I am working on the synthesis of a diester. The starting materials are a long (C9) chain acid and a C5 diol. I need to have at least 95% purity, and the catalyst needs to be pretty nontoxic.
I have tried using tin oxide at over 200 C but I can't get it to go to completion. I also don't have a good way of really monitoring the reaction. I am using xs acid, so watching the acid peak on FTIR only gets me so far. I am having a tough time visualizing it on TLC (using fluorscent plates) or HPLC (RI and PDA detectors). We don't have a GC or GC-MS.
I am thinking that I need to use a better catalyst but I don't have a ton of experience making esters - is p-TsOH the best or will I get side products? How about an organotin compound? I just an not sure I will be able to get one of those by our safety officer.
I have put this project on hold for a bit but I really need to get back to it next week so any advice would be greatly appreciated!