Talk:Cyclohexanone

Cyclohexanone melting point

• I'm probably missing something, but according to the Sigma-Aldrich and Acros websites the mp for cyclohexanone is −47°C at 25°C. The value in the infobox was corrected into −16.4°C. What is the corect value? Berserker79 09:23, 25 August 2005 (UTC)

Yes, the melting point of cyclohexanone does cause a bit of a problem. The value I quoted is from Weast, R. C. (Ed.) (1972). Handbook of Chemistry and Physics (53rd Edn.). Cleveland:Chemical Rubber Co., which also gives the figure of −45 °C as "of questionable accuracy". The original reference appears to be Timmermans, J.; & Hennault-Roland, M. (1937). "Works fom The International Bureau of Physical-Chemical Standards. VIII. Physical constants of 20 organic compunds". J. Chim. Phys. Phys.-Chim. Biol. 34:693. The NIOSH guide also gives −49 °F (− 45 °C), while Sigma-Aldrich Co. gives −47 °C. We have had some problems with Aldrich melting points for other compounds (notably the amino acids): to be fair, they never claim to be a data book, they merely supply literature values for the convenience of their customers. Pine, S. H. Organic Chemistry (5th Edn.). New York:McGraw-Hill. 1987. ISBN 0-07-100242-1. gives the Rubber Bible value of −16 °C, while the International Chemical Safety Card quotes a value of −32.1 °C. The reference for this last value appears to be Sellers, P.; & Sunner, S. (1962). "Heats of combustion of cyclic ketones and alcohols". Acta Chem. Scand. 16:46–52. NIST lists a few more values around −30 °C, and one value from White, A. H.; & Bishop, W. S. (1940). "Dielectric evidence of Molecular Rotation in Crystals of Certain Non-aromatic Compounds". J. Am. Chem. Soc. 62:8–16. at −40°C (but nothing lower). By now, I am beginning to wish I had followed the example of Kemp, W. Qualitative Organic Analysis (2nd Edn.). London:McGraw-Hill. 1986. ISBN 0-07-084158-6., Openshaw, H. T. A Laboratory Manual of Qualitative Organic Analysis (3rd Edn.). Cambridge:CUP. 1955.  .{{cite book}}: CS1 maint: extra punctuation (link) and Fieser, L. F.; & Fieser, M. Organic Chemistry (2nd Edn.). London:Harrap. 1953.  .{{cite book}}: CS1 maint: extra punctuation (link), all of whom decline to give a value for the melting point!

In general, when there is a discrepancy between sources for the melting point, I tend to choose the highest value (impurities tend to lower the observed melting point, as does poor technique in making the measurement). A discrepancy of this size can only really be due to supercooling, which would also mean that the higher values represent the "true" melting point. The only option left (short of measuring the value ourselves, which is not allowed under WP:NOR) is to check the original papers or Beilstein (7², 5). The Merck Index reference is 11, 2732.

I hope this goes some way to answering your question! Physchim62 19:33, 25 August 2005 (UTC)

• Thanks for the detailed explanation. This definetely helps to answer my question! Sigma-Aldrich and other chemicals resellers websites are a quick source for data, but I'll probably check other sources next time, to verify the information is as much correct as possible. Thank you! Berserker79 12:30, 26 August 2005 (UTC)

Don't worry, as a professional chemist the Aldrich catalogue is my single most used source for physical data on compounds (it's free, there's always a copy lying around whichever lab I'm working in). Just remember that any data source may be inaccurate, even though science is knowing the difference between scepticism and paranoia! Physchim62 23:16, 27 August 2005 (UTC)

Nylon 66 and Nylon 6,6

I fix the link. So now will correctly go on the page of Nylon and not in the page of the gun. —Preceding unsigned comment added by Dario1189 (talk • contribs) 10:15, 7 January 2010 (UTC)

According to one of your own cited sources (NIOSH Pocket Guide to Chemical Hazards), cyclohexanone causes "...irritation eyes, skin, mucous membrane; headache; narcosis, coma; dermatitis; in animals: liver, kidney damage." And according to the manufacturer's MSDS, it also causes lung damage. — Preceding unsigned comment added by 50.47.108.209 (talk) 18:17, 1 January 2012 (UTC)

Hazard info

Not to sound too flip but so does almost every organic compound if you mess with them enough. They also ignite readily, etc. We reached a consensus here not to list routine information that is more authoritatively obtained from the MSDS, the links to which we carefully provide. --Smokefoot (talk) 19:20, 1 January 2012 (UTC)

Taste/Smell of Cyclohexanone

Has anyone else searched Sigma Aldrich and the rest of the online literature for the smell and/or taste of cyclohexanone? I can't find any of those sources which agree with the "peardrop sweet" description of its smell. Reference 7, the entry for cyclohexanone in Ullmann's, is cited to support that, but unfortunately is behind a paywall. The non-pay sources generally say cyclohexanone's got a minty and an acetone smell. The perfumers' references also recommend you smell it in 1% or less concentration.

I also notice that there's a kosher version of cyclohexanone offered for sale. Kashrut is generally applied to foods, not scents, so someone's using cyclohexanone as a flavoring agent.

I'll follow this up later, but I thought others here might want to look into the taste/smell of cyclohexanone in other references than Ullmann's. Peardrop sweets are a delight unknown to most of the English speakers in North America, and it's difficult to find any other references which confirm the "peardrop sweet" description of cyclohexanone's odor and taste. loupgarous (talk) 00:24, 1 May 2017 (UTC)

OK I just checked: Ullmann's Encyclopedia doesnt say sweet, but that cyclohexnone's odor is like that of acetone, which is akin to fingernail polish. The pearldrop thing must be vandalism. --Smokefoot (talk) 00:47, 1 May 2017 (UTC)

Vandalism is the most likely explanation. Thanks for the help! loupgarous (talk) 08:08, 2 May 2017 (UTC)

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