Dicarboxylic acid and diol reaction to form a carboxyl group ended diester

[slidemat]

Hello everyone!

I struggle to find a way to create a diester (carboxyl group ended) from dicarboxylic acid and diol reaction. I know that when the reaction between two is acid-catalyzed the polycondensation occurs with creation of polyester. I would like to stop the reaction with A-B-A product (where A is coming from a dicarboxylic acid and B - from diol).

Could someone help me with that?

[John Cuthber]

Use  a large excess of A.

 

[hypervalent_iodine]

I would suggest adding the diacid to a dilute solution of diol. 

[slidemat]

Thank you for the answer. Do you have any suggestions where to search for a recipe to synthesise such compounds?

[hypervalent_iodine]

58 minutes ago, slidemat said:

Thank you for the answer. Do you have any suggestions where to search for a recipe to synthesise such compounds?

I had assumed from your post that you already had compounds in mind. What is this for?

Minor side note: we would generally use the term method, procedure or protocol, not recipe (I realise that English may not be your first language, this is just a small point ). 

[slidemat]

5 minutes ago, hypervalent_iodine said:

Minor side note: we would generally use the term method, procedure or protocol, not recipe (I realise that English may not be your first language, this is just a small point ). 

Yeah, you guessed it right  I'll keep that in mind then.

5 minutes ago, hypervalent_iodine said:

I had assumed from your post that you already had compounds in mind. What is this for?

A latent curing agent for epoxy resins - that's why I need carboxylic groups at the ends. As a polycarboxylic acid I'm thinking on using a natural one - succinic acid for example. I don't have any diol picked at the moment.

Edited April 7, 2019 by slidemat

[hypervalent_iodine]

Ah, I see. I was imaging a cyclic product for some reason. 

Huge excess of the acid might help, as JohnCuthber suggested, but you may also find you need to avoid the diacid entirely. You could use something that has a monoprotected end, or some other functional group that you can oxidise up after coupling to the diol. If you have access, you might wish to look through SciFinder. 

I should also ask if you have experience in synthetic chemistry at all? It’s not a trivial thing to do, not to mention all of the hazards involved. 

[John Cuthber]

The idea is related to this

https://en.wikipedia.org/wiki/High_Dilution_Principle

 but it's a tricky one to use in industrial scale synthesis.

[slidemat]

12 minutes ago, hypervalent_iodine said:

Ah, I see. I was imaging a cyclic product for some reason. 

I am actually looking to obtain a product with a general formula like this:

15 minutes ago, hypervalent_iodine said:

Huge excess of the acid might help, as JohnCuthber suggested, but you may also find you need to avoid the diacid entirely. You could use something that has a monoprotected end, or some other functional group that you can oxidise up after coupling to the diol. If you have access, you might wish to look through SciFinder. 

Unfortunately I'm forced to use a polycarboxylic acid for this. The only compound similar to what I would like to get was 3-[(2-carboxyacetyl)oxymethoxy]-3-oxopropanoic acid. I did not however find any ways of synthesis.

20 minutes ago, hypervalent_iodine said:

I should also ask if you have experience in synthetic chemistry at all? It’s not a trivial thing to do, not to mention all of the hazards involved. 

Yeah, don't worry I do have experience in synthetic chemistry as also I have a supervisor that controls all the actions I take in the laboratory

21 minutes ago, John Cuthber said:

The idea is related to this

https://en.wikipedia.org/wiki/High_Dilution_Principle

 but it's a tricky one to use in industrial scale synthesis.

By carrying out this kind of reaction, I will be able to create linear (or control reaction in a ceratin way to obtain them) or only cyclic products?

[hypervalent_iodine]

Is there any reason you have to use the diacid? I have found some procedures, but they use a monoprotected version of the diacid (such as I mentioned in my previous post). For example, in this patent:

 

Might not be very industry friendly (not sure), but you get the idea. 

I did also come across another paper that might be useful, but I don't have access to it. 

[slidemat]

23 hours ago, hypervalent_iodine said:

Is there any reason you have to use the diacid? I have found some procedures, but they use a monoprotected version of the diacid (such as I mentioned in my previous post).

Unfortunately I do have to use a diacid - they are commercially used latent curing agents for epoxy resins and I need to check if diester synthesised from them will improve the properties of the resin. It is also ment to be some natural acid.

The patent you mentioned looks really interesting but the way of prepering a diester with this method seems really complicated.

After consulting it with my supervisor we've decided to try a simple diol - dicarboxylic acid reaction with a high exceed of acid in organic solvent.

However I do not know in what way I would be able to seperate the product from residual acid?

[peterwlocke]

coolio.

[hypervalent_iodine]

1 hour ago, slidemat said:

Unfortunately I do have to use a diacid - they are commercially used latent curing agents for epoxy resins and I need to check if diester synthesised from them will improve the properties of the resin. It is also ment to be some natural acid.

The patent you mentioned looks really interesting but the way of prepering a diester with this method seems really complicated.

After consulting it with my supervisor we've decided to try a simple diol - dicarboxylic acid reaction with a high exceed of acid in organic solvent.

However I do not know in what way I would be able to seperate the product from residual acid?

 

Your reasoning for only being able to use the diacid still doesn’t make sense to me. There is no reason (based on what you have said) that you couldn’t start with a monoprotected diacid or something with a terminal alkene. These functional groups are converted after esterification with the diol to give you the terminal carboxylic acid groups. You will still get the product you need. The procedure I attached is actually quite straight forward so far as these things go. I certainly wouldn’t describe it as complicated, in any case.

I don’t know what sort of purification is suitable for you, not knowing what you have available. You said you were familiar with synthetic chemistry so I have to assume you know the basic methods we would use for this sort of thing? A column could work, but you might have to pretreat the silica with acetic or formic acid. Depending on the diacid you use, there might be other methods such as recrystallisation or trituration that could work as well.