Talk:Ascorbic acid
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[edit] Vitamin C?
Exactly how is vitamin C different from ascorbic acid? Even if strictly true in a chemical sense, a good encyclopadia will take the average reader to the terminology most used in everyday speech (first)and then gradually inform him or her what all the other alternate words are. "Ascorbic acid" is definately not used as much as the term "vitamin C", right?
W. Whitney
The acid hydrolysis mechanism here uses single-headed arrows. This is wrong. A single-headed arrow implies movement of single electrons (a radical mechanism). Double headed arrows should be used here, implying movement of electron pairs. 24.181.29.106
Ascorbic acid and Vitamin C are not equivalent--Vitamin C is a form of ascorbic acid (I'm believing what I'm reading). Ascorbic acid is more general, so if anything, Vitamin C should redirect into ascorbic acid.
However, I think it's best if they're separate entries; ascorbic acid about the general class of ascorbic acid, Vitamin C about the L-idoslkwhater of ascorbic acid.
--TheCunctator
Exactly. isomer. The L isomer. Althought that isn't the only nomenclature that can be used to describe the isomeric differences. I'm not an expert on the biochemistry of ascorbic acid--it could be that the L form and the D form interconvert to form a racemate in vivo, but I wouldn't bet on it.
one can discuss ascorbic acid as a organic acid without any reference to it as a nutrient. That's why I originally put the stuff in about it's use as a reductant in chemical developer solutions--Eastman Kodak uses tons of this stuff!
--JoeAnderson
Was it Haworth or Szent-Györgyi who got the Nobel for vitamin C? -- Marj Tiefert, Tuesday, June 11, 2002
both...
see:
http://www.nobel.se/chemistry/laureates/1937/haworth-lecture.html
http://www.nobel.se/medicine/laureates/1937/szent-gyorgyi-lecture.html
Malcolm Farmer, Wednesday, June 12, 2002
Could someone check my revision of the SMILES string? I didn't like how it neded with (CC) since I don't see an ethyl in the structure anywhere.
C1(O)=C(O)C(=O)OC1(C(O)CO)
gives the same structure as "ascorbin.gif" when I plug it in at http://www.daylight.com/daycgi/depict, although my head swims when I try to figure it out on paper. Milkfish 11:25 Apr 14, 2003 (UTC)
[edit] Molecular weight ?
An anonymous user amended this from 176.12 to 176.13 Both weights give a similar number of hits on Google however since a large proportion of the 176.12 sites are Wikipedia mirror ones I've left the higher figure. Can anyone give an authorative answer? Lumos3 15:33, 26 Sep 2004 (UTC)
- Using the numbers for atomic weight given on wikipedia for carbon (12.0107), Hydrogen (1.00794), and Oxygen (15.9994), it's 176.12412, which would be the same as 176.12, so I edited it back. --Niffux 06:43, 20 Oct 2004 (UTC)
[edit] Synthesis route?
I know nothing on this, but would like to see a section on how it's synthesized, and when that process was developed etc. Thanks!--Joel 02:53, 25 Apr 2005 (UTC)
- There is a short description of Artificial chemical synthesis on Vitamin C#Sources. But a more detailed chemistry based description would be welcome here. Lumos3 08:10, 25 Apr 2005 (UTC)
[edit] Which is the "acid" hydrogen?
I'm curious since the molecule doesn't have any obvious "acid" component. Does the ring get hydrolyzed, leaving a carboxyl group? GCarty 08:57, 18 July 2005 (UTC)
---
[edit] To Polyparadigm and GCarty
Polyparadigm- I do have infomation on the synthesis of Vitamin C in about 10 different methods, though im not really sure about copyright on the images i would need to explain it.
GCarty - The OH groups on the 'bottom' of the molecule are easily oxidised and the H+ are dissociated into solution, giving the acid, acidic preoperties. (usually only 1 H+ dissociates forming dehydroascorbic acid, therefore its is only a weak acid) the remaining oxygen form a double bonds with the carbon (a carbonyl group like you mentioned)
(Eyehawk78 23:43, 1 March 2006 (UTC))
The acid is the OH on the very last of the string, but not any part or near the ring.
[edit] Decomposition of ascorbic acid
I read somewhere (don't remember where) that vitamin C decomposes with heat. Is this true? (I can't find anything on it on this article so if it's there point me to it.)
If so, does vitamin C continue to decompose while it's at a constant heated temperature (like, heated to 50 degrees C and then kept at 50 degrees C)? And what's the equation for its decomposition?
(I am studying chemistry at senior secondary school level (equivalent to 16-18 year olds).) Neonumbers 10:12, 27 March 2006 (UTC)
- Decomposition?
- At 50°C with oxygen present you get from HO-C=C-OH at the 5membered ring to the oxidated state of O=C-C=0 there this is the reaction normaly ascorbic acid is used for an anti oxidant protecting other substances to be oxidized, by being oxidized.--Stone 10:28, 27 March 2006 (UTC)
So ascorbic acid doesn't decompose, but instead gets oxidised by oxygen? (Ignore the "50 degrees" and replace 50 with some higher number if necessary.) Then (just so I can grasp everything):
- could I ask someone please to elaborate on the melting point "190 - 192°C (decomposes)"?
- Merk calaloug says the same.
- does that mean that if you put ascorbic acid in a closed bottle without any oxidant in it, nothing will ever happen to it no matter how heated it is (practical considerations aside)?
- No! Acid esters with alkohols can give reactions and it contains both groups. The temperature is the point 50°C would be OK but for some time but every 10°C the reaction rate doubles and at this rate with 100-150°C the stuff will turn brown and black within the hour.
- Other reactions then oxidation like ester cleaving is also possible!
- does that mean that heating something with vitamin C merely speeds up the rate of reaction, or shifts an equilibrium, of the redox reaction, or something on the lines of thermochemical/equilibrium principles?
- speed up with temperatur!
- is ascorbic acid oxidised by oxygen at room temperature (albeit slowly)?
- Yes slowly!
Perhaps now is a good time to explain the context of my question: I am planning to investigate the effect of heat on the concentration of ascorbic acid in blackcurrant juice. Neonumbers 12:11, 27 March 2006 (UTC)
May be there is more (papers!)--Stone 16:45, 27 March 2006 (UTC)
[edit] Merger with vitamin c
Oppose This has already been discussed at length see Talk:Vitamin C#Ascorbic Acid vs Vitamin C. Lumos3 19:04, 25 June 2006 (UTC)
The vitamin C article is already plenty long, breaking it into a basic and industrial chemistry article and a separate, more biological one is fine. Also all vitamin C related material is not strictly ascorbic acid alone. Opposed.--69.178.41.55 06:44, 28 June 2006 (UTC) see prior discussion at Talk: Vitamin C late 2005.
- 3 weeks in the sun (5 to 7 days as a decent comment interval, 4-0) with no support, I removed the Merger proposal tags.--69.178.41.55 05:49, 16 July 2006 (UTC)
Oppose for reasons stated above BrianZ(talk) 05:35, 2 July 2006 (UTC)
Oppose, ditto. -- Hongooi 10:43, 2 July 2006 (UTC)
Strong Oppose as above.--TheNautilus 07:27, 1 February 2007 (UTC) ṆјĽÈŲˡΑþŞΞĹ[[Category:]]
[edit] Merge Erythorbic acid into this article?
Articles such as Tartaric acid contain stereoisomer information rather than having it in separate articles. This would probably be the best idea here.
- Support ◄§ĉҺɑʀκs► 13:06, 16 December 2006 (UTC)
- Support Lumos3 14:58, 16 December 2006 (UTC)
- Support: I agree, but don't take me too seriously because I'm not a chemist. Neonumbers 12:31, 17 December 2006 (UTC)
- Oppose Although the chemistry and industrial uses of Erythorbic acid are very simular to ascorbic acid or vitamin C, it took me, as a PhD chemist, about ten minutes and the use of the Acros Organic Catalogue (which I just accidently happen to have on my desk), to reveal the difference between the two compounds. This means, by transfering the Erythorbic acid article, to the ascorbic one, the erythorbic data rappidly drawn in the ascorbic. On the other hand, by focusing on the differences in the erythorbic-article and refering to ascorbic acid on the chemical behavior both points of view may be satisfied. T.vanschaik 22:14, 17 December 2006 (UTC)
- The Eryhthorbic acid article's not that long. How about having it in a section or sub-section in this article? Then those differences can be focused on there. Neonumbers 02:01, 18 December 2006 (UTC)
- Oppose Since there are vitamin, essential food and pharmaceutical uses of ascorbic acid, food antioxidant use of erythorbic and a strong industrial use of erythorbic, I prefer to try to maximize separation to avoid possible confusion. The erythobic acid article needs room to grow.--TheNautilus 07:27, 1 February 2007 (UTC)
- Oppose - distinct chemical compounds Jack · talk · 03:01, Monday, 26 February 2007
