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RogueRose
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[*] posted on 13-6-2017 at 17:09
Acetic Acid from Sodium acetate/diacetate


I was looking at the procedure of mixing H2SO4 and CH3CO2Na (sodium acetate) and was wondering if sodium diacetate could be used NaH(CH3CO2)2. The equations I've come up with are as follows:

Sodium acetate + sulfuric acid
2(CH3CO2Na) + H2SO4 = 2(CH3COOH) +Na2SO4

Sodium acetate + sulfuric acid
NaH(CH3CO2)2 + H2SO4 = 2(CH3CO2H) + NaHSO4
So with the diacetate the result would be sodium bisulfate which may be more useful for some than sodium sulfate. Now I'm not sure how soluble NaHSO4 would be in acetic acid or if it would push a reaction back towards sulfuric acid - both would be good reasons this isn't used but I figured it would be worth knowing.

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clearly_not_atara
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[*] posted on 13-6-2017 at 17:25


I think the product will in all cases depend on the stoichiometry of H2SO4 vs Na+. I am also pretty sure you want to distill acetic acid off.

I think you can convert it to the calcium salt somehow? Not sure.

EDIT: Combining hot concentrated aqueous solutions of calcium chloride and sodium acetate precipitates calcium acetate in about 50% yield, judging by solubity tables.

[Edited on 14-6-2017 by clearly_not_atara]
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JJay
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[*] posted on 13-6-2017 at 18:02


Can you store acetone in HDPE wash bottles, or will it evaporate?



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tsathoggua1
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[*] posted on 14-6-2017 at 01:10


Out of methyl carbonate, ethylene carbonate and propylene carbonate, which is preferable for the purpose of production of small quantities of alkali metals via electrolysis?

Thing is, I have a reasonable sized quantity of Na, but its in the form of one large brick, hermetically vacuum-packed and heat-sealed in an inner, thick plastic liner filled with mineral oil which itself is inside a hermetically sealed bag full of inert gas. I'd sooner make a little and not have to open it, due to shelf-life considerations, I don't need the entire 100g brick right this moment, only maybe 15g or so, so it makes more sense to try electrolysis in one of the carbonate esters of hydroxide, and in any case its something I've wanted to add to my solvent arsenal for a while.

If that doesn't produce the desired results, I'll go with Nurdrage's excellent looking method of thermiting NaOH or KOH using magnesium dust, grinding up the slag in a blender (only variation, backfilling this with an argon purge first and grinding it under positive pressure of Ar. Might have to tweak the bender a little bit but its only ever been me that uses the thing so no loss there), and then separating the sodium out using 1,4-dioxane prepared by the sulfuric acid dehydration of ethylene glycol, which I have plenty of, as I do of concentrated H2SO4. I just don't want to open the Na brick I already have since it won't have an indefinite shelf life, and there is perhaps 15g or so of a ketoxime awaiting preparation so as to be reduced to the corresponding amine with Na/alcohol.
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[*] posted on 14-6-2017 at 07:17


Quote: Originally posted by JJay  
Can you store acetone in HDPE wash bottles, or will it evaporate?


Acetone, b.p. 56oC
so you can store it in an hdpe wash bottle, until it evaporates away :)
I find hdpe bottles with hdpe:hdpe sealed bottle caps ok for acetone starage with negligible loss due to evaporation.




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tsathoggua1
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[*] posted on 14-6-2017 at 07:51


I'd expect the result of destructive distillation performed on the Ca salt to be acetone rather than CH3COOH, that is a known route to P2P, albeit not one optimized for yields, pyrolysis of either the Ca or Pb salt of phenylacetic acid results in dehydration to the ketone, not liberation of the acid. H2SO4 is a fairly strong dehydrating agent itself when concentrated, so I could see either formation of acetone, or perhaps dehydration and elimination to ethene (or worse, ketene, although granted that would make acetic acid if put to use, but its dreadfully toxic stuff)

[Edited on 14-6-2017 by tsathoggua1]
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[*] posted on 14-6-2017 at 08:00


Ignoring tsathoggua's usual cruddy, off-topic, drug chem laced post, yes, you should definitely be able to distill a mixture of sulfuric acid and sodium diacetate to get acetic acid. There would be no reason to convert it to the calcium salt. You do have to distill though. Don't count on getting it to work otherwise.



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Texium
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[*] posted on 14-6-2017 at 09:27


Quote: Originally posted by Sulaiman  
Quote: Originally posted by JJay  
Can you store acetone in HDPE wash bottles, or will it evaporate?


Acetone, b.p. 56oC
so you can store it in an hdpe wash bottle, until it evaporates away :)
I find hdpe bottles with hdpe:hdpe sealed bottle caps ok for acetone starage with negligible loss due to evaporation.


I don't have any sealed caps for my HDPE wash bottles. I wonder if it is still OK to store acetone in them....




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[*] posted on 14-6-2017 at 09:42


What kind of wash bottle is it? I have two, one has the spout through the lid, the other through the side. The one which comes out the side has a cap that lets air in (not sure why, they didn't want air bubbling through I guess). In the former case I think a bunch of PTFE tape would seal it well! As for the latter option I'm not sure.

Edit: the surface area of acetone that is exposed though the "straw" is probably not significant. That would be the only way for acetone to escape.

[Edited on 6/14/2017 by Geocachmaster]




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JJay
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[*] posted on 14-6-2017 at 09:56


The straw on my wash bottles actually goes through the cap. They are about 1/10 the cost of the wash bottles with the straw at the side, and I see very little difference in function....

I guess I'll try filling one with some acetone and see what happens.

[Edited on 14-6-2017 by JJay]




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[*] posted on 18-6-2017 at 19:43
Question


I know this is probably a simple question but how exactly does one discern the peroxide ion from the dioxide ion? Is it something to do with oxygens electronegativity?
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[*] posted on 18-6-2017 at 20:16


Dioxide and peroxide aren't ions... dioxide means it contains two oxygens.

Peroxide means it contains at least two oxygens with a single bond to each other.




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[*] posted on 18-6-2017 at 20:35
Campa Chem MSDS?


I plan to buy some Campa-Chem original holding tank fluid, but it seems that I can't access the MSDS to determine the concentration of formaldehyde and methanol. Does anyone have access to such records and/or does anyone have the concentrations of the two chemicals above?
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[*] posted on 18-6-2017 at 20:37


Quote: Originally posted by JJay  
Dioxide and peroxide aren't ions... dioxide means it contains two oxygens.

Peroxide means it contains at least two oxygens with a single bond to each other.


The peroxide ion is O2 with a charge of -2, as is found in barium peroxide and potassium peroxide.




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[*] posted on 18-6-2017 at 21:33


Quote: Originally posted by ninhydric1  
I plan to buy some Campa-Chem original holding tank fluid, but it seems that I can't access the MSDS to determine the concentration of formaldehyde and methanol. Does anyone have access to such records and/or does anyone have the concentrations of the two chemicals above?


I found the MSDS in the Wayback Machine (which I've attached), but there doesn't seem to be any info on the concentration.

sparky (~_~)

Attachment: Campa Chem.pdf (47kB)
This file has been downloaded 1108 times





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[*] posted on 18-6-2017 at 22:25


Ok - to be fair, "dioxide" is not an ion.

"Peroxide" can be an ion if both of the oxygens are ionically bonded. But it is not a very stable one, and while ionic peroxides certainly should not be ignored, covalently bonded peroxides are more common. Technically, an "oxide" ion also exists, as does a "superoxide" ion, although like peroxide, these ions usually don't last very long as independent species.


[Edited on 19-6-2017 by JJay]




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[*] posted on 19-6-2017 at 01:19


@JJay:

Dioxide and peroxide are both ions, and are formed through single-electron transfer to molecular oxygen. The dioxide ion (also called "superoxide") is O2 and is the result of one electron transfer, while the peroxide ion is O22− and the result of two electron transfers:

O=O + e → [•O−O:] (dioxide)

[•O−O:] + e → [:O−O:]2− (peroxide)

So to answer TheNerdyFarmer, the difference is that the dioxide ion is two oxygen atoms connected through a single bond where one has an unpaired electron and the other a full octet, while the peroxide ion is two oxygen atoms connected through a single bond but with both oxygen atoms having full octets. Potassium dioxide (KO2) is an example of the former, and potassium peroxide K2 O2 ) is an example of the latter.
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[*] posted on 19-6-2017 at 01:26


Superoxide and dioxide are not the same thing. Carbon dioxide is not carbon superoxide, for example.

If you disagree, feel free to cite a reputable reference that describes the dioxide ion.

[Edited on 19-6-2017 by JJay]




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[*] posted on 19-6-2017 at 01:31


"Dioxide" is the correct IUPAC nomenclature for the superoxide anion. For example, if you check the Wikipedia page for potassium superoxide, you will notice that it lists "potassium dioxide" as the IUPAC name. This is also mentioned on the Wikipedia page for the superoxide ion as well.
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[*] posted on 19-6-2017 at 01:39


Quote: Originally posted by Darkstar  
"Dioxide" is the correct IUPAC nomenclature for the superoxide anion. For example, if you check the Wikipedia page for potassium superoxide, you will notice that it lists "potassium dioxide" as the IUPAC name. This is also mentioned on the Wikipedia page for the superoxide ion as well.


The IUPAC name for the superoxide ion is dioxide (1-), and the IUPAC states that superoxide is an acceptable alternative name. The IUPAC name for the peroxide ion is dioxide (2-). While it is permissible to omit the charge notation where there is no ambiguity under IUPAC nomenclature, that is not the case with dioxygen. Again, "dioxide" is not an ion.

Source: https://www.iupac.org/fileadmin/user_upload/databases/Red_Bo...




[Edited on 19-6-2017 by JJay]




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[*] posted on 19-6-2017 at 02:11


Right, but I am assuming that the context of his question was the difference between the anions in salts like "potassium dioxide" and "potassium peroxide." We can argue nomenclature technicalities all day, but unless the anion is specifically designated as dioxide(2-) or the cation is prefixed with di- (like "dipotassium dioxide"), it's probably a safe bet to assume that it is the superoxide anion in simple salts like those.
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[*] posted on 19-6-2017 at 02:19


See page 80 for a discussion of this issue. "Potassium dioxide" is a simple stoichiometric name, *NOT* a compositional name.

[Edited on 19-6-2017 by JJay]




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[*] posted on 19-6-2017 at 03:29


Nice edit, but I am not "confused." I'm agreeing with you that "dioxide" by itself can be somewhat ambiguous. But the poster asked for the difference between "dioxide" and "peroxide" as if they were two different anions. Can they mean the same thing or be confused for one another? Yes. But in my experience you usually see "peroxide" for dioxide(2-), and either "superoxide" or "dioxide" for dioxide(1-). That's all I'm saying. It may not be 100% correct, but that's what I see.

I agree that using "dioxide" by itself can create ambiguity depending on the cation, I'm not denying that.

Edit: And just so it's clear, my original response was to your reply to Draconic before you edited it to include superoxide ions.

[Edited on 6-19-2017 by Darkstar]
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[*] posted on 19-6-2017 at 11:40


My school has given me the opportunity to do a few experiments in there lab. I noticed they had a bottle of anhydrous propionic acid, so I thought I might make a propionate ester.

I would like to try isopropyl propionate. Fischer esterification should work for making this ester right?

Would adding anhydrous magnesium sulphate to the reaction mixture during reflux help to increase yield?

Any advice would be much appreciated.




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[*] posted on 19-6-2017 at 13:06


So does anyone know the concentration of formaldehyde and methanol in Campa-Chem, or is there a method (such as titration) to figure out the concentration?
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