# Talk:Trifluoroperacetic acid

@DMacks: Would you please make an image using the structures of hexamethylbenzene and 2,3,4,5,6,6-hexamethyl-2,4-cyclohexadienone for the following equation?

C6(CH3)6   +   CF3COOOH   →   C6(CH3)6O   +   CF3COOH
Thanks.  EdChem (talk) 04:57, 10 January 2017 (UTC)

No problem! Do you want it balanced (TFPAA on left, TFA byproduct on right), or TFPAA "over the arrow" and not bother with the byproduct? Either way, I'll also include the key BF3 additive. But it's not clear whether it is technically a "reactant" vs "catalyst", so maybe including TFPAA and BF3 together on the arrow gets us away from having to decide:) DMacks (talk) 05:08, 10 January 2017 (UTC)
Thanks.  I would put CF3COOOH / BF3 over the arrow and − CF3COOH under it, so that the organic conversion is highlighted.
 Done DMacks (talk) 08:01, 10 January 2017 (UTC)
Thanks, DMacks, but if I might quibble... to me, CF3COOOH / BF3 implies the peracid is the reagent and the borane a catalyst whereas stacked as you have them, I would initially expect both to be reagents.  Would you interpret them similarly?  I tend to put reagents above arrows, catalysts above after a slash or below followed by "(catalyst)", products below the arrow with a minus and solvents below the arrow.  Does this sound about right to you?
That's one reasonable way to do it except for "after a slash" to denote catalysts. Too easily confused with a mixture of chemicals that both serve the same role (for example, cosolvents or a precatalyst recipe). In this reaction, they use more than one equivalent of BF3 and call it a "reactant", but it is not required to get a moderate yield and it does not have any role in the mass-balance of the equation. That's why I originally advocated not assigning roles or byproduct balance; we just wash our hands of the decision and go with how the cited ref writes it. I'll check H. Hart, Accounts Chem. Res., 4, 337 (1971) later today, which is a review they cite. DMacks (talk) 16:20, 10 January 2017 (UTC)
I take your point, I suggest ignoring my quibble and leaving the image as it is.  EdChem (talk) 21:41, 10 January 2017 (UTC)
I'm about to upload a horrible looking image to the (Bis(trifluoroacetoxy)iodo)benzene article, which I have built in paste from other images, but my meaning should be clear.  The reagent in the last step can be made from trifluoroperacetic acid and so it could be used here too.  If you could turn it into a proper image, that would be great.  Thanks.  EdChem (talk) 13:42, 10 January 2017 (UTC)
That would be this? Easy for me to draw it, but having the first two steps (RCO2H->RCONH2) seems superfluous. It might be how OS does it, but it's not relevant to the chemistry of either PhI(OTF)2 or TFPAA and instead is visually distracting from them. DMacks (talk) 16:20, 10 January 2017 (UTC)
And I think the whole reaction is off-topic here because it's really about the usefulness of PhI(OTF)2, which has its own article. That reagenthas its own article, which proves it's a notable entity, so here saying "TFPAA is useful for making some other notable thing" helps explain why we care about this use of TFPAA (notability). But "why that other thing is notable or useful" is not relevant here, and there's nothing in the OS Hoffmann-rearrangement prep that is tied to this particular prep of PhI(OTF)2 (nor is it even the one they use). DMacks (talk) 16:28, 10 January 2017 (UTC)
I added my image (yes, the one you linked, though I should have named it as something more descriptive, like "Cyclobutylamine hydrochloride from cyclobutylcarboxylic acid", and obviously an SVG would be better and more useful when it ends up on commons) to the PhI(OCOCF3)2 article, as you noticed, and do recognise it is a stretch here, though noting that trifluoroperacetic acid is used to make the hypervalent iodine compound is relevant as a use, IMO.  No objections to removing the image but I think some comment on making it is relevant.  Thoughts?
Quibble, but is OTf or OTF known as an abbreviation for the trifluoroacetate group, as it is usually triflate?
I thought about cutting the image but I was thinking it may be useful on decarboxylation or carbonate ester.  Yes, they could be cut into two parts, but I like to show the surrounding chemistry because, when I am reading, I often see something that interests me and click and delve down the rabbit hole.  :)  It also means red links for cyclobutylcarboxylic acid and the like, and since they are used in an OS report, there is reason to suspect they are notable.  Publishing an OS method is rare for transforming something no one uses into something no one cares about.  :)  Thanks, DMacks.  EdChem (talk) 21:41, 10 January 2017 (UTC)
Also, you may have seen I use expressions like " &nb.sp; + &nb.sp; " in equations as they space things out, though I recognise that this does not actually prevent breaking.  It also makes spacing between reagents and coefficients smaller than that between formulae and + or →.  Compare:2&nb.sp;A &nb.sp; + &nb.sp; B &nb.sp; &ra.rr; &nb.sp; A<sub>2</sub>B     produces     2 A   +   B   →   A2B2&nb.sp;A&nb.sp;+&nb.sp;B&nb.sp;&ra.rr;&nb.sp;AB     produces     2 A + B → A2BIt is a personal idiosynchracy, I admit, but I think the former looks better.  :)  EdChem (talk) 05:51, 10 January 2017 (UTC)
Interesting! I hadn't noticed the visual-layout difference. I do know that it wraps on my narrow monitor, so I only noticed "wasn't behaving as nbsp should". This could be a problem if a break occurs in the middle of the product-side, sending a product to the left of the arrow:
A + B → C + D
A + B → C +D
A + B → C+ D
In the second case, you have to look at the preceding line-end to know that D is what is "+" from the previous line; in the third case, it's wrong with no indication to the contrary. DMacks (talk) 08:01, 10 January 2017 (UTC)
Let me cogitate on that one.  :)  EdChem (talk) 13:42, 10 January 2017 (UTC)
@DMacks: regarding the image File:PIFA synthesis by oxidation.png, the reagents are trifluoroacetic acid and trifluoroperacetic acid, CF3COOOH, which has been written as a diketone, (CF3CO)2 (perhaps you were thinking of the anhydride, and missed an O atom at the end?).  Also, I have a preference for displaying carboxylic acids as –COOH rather than –CO2H, too, as the oxygens are non-equivalent, and carboxylates as –CO2− rather than –COO−, as its oxygens are equivalent.  Whether you want to follow that is up to you, of course.  In any case, I'd appreciate an uploaded new version with the diketone removed.  Thanks, EdChem (talk) 03:46, 15 January 2017 (UTC)

Oops, image fixed. Reading –COOH too closely, a novice reader could just as easily mis-read it as containing a peroxide linkage ("differently wrong" not "clearly superior"). The logical extension of "CF3COOOH" is even worse, because we're using a consecutive list of three "O" to mean two differentthings (two of them are consecutive and third is not). That's the plague of condensed structure notation to an untrained eye I guess, but it usually doesn't matter because it's not the point trying to be illustrated. Both "subscript" and "list of O" are pretty common in the literature. I do strongly object making changes in notation style in the middle of a reaction (breaking parallelism solely for off-topic technical minutae). If it looks different, readers' eyes are drawn to that difference and trying to figure out what is happening there, as a distraction from whatever else we are trying to illustrate in context. DMacks (talk) 04:16, 15 January 2017 (UTC)
Thanks for the fix.  It is the accuracy that matters, of course, rather than personal idiosyncrasies.  You are right that both appear in the literature, but that is read by the chemically knowledgeable.  On parallelism grounds, I suppose I'd use CF3C(O)OH and CF3C(O)OOH, but I'm not suggesting it is worth changing.  Cheers.  EdChem (talk) 04:57, 15 January 2017 (UTC)
@DMacks: About changing the sulfur oxidation example to the generic case, I am concerned that the change is not supported by the reference.  It gives the generic formation of R-S-Cl, but the conversion to R-S(=O)-Cl is given in the reference only for the specific case in my image.  I suggest we use the specific case or we need a reference to the generic applicability of trifluoroperacetic acid in this case.  Thoughts?  EdChem (talk) 01:52, 20 January 2017 (UTC)

If it's not general (or at least a few known examples) I agree we should not have a general reaction—I have not chased refs for it yet. But if it's just a one special case, I also don't think we should include it as prominently (substantial textual description of this case, large image, etc) as the more general (is it?) selenium case. Maybe instead/also add nitrogen oxidation, since e-EROS indicates that this is also a generally usable process? DMacks (talk) 05:09, 21 January 2017 (UTC)
I have altered the content around the conversion, the first step with sulfuryl chloride yields the RS(O)Cl in many cases.  I have added N oxidation and the thiophene case.  I've also added some oxidations to phenols rather than ring-opening in the last section, and tracked the refs you wanted.  EdChem (talk) 01:37, 22 January 2017 (UTC)
The sulfur explanation looks great now as long as the cited ref for the RSCl→RS(O)Cl does support that this is more than just a single case, and well explains why this rare example deserves mention. And the more general sulfone and nitrogen cases look good too. Thanks for the ref details; for some reason that source PDF rendered pretty blurry for me. DMacks (talk) 10:03, 23 January 2017 (UTC)
@DMacks:  Now that the DYK nomination for this article has got a tick, it will soon move to a prep before going to the main page.  There are a couple of image issues I'd like addressed before then, if you can:

File:Conversion_of_F3CCPh2SH_to_F3CCPh2SCl_and_on_to_F3CCPh2S(O)Cl.png would look much better if it was redrawn
 Done. DMacks (talk) 07:36, 25 February 2017 (UTC)
File:Propylbenzene_oxidations.png (which you created) has a red pathway in which the aromatic ring is oxidised, and I wonder about the fate of the other 5 carbon atoms in it.  Is pentanedioic acid produced, or ...?
Other than those, I think is pretty much ready.  :)  Thanks.  EdChem (talk) 14:30, 23 February 2017 (UTC)

The refs say that by 1H-NMR the aromatic signals disappear and no other CH signals appear. Presumably it becomes CO2? DMacks (talk) 07:36, 25 February 2017 (UTC)
@DMacks: Thanks for the new image.  I see you've made a series of changes, which all seem like improvements to me.  On the "contrast", I think when I wrote that I had sources saying RSR to RS(O)R but RSeR to RSe(O)2R, but the formation of sulfones also occurs.  I'll make some tweaks.  On the propylbenzene oxidation, I wondered about formation of CO2, but in that case wonder why the carbon in the ring is fully oxidised but the propyl chain in the resulting butanoic acid is preserved?  EdChem (talk) 08:37, 25 February 2017 (UTC)

This review is transcluded from Talk:Trifluoroperacetic acid/GA1. The edit link for this section can be used to add comments to the review.
Reviewer: AlastairJHannaford (talk · contribs) 12:13, 28 July 2019 (UTC)