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Author: Subject: The Short Questions Thread (4)
Oolong
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[*] posted on 8-12-2015 at 07:15


Are there any practical reasons for choosing a multi-neck flask with parallel side necks vs. angled side necks? I noticed from looking at a catalog from a glassware manufacturer that they tend to come with different combinations of joint sizes, and wondered if they were both supposed to be used for different purposes?
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[*] posted on 8-12-2015 at 08:08


I would have at least one of the outer necks at an angle because
I may want a thermometer or air leak or steam inlet in the liquid.

Things I can think of that may go into the necks;
Fractionating column, reflux condenser, thermometer, stirrer, addition funnel, air or steam inlet and probably others.
So only you can answer your question properly.
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[*] posted on 8-12-2015 at 17:26


I was converting some battery gunk -- MnO2 + impurities --> MnSO4 using nurdrage's method.
https://youtu.be/2gXByJkg0iY?t=203

I passed the exhaust gas through a NaOH scrubber to mop up any remaining SO2. My setup, (see below) seemed pretty effective. No sulfurous smell at all (which is what I like in the absence of a fume hood.)
Once the intended reaction was complete, A white crystalline substance began to build up in the scrubber. I wasn't really even thinking about byproducts, but since I have made it I thought I would collect and label. The liquid is still highly alkaline. What I would like to know is whether I have made sodium sufite or sodium bisulfite. I am pretty certain it is sulfite but thought it worthwhile to check.

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[*] posted on 8-12-2015 at 18:25


If it's highly alkaline, then it would be sodium sulphite. Sodium hydrogen sulphite would be only mildly basic.



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[*] posted on 8-12-2015 at 21:37


Thanks for that DA. Crystals happily drying. :)



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[*] posted on 12-12-2015 at 03:19


Phenol Red

I recently received an unlabelled vial of a reddish powder. A bit of experimentation and I discovered that it was an acid-base indicator. A bit more careful measurement and I was able to identify it as phenol red. But it doesn't seem like a particularly useful indicator for the things I might use it for. I understand that it has a few applications in biology and is also the indicator often used for swimming pool test kits. I don't have any real use in those two areas. It changes colour over quite a wide range and without a colour matching card seems pretty useless.

So, is there anything interesting that could be done with it? I have a couple of grams.




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[*] posted on 12-12-2015 at 03:26


you could prolly buy a replacement colour card from a pool store for a couple of bucks. the advantage is that it is able differentiate over a large range of pH's with high accuracy rather than just turn at a particular acidity.



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[*] posted on 12-12-2015 at 03:32


Yeah, but if I wanted that, I have some full range universal indicator. And some indicator strips. And a pH meter.

It was the multiplicity of phenol rings that caused me to wonder if something might be made from it.




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[*] posted on 12-12-2015 at 15:33


Clorinate it? I have no clue how chlorinated you could get it, but if you took a sample and passed chlorine through it, I'd assume you could at least get that central carbon to a tertiary chloride, and turn the non-phenyl ring into a phenyl ring. Is this just spitballing? I have no clue if it'd work. Versuchschemie.de had a bit of dye chem on it.

Two quick questions:
1. If you add boric acid to 'bicarb, do you get sodium borate or tetraborate? Is the resulting compound capable of precipitating Copper(II) borate from a soluble Copper(II) salt?
2. What's the best way to purify HCl with lots of Iron(III) Chloride in it? I've seen the procedure which involves placing a container with the HCl and a container with water in it in a larger container and letting it sit there. I have no suitable large container.

Thanks for any answers,

[Edited on 12-12-2015 by The Volatile Chemist]




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[*] posted on 12-12-2015 at 15:52


The central carbon on that class of dyes will not halogenate. Instead, you will get either di- or tetra- halo aromatic substitution, depending on whether or not an excess of halogen is used. In the case of phenol red, bromination with bromine in acetic acid will yield bromophenol blue.(See Vogel 3rd, pg. 990)



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[*] posted on 12-12-2015 at 16:09


Bert, I have a question for you. How do you negate all the static build up in the air this time of year? You don't just avoid fireworking I'm sure. When I run my hand down my dogs back and it crackles all the way down, I know not to touch anything that might not like static discharge.
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[*] posted on 14-12-2015 at 15:06


Quote: Originally posted by gdflp  
The central carbon on that class of dyes will not halogenate. Instead, you will get either di- or tetra- halo aromatic substitution, depending on whether or not an excess of halogen is used. In the case of phenol red, bromination with bromine in acetic acid will yield bromophenol blue.(See Vogel 3rd, pg. 990)

Makes sense. Interesting. If I ever get any bromine and phenol red, I'll have to give it a try. Perhaps halogenation with chlorine and bromine would be good projects.




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[*] posted on 17-12-2015 at 09:38


Is it possible to make a grignard reagent from a halo nitroarene,say 3-bromonitrobenzene ?
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[*] posted on 17-12-2015 at 10:35


Grignards react with aromatic and aliphatic nitro compounds to give the disubstituted hydroxylamines. See for example J. Chem. Soc. Perkin Trans. (1990) 2133-2138. 3-bromonitrobenzene would probably polymerize with the addition of magnesium.
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smile.gif posted on 17-12-2015 at 15:56
Nitric Acid Safety,Quick Question.


I have a quick question about safety regarding nitric acid:Why is it classed as a level 4 health hazard on the MSDS and the NFPA 704? As far as I know,getting it on the skin won't kill you unless you spill a whole beaker and all of it lands on your skin.
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[*] posted on 17-12-2015 at 16:13


Skin contact isn't what will kill you,but rather inhalation. Inhaling nitric acid vapor will not only release toxic nitrogen dioxide gas directly into your lungs,but will also paralyze the diaphragm and make it impossible to breathe. In fact, it is produced by the burning of nitromethane,which is used as a booster in racing cars,drivers often have to wear face masks to avoid inhalation of the toxic vapors.



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[*] posted on 18-12-2015 at 21:13


Hello, I'm new here, and am trying to build the sodium cell that len made. Does anyone know where to get the thick steel tube needed? All pipe from hardware store is painted, galvanized, too small.



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[*] posted on 20-12-2015 at 07:55


I have 80ml piranha (60ml H2SO4, 20ml 12%h2o2) that I've used to remove red wine stubborns out of my 1l RBF. I've been doing crude KOH extractions from oak ashes in my backyard. Surely some of my leachate from the ashes would neutralize it safely? No heavy metals or other nasties in it. Arkansas is too pretty to pollute..........



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[*] posted on 20-12-2015 at 08:15


It should be safe to pour out if you dilute it heavily.
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[*] posted on 20-12-2015 at 08:22


Quote: Originally posted by Crowfjord  
Grignards react with aromatic and aliphatic nitro compounds to give the disubstituted hydroxylamines. 3-bromonitrobenzene would probably polymerize with the addition of magnesium.

what if you reacted 3-nitrobenzaldehyde with R-MgX ? would the grignard attack the carbonyl group to give the alcohol.?
In morrison and boyd,it is written that grignard reactions cannot be done on nitro compounds as the nitro group will oxidise the grignard reagent .
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[*] posted on 20-12-2015 at 09:24


Quote: Originally posted by The Garbage Guardian  
Hello, I'm new here, and am trying to build the sodium cell that len made. Does anyone know where to get the thick steel tube needed? All pipe from hardware store is painted, galvanized, too small.


A different hardware store.
Amazon.
EBay?




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[*] posted on 20-12-2015 at 09:47


Quote: Originally posted by The Garbage Guardian  
Hello, I'm new here, and am trying to build the sodium cell that len made. Does anyone know where to get the thick steel tube needed? All pipe from hardware store is painted, galvanized, too small.


http://www.mcmaster.com/#standard-steel-tubing/=10bn3ld
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[*] posted on 20-12-2015 at 10:20




this would be a SECONDARY alcohol? it's honokiol, from magnolia tree bark.




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[*] posted on 20-12-2015 at 10:42


No, since the hydroxyl groups are connected to the aromatic rings, they behave very differently than they would if they were connected to a straight sp3 carbon chain. Short explanation : this is due to the free circulation of electrons in the conjugated pi system greatly changing the reactivity. They have their own nomenclature and are called <b>aryl</b> alcohols.



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[*] posted on 20-12-2015 at 12:16


Quote: Originally posted by CuReUS  

what if you reacted 3-nitrobenzaldehyde with R-MgX ? would the grignard attack the carbonyl group to give the alcohol.?
In morrison and boyd,it is written that grignard reactions cannot be done on nitro compounds as the nitro group will oxidise the grignard reagent .


Are benzaldehydes more easily reduced than aromatic nitro groups? If so, that might work to give the alcohol, as long as the nitrobenzaldehyde is kept in excess. I imagine that in some cases the nitro would oxidize the grignard reagent rather than form a C-N bond. In that case, wouldn't the nitro be reduced to a hydroxyl amine?
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