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Author: Subject: The short questions thread (3)
DJF90
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[*] posted on 3-12-2012 at 15:37


I will send you the requisite amount, remind me when we speak tomorrow.
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Boron Trioxide
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[*] posted on 5-12-2012 at 19:30


Another quick question

What purity is Animal Feed Grade Material, and what might its impurities be?

Thanks
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[*] posted on 6-12-2012 at 03:30


From what I can tell from a cursory search, from a purity standpoint, it's somewhere between technical and reagent grade. As for impurities, it depends largely on the substance in particular and the industrial procedures used. Generally, the only impurities are those that either pose no or little harm to animals, or lack the concentration to be dangerous.
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[*] posted on 21-12-2012 at 08:54


Is gluconic acid very soluble in ethanol, even cold ethanol?



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Vargouille
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[*] posted on 21-12-2012 at 12:01


http://pubs.acs.org/doi/abs/10.1021/ie50518a030

Quote:

It is extremely soluble in water, but only slightly soluble in [ethyl] alcohol, and it is insoluble in most other organic solvents.
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gnitseretni
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[*] posted on 22-12-2012 at 12:24


What do you do when the stirbars keep flying into the walls of the container? The smaller (1"-1.5") stirbars don't but they don't stir well enough. The 2" stirbar I have would stir well enough if it didn't keep flying into the walls of the container. I'm trying to stir about 400ml of mixed acids. I wanted to nitrate some methanol but it being so much lighter than the mixed acids it needs to be stirred pretty well otherwise it just floats on top. I poured the mixed acids in a wider container and that seemed to help a bit, but still not enough.
Are oval stir bars better? What works best for mixed acids?
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smaerd
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[*] posted on 22-12-2012 at 12:41


Generally stirring is a non-issue for liquid solutions of low viscosity. If it's hitting the walls of the container in my experience the stirrer is going too fast, or the container is convex. Usually I solve this by slowly raising the speed of the stirrer, hopefully this helps and aren't stupid answers or things you've already tried.



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gnitseretni
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[*] posted on 22-12-2012 at 15:05


My stirrer goes from 1 to 10 and the stir bar will hit the walls if I go past 7 regardless of how slow I raise the speed.
Anyways, I decided to do the nitration anyway. I used the 2" stir bar and a wider container. I had it stir as fast as it would go without the stir bar flying against the walls. The vortex got smaller and smaller as I added more methanol, but it still must have stirred well enough because I got methyl nitrate. Didn't think I would as it looked like the methanol stayed on top the whole time, but then again it was hard to tell as all liquids were clear as water. Oh well, guess I worried too much :P
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[*] posted on 24-12-2012 at 08:39


I have a quick question:
I wonder about the chemical stability of cyanoacrylates (glue). I really like to use this stuff to make my detonators gas-tight, but I don´t know if there could be any
side reactions with HE´s of the following familys: nitramines, nitric esters, (peroxides), azides(lead and silver) and maybe stability towards reduction (zinc, magnesium and so on).
And what are the products od decomposition?NOx?

[Edited on 24-12-2012 by Simbani]
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elementcollector1
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[*] posted on 25-12-2012 at 19:37


No idea on the last one, but I think it wouldn't be too resistant (considering it's basically Superglue).
My question: is potash pronounced pot-ash or poe-tash?




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Vargouille
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[*] posted on 25-12-2012 at 20:17


Merriam-Webster says "POT-ash" and so do the Canucks, and I trust the Canucks.
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smaerd
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[*] posted on 29-12-2012 at 13:29


In "The Art of Writing Reasonable Organic Reaction Mechanisms" by Robert Grossman

the first problem asks which resonance structure is best. This one kind of confused me because I know boron to be an exception to the octet rule and be "satisfied" with 3 bonds or 6 valence electrons. Ex: boron triflouride, borane, etc.

I said the structure on the left was the best using this knowledge because there is no charges making it 'preferred' but the author says the one on the right is preferred because all of the atoms have a full 'octet'. Not sure who is actually right here but as you'll see even my chemical drawing utility(Marvin Sketch) doesn't force a full 'octet' on boron.

resonance Question.png - 3kB




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[*] posted on 30-12-2012 at 13:17


Question: does anyone know generally how 'clean' "One Shot" drain opener/cleaner is, in terms of chemical purity? Does it usually have dyes in it, or lots of suspended carbon?

Many thanks.

@Vargouille: I've always pronounced it as 'POT-ash', and IIRC several pseudo-scientific television shows have always documented it as 'POT-ash'.




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[*] posted on 31-12-2012 at 05:09


Quote: Originally posted by smaerd  
In "The Art of Writing Reasonable Organic Reaction Mechanisms" by Robert Grossman

the first problem asks which resonance structure is best. This one kind of confused me because I know boron to be an exception to the octet rule and be "satisfied" with 3 bonds or 6 valence electrons. Ex: boron triflouride, borane, etc.

I said the structure on the left was the best using this knowledge because there is no charges making it 'preferred' but the author says the one on the right is preferred because all of the atoms have a full 'octet'. Not sure who is actually right here but as you'll see even my chemical drawing utility(Marvin Sketch) doesn't force a full 'octet' on boron.

The title of the book, "writing reasonable...", is not there for nothing. If you have a B-N bond where boron has a vacant valence orbital and the nitrogen a lone electron pair, it becomes unreasonable to expect no double-bonding interaction. It would be like writing the double bond of the alkenes in the form of C+-C- rather than C=C. While such formality is advised when depicting ylides, nitro groups, sulfoxides, phosphine oxides and the like (in order not to break the Lewis bond conventions), it is unreasonable to do elsewhere. Nevertheless, where writing the more realistic type of interactions would make a mess, like in the case of non-localized B=N bonds, it is preferably avoided. For example, the B-N-B or the N-B-N connectivity is better left depicted as it is.




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smaerd
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[*] posted on 31-12-2012 at 06:40


That makes a lot of sense thanks for clearing that up. For some reason I forgot that just because it can form 3 bonds does not imply that the empty valence shell does not exist to interact in bonding or resonance. MO theory more than likely makes sense of that and I guess some common-sense I need to adapt. Thanks again.



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Glucose Oxidase
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[*] posted on 1-1-2013 at 12:35


Does C(NO3)4 exist?
please note that it is NO3 not NO2 so the bond between the radical and the carbon is via oxygen not nitrogen.
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[*] posted on 1-1-2013 at 12:49


Quote: Originally posted by Glucose Oxidase  
Does C(NO3)4 exist?

No.

Also there is an article where they mention it... Also they made reactions with it, but I'm skeptic, because there is no prep mentioned anywhere.

Khisamutdinov, G. Kh.; Slovetskii, V. I.; L'vova, M. Sh.; Usyshkin, O. G.; Besyrozvannyi, M. A.; Fainzil'berg, A. A.
Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1970 , p. 2397 - 2399

[Edited on 1-1-2013 by kristofvagyok]




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[*] posted on 2-1-2013 at 13:42


I found an eBay seller in Poland who is offering 250mL of benzaldehyde for around $24 (including the shipping cost). Is this a good price for benzaldehyde? Would it arouse suspicion if I purchased it?
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learningChem
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[*] posted on 3-1-2013 at 22:40


Is it possible to go (easily) from formaldehyde to formic acid?
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Hexavalent
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[*] posted on 3-1-2013 at 22:45


In theory, yes. Formaldehyde (or the solution of it, formalin) is an aldehyde, and consequently can be oxidized to formic acid (a carboxylic acid) by refluxing with an oxidant, such as acidified potassium dichromate.

In practice, not quite. I've spoken with DJF90 previously and it seems that formic acid also has a tendency to be oxidize (it itself being a good reducing agent) into carbon dioxide and water, so one would have to be very careful when preparing it via this route and I would imagine that controlling it would be somewhat difficult and problematic.



[Edited on 4-1-2013 by Hexavalent]




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learningChem
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[*] posted on 5-1-2013 at 13:14


Thanks Hexavalent

[Edited on 5-1-2013 by learningChem]
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[*] posted on 5-1-2013 at 16:09


What about using the canizzaro reaction? formaldeyde -> methanol + formate?
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[*] posted on 6-1-2013 at 15:05


You are right. The Cannizzaro reaction would produce sodium formate and methanol. You could isolate the formate and distill it with sulfuric acid (look for an actual procedure, this may not be ideal) If you want a lot of formic acid, you can buy it from Dudadiesel.com. It's not very expensive ($12 a liter or so).
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Hexavalent
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[*] posted on 6-1-2013 at 15:44


Quote: Originally posted by barley81  
You are right. The Cannizzaro reaction would produce sodium formate and methanol. You could isolate the formate and distill it with sulfuric acid (look for an actual procedure, this may not be ideal) If you want a lot of formic acid, you can buy it from Dudadiesel.com. It's not very expensive ($12 a liter or so).


In theory it should work, the equilibrium being shifted to the right due to the formation of a weaker acid.

If you don't want to buy it online, it is sold in many hardware stores as a limescale remover. I bought a sample from a local store a few months ago, and found it to be of 40% concentration, but remarkably pure (clear liquid, no colour at all, very few trace impurities).




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[*] posted on 7-1-2013 at 09:01


Question: why do filtrates tend to froth/foam during vacuum filtrations?

[Edited on 7-1-2013 by Hexavalent]




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