Sciencemadness Discussion Board

Hexane from Adipic Acid?

GreenJames - 18-10-2020 at 13:54

I just thought of a procedure for making hexane from adipic acid today that would involve the following steps:

1. Reduction of adipic acid to 1,6-hexanediol.
2. Halogenation of the diol.
3. Halo-hexane to hexane using zinc and HCl as a catalyst.

I have not attempted this, so I do not know if it works or not. However if it does, this could potentially be a source of hexane that is available to the home chemist. Of course, this would likely be very tedious for relatively small amounts of hexane. I'd like to hear anyone's thoughts and input about this.

njl - 18-10-2020 at 15:34

How were you planning on reducing the acid to the alcohol?

Syn the Sizer - 18-10-2020 at 16:50

PoorMans Chemist reduced the a carboxylic acid to the alcohol using NaBH4 and I2 in THF, it could work for adipic acid

https://www.youtube.com/watch?v=Df-wowEWn8Y

The paper he references is in the description.

DavidJR - 19-10-2020 at 01:13

Sounds like an incredibly expensive way to get hexanes. I'd much sooner buy petrol ("gasoline") and fractionally distill it to get some petroleum ether.

unionised - 19-10-2020 at 01:41

It's an interesting idea but not a practical way to get cigarette lighter (Zippo) fuel.
Also I suspect you might get cyclohexane as a significant by-product of the dehalogenation.

njl - 19-10-2020 at 05:51

What I was getting at is that you would need far more exotic reagents to go through with this procedure than would be worth the time, effort, or money. If you for some reason wanted to try this then more power to you, but frankly it's kind of an absurd process.

Syn the Sizer - 19-10-2020 at 10:19

I get what you are saying, I personally too would just buy the hexane, but maybe in locales where hexane is hard to get, this may be an option.

Texium - 19-10-2020 at 10:59

Quote: Originally posted by Syn the Sizer  
I get what you are saying, I personally too would just buy the hexane, but maybe in locales where hexane is hard to get, this may be an option.
Not really, considering some of the reagents needed are even harder to obtain than hexane. Considering hexane's only typical use is as a solvent, you'd need relatively large quantities. Even if your work is on a small scale, it would be extremely inconvenient and expensive to produce enough by this method.

Not trying to knock this as an interesting proof of concept to try. It's just not a practical way of producing hexane for solvent use, and if you're going to be doing this synthesis just for fun, you might as well at least start with a more interesting substrate that would lead to a more unique and potentially useful product.

I second DavidJR: petroleum ether is a fine substitute for hexanes as a solvent.

unionised - 19-10-2020 at 11:16

If I wanted to make hexane, I'd start with this
https://en.wikipedia.org/wiki/Sorbic_acid
or this
https://en.wikipedia.org/wiki/Caproic_acid

It might be an interesting exercise, but it would be a huge waste of money as a way to get hexane.


mackolol - 19-10-2020 at 11:49

Quote: Originally posted by GreenJames  
I just thought of a procedure for making hexane from adipic acid today that would involve the following steps:

1. Reduction of adipic acid to 1,6-hexanediol.
2. Halogenation of the diol.
3. Halo-hexane to hexane using zinc and HCl as a catalyst.

I have not attempted this, so I do not know if it works or not. However if it does, this could potentially be a source of hexane that is available to the home chemist. Of course, this would likely be very tedious for relatively small amounts of hexane. I'd like to hear anyone's thoughts and input about this.


Wouldn't the last step yield cyclohexane instead of hexane ?

GreenJames - 19-10-2020 at 12:21

Like I said in my original post, this wouldn't be a great source of hexane. I think more than anything, this is just an interesting possible procedure.

Quote: Originally posted by mackolol  
Quote: Originally posted by GreenJames  
I just thought of a procedure for making hexane from adipic acid today that would involve the following steps:

1. Reduction of adipic acid to 1,6-hexanediol.
2. Halogenation of the diol.
3. Halo-hexane to hexane using zinc and HCl as a catalyst.

I have not attempted this, so I do not know if it works or not. However if it does, this could potentially be a source of hexane that is available to the home chemist. Of course, this would likely be very tedious for relatively small amounts of hexane. I'd like to hear anyone's thoughts and input about this.


Wouldn't the last step yield cyclohexane instead of hexane ?


It would likely be a mix of hexanes.

Syn the Sizer - 19-10-2020 at 22:49

Quote: Originally posted by Texium (zts16)  
Quote: Originally posted by Syn the Sizer  
I get what you are saying, I personally too would just buy the hexane, but maybe in locales where hexane is hard to get, this may be an option.
Not really, considering some of the reagents needed are even harder to obtain than hexane. Considering hexane's only typical use is as a solvent, you'd need relatively large quantities. Even if your work is on a small scale, it would be extremely inconvenient and expensive to produce enough by this method.

Not trying to knock this as an interesting proof of concept to try. It's just not a practical way of producing hexane for solvent use, and if you're going to be doing this synthesis just for fun, you might as well at least start with a more interesting substrate that would lead to a more unique and potentially useful product.

I second DavidJR: petroleum ether is a fine substitute for hexanes as a solvent.


Yah I guess I chose the wrong wording what I really did mean was what you worded much better "as an interesting proof of concept to try", because as you said some reagents are fairly hard to come by in large quantities such as NaBH4.

when I first comment, I had just re-watched the video where PMC had reduced the carboxylic acid to the alcohol and when njl ask how the OP would intend to do that, the paper came to mind, before considering the price and rarity of the starting reagents as compared to the cost of buying 1L of hexane(s)
Quote: Originally posted by unionised  
If I wanted to make hexane, I'd start with this
https://en.wikipedia.org/wiki/Sorbic_acid
or this
https://en.wikipedia.org/wiki/Caproic_acid

It might be an interesting exercise, but it would be a huge waste of money as a way to get hexane.




Lol, valid point, why deal with 2 carboxyl groups in the adipic acid when you can deal with one on sorbic acid or caproic acid.

[Edited on 20-10-2020 by Syn the Sizer]

[Edited on 20-10-2020 by Syn the Sizer]