[tracy]

If I had two bottles of which the labels had fallen off and the possibilities for each of the bottles was methyl-3-nitrobenzoate and triphenylphosphine; how would I tell which one is which? They both have more or less the same melting point and no distinct smells or colour differences. Could I react methyl bromide with one of the two? If it reacts with triphenylphosphine, it would release bromide ions into the solution and cause the colour to change reddish-brown (to my understanding). If the methyl bromide reacted with the methyl-3-nitrobenoate - no visible change would take place, right?

[barcrphd]

why dont you use IR. ester peak will be the indication for methylbenzoate.

if you want to distinguish by chemical test then also check for the presence of ester (say ester hydrolysis followed by acidification).

[tracy]

Cannot use IR - we are restricted to cetrtain chemicals and apparatus. To form the methyl-3-nitrobenzoate we used mononitration with nitric acid and sulphuric acid. If I were to add an alcohol and water (acid hydrolysis) I'd form methanol and benzoic acid right? How would that then help me? Does benzoic acid have a distinct smell? Do you know anything about shared melting points, perhaps? Apparently, there is a way one can distinguish between two compounds of similar melting points. Please reply as soon as you can.

[barcrphd]

your reply confuses me. methyl-3-benzoate you have synthesized or purchased? basically what do you want to do? you earlier said the labels were gone and you dont know which is which? is it?

please clarify that. or else do you have authentic samples of any one of them. means authentic sample of triphenyl phosphine or the benzoate? then the easiest thing is to do a tlc with authentic samples as the co spot.