stoichiometric_steve
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Fe/HCl reduction of Nitroalkenes to Ketones and a funky recirculating Steam Distillation Device
I just wanna encourage all those who have yet to try this route!
the ratios are:
1 mol Nitroalkene
- 200g 40mesh Iron powder (no need for reduced or electrolytic iron)
- around 5g FeCl3
- 500ml water
- 130ml concentrated HCl
- some oxalic acid solution to clean out your flask afterwards.
the experimental procedure can be found here.
to avoid the large volumes of water to be collected when steam distilling the ketone, one has to make a little investment in a really marvellous, yet
simple piece of glassware: a pressure equalized dropping funnel with a second take-off stopcock (something every glass blower can do): the regular
stopcock is used to regulate the flow of condensed lower phase (water) back to the still pot. with the second stopcock, one can draw off the upper
phase (preferably toluene) mixed with the ketone.
beware: if the upper phase gets saturated with ketones that are more dense than water, an emulsion or sinking of the organic phase to the bottom can
occur.
a third female ground joint put on the upper part of the funnel enables the refilling of upper phase during running steam distillations (you can also
stick a thermometer in there, whatever sense that would make?!).
of course, the steam distillation itself takes ages, but now that you have such a funky device, all you need to do is let it run until the funnel is
filled 1/3 to 1/2 and adjust the flow accordingly (make sure you have enough space for your ketone), so you can let it run unattended!
i got 85% on my first run.
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Klute
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That's a clever idea! A sort of inverted dean stark.. You fit a condenser above the addition funnel, right?
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stoichiometric_steve
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| Quote: | | Originally posted by KluteYou fit a condenser above the addition funnel, right? |
of course, smartypants 
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azo
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very good ! I like the idea of the water collection , but have done this many times and i didin't get all that mutch water
because i used a pressure cooker for a steam source and put an earn element in it. My findings are the better the steam source the more oil you will
volatilize with less water.
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stoichiometric_steve
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| Quote: | | Originally posted by azo My findings are the better the steam source the more oil you will volatilize with less water.
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true, with superheated steam, things are a lot easier, but you can let that run unattended. thats the best thing about the customized funnel!
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Klute
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I remember using a steam machine (to strip wall paper off) for so steam distn, and although it did indeed carry much more organics over, it was
impossible to condense all of it, because of the flow, even with 2 condensers (400+200mm).. As i couldn't be bothered building a electrical
controler, as i have read elsewhere (on Len's excellent report on toluene chlorination i think), i stuck to lenghty insitu distn... That has caused a
few mishabs though....
For people not willing to sick another outlet on their addition funnel, it could be possible to simply use a large on, and to stop the heating and
empty the organics once in a while. That still can save alot of time, as long as a constant take off is maintained.
At which height is your second outlet Steve?
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azo
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I have a multi coil graham condenser 660 mm long / 1900cm2 surface area and never had that problem . In fact i can't remeber anything i have done that
has used any more than a 1/4 of the condeser.
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stoichiometric_steve
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| Quote: | | Originally posted by Klute At which height is your second outlet Steve? |
as far at the bottom as possible!
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