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Author: Subject: Proposed synthesis of acetylenedicarboxylic acid
Volitox Ignis
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[*] posted on 27-3-2018 at 17:21
Proposed synthesis of acetylenedicarboxylic acid


I forgot the proper name for it, but its structure is like that of acetylene, but with the hydrogens replaced by carboxyl groups.

I plan to make the acid using a Grignard reaction.
I've been told in the short question thread that making alkynylmagnesium halides would require using a metathesis reaction, rather than just reacting dihaloacetylene with magnesium.


Here is my plan:


  • Mix some potassium iodide,ethanol and monoammonium phosphate in stoichiometric amounts
  • Slowly distill the mixture for a few hours, hopefully resulting in ethyl iodide
  • Place a piece of dry ice and pieces of magnesium into a flask so that the CO2 would drive out air from it, wait for the dry ice to finish subliming, and close the flask with a rubber stopper.
  • Mix the ethyl iodide with ether, inject it into the flask with a syringe, and stir. It should form ethylmagnesium iodide.
  • Slowly add water to some calcium carbide and pipe the resulting acetylene gas into the flask,hopefully resulting in Ethynyldimagnesium diiodide and ethane gas being formed.
  • Drop some more dry ice in and stir, hopefully resulting in the final product.
  • Distill

I have a few questions before I attempt this.
Firstly, ethyl iodide boils at 72 C. Will ammonia be produced from the MAP at that temperature, will the MAP react with the ethyl iodide?
Secondly, I am concerned about water vapor entering the vessel along with the acetylene and ruining the reaction. How do I make sure that that doesn't happen?
Thirdly, how do I know when the ethylmagnesium iodide has finished reacting, without bubbling in an excess of acetylene? Is there any way to make sure that mostly ethynyldimagnesium diiodide is produced?
Fourthly, I'm concerned about the acetylene igniting and the ether igniting along with it, what precautions should I take to minimize the risk of that happening?
Fifthly, how do I verify that the final product is the acid I want?
And finally, do you have any other suggestions for me?

[Edited on 28-3-2018 by Volitox Ignis]

Edit by Texium: Changed title to be more descriptive

[Edited on 3-28-2018 by Texium (zts16)]
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[*] posted on 27-3-2018 at 17:41


Never run a Grignard?

You need a mentor.
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[*] posted on 27-3-2018 at 17:48


Acetylenedicarboxylic acid?

You probably could make it via a Grignard reaction followed by transmetallation with acetylene gas, but ensuring dryness and purity (no H2S, CO2, or PH3!) of acetylene produced from calcium carbide might be annoying. Also, I'm not sure if the doubly deprotonated acetylene would form under such conditions, but working up the propiolic acid formed from single deprotonation and doing the reaction again should get you to your product in the end.

Orgsyn has a reference for the preparation of acetylenedicarboxylic acid, starting from maleic acid instead. I'd expect that one to work better than trying to go through acetylene.
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[*] posted on 27-3-2018 at 18:08


We used to use the diethyl and dimethyl esters of this acid as ligands.



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Volitox Ignis
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[*] posted on 27-3-2018 at 18:26


Quote: Originally posted by Cryolite.  
Acetylenedicarboxylic acid?

You probably could make it via a Grignard reaction followed by transmetallation with acetylene gas, but ensuring dryness and purity (no H2S, CO2, or PH3!) of acetylene produced from calcium carbide might be annoying. Also, I'm not sure if the doubly deprotonated acetylene would form under such conditions, but working up the propiolic acid formed from single deprotonation and doing the reaction again should get you to your product in the end.

Orgsyn has a reference for the preparation of acetylenedicarboxylic acid, starting from maleic acid instead. I'd expect that one to work better than trying to go through acetylene.

Yeah, acetylenedicarboxylic acid
Don't Grignard reagents react with carboxylic acids to produce tertiary alcohols? How would I go about converting the propiolic acid to the acetylenedicarboxylic acid?
I searched "orgsyn acetylenedicarboxylic acid", and got this link:
http://orgsyn.org/demo.aspx?prep=cv2p0010
They use dibromosuccinic acid. Searching the site using "Acetylenedicarboxylic acid" just gave me that link again and a procedure for making the acid's dimethyl ester using said acid.
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[*] posted on 27-3-2018 at 18:31


They make the dibromosuccinic acid from maleic acid (or maybe it was fumaric acid? doesn't matter the isomerization is trivial)-- i think it's the article right before that one.

Grignard reagents simply deprotonate carboxylic acids. While they do react with esters to form tertiary alcohols, the acidic proton in a carboxylic acid will immediately pop off and give you the bromomagnesium salt of your acid. The carbon of the deprotonated carboxyl group is no longer electrophillic, so it won't react further with a Grignard reagent.
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Volitox Ignis
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[*] posted on 27-3-2018 at 19:07


Quote: Originally posted by Cryolite.  
They make the dibromosuccinic acid from maleic acid (or maybe it was fumaric acid? doesn't matter the isomerization is trivial)-- i think it's the article right before that one.

I don't have any maleic/fumaric acid on hand,sadly. However,I just realized that I have tartaric acid. Could that be used instead?
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[*] posted on 28-3-2018 at 09:18


if you have some soda amide,you don't need to make a grignard at all.Just mix the NaNH2 with acetylene and drop in some dry ice.https://onlinelibrary.wiley.com/doi/abs/10.1002/cber.1926059...
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[*] posted on 28-3-2018 at 09:46


Quote: Originally posted by Volitox Ignis  
I forgot the proper name for it, but its structure is like that of acetylene, but with the hydrogens replaced by carboxyl groups.

I plan to make the acid using a Grignard reaction.
I've been told in the short question thread that making alkynylmagnesium halides would require using a metathesis reaction, rather than just reacting dihaloacetylene with magnesium.


Here is my plan:


  • Mix some potassium iodide,ethanol and monoammonium phosphate in stoichiometric amounts
  • Slowly distill the mixture for a few hours, hopefully resulting in ethyl iodide
  • Place a piece of dry ice and pieces of magnesium into a flask so that the CO2 would drive out air from it, wait for the dry ice to finish subliming, and close the flask with a rubber stopper.
  • Mix the ethyl iodide with ether, inject it into the flask with a syringe, and stir. It should form ethylmagnesium iodide.
  • Slowly add water to some calcium carbide and pipe the resulting acetylene gas into the flask,hopefully resulting in Ethynyldimagnesium diiodide and ethane gas being formed.
  • Drop some more dry ice in and stir, hopefully resulting in the final product.
  • Distill

I have a few questions before I attempt this.
Firstly, ethyl iodide boils at 72 C. Will ammonia be produced from the MAP at that temperature, will the MAP react with the ethyl iodide?
Secondly, I am concerned about water vapor entering the vessel along with the acetylene and ruining the reaction. How do I make sure that that doesn't happen?
Thirdly, how do I know when the ethylmagnesium iodide has finished reacting, without bubbling in an excess of acetylene? Is there any way to make sure that mostly ethynyldimagnesium diiodide is produced?
Fourthly, I'm concerned about the acetylene igniting and the ether igniting along with it, what precautions should I take to minimize the risk of that happening?
Fifthly, how do I verify that the final product is the acid I want?
And finally, do you have any other suggestions for me?

[Edited on 28-3-2018 by Volitox Ignis]

Edit by Texium: Changed title to be more descriptive

[Edited on 3-28-2018 by Texium (zts16)]


Hah, here I was getting hyped up for a possible synthesis of ACETONEdicarboxylic acid not ACETYLENEdicarboxylic acid. I thought I'd finally get Diisonitrosoacetone after all these failed attempts, but acetylene compounds are cool on their own, too! Guess I'm not out of the woods yet :P




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[*] posted on 29-3-2018 at 01:17


What is wrong with the fumaric acid method mentioned above? Fumaric acid is a permitted food acidifier and is available OTC in most of Europe. I admit that bromine isn't but its preparation is simple. There are numerous published accounts of this preparation and they work well if you follow the instructions carefully.

I was interested in the sodamide reaction referred to by CeReUS though.
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