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Author: Subject: The short questions thread (1)
Nicodem
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[*] posted on 11-9-2008 at 23:57
The short questions thread (1)


This is a thread where you can post all those short questions you always wanted to ask but did not consider them worthy of a new thread. You can ask amateur science related questions of all kind as long as you think they are simple enough to be answered by other forum members in a preferably single post.
Consequently, self discipline in avoiding off topic replies is expected.
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Panache
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[*] posted on 12-9-2008 at 01:02


Does anyone have any relevant data on the polymer PPP, or poly(p-phenylene), things like glass transition temperature, % crystallinity, solvent resistances etc. My old crc handbook is too outdated (1972) and the infinet gave me nothing except derivatives of said polymer.

[Edited on 12-9-2008 by Panache]




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Nicodem
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[*] posted on 12-9-2008 at 06:06


You can find some data here: http://xxx.lanl.gov/PS_cache/cond-mat/pdf/0507/0507515v1.pdf
(Probably useless but check also http://dx.doi.org/10.1002/macp.1995.021961110)
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kclo4
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[*] posted on 12-9-2008 at 22:56


This is a great idea Nicodem! :D

I've have been wondering what would happen (although I haven't searched, so I really guess I shouldn't be asking it here) if acetic acid were dripped into hot concentrated. H2SO4 in a setup analogues to the Diethyl ether setup? I know it probably wouldn't make Acetic anhydride, but probably something interesting?

[Edited on 13-9-2008 by kclo4]
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[*] posted on 13-9-2008 at 09:34


I heated once concentrated sulphuric acid with 80% acetic acid, after a while it a few black particles were observed, but this could also have been just impurities.
And I don´t think that something new is formed, the acetic acid just would distil over I think.

And I´ve also a questin, everybody knows triphenylmathane and it´s preparation step.
I asked myself if it would also be possible to prepare trinaphthalenemethane out of naphthaline and chloroform catalyzed by AlCl3?
I wanted to attempt this but the first problem I couldn´t solve was finding a solvent for the reaction which wouldn´t react.
Until now I couldn´t find anything about this stuff.
And it doesn´t matters which isomer would be formed, if the naphthalene is attached at the 1 or the 2 position. Also many other things will be formed because naphthalene and AlCl3 are reacting at their own, so the desired stuff must be isolated from this other stuff and the reaction must be brought to a way in which the formation of trinaphthalenemethane is preferred.

And does anybody know if it could be from interest for chemiluminescence?
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Picric-A
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[*] posted on 13-9-2008 at 10:02


@ the acetic acid question- nothing new is formed however considerably stronger acetic acid distills off.
i am pretty certain this was acetic acid as it passed all the salt tests...
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kclo4
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[*] posted on 13-9-2008 at 13:56


Well, I was thinking of doing it like the ether synthesis where you heat up the sulfuric acid to 140*C and then drip Glacial Acetic acid in.
If you got it hotter, say 200*C and then dripped in the GAA maybe something would form if not from the first experiment. I assume at some point methane would be produced.
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panziandi
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[*] posted on 13-9-2008 at 15:18


I treated sodium chloroacetate with conc H2SO4 and it fizzed... any ideas?



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kclo4
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[*] posted on 13-9-2008 at 15:55


Could you have perhaps had some impurities such as carbonates etc?
I noticed my Sodium acetate that I made from vinegar and baking soda fizzed, It had sat on a shelf with out a lid for a few months. I believe I made sure to use an excess of Vinegar at the time of producing it.

Could you explain how you obtained your Sodium Chloroacetate? This may help.
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[*] posted on 13-9-2008 at 16:12


Its GPR grade from BDH :D... so probably 97% - 99%. I suppose it could be carbonate impurities, that did not occur to me at the time.

I did it at the start of summer. I will try it again and pass the gasses into lime water etc.

[Edited on 14-9-2008 by panziandi]




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kclo4
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[*] posted on 13-9-2008 at 18:26


Another thought, if chloroacetic acid is produced from chlorine, and HCl is a byproduct perhaps their were very small amounts of HCl that got to react with the Sodium base to form Sodium chloride. The gas would then obviously be Hydrogen Chloride when it was reacted with the Sulfuric acid.

I assume gases couldn't be dissolved in your Sulfuric acid, right?
If for some reason gases even dissolve in concentrated sulfuric acid, the possibly of it dissolving more of one gas then Chloroacetic acid + Sodium Bisulfate could, may perhaps cause the gas to evolve and fizz away leaving the allusion that you have impurities. This only seems like a very slight possibility to me, and I'd say that it was probably a carbonate or a chloride impurity.
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[*] posted on 14-9-2008 at 09:04


I have been unable to locate the refractive index of l,psudoephedrine HCL ....does anyone have this information handy....as I searched and have not been able to find it....many thanks.....solo

What is Refractive index....?

http://en.wikipedia.org/wiki/List_of_refractive_indices


[Edited on 14-9-2008 by solo]




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[*] posted on 14-9-2008 at 10:06


http://www.erowid.org/archive/rhodium/chemistry/comparison.e...

Bottom of the page, hope it helps :)
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[*] posted on 14-9-2008 at 12:06


I think i found some information in pages 634-648 in the book of Alkoloids found here.....thanks...java

http://www.sciencemadness.org/library/books/the_plant_alkalo...




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[*] posted on 17-9-2008 at 11:32


Kinda random, is the fillament of a sodium lamp made of mettalic sodium?
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[*] posted on 17-9-2008 at 13:42


I beleive there is a small piece of sodium metal that needs to vaporise before the characteristic yellow light is observed.
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[*] posted on 17-9-2008 at 17:40


I found a neat way to test for ketones using...p-nitrophenylhydrazone, however I can't seem to find it's CAS# or much about it .......solo


Quote:
...1 Phenylacetone forms a beautifully crystalline paranitrophenylhydra-
zone melting after crystallization from alcohol or pyridin at 145’ to 145.5’.
It usually crystallizes in rosettes of platelets which are only moderately
soluble, even in hot alcohol. The substance serves well for the identi-
fication of phenylacetone.


....................source,



FURTHER STUDIES OF THE MODE OF OXIDATION OF PHENYL DERIVATIVES OF FATTY ACIDS IN THE ANIMAL ORGANISM. III. SYNTHESIS OF SOME DERIVATIVES OF PHENYLPROPIONIC ACID
H. D. Dakin
J. Biol. Chem., Oct 1908; 5: 303 - 309

[Edited on 17-9-2008 by solo]

Attachment: 173.pdf (735kB)
This file has been downloaded 939 times





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Panache
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[*] posted on 18-9-2008 at 07:12
Drying glassware using solvents, does it work?


i have always had this technique for when if i needed a piece of glass dry but i didn't have time for the oven and if absolutely super dry wasn't in need. Everytime i do it i wonder if i'm completely delusional. Its fairly simple i just swirl the flask in the dry solvent i will be using in the flask, then discard that solvent to recycle and proceed with the glass as if it were dry. it always plays on my mind because it is reasonable theory but i know i have little evidence of its efficacy
How long would it take say a 250mL round bottom to dry out effectively at 140 C, how long would it take if you immersed it in dry ether or dry toluene at RT.


[Edited on 18-9-2008 by Panache]




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[*] posted on 18-9-2008 at 08:10


To Solo:

I'm not sure you are asking for the CAS number of p-nitrophenylhydrazine or the p-nitrophenylhydrazone of phenylacetone, but here are the numbers of both:
p-nitrophenylhydrazine, CAS 100-16-3, 158°C dec.
phenylacetone p-nitrophenylhydrazone, CAS 70063-29-5

More commonly than p-nitrophenylhydrazine the 2,4-dinitrophenylhydrazine (CAS 119-26-6) is used for the derivatisation of ketones (actually I should say that it used to be used since nearly no one does characterisation based on derivatisation any more). The melting points reported for phenylacetone 2,4-dinitrophenylhydrazone (CAS 19072-92-5) are 157-158°C, 153-155°C and 149.5°C.

To Panache:

Since the hardest to remove water from glass is the one that is chemisorbed on the silicate surface I think just washing your glasware with a dry solvent does not do much. Generally in the lab one would let the flask stay at 120-150°C for at least five hours and let it cool in a desiccator or under dry argon or nitrogen flow. However, myself being too lazy, I just heat the flask under the argon flow with a heat gun (max air temperature of 400°C) for some 15 min and let it cool while still being purged with argon. Works well for organolithiums and Grignards.

[Edited on 18/9/2008 by Nicodem]




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[*] posted on 18-9-2008 at 10:50


Has anyone got any info on Aluminium carbonate? eg, decomp temp?
cheers!
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[*] posted on 18-9-2008 at 19:20


In a rearrangement of a well known aldehyde poured into a very cold H2SO4 (-16C) rearrangement of the aldehyde occurs and a ketone is produced .......along with a large amount of water with a distinctive rooten egg smell......my question is what can i treat this water with to salt out the sulfur and rid of the smell as it makes for a very uncomfortable reaction waste product that I don't want to pour down the drain.....solo



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[*] posted on 19-9-2008 at 06:39


Quote:
Originally posted by Picric-A
Has anyone got any info on Aluminium carbonate? eg, decomp temp?
cheers!


Aluminum is too acidic in solution. There isn't even a bicarbonate. In fact, aluminum is acidic enough that it might displace the carbonate, turning sodium carbonate, at least in part, into sodium aluminate. Sodium aluminate solution is stable in air.

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[*] posted on 19-9-2008 at 09:08


It will form the hydroxide. Aluminium hydroxide decomposes to aluminium oxide at 300*C according to my CRC handbook (I just got the 75th edition from the chemistry library they sold it for £5 woo)



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[*] posted on 19-9-2008 at 16:31


Could I please ask for a little assistance in translating this German sentence:

dann wurde unter Feuchtigkeitsabschluß trockner Chlorwasserstoff eingeleitet.

babelfish gives me: then under humidity conclusion dry hydrogen chloride was introduced.

So the problem is with "Feuchtigkeitsabschluß," does it just mean a dry atmosphere (drying tube) or does it imply heating of some kind?

(I think it's a really nice idea for a thread by the way Nicodem ;))
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[*] posted on 19-9-2008 at 16:44


Feuchtigkeitsabschluß simply means exclusion of moisture, anhydrous conditions. So use a drying tube or something like that to keep atmospheric moisture away, and, of course, dry the HCl gas as good as possible.



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