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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: Canadianchemist on January 23, 2005, 01:52:31 AM

Title: Reason for keeping the nitrating mixture at a low temp
Post by: Canadianchemist on January 23, 2005, 01:52:31 AM

This may come across as being an elementary question but I am struggling to find a good answer.  Recently in Organic lab we made p-nitroaniline from acetanilide, one of our questions from our lab manual is "why is the reaction mixture cooled during the addition of the acids?"  I know that by the addition of the acids the temperature of the overall mixture is increased; therefore, keeping it in ice keeps the temperature down.  However, I think they are looking for something more in depth than that for an answer.  I have been looking for a decent answer for the past two hours, but have found nothing.  So if anyone can give me a hand or point me in the right direction it would be greatly appreciated.  Thank-you for your time

Title: Re:Reason for keeping the nitrating mixture at a low temp
Post by: Mitch on January 23, 2005, 01:55:46 AM

Increasing the temperature typically also increases the risk of side reactions. What side reactions do you think could of occured with increased temperature?

Title: Re:Reason for keeping the nitrating mixture at a low temp
Post by: Canadianchemist on January 23, 2005, 02:03:38 AM

To be honest I am not exactly sure, but taking a guess at it, could it have something to do with the NO2 forming a bond on somewhere other than on the para site, for example maybe forming a bond with the Meta site?

Title: Re:Reason for keeping the nitrating mixture at a low temp
Post by: Mitch on January 23, 2005, 04:20:38 AM

That should be good enough for a lab report.

Title: Re:Reason for keeping the nitrating mixture at a low temp
Post by: Canadianchemist on January 23, 2005, 12:15:35 PM

Yep that sounds good, thank you very much for the help

Title: Re:Reason for keeping the nitrating mixture at a low temp
Post by: Chris_Whewell on January 25, 2005, 09:06:19 PM

Nitric acid is a powerful oxidizing agent.   It destructively decomoses organic matter in general when heated together with same.

If you are an experimenter, then try and raise the temperature and see what happens for yourself.  No answer on a forum can be a substitute for experience.

I suggest trying a small amount, less than one gram of organic substance, to avoid harm.  Also, you should ask the instructor for permission first.  This will display your respect and inquisitiveness.