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-   -   Help with writing balanced molecular equation of Electrophilic aromatic substitution (https://www.askmehelpdesk.com/showthread.php?t=510037)

  • Sep 22, 2010, 10:46 PM
    blitzace588
    Help with writing balanced molecular equation of Electrophilic aromatic substitution
    Basically we performed this reaction in lab (specifically we started with 2.7g of acetanilide (step 2) then went to 3b and 4b to end up with p-nitroaniline.

    http://en.wikipedia.org/wiki/File:Synthesis_of_nitroaniline.svg

    My goal is to write a balanced chemical equation and the percent yield (which once I just need the theoretical yield and I know how to do the rest) Thanks!
  • Sep 22, 2010, 10:51 PM
    shawde_da_bait
    Comment on shawde_da_bait's post
    OK

  • Sep 23, 2010, 02:30 AM
    Unknown008

    I'm a little confused about what you are asking for...

    The step from 2 to 3b is an electrophilic substitution. You have

    formed from reacting conc. HNO3 and conc. H2SO4, substituting in the ring.

    Then, you are hydrolysing the peptide bond which forms p-nitroaniline and the carboxylic acid ethanoic acid.

    Hence, you start with 1 mol of 2, reacting with 1 mol of nitronium ion and 1 mol of water to form 1 mol of p-nitroaniline, 1 mol of H^+ ions and 1 mol of ethanoic acid.
  • Sep 23, 2010, 01:16 PM
    DrBob1
    Surely you remember how to determine a theoretical yield!
    Your Wiki reference shows the balanced reaction. Note you get both the a and b products; you don't just "go on to 3b and 4b"
    That's why you are asked for the percent yield.
    So: how many moles is 2,7g of acetanilide?
    How much does that many moles of p-nitroaniline weigh?
    I think I would refer to the protecting group as an amide rather than a peptide. (All peptides are amides, but not vice versa.)
  • Sep 23, 2010, 01:31 PM
    DrBob1
    Another thought: don't you just love a reaction that uses Nitric Acid as a base!!

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