jense927
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Isothiocyanate Synthesis
I am trying to synthesize an aryl isothiocyanate using thiophosgene but depending on how long I let it react, I get 20-80% formation of the bis
thiourea. Any ideas on how to prevent this from happening?
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Nicodem
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Thread Moved
2-8-2012 at 06:48 |
Nicodem
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I advise you to provide the experimental and/or the reference, because as far as I know we do not have members that can read your mind. How can
anybody know why you get so much thiourea, if no one knows what you did?
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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jense927
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Wow...had anticipated how rude of a response I would have gotten I never would have posted here in the first place. Way to be welcoming. I cannot
believe you are a moderator with an attitude like that. I will get advice elsewhere. Thanks for nothing.
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Nicodem
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You give nothing, you get nothing.
You post an unanswerable lazy question without even giving us the necessary information for any reply whatsoever. Furthermore, this is a forum for
amateurs and you arrogantly came here with your research problem that you are being paid to solve. You expect us to do your job and then complain
about us being rude? Get real.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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BromicAcid
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Your problem is thiourea... the only things I can offer are possibilities as to what you are doing wrong.
Here are the possibilities:
1) You have a molar excess of your aniline (I'm assuming you're starting from an aniline if your making an aryl isothiocyanate).
2) At some point during your feed you had a molar excess of your aniline.
These are the obvious problems that you had, at some point the following has to happen:
Your aniline reacts with your thiophosgene to form your isothiocyanate, then this isothiocyanate reacts with some of the aniline floating around and
makes your thiourea. Simple chemistry. You need a controlled feed to avoid this and you have to make sure your reaction is readily going to
completion otherwise you will see this accumulation of starter. How are you driving this to completion? Seeing as how I made isothiocyanates for a
living I know certain things that my employer might now like me to divulge beyond this but my statements still stand.
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