Methyl Benzoate We can t heat the reaction we must Change it to R O oxides 03 26 2015 o Powerful Nu and base So we ll get an alcohol Acyl halides o Problems not very long shelf life you have to buy them right before the reaction o So we won t do it Usually for upper division labs Not particularly safe You don t need it you can Fischer o Reaction under acidic reactions you can make an ester o Emil Fischer big name in orgo History about this guy Adolf synthesized indigo that s who he got his pHD from Married when he was 36 his wife passed away 7 years later first son died in WWI second committed suicide third son was faculty at UC Berkeley Was awarded Nobel prize in 1902 then he committed Fischer projections peptide synthesis fischer spier suicide in 1919 esterification Not in any organic textbook Comes from original paper published in blank with Arthur speier o It needs to be a strong acid usually conc sulfuric acid Why You need to protonate a double bonded Oxygen that isn t a good base really We need a sufficient quanitity of that oxygen to get protonated for a good yield You can sometimes use phosphoric acid weaker acid successfully What situations Major problem the whole reaction is in equilibrium o Keq 4 water and ester over acid and alxhohol o Carry out limiting reageant to 4th decimal place Three issues Proton acid choice Why are we keeping the reactants at an almost 1 1 ratio To save cost lmao We need to shift equilibrium toward the products to help with the expected yield it s only 67 Using la chateliar s principle You can t remove on of the products so you have to add more reactant one reactant Why does this make more product Look at the math if keq is a constant and the bottom number gets bigger than the top number also has to get bigger to maintain that constant Can t ever get to 100 because that would mean the bottom number was zero We run the reaction in excess alcohol o Weird problem don t add any product to the reaction Why Doesn t mean by adding esther to reaction he means don t ADD ANY WATER It will screw up the whole equilibrium We have to make sure the solvent is 100 alcohol Our reaction is the synthesis of methyl benzoate Doing under reflux for speed Reaction is straightforward but after the reaction o We are extracting with ether the water ether layer line may get fuzzy If this happens Add a little bit more ether Or add a brine solution saturated sodium chloride o Product analysis is yield and IR No halide tests because esther tests are difficult We need it to be totally dry for the IR DO NOT WANT OH PEAK Dry product with sodium sulfate Methyl benzoate smells great o Esthers in general smell good remember ochem 1 involved in perfumes o Largest natural source for methyl benzoate is the snapdragon flower Lab takes two hours that s it Good percent yield is 60 Safety conc sulfuric acid please be careful 03 26 2015 03 26 2015