Volitox Ignis
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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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zed
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Never run a Grignard?
You need a mentor.
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Cryolite.
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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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DraconicAcid
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We used to use the diethyl and dimethyl esters of this acid as ligands.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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Volitox Ignis
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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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Cryolite.
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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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| 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.
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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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CuReUS
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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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Rhodanide
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| 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 
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Boffis
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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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