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Author: Subject: The short questions thread (2)
Picric-A
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[*] posted on 17-9-2009 at 22:31


Quote: Originally posted by entropy51  
There is an OTC product which consists mainly of sodium dithionite and carbonate. I don't know about the luminol synthesis, but it works for a number of other purposes.

Rit Color Remover http://www.ritdye.com/Fabric+Treatments.28.51.7.49.lasso

Dithionite can also be prepared by reducing SO2 with sodium formate in aqueous methanol. There is a reference posted around here somewhere on this method.

[Edited on 17-9-2009 by entropy51]


I have not found an OTC product containing Dithionite here in the UK.
As to the synthesis via reduction of methanol, there are lots of reperences and patents to that but i decided it only looked viable on an industrial scale.

Attachment: sodium dithionite from formate + SO2.pdf (603kB)
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entropy51
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[*] posted on 18-9-2009 at 07:15


Quote: Originally posted by Picric-A  

As to the synthesis via reduction of methanol, there are lots of reperences and patents to that but i decided it only looked viable on an industrial scale.
Oh did you now?

I guess an amateur like myself shouldn't attempt it then?:P

It works in the lab if one has source of SO2.

You can also prepare an aqueous solution by stirring up NaHSO3 with Zn dust.
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Picric-A
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[*] posted on 18-9-2009 at 07:24


Quote: Originally posted by entropy51  
Quote: Originally posted by Picric-A  

As to the synthesis via reduction of methanol, there are lots of reperences and patents to that but i decided it only looked viable on an industrial scale.
Oh did you now?

I guess an amateur like myself shouldn't attempt it then?:P

It works in the lab if one has source of SO2.

You can also prepare an aqueous solution by stirring up NaHSO3 with Zn dust.


I was not questioning your ability, i was meerly stating large reactors are needed, solutions containing mixtures of methyl formate, and lots of other chemicals are needed as a reaction base (see lit.) followed by a cheap SO2 source (my only source is H2SO4 + Cu- i am going to buy a cylinder soon though). Overall it seems like more trouble than its worth

I have given the NaHSO3 method a shot, but i didnt have powdered Zn, only granules. upon standing in a NaHSO3 solution for 24 hours, i got a colourless solution with the lump of Zn in and a lot of white ppt in the bottom (Zn(OH)2).
Could be a good method however powdered Zn if definitly needed

[Edited on 18-9-2009 by Picric-A]
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[*] posted on 18-9-2009 at 07:51


Powdered Zn is dead easy to get. It was the first chemical I bought.
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Jor
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[*] posted on 18-9-2009 at 08:22


Garage chemist gas mentioned the anhydride of periodic acid (diiodine heptoxide) on this forum once. It is supposed to be an orange polymeric solid.

I added a spatula of periodic acid to 2mL of conc. H2SO4, and I then heated with a propane burner. The solid just dissolves, but no orange color is produced.
I added 3mL of DCM and shook vigorously, I then took the DCM layer, and boiled away the DCM. No residue remained. My guess is that I2O7 should be soluble in DCM, so no anhydride was formed.

Does anyone know how it can be synthesised? Without using things like oleum. Maybe heating periodic acid with phosphorus pentoxide?
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entropy51
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[*] posted on 18-9-2009 at 09:29


Quote: Originally posted by Picric-A  
i was meerly stating large reactors are needed, solutions containing mixtures of methyl formate, and lots of other chemicals are needed as a reaction base (see lit.)

The patent you posted specifies a reactor because they're describing a large-scale industrial application of the reaction.

It works just fine in a stirred flask. You need only sodium formate, methanol and SO2.

The Zn reduction of NaHSO3 is even easier, but does require Zn dust.
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[*] posted on 18-9-2009 at 14:54


What is produced at the anode if I electrolyze molten ammonium acetate (ammonia at the cathode, I expect)? Assume I use a PbO2 anode or the like, making the formation of a metal acetate or the like from the anode material unlikely. I'm having trouble seeing what the C2H3O2 anion would turn into, and the references I see online mostly talk about using ammonium acetate to assist in the electrolysis of something else (or turning it into nanocrystalline diamond via unorthodox voltage and electrodes).
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[*] posted on 18-9-2009 at 19:15


^interesting question. The way I imagine it is that the AcO* radical would do a hunsdiecker type thing and make CH3* + CO2, two of the CH3* combining to make CH2CH2. Or it could make Ac-O-O-Ac, and decompose into something.

How do you know when an alcohol can be chlorinated with HCl? Is it correct that you can make tertiary halides from tertiary alcohols simply with HCl at RT?
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[*] posted on 18-9-2009 at 19:45


Quote: Originally posted by bbartlog  
What is produced at the anode if I electrolyze molten ammonium acetate (ammonia at the cathode, I expect)? Assume I use a PbO2 anode or the like, making the formation of a metal acetate or the like from the anode material unlikely. I'm having trouble seeing what the C2H3O2 anion would turn into, and the references I see online mostly talk about using ammonium acetate to assist in the electrolysis of something else (or turning it into nanocrystalline diamond via unorthodox voltage and electrodes).


Quote: Originally posted by ketel-one  
^interesting question. The way I imagine it is that the AcO* radical would do a hunsdiecker type thing and make CH3* + CO2, two of the CH3* combining to make CH2CH2. Or it could make Ac-O-O-Ac, and decompose into something.

How do you know when an alcohol can be chlorinated with HCl? Is it correct that you can make tertiary halides from tertiary alcohols simply with HCl at RT?


Look up the Kolbe Electrolysis. I'm going to guess that you'd turn two NH4+ into 2 NH3 and a H2 at the cathode and perform the standard kolbe electrolysis at the anode, forming ethane and CO2.

ketel-one A mixture of conc. HCl and zinc chloride is called Lucas's reagent and may be of some assistance here. Usually the reaction is done at reflux to get good yields.




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[*] posted on 18-9-2009 at 20:23


Many thanks Chaos, that explains everything.

Oh and that CH2CH2 should have been CH3CH3 obviously.

[Edited on 19-9-2009 by ketel-one]
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[*] posted on 18-9-2009 at 20:34


Quote: Originally posted by Jor  
Garage chemist gas mentioned the anhydride of periodic acid (diiodine heptoxide) on this forum once. It is supposed to be an orange polymeric solid.


From Inorganic chemistry Egon Wiberg, Nils Wiberg, Arnold Frederick Holleman, 2001, comes the attached.

References from the 1990s talk about the heptoxide, mention it as orange, and state a very similar preparation to the hexoxide. Guess we need to find some journal references.

I2O6.png - 24kB
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[*] posted on 18-9-2009 at 23:55


Alkylation reactions have to be performed in nonpolar solvent right? A 40% aqueous alkyl halide would have to be distilled out first, yes?
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[*] posted on 18-9-2009 at 23:59


No not really. I think it is better in a polar solvent in fact. But likely it depends on what you are alkylating. Phenols are alkylated with dimethyl sulfate in water, alkyl halide in alcohols etc. (I have not heard of alkyl halide in water being used though - likely it is better to have it in alcohol but it may work.) As I say it depends what you have to alkylate and the size of the alkyl group though. :)
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[*] posted on 19-9-2009 at 09:10


Quote: Originally posted by not_important  

From Inorganic chemistry Egon Wiberg, Nils Wiberg, Arnold Frederick Holleman, 2001, comes the attached.

References from the 1990s talk about the heptoxide, mention it as orange, and state a very similar preparation to the hexoxide. Guess we need to find some journal references.

I have the book "Chemistry of the Elements" from Earnshaw and this tells that I2O7 does not exist. There is no anhydride of periodic acid. The compound I2O6 certainly may exist, but I2O7 probably does not. The orange material, mentioned by Jor, probably is an impure compound, contaminated with iodine, which can explain the orange color.

[Edited on 19-9-09 by woelen]




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[*] posted on 19-9-2009 at 14:23


40% aqueous alkyl halide solution? What alkyl halide is soluble to the extent of 40% in water? Are you not confusing with the amine? Or a solution in alcohol?



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[*] posted on 19-9-2009 at 21:30


Lol, good point. I Must've had some unreacted alcohol.

Does anyone know... if you try to halogenate piperidine (or pyridine), would it halogenate at the 2 or the 4 position? Could iodine be used for that purpose with acetone as solvent?
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[*] posted on 20-9-2009 at 07:06


Pyridine will be halogenated to the 3 and 5 positions with difficulty, requiring hot temperatures. See p. 58 in the book "Preparation of organic intermediates" that sonigasira posted in the aluminium alkoxide thread (org chem forum).



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[*] posted on 20-9-2009 at 07:53


Quote: Originally posted by ketel-one  
Lol, good point. I Must've had some unreacted alcohol.

Does anyone know... if you try to halogenate piperidine (or pyridine), would it halogenate at the 2 or the 4 position? Could iodine be used for that purpose with acetone as solvent?


From Joule & Mills' Heterocyclic Chemistry:
"2-Bromo- and 2-chloropyridines can be made extremely efficiently by reaction of pyridine with the halogen, at 0-50C in the presence of palladium(II) chloride[25]"
And reference 25 is attached.

4-position is via the N-oxide


Attachment: s-1980-29025.pdf (129kB)
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[*] posted on 21-9-2009 at 18:36


Sorry to butt in...

Say a clumsy chemist was to break a piece of glassware, what is the best adhesive they should use?

I fixed the outlet on the water jacket of a condenser with cyanoacrylate which works perfectly, but what if you were repairing something that may come into contact with organic solvents?

Cyanoacrylates are soluble in acetone, DCM etc.. before they set. (eg, directions on super glue says clean excess with acetone before dries).

Does anyone one if it will hold up once set, to at least acetone, hopefully DCM too?
Or is there a better adhesive to use?
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[*] posted on 21-9-2009 at 20:56


Cyanoacrylate glue ("Superglue") is supposed not to work on materials containing alkalis, including soda glass. Two-pot epoxide glues - "Araldite" - are supposed to be the appropriate glue for such materials.
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[*] posted on 21-9-2009 at 20:58


Quote: Originally posted by Siddy  
Say a clumsy chemist was to break a piece of glassware, what is the best adhesive they should use?
It's torch heat. Blow during and anneal afterward.

Really? If there were an adequate resin or polymer to repair glass, wouldn't there be labware made out it?—since it's cheaper to cast plastic than to blow glass.
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[*] posted on 22-9-2009 at 01:30


dont bother :) you broke it hehe you buy another simple.

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[*] posted on 22-9-2009 at 02:34


Thanks JohnWW!
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[*] posted on 22-9-2009 at 06:20


I'm currently doing the synthesis of 3-nitrophtalhydrazide. I added NaOH to a suspension of 2,11g 3-nitrophthalic acid until the solution turned pink (phenolphthalein). i then added a pinch of 3-nitrophthalic acid to make it yellow again. I then added 1,35g (slight excess) of hydrazine sulfate, and boiled the solution down to the point where a crystal crust formed. I then added about 15mL of glycerin, and heated the solution at 170-185C for 1 hour.

Now my first question is, at this point there was already quite some precitipate, while in the method on versuchschemie, a clear red liquid is obtained. How is this possible? Might it be possible that phtalhydrazide or 4-nitrophthalhydrazide precitipated, because of impurities in the 3-nitrophthalic acid (i made this myself).

Next I made a very stupid mistake. I added water about 1,5x the volume, to the still 150C solution (I was impatient) and there was some boiling.
Now what i forgot is possible hydrolysis. Is it possible that at those temperatures a lot of my 3-nitrophthalhydrazide hydrolysed? How prone is a hydrazid group to hydrolysis at slightly acidic pH?
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[*] posted on 22-9-2009 at 12:48


Quote: Originally posted by not_important  

You can use iodine, water, and H2S, which give aqueous HI and elemental sulfur; iodine, water, and SO2, which gives you aqueous HI and H2SO4; or I2, H2O, and red phosphorous, the favorite of meth makers.

I've thought of an easier way, (no sulfur or phosphorous required); iodine is extracted very easily from medicinal iodine, and it reacts very violently with aluminum (you don't even need aluminum powder, just small squares cut with scissors out of aluminum foil); reaction starts spontaneously, produces lots of heat, and should be contained or lots of iodine will vaporize. That's to get Al-I3.

Then what I'm thinking is:
Al-I3 + 33%HCl = AlCl3 + 63%HI
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