,,,,(5) Muller and Harries, Ber., 36, 9BG (1902).,,,,,,,,,,,,if anyone could find this it would be very helpfull.

I think perhaps the reason my recent yield was so much better (79%) is that I went slower to keep the temp below 5deg and based on earlier results added HCL to compensate for the weight not gained from what was passed. This resulted in a more saturated solution. The amount given (.58 mole HCL) does result in a saturated solution but it is easy to have a lot gas off. I also left it in the ice bath overnight to warm up.

Now if we can only find a non-exotic catalyst for the oxidation this method begins to get very attractive.

Rhodium:
Ueber die Condensation von Aethylmethylketon mit Benzaldehyd
C. Harries, G. H. Müller
Chem. Ber. 35, 966-971 (1902) (https://www.thevespiary.org/rhodium/Rhodium/pdf/mek-aldol-ber.pdf)

Summary
A mixture of 100g methyl ethyl ketone and 140g benzaldehyde is cooled in an ice/salt bath, and saturated with dry hydrogen chloride gas. The reaction mixture turns red, and is allowed to stand for 1-2 days, after which time the oily product is shaken with dilute sodium hydroxide, washed with water and dissolved in diethyl ether. From the ether the product crystallizes in large needles, which smells of camphor. The yield is quantitative. The ketone can be recrystallized from petroleum ether (1g is soluble in 8-9 mL at 20°C) to give fine needles, mp 38°C/bp 127-130°C/12mmHg.
____ ___ __ _

The Condensation of Phenolic Aldehydes and Their Ethers with Methyl Ethyl Ketone
Kenji Iwamoto
Bull. Chem. Soc. Jap. 2, 51-57 (1927) (https://www.thevespiary.org/rhodium/Rhodium/pdf/mek-aldol-bcsj.pdf)

Summary
Condensation of benzaldehydes with MEK under basic conditions (yielding PhCH=CHCOCH2CH3) and acidic (yielding PhCH=C(CH3)COCH3). The reactions are performed with 4-methoxy-, 4-hydroxy-, 3-methoxy-4-hydroxy-, and 3,4-methylenedioxy-benzaldehyde.

Rhodium:
Here are all Boeseken's articles on the topic of peracid oxidation of unsaturated ketones, including the one mentioned in Post 471343 (Rhodium: "Acidic condensation of Benzaldehyde & MEK", Novel Discourse)
The articles mentioned in Post 246863 (lugh: "Re: New method for P2P", Novel Discourse) does not contain any experimental parts, only theoretical studies of benzalacetones.

Sur L'Iso-Phényl-Vinyl-Acetate, C6H5CH=CHOAc, Produit de L'oxydation de la Mono-Benzalacétone par les Peracides
J. Boeseken, A. Kremer
Rec. Trav. Chim. 50, 827-832 (1931) (https://www.thevespiary.org/rhodium/Rhodium/pdf/boeseken1931.pdf)
____ ___ __ _

Le Produit de L'oxydation de la Benzalacétone par L'acide Peracétique
J. Boeseken, A. L. Soesman
Rec. Trav. Chim. 52, 874-880 (1933) (https://www.thevespiary.org/rhodium/Rhodium/pdf/boeseken1933.pdf)
____ ___ __ _

L'oxydation par les Peracides de la Double Liaison à Côte d'un Groupe Carbonyle
J. Boeseken, J. Jacobs
Rec. Trav. Chim. 55, 786-790 (1936) (https://www.thevespiary.org/rhodium/Rhodium/pdf/boeseken1936a.pdf)
____ ___ __ _

L'oxydation des 1,3-Dicétones par L'acide Peracétique
J. Boeseken, J. Jacobs
Rec. Trav. Chim. 55, 804-814 (1936) (https://www.thevespiary.org/rhodium/Rhodium/pdf/boeseken1936b.pdf)

chilly_willy:
First of all I want to say that twodogs procedure works just as described.  I also want to mention that somebee has tried both aldehyde:ketone aldol ratios mentioned. Literature 1:1, and twodogs 1:2.2.  The yields from both trials were roughly the same 220-230g from 200g aldehyde.  The only difference was the latter contained a larger MEK forerun upon distillation.  The 1:1 ratio experiment might have yeilded a bit more (20-30g) if the experimenter was willing to relocate the heavy "tar" layer into a smaller flask and finish off the distillation..but it just didnt seem worth the time.
Two questions arise and I thought maybe to just include them in this post instead of starting a new thread.
1. Will heating the twodogs baeyer-villiger product (P2P enol ester) with 33% HCl perform the same function as the saponification step to arrive at P2P??
2.  If not, can another alcohol such as IPA, or MeOH be substituted for the 95% EtOH (everclear) in the saponification step?  Ironically the ethanol is probably the most expensive chem needed in the whole procedure ($13 750mL).

bio:
The only thing I can see that bio has been doing (not reading german)different is that Harries et al saturated at salt bath temp and let sit for one to 2 days. So this was done at minus 5 degrees whereas previous runs were plus 5 degrees 21.2g/mole HCl passed about 18 absorbed. It did hold about 3 grams per mole more HCl and has not been worked up yet. Now twodogs stated too much HCl promoted polymerization so we will see. The 1:1.05 trial at 5 deg sat 10 hours and crystallized  nicely without distilling. First crop weighed in at 75g and the other is in the freezer. 1st crop washed with 96% EtOH will not need recrys. Looks as clean as the fractionated stuff.

Damn, Chilly are you paying alcohol tax? 96% EtOH here is $1.20 in then discount stores a little more in the drug stores. Actually cheaper than the tech stuff from the chem house and you get a nice heavy HDPE bottle to play with. Seems like no one else is interested in this simple non suspicious procedure. I wonder why?

I think the french articles discuss the concentration of HCl to saponify but I can't read it and what I can decipher may bee wrong. I'll ask bio to pst the pertinent paragraphs and maybee some kind frenchbee can translate. It's actually very short did you see it? Look at the 1936 Jacobs one.

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