June 05, 2020, 03:08:39 PM
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Organic Chemistry Forum / Re: NaF in water dangerous?
« Last post by Babcock_Hall on Today at 01:35:00 PM »
If I recall correctly, fluoride ion is an alternate acceptor of a phosphoryl group in the reaction catalyzed by pyruvate kinase (the paper I cited mentioned glycolytic enzymes but did not go into detail).  As you implied however, the dose makes the poison, and I don't even know whether or not this reaction is the main reason.
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Organic Chemistry Forum / Re: NaF in water dangerous?
« Last post by kamiyu2550 on Today at 01:29:43 PM »
If someone is interested in the toxicity of sodium fluoride, here is an older reference:  https://jada.ada.org/article/S0002-8177(85)02022-0/pdf

Indeed, I wrote a paper during my postdoc using fluoride as catalyst and I claim it to be non-toxic. But I also came across some sources stating that fluoride is toxic.

Well, whenever it comes to toxicity, it is the matter of dose. Don't forget toothpaste contains fluoride and also our tap water.
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High School Chemistry Forum / Re: Question about Solution making
« Last post by david222hughes on Today at 01:13:21 PM »
Thanks for the reply.

Yeah its a solution containing both potassium carbonate and sodium bicarbonate at the stated concentrations of 30.18% and 6.04%.

Sounds a lot less complicated with your method :) I wasn't aware you could add the salts together in the same solution by simply using the same percentage concentrations converted directly to grams without having to alter the numbers. Happy days.

I'll follow your advice  on mixing them up adding around 90mls distilled water to the salts in the flask, then popping on a stopper and mixing them up before making the solution up to the 100ml mark.

Thanks for your guidance.
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Organic Chemistry Forum / Re: How do I hydrolyse ammonium ?
« Last post by AWK on Today at 12:45:31 PM »
Many beginner chemists do not understand the procedures for isolating synthesis products from the reaction mixture - in this case, it is the isolation of dimethyl nonanedioate. You need to read a good organic preparation manual.
In your case, you need to neutralize sulfuric acid and unreacted azelaic acid. The amount of concentrated ammonia must be calculated based on the amount of sulfuric acid and the assumed ester yield (e.g. 70%). Ammonium chloride with ice (3:10) forms a freezing mixture giving about -5C. In this way, you will get a solid ester (check its melting point). Then you can clean the ester by vacuum distillation (check the boiling point). Remember that your procedure has been checked many times and using it as accurately as possible will give you the best synthesis result.
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Thanks, AWK.
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Organic Chemistry Forum / Re: NaF in water dangerous?
« Last post by Babcock_Hall on Today at 12:25:17 PM »
If someone is interested in the toxicity of sodium fluoride, here is an older reference:  https://jada.ada.org/article/S0002-8177(85)02022-0/pdf
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Organic Chemistry Forum / Re: NaF in water dangerous?
« Last post by AWK on Today at 12:12:35 PM »
Several sources I read claim that when Sodium Fluoride is dissolved in water it forms fluoride, hydrofluoric acid, and silicic acid.

Either you read carelessly or you read unbelievable sources.
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Organic Chemistry Forum / Re: NaF in water dangerous?
« Last post by kamiyu2550 on Today at 12:02:09 PM »
Several sources I read claim that when Sodium Fluoride is dissolved in water it forms fluoride, hydrofluoric acid, and silicic acid.

The key is concentration.

Sodium fluoride means "fluoride" ion in water, which overall is basic instead of acidic. Acids might form, but in tiny concentration in equilibrium
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Organic Chemistry Forum / Re: NaF in water dangerous?
« Last post by zorba9112 on Today at 11:40:58 AM »
Several sources I read claim that when Sodium Fluoride is dissolved in water it forms fluoride, hydrofluoric acid, and silicic acid.


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Organic Chemistry Forum / How do I hydrolyse ammonium ?
« Last post by Aurelius8989 on Today at 11:38:05 AM »
I tried to convert carboxylic acid to ester. But I do not understand the following
[D14]Azelaic acid (30 g, 148 mmol), anhydrous MeOH (150 mL) and
concentrated H2SO4 (3 mL) was refluxed under N2 for 48 h. The solvent
was evaporated until a small amount of MeOH remained. This was then
poured onto a mixture of crushed ice and ammonium chloride, containing some ammonium hydroxide

Do I just mix the ice and NH4Cl or do I have to add the hydroxide too ?

how do i calculate the measurments required ?
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