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DJF90
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[*] posted on 30-4-2011 at 05:31


I don't know about acetate, but both CuBr2 and CuCl2 will a-halogenate aldehydes and ketones. If Methanol is used as the solvent then the a-chloro-dimethylacetal is furnished.
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[*] posted on 30-4-2011 at 12:29


What is the easiest Amine protecting group that a home chemist can get there hands on?


Its sort of besides the point but I want to attempt to protect the amino grouping on glycin in an attempt to form Ethylene Diamine thru the Kolbe electrolysis. This normally produces low yeilds but I wish to see if higher yeilds can be had by protecting the amine. However all I read gives unreasonable protecting groups that are out of my range.





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[*] posted on 30-4-2011 at 15:37


Quote: Originally posted by experimenter  

...sodium acetate in water, when reacted with cupric chloride (CuCl2) gave a white precipitate (CuCl I suppose).


What concentration were your solutions? Which was in excess? I would suspect NaCl rather than CuCl in this situation, if the solutions were concentrated. Did you do any testing to verify that the precipitate was CuCl? You could just set it out (still wet) on some filter paper and see if the air turns it green; the oxidation proceeds pretty rapidly. Anyway, it's just not clear to me what would be getting oxidized here to reduce the copper, which is why I have a hard time seeing CuCl as likely. Heck, in semidilute solution NaCl (which you would have) should solubilize CuCl anyway, it probably wouldn't precipitate even if present...
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[*] posted on 30-4-2011 at 19:05


I need to convert an amine from an electron releasing group to an electron withdrawling group so that it does not stabilize the formed radicals.

Im considering protecting the amine some how, as seen in my above post, which I feel will help this some what but conversion of the Amine by oxidation to an Nitro group, converting it to an EWG, may be a better option.

Does any one have any other suggestions as to what the best means of converting the amine to some form of EWG would be.





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[*] posted on 30-4-2011 at 23:55


Thanks for your answers.
Quote:

What concentration were your solutions? Which was in excess?

I can't accurately reply to this now, I must repeat the experiment.
Quote:

Did you do any testing to verify that the precipitate was CuCl? You could just set it out (still wet) on some filter paper and see if the air turns it green; the oxidation proceeds pretty rapidly.

Here is a picture of the precipitate today (one day after filtering), I remember well it wasn't green yesterday, when fresh:



It is baffling me too, how could the reaction be if this is really CuCl. Maybe copper acetate is formed? (+NaCl + CuCl)
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[*] posted on 1-5-2011 at 06:56


Hm... very interesting. Looks like you have CuCl, all right! Copper acetate (or one of the copper acetates) would logically form (as well as NaCl) if you precipitated everything by removing the water, but I don't think that explains the change in oxidation state.
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[*] posted on 1-5-2011 at 09:37


Well, I tried it again with pure sodium acetate salt and it gave nothing.
The first time I used contaminated sodium acetate (it had a ph around of 10) and probably it had some baking soda in excess in it (I made it by neutralizing soda and vinegar).
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[*] posted on 1-5-2011 at 12:13


Vinegar might have provided some organic stuff that would reduce Cu++. Excess NaHCO3/Na2CO3 should precipitate CuCO3, but that would be green from the beginning.
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[*] posted on 2-5-2011 at 10:23


if i had a light globe (incandescent) and it was for 120V power supply, if i ganged two in series and plugged them into 240V would they work as normal, ie as i they were plugged individually or in parallel in 120V?
lazy question.

[Edited on 3-5-2011 by Panache]




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[*] posted on 7-5-2011 at 21:01


Quote: Originally posted by Panache  
if i had a light globe (incandescent) and it was for 120V power supply, if i ganged two in series and plugged them into 240V would they work as normal, ie as i they were plugged individually or in parallel in 120V?
lazy question.

[Edited on 3-5-2011 by Panache]


the answer is yes apparently, large casino's here in melbourne have themselves wired so that there are always two 120V sockets in parallel and they use globes from america, apparently there is a wattage saving in it somehow that is appreciable over so many light.




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[*] posted on 8-5-2011 at 05:48


But is that what you were originally asking? It sounds like they might have cobbled together a pair of bastard 120V sockets from a 240V source, whereas your question is whether you could just put two of the globes in series plugged in to a 240V outlet.
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[*] posted on 10-5-2011 at 14:56


Hai.

Suppose that one is chlorinating an organic liquid, as toluene or similar, with an appropriate setup.

Is it realistic to expect an absorption of Cl2 that is quantitative or nearly so? That is, can the flow rate be regulated to ensure that most all of the gas is absorbed while still maintaining a steady reaction rate, or is offgassing of Cl2 a given?

Regards
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[*] posted on 12-5-2011 at 05:30


Quote: Originally posted by bbartlog  
But is that what you were originally asking? It sounds like they might have cobbled together a pair of bastard 120V sockets from a 240V source, whereas your question is whether you could just put two of the globes in series plugged in to a 240V outlet.


i have 10 120V, 1000W projector globes that i wanted to make use of, but couldn't be assed with hasel of needing stepdown transformer everytime i needed to light something, so yes and no, but my very compact 2000W light source is pretty bright, at the moment its on my desk, when i have visitors i say, hey look at this holding my hand next to the lamp, when they lean in i turn on the light.
i think i am contributing.




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[*] posted on 28-5-2011 at 18:38


Why are hydrobrominations frequently done with HBr in glacial acetic acid solvent? What is wrong with acetone?
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[*] posted on 28-5-2011 at 19:11


I'm guessing that HBr will cause acetone to form condensation products the same way that HCl would. But there may well be other solvent effects that make specifically acetic acid the solvent of choice; I don't know anything about that.
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[*] posted on 30-5-2011 at 07:57


After atempting to reduce 1,3-dinitrobenzene with NaBH4 in methanoic solution I instantly obtained a dark purple colouration, very similar to KMnO4 solution, to the point where it was nearly black.

Does anybody know what is going on here? I cant see why 1,3-benzenediamine would change to this colour?
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[*] posted on 30-5-2011 at 08:43


Quote: Originally posted by Picric-A  
After atempting to reduce 1,3-dinitrobenzene with NaBH4 in methanoic solution I instantly obtained a dark purple colouration, very similar to KMnO4 solution, to the point where it was nearly black.

Does anybody know what is going on here? I cant see why 1,3-benzenediamine would change to this colour?
I wonder where you got the idea that borohydride will reduce aromatic nitro to amine?? An hour in the library can save a day in the lab. To the best of my limited knowledge you will get a mixture of azo compounds. Typically colored ones.

Here's one reference.




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[*] posted on 30-5-2011 at 17:24


Quote: Originally posted by Picric-A  
After atempting to reduce 1,3-dinitrobenzene with NaBH4 in methanoic solution I instantly obtained a dark purple colouration, very similar to KMnO4 solution, to the point where it was nearly black.

Does anybody know what is going on here? I cant see why 1,3-benzenediamine would change to this colour?


Mixing chemicals without doing the background reading is a decent method of getting yourself damaged. Any textbook on Functional Group Interconversion will tell you that NaBH4 is incapable of reducing nitro groups to amines. If you'd have cared to do a literature search you'd find that in some cases, addition of a metal salt can reduce aromatic and aliphatic nitro groups. But I'll let you read up on that one...

Note that 1,3-dinitrobenzene isn't a particularly nice material. Also note that selective reduction to 3-nitroaniline ought ot be possible with a reagent like sodium sulfide.
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[*] posted on 8-6-2011 at 18:17
Aldol Condensation


What is the difference between a mixed aldol and a cross aldol condensation. From what I've read they can be the same aldehyde/Ketone, a different aldehyde/ketone or an aldehyde and a ketone. The only key difference I could find out was crossed aldol condensation only works if there is an Aldehyde that has no alpha hydrogens so it will never form the enol or enolate anion intermediate depending if you are catalyzing with acid or base. That was mentioned from a university undergraduate lab.

http://www.faculty.sbc.edu/jowens/Chem232_S07/Labs/Exp_5_AlC...

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[*] posted on 12-6-2011 at 20:23


What is downward distillation?
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[*] posted on 12-6-2011 at 20:25


There is way for prepare Tin(II) Chloride from Potassium Stannate?
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[*] posted on 16-6-2011 at 14:52


Hello members,
I have a quick question about ceramic tubing, typically how much would one expect to pay for a a 36'' length, an inch ID relatively thin walled. I am not looking for a supplier quote I am merely looking for someone with experience in buying a similar piece. What would be a fair price for this? I am interested in making a tube furnace kanthal wound and I would preffer a ceramic or alumina heating tube. So I guess what I am asking is, memebers who have bought this type of piece in the past what would you pay? I will thank you in advance for your help you are willing to provide.

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[*] posted on 16-6-2011 at 16:07


How to activate reagent Aluminum Oxide for column chromatography?
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[*] posted on 24-6-2011 at 23:15


Does Carbonation of Grignard Reagents done at room temp by CO2 gas or it need lower temp(provide this temp by dry CO2)?
RMgX + CO2 -> RCO2H

[Edited on 25-6-2011 by Waffles SS]
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[*] posted on 25-6-2011 at 15:21


Anyone have any solubility miscibility data for different solvents with butyl diglyme (diethylene glycol dibutyl ether)? Specifically things like toluene, benzene, methanol, and ethanol. I already know it has very limited solubility in water, as well as water in it. Even any personal experiences in lieu of solid data would be appreciated.
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