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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: erinem on October 11, 2006, 02:21:17 PM

Title: Why is nitroacetanilide yellow?
Post by: erinem on October 11, 2006, 02:21:17 PM
I just finished a nitration of acetanilide lab, and I'm wondering why the nitroacetanilide crystals are white when the nitroacetanilide crystals are yellow? How does nitrating the compound affect the color?
Also, we were given the option to let our reaction mixture sit in the ice bath from 30 to 45 minutes. Does the amount of time matter, how does it affect the product I obtained?

Thanks a bunch,
Erin
Title: Re: Why is nitroacetanilide yellow?
Post by: FeLiXe on October 11, 2006, 05:04:35 PM
consider that the nitro group is conjugated to the system

generally conjugation lowers the absorption wavelength. a nitro group lowers the absorption wave length even more than just conjugated carbons because the electron cloud is delocalised.

the absorption wavelength moves from ultraviolet to violet. violet absorption means that your substance is yellow.
Title: Re: Why is nitroacetanilide yellow?
Post by: Borek on October 12, 2006, 02:25:45 AM
why the nitroacetanilide crystals are white when the nitroacetanilide crystals are yellow?

 :)
Title: Re: Why is nitroacetanilide yellow?
Post by: AWK on October 12, 2006, 02:48:03 AM
Acetanilide is white, nitroacetanilide is yellow.
Title: Re: Why is nitroacetanilide yellow?
Post by: Donaldson Tan on October 17, 2006, 05:41:24 PM
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