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Topic: Simulate the degradation of nonylphneol ethoxylates  (Read 4280 times)

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Offline xXCuteGoatXx

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Simulate the degradation of nonylphneol ethoxylates
« on: August 03, 2017, 07:52:08 AM »
Hi :)

I'm wondering if it's possible to, in a lab, break down nonylphenol ethoxylates to nonylphenol. You see, I think I can use Molisch's test in order to confirm the presence of nonylphenol (since it's an aromatic phenol). I don't think I can use Molisch's test directly on nonylphenol ethoxylates, since those molecules don't look like they have an aromatic phenol in its strucure.

Therefore, I'm wondering if I can break down nonylphenol ethoxylates in a lab to nonylphenol, which I can then examine using Molisch's test? Is this at all possible? I can't seem to understand why it wouldn't be.

The purpose is, by breaking down nonylphenol ethoxylates (which I then examine using Molisch's test), to see if products contain these forbidden chemicals (atleast in the EU).

Have a great day, and I thank you for any help I can get regarding this problem (and I'll have to apologize since I'm horrible at explaining things, but the main thing is: can I break down nonylphenol ethoxylates to nonylphenol in a lab? And how do I do that?)


Offline pgk

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Re: Simulate the degradation of nonylphneol ethoxylates
« Reply #1 on: August 03, 2017, 08:41:06 AM »
1). Ethers are cleaved by heating with strong acids, such as HI and H2SO4.
Take a look at the Vogel’s or at a similar textbook, in order to see how you will work.
2). in addition, aryl ethers can be cleaved by heating with HBr/ BF4- but the reaction is long.
J. Org. Chem., 2004, 69 (10), pp 3340–3344
http://pubs.acs.org/doi/abs/10.1021/jo035886e
3). Molisch’s test works is valuable for sugars and not for phenols, such as nonylphenol.
Phenols are characterized by the red colour when treated with FeCl3 in combination with the bromine test because various other compounds react with FeCl3 and Br2.
Even better, you can isolate nonylphenol by chromatography and take the IR and 1H-NMR spectrums.

Offline xXCuteGoatXx

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Re: Simulate the degradation of nonylphneol ethoxylates
« Reply #2 on: August 03, 2017, 09:08:59 AM »
1). Ethers are cleaved by heating with strong acids, such as HI and H2SO4.
Take a look at the Vogel’s or at a similar textbook, in order to see how you will work.
2). in addition, aryl ethers can be cleaved by heating with HBr/ BF4- but the reaction is long.
J. Org. Chem., 2004, 69 (10), pp 3340–3344
http://pubs.acs.org/doi/abs/10.1021/jo035886e
3). Molisch’s test works is valuable for sugars and not for phenols, such as nonylphenol.
Phenols are characterized by the red colour when treated with FeCl3 in combination with the bromine test because various other compounds react with FeCl3 and Br2.
Even better, you can isolate nonylphenol by chromatography and take the IR and 1H-NMR spectrums.

Thank you for the reply, even though I must argue that you in fact can use Molisch's test in order to detect  aromatic phenols, such as nonylphenol (even thought it's most commonly used to detect carbohydrates). You see, the way Molisch's test work, is by showing the precense of a carbohydrate with the help of an aromatic phenol (such as bisfenol a, or in my case, nonylphenol). If you already have a solution of, let's say glucose, this will react with sulfuric acid to form 5-(hydroxymethyl)furfural, which then reacts with 2 aromatic phenols in order to produce a colored complex.

Now, to come back to your suggestion to break ether bonds by heating with a strong acid (such as sulfuric acid); let's have a look at this picture: http://www.pcimag.com/ext/resources/Issues/October2012/pci1012-Sasol-F1-615.jpg

If I break the bond, how do I know that a hydrogen atom will react with my left-over oxygen, in order to form a hydroxy group and therefore produce an aromatic phenol? How do I know nothing else will react with the oxygen?

Edit: hang on, the acid will donate a proton to the oxygen I guess?

Offline pgk

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Re: Simulate the degradation of nonylphneol ethoxylates
« Reply #3 on: August 03, 2017, 09:53:20 AM »
1). As an advice, do not use coloration tests for different compounds than the ones that are originally invented for.
Coming to the point! Your idea is smart, it sounds nice and may give positive results. So, try it.
On the other hand, if you take a closer look at the reaction scheme of Molisch’s test, you will observe a para- phenol condensation. But in your case, you will get ortho- phenol condensation that will lead to less extended conjugation and therefore, less intense coloration and probably, obscured conclusions.
2). If you take a look at the reaction mechanism of acidic cleavage of ethers, you will observe that the first step consists on the protonation of the ether oxygen atom.
« Last Edit: August 03, 2017, 12:53:57 PM by pgk »

Offline xXCuteGoatXx

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Re: Simulate the degradation of nonylphneol ethoxylates
« Reply #4 on: August 03, 2017, 10:21:44 AM »
Alright, thank you so very much for the advice. I only have a couple more question.

As we can see, there are several ether bonds in nonylphenol ethoxylates. So the acid going to destroy all the ether bonds? Would those "biproducts" maybe interfere with my experiment?

And btw, according to wikipedia (which may not be a very reliable source), one can use thymol instead of alfa - naptol (which is most commenly used in Molisch's test). And the thymol molecule looks rather similar to the nonylphenol molecule. This makes me think it could work.

Annnnd, would it just be better to preform the acidic cleavage of ethers, and then use like chromatography instead of trying to do Molisch's test?
« Last Edit: August 03, 2017, 10:42:01 AM by xXCuteGoatXx »

Offline pgk

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Re: Simulate the degradation of nonylphneol ethoxylates
« Reply #5 on: August 03, 2017, 10:57:44 AM »
1). Theoretically, these byproducts do not interfere but sometimes, heating aromatic compounds and polyethylene glycol derivatives with concentrated acids may lead to yellow or dark coloration that complicates further coloration tests.
On way to avoid this, is further extraction in an organic solvent, followed by addition of a little amount of activated charcoal and filtering. Then, concentration in the rotary, etc…
Another way, is the method that is described in the cited publication, which is specific for aryl ethers and uses simple reagents.
http://pubs.acs.org/doi/abs/10.1021/jo035886e
Note that various other methods for specific aryl ether cleavage, figure in the literature. But the most of them demand precious organometallic compounds and/or other exotic reagents.
2). Aldehyde condensation occurs at the para- position with both α-naphthol and thymol, during the Molisch’s test procedure. But once again, try the Molisch’s test; it may work in this case. Besides, chemistry is an experimental science.
« Last Edit: August 03, 2017, 11:31:11 AM by pgk »

Offline xXCuteGoatXx

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Re: Simulate the degradation of nonylphneol ethoxylates
« Reply #6 on: August 03, 2017, 11:06:34 AM »
Alright, THANK YOU SO MUCH! I really appreciate it!! I've been trying to find information about this on google for like 3 days, but couldn't find any (maybe I just suck at googleling).

Again: THANK YOU!!!!!!

Offline pgk

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Re: Simulate the degradation of nonylphneol ethoxylates
« Reply #7 on: August 03, 2017, 11:11:22 AM »
Glad, if I can help you.
PS: If the Molisch’s test works in this case, please communicate it.

Offline xXCuteGoatXx

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Re: Simulate the degradation of nonylphneol ethoxylates
« Reply #8 on: August 03, 2017, 11:18:20 AM »
I will, for sure.  I will preform the experiment in approximately 2-3 weeks :)

Offline pgk

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Re: Simulate the degradation of nonylphneol ethoxylates
« Reply #9 on: August 03, 2017, 11:26:52 AM »
Good luck!

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