ThunderSkunk
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Valeric Acid Preparation Ideas
I am looking to find a way to extract or conveniently produce Valeric acid [pentanoic acid]. I was hoping someone out there knows of a neat way to do
this.
The end goal is to synthesize methyl valerate [a fairly common fruity aroma added to foods and detergents] by means of Fischer Esterification.
I was just hoping to pick people's brains. I figured since that the stuff is produced naturally by the plant Valeriana officinalis, that
there might be some published paper out there which detailed a synthesis or fermentation to exploit. My Google keywords can back empty though... 
Thank you in advance!
P.S.
I am aware of the oxo process which uses carbon monoxide and butylene to form a "Valeraldehyde" intermediate... I just think smelling good is slightly
less important than my ability to breathe. 
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chemrox
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I would encourage you to do your own research. Butyl bromide + Mg + CO2 --> pentanoic acid should work. Please look up preparation and reactions
of Grignard reagents.
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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ThunderSkunk
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Wow, that was fast! Sorry for being lazy and ignorant. You have a nice evening.
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Endimion17
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Wrong place to search for such ideas. This is Reagents and Apparatus Acquisition, you need Organic Chemistry.
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kavu
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In case you don't want to bother with a grignard reaction straight forward oxidation of n-pentanol works too. Refluxing with KMnO4 in basic aqueous
solution should work like a charm.
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Dr.Bob
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Warning, while the esters of valeric acid may be lovely to smell (I remember amyl acetate being the small of bananas), the acid itself is not very
pleasant and smells of body odor. It is far better than butanoic acid (which smells like bad foot odor and underarm pit all mixed with some fungal
infection), but will still leave you smelling like someone who hasn't bathed in days. But the Grignard will work well with CO2. I think even just
going to hexanoic acid makes the acid's smell much better, but not sure what those esters small like.
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Ozone
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You could also extract it from valerian: http://en.wikipedia.org/wiki/Valerian_(herb)
O3
-Anyone who never made a mistake never tried anything new.
--Albert Einstein
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bahamuth
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Quote: Originally posted by Dr.Bob  | | Warning, while the esters of valeric acid may be lovely to smell (I remember amyl acetate being the small of bananas), the acid itself is not very
pleasant and smells of body odor. It is far better than butanoic acid (which smells like bad foot odor and underarm pit all mixed with some fungal
infection), but will still leave you smelling like someone who hasn't bathed in days. But the Grignard will work well with CO2. I think even just
going to hexanoic acid makes the acid's smell much better, but not sure what those esters small like. |
Amyl acetate is not made with valeric acid, and valeric acid smells more like fatty acetic acid than body odor. Additionally hexanoic acid smells like
horny male goat... Larger carboxylic acid chains give a more "fatty" smell.
I'd do the oxidation of n-pentanol, you could even do the oxidation and methylation in one step with trichloroisocyanuric acid.
The Oxidation of Primary Alcohols to Methyl Esters and Diols to Lactones Using Trichloroisocyanuric Acid -SYNTHETIC COMMUNICATIONS?
Vol. 33, No. 12, pp. 2003–2009, 2003
Any sufficiently advanced technology is indistinguishable from magic.
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Doc B
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Hydrolysis of N-butylcyanide will afford n-valeric acid (b.p 186degC)
N or iso- valeric acid can also be prepaired from the oxidation of N or iso-amyl alcohol respectively. KMnO4, dil. H2SO4 ate two common reagents
suitable for the task.
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