Talk:Hexane
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Query
editRelated compounds - hexanes? Rich Farmbrough 21:27 4 May 2006 (UTC).
can i use hexane to clean Li will it react with it? —Preceding unsigned comment added by 86.31.40.46 (talk) 14:04, 24 February 2008 (UTC)
- yes you can use hexane or other hydrocarbons to wash lithium without worrying about it reacting —Preceding unsigned comment added by 96.227.63.41 (talk) 18:11, 24 February 2008 (UTC)
Received from OTRS
editThis is regarding the safety diamond on the hexane page.
1. The flash point of hexane is -23 degree centigrade and what the law says is if its less than 23 it should be 4 while the page shows its 3 2. The Blue health says "4. Very short exposure could cause death or major residual injury" so shouldn't it be 4 rather than 1? 3. The reactivity shows "0" which the article says "0. Normally stable, even under fire exposure conditions, and is not reactive with water". This, to out information is an explosive.
Vandalism
editThis article has obvously been the target of vandalism. Can someone fix this?
n-hexane?
editCould someone please clarify what the difference is between n-hexane and hexane, if any, and what the "n" means? Is n-hexane a term that is inclusive of all the isomers? Does it refer exclusively to the straight-chain compound? Thanks. --Barefootmatt 22:36, 16 March 2007 (UTC)
I have no idea either, but apparently, the people here are too busy to answer our question... —Preceding unsigned comment added by 71.161.49.166 (talk) 15:01, 2 October 2009 (UTC)
- I hope it is now clear. --Jorge Stolfi (talk) 16:58, 15 November 2009 (UTC)
- Think of the n as standing for "normal" 82.1.82.155 (talk) 15:40, 12 September 2011 (UTC)
5 Isomers??
editThere are more than 5 isomers of hexane, no? What about cyclohexane? What about 1-methyl-cyclopentane? There are a bunch of others. Someone either tell me I'm wrong, or correct the article, please. —Preceding unsigned comment added by Ayengar (talk • contribs) 16:38, 20 December 2007 (UTC)
- Without the prefix, "cyclo," the term, "hexane," is taken to mean an open-chain, saturated, 6-carbon hydrocarbon. Note that cyclohexane is not an isomer of hexane as it contains a different number of hydrogens: hexane = C6H14; cyclohexane = C6H12. Karl Hahn (T) (C) 21:37, 20 December 2007 (UTC)
Cyclohexane
editHi Am a Local Friend From Sri Lanka Nick Namd Char!! Some Call me BG well i want to know How Alkyl Groups Make Hexyl and Create A dimension of Several Carbons and not any Other ??? any1 knows the answer please write to [email protected]
There are more than 5 isomers of hexane, no? What about cyclohexane? What about 1-methyl-cyclopentane? There are a bunch of others. Someone either tell me I'm wrong, or correct the article, please.
In my organic chem class im in, n-hexane refers to normal hexane. which is a way to refer to the unbranched isomer.
- Cyclohexane (C6H12) is not an isomer of hexane (C6H14), because they have different formulas. --Itub (talk) 11:35, 3 July 2008 (UTC)
About hexane in general or only n-hexane?
editThe "chembox" on the right of the page is exclusively relative to n-hexane. However, much of the body of the article seems to be about hexane in general (i.e. C6H14; excluding cyclohexane); the very fact it states that there are five isomers implies this.
Something should be done to clarify this. I'm not sure each isomer merits its own whole article, but five chemboxes, or including all isomers in the one chembox, might be useful.
David Olivier (talk) 22:30, 21 July 2009 (UTC)
- The box now says "n-hexane" at the top. This should resolve the ambiguity. --Jorge Stolfi (talk) 17:00, 15 November 2009 (UTC)
- It seems much clearer now and more informative. Good work! David Olivier (talk) 16:55, 16 November 2009 (UTC)
removal - this
edit"The unusual toxicity of n-hexane (compared with other alkanes) has resulted in the chemical industry switching away from n-hexane in favour of n-heptane where possible.[citation needed]"
First part is debatable (or unproven), second part doesn't appear to be true.
see http://www.cdc.gov/niosh/pel88/142-82.html "the ACGIH concluded that heptane was more acutely toxic than hexane. The ACGIH therefore recommended limits for heptane that are somewhat lower than the limits for the hexane isomers." , also "because NIOSH believes that "it would be incorrect to conclude that the neurotoxic properties ascribed to n-hexane are unique to this compound [n-hexane]. Other alkanes or related chemicals [such as heptane] that are ultimately metabolized to gamma diketone may have similar toxicity"
However it does say that OSHA believes hexane is unique.
Unless there is evidence for a switch the above statement seems unlikely, or simply wrong, especially considering the above report.83.100.251.196 (talk) 14:22, 18 September 2009 (UTC)
According to the article hexane is apparently odorless when pure. How pure does it have to be? I'm having a bottle of Hexane (ReagentPlus >=99% from Sigma-Aldrich, 139386-100ML) on the table and I can smell it immediately if I open it and I'm not under the fume hood. In the box on the right the article describes the odor as petrolic.Mooto85 (talk) 19:58, 20 January 2016 (UTC)
Remove the section on food toxicity
editThe section 5.1, entitled "Use in food processing" should not be included in this article. Its sole source is a study from the Weston A. Price Foundation's front group, the Cornucopia Institute. The WAPF is notoriously anti-soy and in general, exists to produce publications that increase the demand for livestock products. In this case, unless the findings of the study can be independently corroborate -- specifically the claims about toxicity of the levels of hexane in these foods -- it should be removed. Currently, this article contradicts itself, as the preamble claims that the boiling point is very low and that hexane is a safe, non-reactive solvent. Any amounts of hexane present in food would be boiled off in cooking. —Preceding unsigned comment added by Tobor0 (talk • contribs) 00:54, 16 April 2010 (UTC)
Do you have any evidence of the Cornucopia Institute being linked to WAPF? I haven't found any yet, but may believe it if there is credible evidence. --Tekhnofiend (talk) 14:54, 12 January 2012 (UTC)
- Toxicity from Hexane isomers appears to be from inhalation; I can't find any evidence of the background levels remaining in food having any appreciable effects on human health. This is the sort of BS that Food Babe and others come out with. Smidoid (talk) 02:08, 17 March 2015 (UTC)
- Websearching "hexane food health" shows plenty of discussion of alleged health effects from hexane residues in food. I am somewhat skeptical of hexane remaining in processed food, but there may be contaminants transported by this very effective solvent. Complete removal of any mention of this controversy would not be WP:NPOV. Wikipedia should not ignore the existence of an ongoing controversy about the subject. Reify-tech (talk) 03:09, 17 March 2015 (UTC)
List to table
editI have replaced the itemized list of isomers by a table with molecular diagrams. The old itemized list is pasted below, just in case (for one thing, the text formulas may be useful elsewhere). All the best, --Jorge Stolfi (talk) 17:49, 16 November 2009 (UTC)
- normal or n-hexane, CH3(CH2)3CH3, a straight chain of six carbon atoms.
- 2-methylpentane or isohexane, (CH3)2CH(CH2)2CH3, a five-carbon chain with one methyl branch on the second.
- 3-methylpentane, CH3CH2CH(CH3)CH2CH3, a five-carbon chain with one methyl branch on the third.
- 2,3-dimethylbutane, CH3CH(CH3)CH(CH3)CH3, a four-carbon chain with one methyl branch on the second and third.
- 2,2-dimethylbutane or neohexane , CH3C(CH3)2CH2CH3, a four-carbon chain with two methyl branches on the second.
Poisoning from touchscreen cleaner
editI find it highly unlikely that hexane alone caused severe poisoning in these 63 people. Does anyone have a second (or better) source for this?
Another question: Why don't millions of people die each year from gasoline poisoning if hexane(s) are so poisonous?—Preceding unsigned comment added by 144.167.151.205 (talk) 20:16, 2 July 2010 (UTC)
- I saw an interview on TV and this person would wipe the screen with a cloth or paper towel. I believe that she didn't use gloves. Apple said that they made the company improve ventilation. One generally does not touch gasoline and works with it outdoors. Paul Studier (talk) 01:12, 14 April 2011 (UTC)
I wonder why would they replace alcohol as the cleaner of choice. Due to probable abuse by the workers (drinking) ? Martian742 (talk) 09:24, 2 May 2011 (UTC)
Most probably denatured alcohol was used that is unsuitable for drinking. Hexane was probably found cheaper than alcohol and to increase profits the factory switched. But safety protection is more important when using hexane. So it's probably not cheaper considering the costs of gloves and better ventilation but Chinese factories tend not to care much about the safety of their workers, sadly. —Preceding unsigned comment added by 85.229.182.19 (talk) 21:12, 9 May 2011 (UTC)
The official reason cited in this radio show is that hexane dries up faster than alchol, so it increases productivity. The show explains other details of the manufacturing process. http://www.thisamericanlife.org/play_full.php?play=454 — Preceding unsigned comment added by 84.221.197.229 (talk) 15:50, 22 February 2012 (UTC)
- Should be noted that This American Life has retracted[1] that story, so we should be careful using it. It's probably true that n-hexane does dry faster than alcohol, but I'd suggest other sources be used to support it. Lekoman (talk) 10:20, 18 March 2012 (UTC)
- ^ "Retraction". This American Life.
"Contradiction"
editSome anon recently tagged the article as appears to contradict itself. The reason given is that hexane is relatively safe as stated in the introductory section contradicts the warnings later in the article. IMO, as compared to some other nastier organic solvents such as methanol, chloroform, benzene, etc, there is no issue stating that hexane is relatively safe with proper protection. --Joshua Say "hi" to me!What I've done? 07:39, 15 February 2012 (UTC)
Anything can be toxic in large amounts. I'm sure it's toxic (NIH states that it's toxic to humans over 190 ppm), but as Joshua said, I also believe it is "relatively" safe compared to other nastier chemicals, hence it's wide usage (even in beginning undergraduate labs). Lisdavid89 (talk) 03:45, 28 April 2012 (UTC)
Separating n-hexane from "hexanes in general"
editI hope that this change will make everything easier in the long-term, so please read my explanation below.
This page will refer to non-cyclic hexanes in general, and it will also point the user toward the new "n-hexane" page.Armadillo1985 (talk) 15:17, 11 May 2012 (UTC)
External links modified
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"see Table"
editThe 'Safety' section starts, "The acute toxicity of n-hexane is rather low, requiring grams per kilogram (see Table)." What table? Bruce Mardle (talk) 20:59, 12 April 2017 (UTC)
- Thanks. Good catch.JSR (talk) 22:01, 12 April 2017 (UTC)
External links modified
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mmHg? Shouldn't it be inHg?
editNo scientist but think this is inconsistent — Preceding unsigned comment added by 67.3.7.245 (talk) 00:24, 30 March 2022 (UTC)
Better opening to article
editThere are inaccuracies and inadequacies to this article introduction (at least), says this lifetime OChemist.
First, if indeed the only chemical meaning of the title term is for the normal isomer, why does a following sentence use boiling "points" in the plural? And, same sentence, why is the suggestion that the b.p. an approximate value (and why no STP or other statement of the conditions for the physical parameter reported)? Bottom line there, if the title term can only be understood as n-hexane, then it should be have a precise b.p., at a specified set of conditions.
But there lies the deeper problem. Hexane refers both to a specific compound (n-hexane), but also to a class of compounds, more generally, the C6 unsaturated hydrocarbons. ("That compound is a hexane. And that compound too is a hexane.") Hence, the Merriam-Webster and other definitions of the term, as "any of several isomeric volatile liquid alkanes C6H14 found in petroleum" (https://www.merriam-webster.com/dictionary/hexane). Both the given and the excluded uses of the term are common, and correct, and the omitted general MW-type definition should also appear near the opening of this article's introduction.
That correction made, it should be explicitly stated that referring to n-hexane as hexane represents a shorthand of the general sort that plagues students of OChem—that alongside formal, systematic naming, a variety of popular naming conventions still exist and are in regular use (the convention here being that the shortened name could refer to either n-hexane, or to the C6 class of various isomers). That "hexane" can refer to either means one must infer which meaning is in use from the context of any given occurrence of the term.
In addition to these confusing opening elements, the article goes on to say a number of other things that likewise suggest someone contributing/controlling the current content is not a real chemist, or lacks nuance and experience. For instance, you will hear only later that hexane can refer to a mixture of C6 compounds (whereas this is the sole MW definition), but when it appears, there is no mention of this being the consequence of it being a an industrial distillation fraction. And then it's said that some gasoline mixture—which one for heaven sake, these are carefully defined and specified—contains a fixed percent of "hexane". But surely, it cannot be the suggestion that in the formulation of gasoline mixtures, a very pure n-hexane product is added to give this fixed percent. Without consulting the source from which that "fact" was drawn (or engaging in a discussion regarding interpretation of that source), it's hard not to suppose that what the source means is that what is added in the formulation of the fuel mentioned is a volume of an industrial fraction of hexanes (and not n-hexane, as the article currently suggests).
All of this is to say that, by not properly defining the term at the opening—that it can be in one of two things—the authors of this introduction paint themselves into a a variety of corners. A good review/re-write along the lines suggested, by a broadly experienced organic chemist, perhaps a professor, is needed. 2601:246:C700:F5:C8AE:A4C8:CDD5:B7FA (talk) 22:16, 26 March 2023 (UTC)