Grignard Reaction 03 09 2015 Experiment Super hard okay buddy chemistry wise Lots can go wrong because it fucking hates water okay It s a proton source Gotta dry glassware put in oven for 15 minutes o Claisen adapter and round bottom flask okay Drying tube TA gives you You re gonna add everything using a syringe No separatory funnel Everything half scale buddy Poweder Mg so don t put it in the oven MUSt grease joints Claisen adapter joints glass glass ADD MG POWDER BEFORE GREASING JOINT Will stick to joint Adding everything via a syringe Uncapping the needle o Be very careful pulling off the needle Bend it and break the seal Make sure the plunger is not sticky get another Melting point and percent yield 60 o Is weather dependent humidity o Also doing IR After adding Sulfuric acid you do a liquid solid extraction and then a liquid liquid extraction the neutralize The electronegativity difference between carbon and metal Usually with other atoms O Cl you get an electrophilic carbon But when Carbon is bonded to a metal you have a nucleophilic carbon So an organometallic carbon and a electrophilic carbon you can make a carbon carbon bond Mg these are Grignard reactions o French chemist Victor Grignard o Son of a sail maker from france started off at U of Leons in France military Failed his exams in mathematics degree 1892 was going to fulfill his requirements to join the Did a year of service came back to school and was successful in getting his mathematics degree A friend suggested he gave chemistry a try convinced him even though he didn t like it very much In Leons there was another chemist named Philip father of organometallic chemistry Began a relationship with him Barbiea had noticed methyliodide mg ketone you get tertiary alcohol He was busy and gave the task to Victor as his phD thesis 1912 Grignard gets nobel prize Basically every grad student s dream C Mg you can buy it o Relatively expensive short shelf life o Not conducive to a teaching lab o But luckily you can make them o You start with a halide typically br sometimes cl rarely I o In the presence of mg you make Grignard You end up with a nucleophilic carbon Solvent problem o It s also a powerful base o You need to concerned with a proton source o Needs to be run in a non proton environment o Needs an aprotic solvent o Hexane cyclohexane But the first function of a solvent is that everything can be soluable In lit only two solvents are used Side reactions Predominately diethyl ether Big difference is the oxygen in diethyl ether o Oxygen has lone pairs o Grignard is partial positive so those lone pairs will go toward the partial positive C so ethers fit well with grignards Other is THF So Hexane might be aprotic but it can t complement grignards like an ether can o 1 Grignard reageant reacting with oxygen Generates peroxides o 2 With CO2 to make a carboxylate o Oxygen and Co2 are in the air But you don t have to worry about it too much Because not that much of it actually in solution The amount of product from these two side reactions will be very very small o 3 real problem Grignard reageant reacting with the original halide will form new carbon carbon bond R MgX R X R R MgX2 This reaction will happen there is nothing we can do it about We can minimize it by statistics game Relative concentrations So the halide has a much higher chance of running into mg than a Grignard You use timing All the Mg at once then a little bit on the halide then the rest of the halide over the course of time Will keep relative conc of the halide low compared to mg So statistically the chance of halide running into Grignard as the reaction goes on but it only turns into a major problem at the end because that s when you have the most R MgX We have minimized it and controlled it We are doing a classic Grignard reaction Bromobenzene with Mg to get phenyl magnesium bromide Then we ll add Co2 to this to get a carboxylate and then we will protonatate it to get benzoic acid 03 09 2015 03 09 2015