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Author: Subject: The Short Questions Thread (4)
Zyklon-A
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[*] posted on 8-4-2014 at 07:30
Ozone


Ozone can be produced by electrolysis of dilute sulfuric acid, with a Pt anode. The process is described here as well as many other places. My question is, could MMO be employed as an anode in place of platinum, or would it be chemically degraded by the ozone produced, or the sulfuric acid?



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Zyklon-A
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[*] posted on 11-4-2014 at 09:13


Does this look like it would be a good power supply unit for chlorate production?
5 volts 30 amps, for only $26.00, the only reason I'm asking is because I can't see anywhere were it says weather it's DC or AC - which will definitely make a huge difference.
Some more options on amps.

[Edited on 11-4-2014 by Zyklonb]




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[*] posted on 11-4-2014 at 20:28
Vigreux column?


Everywhere I look it seems as vigreux columns are looked down upon. Why? I realize they are difficult to clean, but apart from that? I wish to run my first esterification tomorrow, specifically methyl benzoate.

For the reflux I have a 300mm liebig condenser and a 480mm vigreux column [all 24/40]. I really want to use the column as it doesn't require a water setup - which is not a problem I have a pump, but if there a functional simpler route why not use it?

So will it be sufficient? Thanks!




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Chemosynthesis
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[*] posted on 11-4-2014 at 20:45


Quote: Originally posted by numos  
Everywhere I look it seems as vigreux columns are looked down upon. Why?

I have been told they are overrated by people who aren't distillation/reflux afficionados, mostly in fractionation, from what I have seen. I'm an ignorant overrater.

Todd columns and packed columns have always been praised when I've asked people who really specialize in this sort of thing. Todd columns allow you to alter the temperature pretty easily and are supposed to give good resolution. If you want to get even fancier, spinning band columns are good for fractionation too, which I have not used.

I am pretty sure you will be suited well with a Vigreux. I like them, but I am not a specialist in that type of thing. It won't let you use Raschig rings for packing, but you might use beads or broken glass with a glass wool or cotton plug to keep the packing from falling into your reaction mix. For your purposes, a normal packed column is good too because it allows you to tailor the theoretical plate number for separations very easily.

Fill your column up and you rest fairly easy about not losing volatile solvent or product to the atmosphere, but you will have some stuck on your packing material. This can be good, by shifting reaction equilibria due to sequestration, or annoying due to the need to extract said material from your packing.
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The Volatile Chemist
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[*] posted on 18-4-2014 at 11:44


Quick question, where is the post on size limitations and maximum resolutions of images? I don't care what the maxes are, I just want to see the post.

(Woot! Over 100 posts!)

[Edited on 4-18-2014 by The Volatile Chemist]




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DubaiAmateurRocketry
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[*] posted on 19-4-2014 at 01:37


What shall we do before we touch things like cyanide, hydrazine, azides? Cyanide and azide stops cecullar respiration which is fatal, is there any antidote or things you can do if you're poisoned? I am obviously not touching any cyanides, just asking out of curiosity. I heard vitamine B12 could get rid of cyanide and azide anion? However if lets say I ate twice more than the LD50 for a cyanide poison, however I took equivalents of vitamine B12 tablets prior to the ingestion, will I still die?
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[*] posted on 19-4-2014 at 14:22
Question


When distilling nitric acid, would it not be more practical to use a water bath as a heat source? The boiling point of nitric acid is 83°C, so even below water's BP should work fine. I ask because I've never seen or heard of people using water - an oil bath or just raising it above the hotplate is what I have seen.



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[*] posted on 19-4-2014 at 14:42


Quote: Originally posted by Zyklonb  
When distilling nitric acid, would it not be more practical to use a water bath as a heat source? The boiling point of nitric acid is 83°C, so even below water's BP should work fine. I ask because I've never seen or heard of people using water - an oil bath or just raising it above the hotplate is what I have seen.


Depends what type of distillation you're doing. If you're trying to concentrate nitric acid from a dilute solution (reason for most of us to do distillation on nitric acid) I am sorry to tell you that nitric acid does not boil in a water solution up to 121 degree celsius. You can try an oil bath.
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[*] posted on 19-4-2014 at 14:57


Well I would guess that the contaminants would raise the boiling point of the HNO3 to a point when using water would be pointless or inefective. This is, however, merely an educated guess.
Oops I posted to late


[Edited on 19-4-2014 by bismuthate]




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[*] posted on 19-4-2014 at 15:07


Ok, I was just checking. I will be preparing it, from 98% sulfuric acid and a nitrate salt.



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[*] posted on 21-4-2014 at 06:15


Quote: Originally posted by DubaiAmateurRocketry  
What shall we do before we touch things like cyanide, hydrazine, azides? Cyanide and azide stops cecullar respiration which is fatal, is there any antidote or things you can do if you're poisoned? I am obviously not touching any cyanides, just asking out of curiosity. I heard vitamine B12 could get rid of cyanide and azide anion? However if lets say I ate twice more than the LD50 for a cyanide poison, however I took equivalents of vitamine B12 tablets prior to the ingestion, will I still die?

Cyanide antidote kits consist of inhalational amyl nitrite, a "popper," IV sodium nitrite/thiosulfate, or hydroxocobalamin. Not sure off the top of my head how therapeutic B<sub>12</sub> would be given the last one. I've only seen the old kits lying around so far.
Azides have no real prophylaxis or prognostic treatment last I checked, and I work with them daily. PMID: 17724902 suggests that cyanide kits may be effective in mitigating azide poisoning, but I'm a little sceptical given what I'd read previously. Either way, Br J Clin Pharmacol. Jan 1998; 45(1): 83–86 (doi: 10.1046/j.1365-2125.1998.00642.x) suggests that insufflation of hydroxocobalamin reaches peak plasma concentration within about 35 minutes, and inhalation/insufflation should be less variable than ingestion. I'm not about to suggest stocking up on IM solutions and insulin syringes, so the pharmacokinetic question then would be what type of cobalamin are you getting at the store, and what is the interconversion to the free plasma hydroxocobalamin?
Best never to work with these types of substances alone and always use adequate protective gear.

[Edited on 21-4-2014 by Chemosynthesis]
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[*] posted on 21-4-2014 at 10:39


Quote: Originally posted by numos  

For the reflux I have a 300mm liebig condenser and a 480mm vigreux column [all 24/40]. I really want to use the column as it doesn't require a water setup - which is not a problem I have a pump, but if there a functional simpler route why not use it?

So will it be sufficient? Thanks!


I often put first a Vigreux column and then on top of that an extra liebig (no water attached) as a simple reflux condenser. Then you simply moderate the heat such that the liquid condenses on the bottom of the Vigreux. Remember, once the liquid is boiling, you can often turn the heat down a bit until it is just barely boiling, such that you don't need much cooling ability to keep the solvent condensing.

There is no temperature advantage to vigorously boiling the reaction verses simply letting it barely boil-both will be the same temp, the BP. Any boiling will require the same amount of heat to be extracted from the condenser as applied by the heat source to boil the solvent, but keeping the temp just at the BP can be done with only enough heat to replace that lost to the surroundings.
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[*] posted on 22-4-2014 at 20:36
Iron - Iron oxalate


Is it possible to decompose iron oxlate to get iron that is NOT pyrophoric? Is there a way to control the particle size?
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[*] posted on 22-4-2014 at 20:37


oops - I meant to post this in the short questions thread - feel free to delete the post.
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[*] posted on 27-4-2014 at 15:43


I got found this from a friend who thought it came from an old lab, does anyone know what it is?
My best guess is that its a TLC plate, but I can not find any like it. If it is a TLC plate, would I prepare it by spreading the media in the indent? Like how microscope slide TLC plates are made?
you can't see it in the picture, but it says KONTES 1000µ. This obviously the brand, and the groove is 1000µ deep?





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[*] posted on 27-4-2014 at 16:54


It might be a gel electrophoresis plate. I'd assume your guess about the depth is correct.



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[*] posted on 29-4-2014 at 12:54


What are the best coloring agents for methanol? I've tried the "thunder flask" demo where methanol is added to a narrow-necked flask and ignited. However, I haven't found any good coloring agents other than boric acid. Are there any other good and easily available ones? I've tried copper chloride and strontium nitrate, but they don't disperse and therefore leave the flame only partially colored.



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[*] posted on 30-4-2014 at 12:10


How high a concentration of nitric acid in water can be achieved by dissolving NO2 + O2 in H2O at 2 ATM at 10°C?
[4 NO2 (g) + O2 (g) + 2 H2O (l) → 4 HNO3 (aq)]




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[*] posted on 30-4-2014 at 15:40


May be a better idea to use hydrogen peroxide, if available. It provides a higher yield. Even 3% is better than nothing. The reaction is a disproportionation and nitrous acid is formed as well when just water is added.



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[*] posted on 1-5-2014 at 06:16


I'm asking about how it could be done large scale, I have H2O2, but I don't want to use it. Excess oxygen is much cheaper, under pressure gasses dissolve better, so a decent concentration could be made, I just don't know what.

[Edited on 1-5-2014 by Zyklonb]




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[*] posted on 1-5-2014 at 07:14


Quote: Originally posted by Brain&Force  
What are the best coloring agents for methanol? I've tried the "thunder flask" demo where methanol is added to a narrow-necked flask and ignited. However, I haven't found any good coloring agents other than boric acid. Are there any other good and easily available ones? I've tried copper chloride and strontium nitrate, but they don't disperse and therefore leave the flame only partially colored.


We do colored methanol fireballs as part of pyrotechnic special effects work- But OUTDOORS! Sometimes with many liters of methanol, which produces some formaldehyde in open burning (or in your liver if you inhale the fumes), and organic chlorine donors to improve blue flame color- Which produces a little PHOSGENE in open burning. Not a classroom demo, outside of a good fume hood.

If you want a colored alcohol flame, you will need a metal salt that dissolves in the methanol. About 13 grams per liter of any of the chemicals below is plenty-

Don't bother with the usual Strontium for red and Barium for green. You would need the chlorine donors, better to use Boron, Lithium and Potassium.

Boric acid dissolves and creates methyl borate, gives a good green but somewhat toxic (not that breathing Barium would be any better!).

Try Potassium iodide for a nice purple color. Dissolves in methanol well, I like it better than Strontium colors.

Calcium chloride gives orange.

Sodium chloride for yellow. And it will contaminate any of the others and turn them yellow too (even a slight amount of contamination is too much), so handle it LAST. Sodium is an incredibly strong emitter in that narrow orangey yellow range- Destroys colors in solid pyrotechnic color compositions in small amounts too.

Copper chloride + an organic chloride or fluoride (methylene chloride is one choice) gives a blue- along with phosgene. You CAN substitute hydrochloride acid, but then you have acid mist. Blue is pretty, pretty dangerous that is.

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[*] posted on 1-5-2014 at 17:13


I've tried strontium nitrate in methanol, but it doesn't dissolve volatilize and give an even color to the flame, unlike, for example, alkylborates. I didn't think of chlorine donors, though - this may be a good idea.

I tried strontium nitrate, but it didn't dissolve in the methanol at all, and it had a mix of red, blue, and gray in the flame. (I think the gray is a methyl nitrite or methyl nitrate ester.)

Anyone know any strontium/lithium or any other red-burning salt that is soluble in methanol?

[Edited on 2.5.2014 by Brain&Force]




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[*] posted on 1-5-2014 at 17:36


Quote: Originally posted by Pinkhippo11  
I got found this from a friend who thought it came from an old lab, does anyone know what it is?
My best guess is that its a TLC plate, but I can not find any like it. If it is a TLC plate, would I prepare it by spreading the media in the indent? Like how microscope slide TLC plates are made?
you can't see it in the picture, but it says KONTES 1000µ. This obviously the brand, and the groove is 1000µ deep?



The fact that they give you the dept with such precision makes me believe it is actually used for physics experiments with light, maybe on refraction or on light interference. In optical physic, you work a lot with glass instruments with depths and slots in micrometers and wavelengths in nanometers, so it would make sense to give such a precise depth while it doesn't really matter in TLC or electrophoresis at my knowledge. Why would they bother give the depth number with 4 significative digits instead of just writing "1 mm" if it didn't matter :p If you find what it's used for let us know ;)

[Edited on 2-5-2014 by alexleyenda]
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[*] posted on 4-5-2014 at 02:31


Quote: Originally posted by DraconicAcid  
Quote: Originally posted by DubaiAmateurRocketry  
Are there any complex salts of Aluminum with hydrazine or ammonia? I heard Al(NH3)6 exist?

I don't think aluminum forms stable complexes with nitrogen donors, outside of being dissolved in liquid ammonia. Lang's handbook of chemistry doesn't even list an ethylenediamine complex.


https://docs.google.com/viewer?url=patentimages.storage.goog...

I found this patent describing Al(N2H4)6(ClO4)3.

I am not sure if the nitrate or dinitramide salt exist, these would be interesting in energetics.
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[*] posted on 4-5-2014 at 18:25
Barbier Reaction


I know the Barbier reaction is usually used for allylation. Can it also work for benzylation?

[Edited on 5-5-2014 by Cheddite Cheese]




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