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Inorganic Chemistry Forum / Re: Synthesis of K(AuCl4) Potassium gold(III) chloride
« Last post by bryanking8 on Today at 01:04:39 AM »If you use K2CO3 the solution could be at drag in to alcaline and gold oxide would precipitate.
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Inorganic Chemistry Forum / Re: Less toxic substitute for Hydrazine?
« Last post by TheodorCurtius on Yesterday at 06:04:34 PM »You could try formazine...It is used in the combustion synthesis of various semiconductors IIRC. It can be synthesized from the reaction of hydrazine sulfate and hexamine and precipitates from aqueous solutions as an insoluble and relatively benign polymer.
https://en.wikipedia.org/wiki/Formazine
https://en.wikipedia.org/wiki/Formazine
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Citizen Chemist / Electrosynthesis of sodium nitrite and sodium nitrate by electrolysis of ammonia
« Last post by TheodorCurtius on Yesterday at 05:57:05 PM »Found this cool document describing the synthesis of sodium nitrate and sodium nitrite by simple electrolysis of ammonia with iron electrodes!
https://figshare.com/articles/journal_contribution/Amateur_synthesis_of_sodium_nitrate_and_sodium_nitrite_by_electrolytic_oxidation_of_ammonia_in_a_diaphragm_separated_cell/28806389?file=53701400
Thought it might be interesting to share...
https://figshare.com/articles/journal_contribution/Amateur_synthesis_of_sodium_nitrate_and_sodium_nitrite_by_electrolytic_oxidation_of_ammonia_in_a_diaphragm_separated_cell/28806389?file=53701400
Thought it might be interesting to share...
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Organic Chemistry Forum for Graduate Students and Professionals / Re: Handling and storing fuming nitric acid
« Last post by Babcock_Hall on April 11, 2025, 09:04:07 AM »Good idea. We have made other nitro-aromatics or -heteroaromatics and the carbon attached to the nitrogen is often broader than the others.
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Organic Chemistry Forum for Graduate Students and Professionals / Re: Handling and storing fuming nitric acid
« Last post by rolnor on April 11, 2025, 02:04:56 AM »The signals may be overlapping. You can change solvent to pull them apart or use INEPT if they have different multiplicity I think.
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High School Chemistry Forum / Re: Claisen condensation....
« Last post by Hunter2 on April 11, 2025, 01:35:12 AM »Generally Claisen condensation
Ester enolates can be formed with alkoxides, and they are good nucleophiles
Esters can undergo addition-elimination reactions with nucleophiles, otherwise known as nucleophilic acyl substitution. In the Claisen condensation the nucleophile is the ROC(O)CH2 group which displaces (RO-).
Alkoxides can be adequate leaving groups in this case, since they’re significantly weaker bases than ester enolates.
The product of a Claisen condensation is a beta-keto ester, which is a significantly stronger acid (pKa = 11) than either alcohols (pKa = 16-17) or esters (pKa = 25).
The reaction requires at least one equivalent of base since the enolate of the beta-keto ester product is not a strong enough base to deprotonate the starting ester.
A “crossed” Claisen condensation involves the enolate of one ester reacting as a nucleophile with a different (ideally non-enolizable) ester to give a beta-keto ester.
Mixed Claisen condensations are possible if the excess ester does not have protons at C-α. If both esters have α-protons, predominantly statistical mixtures of products can be expected.
Ester enolates can be formed with alkoxides, and they are good nucleophiles
Esters can undergo addition-elimination reactions with nucleophiles, otherwise known as nucleophilic acyl substitution. In the Claisen condensation the nucleophile is the ROC(O)CH2 group which displaces (RO-).
Alkoxides can be adequate leaving groups in this case, since they’re significantly weaker bases than ester enolates.
The product of a Claisen condensation is a beta-keto ester, which is a significantly stronger acid (pKa = 11) than either alcohols (pKa = 16-17) or esters (pKa = 25).
The reaction requires at least one equivalent of base since the enolate of the beta-keto ester product is not a strong enough base to deprotonate the starting ester.
A “crossed” Claisen condensation involves the enolate of one ester reacting as a nucleophile with a different (ideally non-enolizable) ester to give a beta-keto ester.
Mixed Claisen condensations are possible if the excess ester does not have protons at C-α. If both esters have α-protons, predominantly statistical mixtures of products can be expected.
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High School Chemistry Forum / Claisen condensation....
« Last post by ve_90 on April 10, 2025, 05:07:07 PM »Claisen condensation between cyclohexyl acetate and methyl acetate. Both have alpha hydrogens, so I’m wondering: which one will act as the electrophile and which as the nucleophile? Is it indifferent? I have this doubt in order to understand which mechanism is correct, since, in theory, I could obtain multiple products.
Thank you for your help.
Thank you for your help.
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Organic Chemistry Forum for Graduate Students and Professionals / Re: Handling and storing fuming nitric acid
« Last post by Babcock_Hall on April 10, 2025, 04:40:15 PM »We are short one signal in the C-13 spectrum; we could use LC-MS data to confirm this product.
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Organic Chemistry Forum for Graduate Students and Professionals / Re: Handling and storing fuming nitric acid
« Last post by Babcock_Hall on April 10, 2025, 11:00:04 AM »Probably worth trying the 90% before screwing around to try to make the 98% yourself. Both are nasty stuff, even in small amounts they spit out NOx smoke in surprising amounts just from being exposed to the air. It lives up to the name "fuming nitric acid" I assure you.Thank you for this suggestion. We have now performed a medium-scale nitration using 90% nitric acid by adapting a protocol that had been used on a derivative of pyrrole, and we purified it via silica. We had to use more acetic anhydride to address solubility of the starting thiophene aldehyde. The yield was 38%, which is certainly adequate for our purposes and in the same range as what was reported for a similar thiophene aldehyde.
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Citizen Chemist / Re: Ferric Chloride help please
« Last post by Borek on April 08, 2025, 08:19:52 AM »No idea.
Note: in most cases when it comes to reagents it doesn't matter how they were produced - a compound is a compound, no matter where it does come from. Things like concentration, pH, presence of other reagents recipe calls for are much more important. In practice sometimes (rarely, but often enough it is always a thing to remember) minute amounts of byproducts (which do depend on the production method) can influence the output of a process. The purer the reagent, the lower chances of the problem - but purity typically comes at a hefty price.
As I wrote earlier - the only to make sure it works is to try.
Note: in most cases when it comes to reagents it doesn't matter how they were produced - a compound is a compound, no matter where it does come from. Things like concentration, pH, presence of other reagents recipe calls for are much more important. In practice sometimes (rarely, but often enough it is always a thing to remember) minute amounts of byproducts (which do depend on the production method) can influence the output of a process. The purer the reagent, the lower chances of the problem - but purity typically comes at a hefty price.
As I wrote earlier - the only to make sure it works is to try.
