Draft talk:Urea hydrochloride

Article creation is preceded by finding great refs

good refs = WP:secondary or WP:tertiary. Smokefoot (talk) 00:17, 4 July 2024 (UTC)

I did some research and found more on applications. Looks to be deeper than I first thought. Reconrabbit 19:05, 4 July 2024 (UTC)

Frankly, it looks pretty weak. Contrived, 3rd world refs, nothing of real authority.

In commercial chemistry, there all kinds of stuff sold for killing ants, cleaning toilets, washing cars, removing rust, on and on. Those topics are certainly legit. But teasing the chemistry out of such products requires some sophistication.

I cannot find any mention in the big (or little) chem books for urea-hydrochloride. I mean, what is urea hydrochloride supposed to be? Do you have structure in mind? If not, what are you writing about... and why??? I think that mixing hydrochloric acid and urea gives ammonium chloride and CO2. This item relates to a bigger issue: you dont seem to understand the chemistry very well. Of course you're probably young and will be learning a lot. --Smokefoot (talk) 20:14, 4 July 2024 (UTC)

I will add that patents are poor sources. They often just make up all possible combinations, without ever testing if they work or exist. The idea is just to stop someone else doping a variation of the patent. So they are usually not reliable sources. They may however point you to a more useful reference. Some "applications" are not actually used, but may have had just one experiment to show it could be used that way. This type should probably go into a properties section. Graeme Bartlett (talk) 00:51, 5 July 2024 (UTC)

I am seeing where I am running into mistakes. My impetus to start putting something down was when I was at a hardware store and discovered that the etchant commonly available was now using urea (mono)hydrochloride as the active ingredient and that it was much harder to find muriatic acid. I thought there might be somewhere to go off researching from that point, but it seems there isn't much. Maybe best to abandon this as the relevant references are so old they may not be really reliable. Reconrabbit 03:07, 5 July 2024 (UTC)

Since the product is actually used, it is pretty sure to be notable. But can you find the good sources? Smokefoot may be excessively pessimistic about California being third world country. But the best kind of sources are books. Review articles are also good. Does your substance exist as a solid? If so I hope there is a crystal structure that would prove its structure and reality. (For etching concrete I used citric acid). Graeme Bartlett (talk) 04:19, 5 July 2024 (UTC)

I'm getting mixed information whether it exists as a solid. Historical literature implies that the urea salt is a solid and is dissolved into quinine (this article gives a concentration of 15 grains in 2 cc suspension), and that this composes a double salt. NIST has NMR spectra, but very poor reference data. Density and melting point are given on CAS common chemistry. Wood Library Museum of Anesthesiology provides some background on the historical process, claiming it is still used today. But, there is no obvious vendor of the pure substance anywhere, and all the current references I can find are primary research or patents. Reconrabbit 05:02, 5 July 2024 (UTC)

Review article: mentions diurea hydrochloride and monourea hydrochloride and a couple of reactions. Information referenced from Hoffman, Ber., 4,262 (1871). The Pharmacopoeia of the United States of America has come content on it. With quinine, that would be a mixture in solution for injection. But it is a valid use, so should be written about in the article. Graeme Bartlett (talk) 05:22, 5 July 2024 (UTC)

structure:

To be crude, where I come from what you are doing is "pushing shit uphill". You start with the fervent (I think, irrational) commitment to write something about which you dont understand. You are focused on a chemical the existence of which you cannot document in the lede. So, what are you trying to do - damage Wikipedia further?

The best you can do is a 1936 chemE article? Here is my guess. Urea hydrochloride is a cleaning agent made by neutralizing HCl (muriatic acid) with urea. The solution consists of NH4Cl, a decent weak acid.--Smokefoot (talk) 14:14, 5 July 2024 (UTC)

You're right. The evidence for this compound is extremely weak. At this point the only reasonable move I can see is to scrap this and extract a historic account of quinine urea hydrochloride, a notable historic anesthetic with very unclear provenance. Reconrabbit 16:13, 5 July 2024 (UTC)

Well actually ... uronium is stabilized by charge delocalization, analogous to guanidinium; protonation occurs at the oxygen, as noted in https://goldbook.iupac.org/terms/view/U06580. Uronium salts have been characterized by X-ray/neutron diffraction, e.g. urea nitrate: https://ris.utwente.nl/ws/portalfiles/portal/6487049/Harkema69crystal.pdf and https://journals.iucr.org/paper?a06669 (which also states "The prevalence of salts of urea made these compounds obvious choices for consideration"), urea phosphate: https://doi.org/10.1107/S0365110X57001425 (technically not a uronium salt), and uronium sulfate: https://doi.org/10.1107/S0108270198014619. The (hydro)chloride is the only common salt for which I can't find a structure paper, though I'd be extremely surprised if it had a different structure to the nitrate / sulfate.

It's a pity we haven't yet been able to dig up the reference cited by CAS: G. M. Strongin, "Trudy po Khimii i Khimicheskoi Tekhnologii" (Studies in Chemistry and Chemical Engineering), Gorky, 1966, No. 2, p. 323-5, which I think would help with all this. As for notability? I'll leave that to y'all to decide. Preimage (talk) 16:31, 5 July 2024 (UTC)

One idea, since you seem motivated to address the casual consumer's question of "what is this stufff?" is to build in a redirect to ammonium chloride#Concrete treatments for the term "urea-hydrochloride", but spare us of those references! I can do this chore is you want. --Smokefoot (talk) 17:47, 5 July 2024 (UTC)

Urea hydrochloride is not the same as ammonium chloride - see discussion (with links) above. Preimage (talk) 17:55, 5 July 2024 (UTC)

You are correct: urea hydrochloride is not the same as ammonium chloride. Very good. One (urea hydrochloride) is fiction, which someone who knows almost no chemistry, is trying to shoehorn into Wikipedia. The other (ammonium chloride) is nonfiction. It is a real compound. It is one product from mixing urea and hydrochloric acid. Ammonium chloride is discussed by someone who is a chemist to avert the insertion of some stinky garbage into this encyclopedia.--Smokefoot (talk) 20:37, 5 July 2024 (UTC)

For my own sake I would like to say that I am writing about an area I am wholly unfamiliar with. I would hope that my knowledge of chemistry as a whole is a little more than nothing. Is the prose here completely useless as a historical record, if only of people without the background to realise what they were naming was not actually urea hydrochloride (which I ended up repeating)? There is a pervasive idea that you can somehow get urea hydrochloride from mixing HCl and urea, even though urea forms ammonium species when it's reacted with most other strong acids, and there is literature that supports the existence of such an acid salt formed through this mechanism (but the mechanism and product is always described in vague terms). Any meaningful discussion of "urea hydrochloride" would be venturing into territory of original research. I see just how badly I've screwed up here and am glad this isn't leaving draft space. Reconrabbit 16:04, 6 July 2024 (UTC)

User:Smokefoot, I appreciate all the work you've put into Wikipedia. I can imagine how frustrating it must be dealing with non-expert editors on a daily basis. I agree with you that urea hydrolysis is a form of amide hydrolysis - typically slow at neutral pH but accelerated by strongly acidic or basic conditions. However, I think you're missing the fact that urea, unlike a typical amide, "is basic and is protonated readily", undergoing protonation at oxygen to form a resonance-stabilised uronium ion, analogous to guanidinium and amidinium. With the exception of urea phosphate (which does not appear to contain uronium, instead being stabilised by hydrogen bonding), this seems to be the reason why urea salts are comparatively stable (particularly in solid form).

OK, that's the theory; we still need to find good chemistry references demonstrating this is actually what happens. (I agree with you that the current version of the article is grossly lacking here.) As far as I can tell, the reason why it's hard to find good references is that the preparation of urea salts is such ancient and uninteresting chemistry that no-one has bothered publishing much about it post-1910. I was able to dig up a 1903 PhD dissertation characterizing 30-odd new urea salts and cocrystals: Montgomery, Jack Percival (1903). Some New Compounds of Urea with Acids and Salts (Thesis). hdl:2027/mdp.39015028798968. To quote from its preface, "Very early in the history of urea it was found that it combines with acids, acting as a weak base. A number of these compounds were described prior to 1860, but since that time contributions to the list have been rare, notwithstanding the fact that a number of acids had not been combined with urea. In this paper are described some compounds not previously presented." The new compounds it describes include urea hydrofluoride, hydrobromide, and hydroiodide. But most importantly, it provides a reference for the synthesis of urea hydrochloride.

Its reference is Gmelin-Krauts Handbuch der Chemie, a sibling of Gmelins Handbuch der Anorganischen Chemie, which you may recognise as the most famous reference work in all of inorganic chemistry. Why would Gmelin's cover urea? Turns out that the 1848 edition has an extra 5 volumes on organic chemistry, with Volume 4 (the first extra volume) including a section on urea. Here's the paragraph describing the preparation of urea hydrochloride by reacting urea with hydrogen chloride.

Gmelin, Leopold; Kraut, Karl Johann (1848). Gmelin-Krauts Handbuch der Chemie. Vol. 4. p. 294. hdl:2027/chi.13130191. [Verbindungen] (b) Mit Salzsäure. Der Harnstoff absorbirt das salzsaure Gas. PELOUZE, HAGEN. Sättigt man ihn damit, anfangs in der Kälte, zuletzt bei 100°, und befreit das gebildete blassgelbe Oel durch einen Luftstrom von der überschüssigen Salzsäure, so erstarrt das Oel beim Erkalten unter Wärmeentwicklung zu einer weißen, harten, blättrig strahligen Masse. Dieselbe zerfließt an der Luft rasch zu einer sehr sauren Flüssigkeit, welche Salzsäuredampf verbreitet; eben so wird sie durch Auflösen in Wasser sogleich in freie Salzsäure und freien Harnstoff zersetzt. In kochendem absoluten Weingeist scheint sie sich unverändert zu lösen, doch krystallisirt hieraus beim Erkalten sehr wenig Salmiak, der wahrscheinlich schon bei der Absorption des salzsauren Gases gebildet wurde. Salpetersäure fällt aus der weingeistigen Lösung sogleich salpetersauren Harnstoff. ERDMANN u. KRUTZSCH (J. pr. Chem. 25, 506).

Lastly, I should again mention that I don't have a strong view re: notability. Personally, I don't think urea hydrochloride is particularly interesting, and chemistry-wise I think it should suffice to just add a section to urea on the uronium ion, analogous to the section of guanidine talking about the guanidinium ion. But there do seem to be some historical medical uses (in combination with quinine hydrochloride), as well as more modern uses as a cleaning agent, that might warrant a standalone article. I'll leave it to more experienced editors to make a judgment call here. Preimage (talk) 18:07, 6 July 2024 (UTC)

Finally, the last freely available version of Beilstein available on HathiTrust (published 1893–1899) covers diurea hydrochloride and urea hydrochloride. You'd have to be pretty brave to claim that's an unreliable source.

Beilstein, Friedrich Konrad (1893). Handbuch der organischen Chemie. Vol. 1. p. 1294. hdl:2027/osu.32435020872065. Verbindungen des Harnstoffes mit Mineralsäuren. 2CH₄N₂O·HCl. Zerfließliche Blätter (DESSAIGNES, J. 1854, 677). — CH₄N₂O·HCl. Sehr zerfließliche, blätterige Massen. Zerfällt, beim Lösen in Wasser, in HCl und freien Harnstoff (ERDMANN, KRUTSCH, J. pr. 25, 506). Zerfällt, beim Erhitzen, in Salmiak und Cyanursäure. Preimage (talk) 08:28, 7 July 2024 (UTC)

I will note here that I could not find a crystallographic structure in COD or CCDC. That may be just due to my limitations though. Graeme Bartlett (talk) 22:29, 6 July 2024 (UTC)

Graeme: I looked too for the same. Many structures of O-prototonated versions of urea: phosphate, sulfate, nitrate . (doi 10.1107/S0108768101004359, 10.1107/S0108270198014619, 0.1107/S0567740869002603). No chloride. Preimage: when you go to Gmelim (now defunct?), that source is exhaustive. If that source provided not good refs, you are basically done. Good luck to you all, was fun. --Smokefoot (talk) 13:05, 7 July 2024 (UTC)

Even garbage

This article, if it makes it to main space, would be an example of mediocrity triumphing over notability and quality. Garbage. --Smokefoot (talk) 13:17, 10 July 2024 (UTC)

I think there's a disconnect in how we've been approaching this article. I think we both agree the article isn't in a publishable state right now. As a (relative) newbie, I've been viewing it as an opportunity to learn more about WP editorial policies (GNG, V, MEDRS, etc.) in a low-stakes environment (because it's not about something I feel particularly invested in). What I'm going to do next is write up a detailed review of the current version, under a separate header. Once I've posted this, I'd appreciate any specific feedback you might have about it. Cheers, Preimage (talk) 05:22, 14 July 2024 (UTC)