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Magpie
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Can you smell any butyric acid?
The single most important condition for a successful synthesis is good mixing - Nicodem
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Hockeydemon
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No :/. It just smells like a solution of KMnO4.. I followed the procedure from Vogel exactly - it is a very easy procedure to follow.
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Magpie
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IMO if you can't smell it at this point it probably doesn't exist.
But if you feel it's worth the effort to follow through on the procedure then that is up to you.
The single most important condition for a successful synthesis is good mixing - Nicodem
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Hockeydemon
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Is it possible there was steric interference preventing the reaction from occurring that wasn't there with the iso form of the molecule? Or just some
reason that the iso form would work, and the 1-butanol would not be able to in this case specifically?
[Edited on 26-7-2013 by Hockeydemon]
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adamsium
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I found a patent that you might find interesting. They used nitric acid (and lots of it) and supposedly achieved very god yields. You'll notice that
the alcohol was added slowly, rather than all at the beginning.
Attachment: GB771583A.pdf (224kB)
This file has been downloaded 758 times
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bfesser
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Thread Moved
26-7-2013 at 06:29 |
Rich_Insane
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Would the Jones reagent not work in this case? I thought it was quite suitable for oxidation of alcohols into carboxylic acids....
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Hockeydemon
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So I had 25mL of nitric acid left, and I went ahead and did reaction IV in the document adamsium provided. I scaled it down to 25mL HNO3, 1.5mL H2O,
& 4.8mL of 1-butanol. Unfortunately I wasn't able to maintain 25-30C well enough, and a run away reaction happened. It was a neat occurrence
actually.. The temperature wasn't too far off 30C, and with the addition of 1 drop it just took off, and billowed out an amazing amount of nitrogen
dioxide. It made a waterfall of dark red smoke from my work bench to the floor, and crawled across the floor.
Anyways I'm going to make another batch of nitric acid, and give the rxn another go. I'll probably try to keep the water bath ~15C in hopes that will
keep the reaction around 30C with vigorous stirring.
Thanks for the document adamsium. Hopefully I'll have time tomorrow to try again.
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Hockeydemon
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Okay, I went ahead and redid the reaction same way as in my previous post, but I made sure to keep the reaction at 30C. I ended up with a light green
liquid I still don't smell any butyric acid however.
I'm not sure why I don't smell any butyric acid :/. I'm also not sure what I'm making if it isn't making butyric acid..
Edit:
I read here that HNO3 + alcohol --> nitrate ester + H2O, and I have found no mention (outside of that patent linked above) that I can use HNO3 to
oxidize the alcohol to an acid.
Is this correct?
[Edited on 29-7-2013 by Hockeydemon]
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Waffles SS
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Usually Nitrate ester prepared by action of conc. nitric acid(>90%) on alcohol + sulfuric acid as catalyst in below 15c(above this temp run away
occur and maybe explosion happen)
I think you made Butyl Butyrate.Try to hydrolysis it by NaOH solution and then add Acid for making butyric acid.
[Edited on 29-7-2013 by Waffles SS]
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adamsium
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I hadn't heard of using nitric acid, either. Based on what I've learned in my organic chem classes so far, I'd have done something similar to what you
were doing. I'm quite curious about this, too.
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Magpie
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Welcome to organic chemistry. There are many general procedures for syntheses but the yields in specific cases can vary widely. I am surprised that
the procedure in Vogel didn't work, but then again why would it call out the isobutyric form if there wasn't some specificity involved. I have seen a
procedure specifically for n-butyric acid in Gatterman, 1937 edition (forum library) but it uses a different precursor, ie, ethyl malonic acid, IIRC.
I know you want to make this acid using the precursor you have on hand, ie, n-butanol. I am also very puzzled as to why you have had no success so
far. There are two other oxidants that you might try, ie, potassium (or sodium) dichromate w/H2SO4, and sodium (or potassium) persulfate.
If you really, really wanted to make butyric acid you could try other routes, eg, Grignard reaction using n-propanol and CO2 (dry ice), or hydrolysis
of propyl cyanide. I have made an acid using the Grignard route but not the cyanide route. You likely don't want to go to these extremes. I, too,
have to believe it is possible to make it from n-butanol. If you find a route you will have something worthwhile to contribute to SM.
[Edited on 29-7-2013 by Magpie]
----------------------------------------------
Here's a synthesis of butyl butyrate that provides some insight into making butyric acid. It looks like control of mole ratios and temperature are
important. As indicated, if there is too much alcohol the ester is made, as previously pointed out upthread by woelen:
http://www.orgsyn.org/orgsyn/default.asp?formgroup=basenpe_f...
One could approach the making of n-butyric acid by first making the aldehyde and isolating it. That should be easily oxidized to the acid, possibly
using just stirring in air with a little heat and time.
[Edited on 30-7-2013 by Magpie]
[Edited on 30-7-2013 by Magpie]
The single most important condition for a successful synthesis is good mixing - Nicodem
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Hockeydemon
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I know I'm making butyl butyrate in the test tube when I follow the instructions Woelen gave me. The liquid is clear, insoluble in water, and smells
pleasant.
I don't know that in the reaction I followed with nitric acid I made butyl butyrate. The liquid was a light green/light cyan color, and there was no
other layer in the liquid. I added NaOH solution to until until the pH went up to 7 which made the liquid yellow. Then I added a little more, and the
solution went to orange (pH of ~9). The solution was still miscible, and there was plenty of water in the mixture. I then added H2SO4 to the mixture,
and it simply returned to it's original form (light green/light cyan).
I will however make that ester of butyl butyrate using Woelen's instructions, and separate the ester. Then I will hydrolyze the ester, and re-acidify
it.
Quote: Originally posted by Magpie  |
Here's a synthesis of butyl butyrate that provides some insight into making butyric acid. It looks like control of mole ratios and temperature are
important. As indicated, if there is too much alcohol the ester is made, as previously pointed out upthread by woelen:
http://www.orgsyn.org/orgsyn/default.asp?formgroup=basenpe_f...
One could approach the making of n-butyric acid by first making the aldehyde and isolating it. That should be easily oxidized to the acid, possibly
using just stirring in air with a little heat and time.
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The link you provided just takes me to the search engine for the website. Can you tell me what you searched for, and I can look it up?
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Magpie
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| Quote: Originally posted by Hockeydemon |
The link you provided just takes me to the search engine for the website. Can you tell me what you searched for, and I can look it up?
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search for: n-butyl n-butyrate
The single most important condition for a successful synthesis is good mixing - Nicodem
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Hockeydemon
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Since I can't seem to oxidize 1-butanol to butyric acid with KMnO4 I think I'm going to try as you suggested Magpie & isolate the aldehyde. Rather
than using KMnO4 at all I am going to try a copper catalyzed dehydrogenation to it's aldehyde. From there I should hopefully be able to carboxylize
it.
We shall see how it goes I guess - I'll give it a go later in the afternoon.
How should I go about converting the aldehyde to the carboxylic acid?
[Edited on 31-7-2013 by Hockeydemon]
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Waffles SS
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| Quote: Originally posted by Magpie |
It should be easily oxidized to the acid, possibly using just stirring in air with a little heat and time
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Butyraldehyde
Vogel 3th.Edition 320p
[Edited on 30-7-2013 by Waffles SS]
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Paddywhacker
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In that case I should tell you that there is no way in the word that you will get an aldehyde by dehydrating butanol. You know butanol has just one
oxygen, and water has one oxygen, and butyradehyde has one oxygen, so if you subtract water from butanol then the result won't have any oxygens left.
About your oxidation.... you do know that KMnO4 reduces to an alkaline solution... just look at the equation. So you will end up with a butyrate salt.
In order to get any butyric acid you could possibly filter off the manganese dioxide, evaporate the filtrate to dryness, and then distill with a
little H2SO4.
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Hockeydemon
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| Quote: Originally posted by Paddywhacker | | In that case I should tell you that there is no way in the word that you will get an aldehyde by dehydrating butanol. You know butanol has just one
oxygen, and water has one oxygen, and butyradehyde has one oxygen, so if you subtract water from butanol then the result won't have any oxygens left.
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Source
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When the vapours of a primary or a secondary alcohol are passed over heated copper at 573 K, dehydrogenation takes place and an aldehyde or a ketone
is formed while tertiaryalcohols undergo dehydration.
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| Quote: Originally posted by Paddywhacker |
About your oxidation.... you do know that KMnO4 reduces to an alkaline solution... just look at the equation. So you will end up with a butyrate salt.
In order to get any butyric acid you could possibly filter off the manganese dioxide, evaporate the filtrate to dryness, and then distill with a
little H2SO4.
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Source
Am I missing something?
[Edited on 31-7-2013 by Hockeydemon]
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adamsium
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He is not trying to dehydrate anything. He is attempting an oxidation - specifically, a dehydrogenation - of butanol to butanal and,
ultimately, to butyric acid.
I'd also submit that posts with no content other than, essentially, "this should be in beginnings" are entirely useless.
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bfesser
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Thread Pruned
31-7-2013 at 07:20 |
Waffles SS
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Oxidation of Dibutyl Ether with Sodium Bromate lead to Butyl Butyrate and Butyric acid
[Edited on 19-10-2013 by Waffles SS]
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