1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Organic Chemistry Geometric Isomers Lab

  1. Sep 25, 2009 #1
    1. The problem statement, all variables and given/known data
    The experiment was changing dimethyl maleate into dimethyl fumerate, with the intent of being analogous to changing maleic acid into fumeric acid. In the experiment, we added 1 M Bromine in dimethylchlorine to our dimethyl fumerate, put the mixture in a hot water bath and next to a light for 10 minutes, then recrystallzied, filtered and got the melting point of the new substance.

    I'm having trouble with one of the post-lab questions: Could you start with dimethyl fumerate, do the same reaction (and under experimental conditions where dimethyl maleate could be recovered) and get dimethyl maleate?

    2. Relevant equations

    I can't find the reaction anywhere online and I don't know how to type it out, but basically what happens is that Bromine with a free radical reacts with one of the double-bonded carbons to break the double bond and allow for rotation. Once rotation occurs, Bromine breaks free and a double bond is formed again. Thus producing the geometric isomer.

    3. The attempt at a solution

    I'm thinking it's NOT possible to do the reverse direction. Dimethyl fumerate is the trans-isomer, and is therefore more stable. In equilibrium with a single bond, most of the molecules are going to be in trans. Therefore I think if you redid the experiment in the reverse direction, you might get some yield but not a respectable amount.

    I'm not really sure and don't have a whole lot of confidence in this answer, so I just wanted to bounce the idea off of someone else, see if it makes sense to them. Thanks :)
  2. jcsd
  3. Sep 29, 2009 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Sounds good to me.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook