I have access to reasonably pure toluene, potassium dichromate, and 90% sulfuric acid. I've been reading about the Etard reaction and am thinking about synthesizing some chromyl chloride to oxidize toluene to benzaldehyde. There's a youtube video (http://www.youtube.com/watch?v=D9qEmaiYSPk) that demonstrates the K2Cr2O7 + 4NaCl + 6H2SO4 >>> 2 CrO2Cl2 + 2KHSO4 + 4NaHSO4 + 3H2O reaction, and it seems pretty straightforward; the chromyl chloride in the vial seems to want to climb up the sides, but I was thinking maybe a long-necked volumetric flask might be one way to contain the fumes a bit.
I'm concerned about the concentration of the sulfuric acid, though, because chromyl chloride releases HCl and hexavalent chromium on contact with water, neither of which I am super keen on the idea of. How difficult is it to dry sulfuric acid? The idea of distilling H2SO4 gives me the willies but could I add some CaCl2 or MgSO4 or CaO to suck out the water? Or does it actually even matter given that water is a reaction product?
Now of course all that said, http://www.sciencemadness.org/talk/viewthread.php?action=printable&fid=10&tid=2223 discusses another route from toluene involving MnO2 (look for "Patent DE102221 from 1897"), and immediately below, a description of the preparation of chromyl chloride and that its use is similar to the MnO2. Which is now making me wonder whether one could simply prepare chromyl chloride in a long-necked flask to minimize fume escaping, then add toluene and H2SO4 into the flask with the CrO2Cl2 (and some sodium/potassium bisulfite). What would happen to the aqueous bisulfites?
Also, a little farther down the SM page there is a mention of using CCl4 as the solvent -- I assume that is for a liquid-liquid extraction during workup?
Any advice is appreciated -- btw, benzaldehyde is commonly used in soap making to give the soap the smell of almonds, several hundred mL are needed for a one-kilogram batch of soap. Saponification reactions are cool to do at home and soap making is a very good reason to have sodium hydroxide in bulk ...
I'm concerned about the concentration of the sulfuric acid, though, because chromyl chloride releases HCl and hexavalent chromium on contact with water, neither of which I am super keen on the idea of. How difficult is it to dry sulfuric acid? The idea of distilling H2SO4 gives me the willies but could I add some CaCl2 or MgSO4 or CaO to suck out the water? Or does it actually even matter given that water is a reaction product?
Now of course all that said, http://www.sciencemadness.org/talk/viewthread.php?action=printable&fid=10&tid=2223 discusses another route from toluene involving MnO2 (look for "Patent DE102221 from 1897"), and immediately below, a description of the preparation of chromyl chloride and that its use is similar to the MnO2. Which is now making me wonder whether one could simply prepare chromyl chloride in a long-necked flask to minimize fume escaping, then add toluene and H2SO4 into the flask with the CrO2Cl2 (and some sodium/potassium bisulfite). What would happen to the aqueous bisulfites?
Also, a little farther down the SM page there is a mention of using CCl4 as the solvent -- I assume that is for a liquid-liquid extraction during workup?
Any advice is appreciated -- btw, benzaldehyde is commonly used in soap making to give the soap the smell of almonds, several hundred mL are needed for a one-kilogram batch of soap. Saponification reactions are cool to do at home and soap making is a very good reason to have sodium hydroxide in bulk ...