blacklung
2008-06-30, 07:10
Been doing a few benzaldehyde experiments this weekend. A few misses, and one success.
Okay, as some know you can oxidize toluene into benzaldehyde using potassium peroxymonosulfate, ferrous sulfate, and copper acetate. The potassium peroxymonosulfate is in Oxone, which can be found rather easily.
You will not - I repeat - will not find 100% pure potassium peroxymonosulfate in non-chlorine pool shock. If it says "100%" then it is actually saying "100% Oxone;" Oxone is a mixture of chems, about 47% of which is the potassium peroxymonosulfate. Check the MSDS of oxone to see what I'm talking about.
Okay, anyway. I did the experiment, and out of everything there was only one problem: Oxone compound does not like to dissolve in workable amounts of water and methanol. The first time I did the reaction, I got everything (toluene, ferrous sulfate, copper acetate, water, methanol) at 70C (it's a brown(ish) mixture), and began adding the water/alcohol/peroxymonosulfate (mixture with a sludge in it) to the reaction mixture slowly to keep the temp at a steady 70C. I kept this stirring the entire time. I decided to just dump the sludge in slowly while stirring so it could all get in there to oxidize. This would have been okay, but I had a runaway reaction, and the methanol flashed due to a sudden rise in temperature - oh joy. A bunch of stinking shit all over my kitchen, methanol fumes and all.
Anyway, did it again, this time being more cautious with the powder sludge that is added last (went a LOT slower, and let the temperature go down a lot more before adding more). Got it in there, kept the temperature at a sustained 70C, and let it react for a little over two hours. Once it was done, I was left with a light green(ish) liquid with white oxone compound collecting at the bottom. Simply decanted the liquid from the powder crappola, and put in the sep funnel. There was a little bit of toluene floating at the top, but not much at all, about 5ml probably (I started with about 50ml); this is just unreacted toluene. Extracted the aqueous greenish crap with some fresh toluene (added the 5ml of unreacted toluene to it), and distilled. I got back about 42ml of what seems to be pure benzaldehyde.
I am convinced that this method is somewhat worthless. It's way too touchy, and requires literal buttloads of oxone to get it going. The amount of oxone required to react with toluene is simply too much; a 1000ml flask is filled to the gill with oxone sludge/solution alone, and just to get 50 or so ml of benzaldehyde. It's just not worth it.
Anyway, I'm done with benzaldehyde, time to move on to something cooler. I think I'm going to start trying to make my own pesticides now.
Okay, as some know you can oxidize toluene into benzaldehyde using potassium peroxymonosulfate, ferrous sulfate, and copper acetate. The potassium peroxymonosulfate is in Oxone, which can be found rather easily.
You will not - I repeat - will not find 100% pure potassium peroxymonosulfate in non-chlorine pool shock. If it says "100%" then it is actually saying "100% Oxone;" Oxone is a mixture of chems, about 47% of which is the potassium peroxymonosulfate. Check the MSDS of oxone to see what I'm talking about.
Okay, anyway. I did the experiment, and out of everything there was only one problem: Oxone compound does not like to dissolve in workable amounts of water and methanol. The first time I did the reaction, I got everything (toluene, ferrous sulfate, copper acetate, water, methanol) at 70C (it's a brown(ish) mixture), and began adding the water/alcohol/peroxymonosulfate (mixture with a sludge in it) to the reaction mixture slowly to keep the temp at a steady 70C. I kept this stirring the entire time. I decided to just dump the sludge in slowly while stirring so it could all get in there to oxidize. This would have been okay, but I had a runaway reaction, and the methanol flashed due to a sudden rise in temperature - oh joy. A bunch of stinking shit all over my kitchen, methanol fumes and all.
Anyway, did it again, this time being more cautious with the powder sludge that is added last (went a LOT slower, and let the temperature go down a lot more before adding more). Got it in there, kept the temperature at a sustained 70C, and let it react for a little over two hours. Once it was done, I was left with a light green(ish) liquid with white oxone compound collecting at the bottom. Simply decanted the liquid from the powder crappola, and put in the sep funnel. There was a little bit of toluene floating at the top, but not much at all, about 5ml probably (I started with about 50ml); this is just unreacted toluene. Extracted the aqueous greenish crap with some fresh toluene (added the 5ml of unreacted toluene to it), and distilled. I got back about 42ml of what seems to be pure benzaldehyde.
I am convinced that this method is somewhat worthless. It's way too touchy, and requires literal buttloads of oxone to get it going. The amount of oxone required to react with toluene is simply too much; a 1000ml flask is filled to the gill with oxone sludge/solution alone, and just to get 50 or so ml of benzaldehyde. It's just not worth it.
Anyway, I'm done with benzaldehyde, time to move on to something cooler. I think I'm going to start trying to make my own pesticides now.