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Author: Subject: Aniline
Magpie
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[*] posted on 26-3-2007 at 10:20


Nicodem says:


Quote:

Since HCl is only used to start up the reaction (FeCl3 can be used instead) and Fe is in large excess


This is also something that I have wondered about. In the procedures using tin a great deal of HCl is used whereas with the iron only a minor amount of HCl is used. Since the purpose of the metal in both cases is to generate nascent hydrogen (I think) it appears that most of the H2 from iron must be from its reaction with water. But in the case of tin the reaction would be more with HCl. Is this true?




The single most important condition for a successful synthesis is good mixing - Nicodem
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Eclectic
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[*] posted on 26-3-2007 at 11:29


You might try brake turnings to get better exposed surface area and less compaction. Also they are cheap (free) and may be more reactive than pure iron powder.
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[*] posted on 29-3-2007 at 14:56


I remade my aniline this time using tin. Everything went well and I got the 80% expected yield, if not a little more. I never saw any hydrogen bubbles. I assume that was because the hydrogenation was very efficient.

I must have 5 or 6 procedures for making aniline using either tin or iron laying around in various books. Yesterday I stumbled on one that I had forgotten about, ie, that in Brewster, 4th edition. It gives two procedures, one with tin and one with iron. It is interesting that for the one using iron it says "If iron powder is selected as the reducing agent, the use of an efficient stirring apparatus is imperative." I think that was my downfall. My iron powder just hung on the bottom.

Also I would much rather work with tin than iron. Iron powder gets into any crevice and stains everything. Tin is well behaved.

It was also interesting that Brewster's 4th ed (1977) said that reduction via catalytic hydrogenation using a nickel or platinum catalyst was an option for "interested students." This used elemental hydrogen as supplied by a Parr hydrogenator (drool) like the one owned by NERV. I think garage chemist also mentioned this method in a previous post.




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[*] posted on 1-4-2007 at 21:15


Quote:
Originally posted by a_bab
One interesting thing about aniline is that it was recognised as carcinogen only about 20 years ago or so...

I don't think this is right...aniline's carcingeneity has been known from before 1970. Computers were mainframes and ran Fortran 4 and Cobal. The calculator as we know it was just being born. Chemists used slide rules.
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[*] posted on 6-4-2007 at 21:04


Bravo Magpie! That is the same steam genrator I use .. I use a trap with it to catch water. Why do you run it into the wall? presumably it comes right back out and into the flask? Through a water trap? Otherwise you're distilling from a mixture of your product and boiling water .. a way to do steam distillation but inferior to live steam which you've got from the P cooker and a trap...
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[*] posted on 7-4-2007 at 09:14


from chemrox:

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Why do you run it into the wall?


This is merely a way of not consuming valuable real estate inside my fume hood (other side of that wall). I also keep my water supply sump & pump for condenser cooling water outside of the hood for the same reason.

When using the copper plated steam bath shown I don't use a steam trap as the condesate just drains harmlessly into the bottom of the bath. But when doing steam distillations I definitely use a steam trap.

Yes, the pressure cooker works pretty good as a steam supply. Condensate tends to build up in the Tygon line low spots and then get pushed out in slugs. I think this actually helps as it builds a little back pressure thereby providing slightly superheated steam when it breaks through.




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[*] posted on 27-2-2008 at 12:45


A lot of time ago I added aniline to a NH4NO3/H2SO4 mix. When I added the aniline after several seconds it boiled violently and aniline was converted to some tar. I think that it happened because I added too much aniline whit out proper cooling. I wanted to make nitroaniline. Can it be even made that way or is something else produced?



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[*] posted on 28-2-2008 at 02:34


Quote:
Originally posted by Zinc
A lot of time ago I added aniline to a NH4NO3/H2SO4 mix. When I added the aniline after several seconds it boiled violently and aniline was converted to some tar. I think that it happened because I added too much aniline whit out proper cooling. I wanted to make nitroaniline. Can it be even made that way or is something else produced?


Following wich nitroanilline you wish to do, you have or to use diluted acids (meta) , or to protect the amino group by acetylation (ortho-para).
Too high a HNO3 concentration or heat, will result in parabenzoquinon oxydation.
C6H5-NH2 -ox-> O=C(-CH=CH-)2C=O
The later can react to polycondense with aminogroup of aniline resulting in brown-black tar like polymer.




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[*] posted on 28-2-2008 at 20:50


Distilling aniline in vacuum in the presence of sodium gives a colorless product that darkens only very slowly even when stored in the light.
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[*] posted on 1-3-2008 at 12:17


Quote:
Originally posted by PHILOU Zrealone
Following wich nitroanilline you wish to do, you have or to use diluted acids (meta)


How much should I dilute? I will be using NH4NO3 or NaNO3 and H2SO4.




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[*] posted on 4-3-2008 at 07:21


Quote:
Originally posted by Zinc
Quote:
Originally posted by PHILOU Zrealone
Following wich nitroanilline you wish to do, you have or to use diluted acids (meta)


How much should I dilute? I will be using NH4NO3 or NaNO3 and H2SO4.


Add 30-50% water to the mix




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[*] posted on 26-10-2008 at 18:20


Has anyone ever tried using lead-solder as their source of tin? The stuff I have is of 95% purity. The rest is made up of small amounts of antimony, copper, and silver. Would these trace metals somehow adulterate the tin if used for a nitrobenzene reduction?
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[*] posted on 26-10-2008 at 19:13


Lead solder that is 95% tin, with the rest being made up of antimony, copper, and silver?
Dang! whats going on?
haha, perhaps you meant Tin solder?
The copper and silver might cause some problems since they don't react with HCl, but you could try it to find out I guess.
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