Good day, I recently conducted esterification process using a benzoic acid derivative and ethanol as its solvent under reflux conditions using sulfuric acid as catalyst. after doing reflux to around 4-5 hours under an oil bath, I monitored the progress of the reaction using Thin Layer Chromatography with a good solvent system. based on the TLC profile, all the benzoic acid derivative was consumed in the reaction process leaving no trace of the reactant but the esterification process produced 2 distinct spots with the spot that has a larger rf value exhibits fluorescence at around 254 nm under a UV-lamp while the other spot (small rf value) does not exhibit fluorescence. I would just like to ask if is there any condensation process that could happen between two benzoic acid derivatives rather than forming an ester product? I was thinking that aside from following an ester-condensation, it would probably follow a Philips-Ladenberg pathway in the formation of Benzimidazoles. I hope someone can help me with this. Thank you so much. and have a good day.
Jerson Lapetaje
Department of Chemistry, College of Science and Mathematics
Mindanao State University- Iligan Institute of Technology
Iligan City, Philippines, 9200
In ideal conditions no side products would be. But we have not an ideal reagents
1) Check the quality of ethanole. It is the most often metter of the "extra" spot. The impurties of another alkoholes give you the impurity in the ester.
2) Check the qulity of you acid.
3) May be. ... the quantity of your impurity is too small. So work up the reaction (in a little scale). Perhaps it is possible to obtain pure ester after the standart puryifuing procedure
I suggest you to first isolate both the products and analyse by nmr. I believe the spot which isnt fluorescent must be the required product. As the other guys said just check the purity of the reactants also. Once confirmed may be u can optimize the reaction for better yield. All the best.
As Michael said, which "benzoic acid derivative"? Is there any nitrogen atom in the starting material? Why did you think to benzimidazole as side-product?
yes there is. sorry for that. the benzoic acid derivative is a 3,4-diaminobenzoic acid. that is why i thought that the side-product would be a benzimidazole.
I suggest to isolate the reaction products mixture and then analyze the mixture by GC-MS. This rapidly will give you valuable and probably definitive information on the molecular weight and structure of the products formed.
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