The compound 2-(2,4)-dinitrobenzyl pyridine (DNBP) is a photoreactive crystal that changes from a sandy-brown to a dark purple color when exposed to light. It then remains dark purple for several hours after being exposed to light. The original synthesis procedure was developed at Cornell by Professor Ault and Cornell students. Since its development, it has been improved several times and is still run in the Organic Chemistry Lab course today. The procedure for making DNBP involves an ether extraction with large amounts of the solvent, along with the use of sodium hydroxide. Both of these compounds have drawbacks. Sodium hydroxide is a caustic compound with a high pH. Ether is a low boiling solvent that produces fumes that were at one time used as an anesthetic. Also, ether is highly flammable and open flames need to be avoided in the lab when it is in use. During the summer, the procedure was altered in order to eliminate the use of both ether and sodium hydroxide from the procedure.
The sodium hydroxide was replaced by sodium carbonate, a weaker base. The ether extraction was replaced with a precipitation and filtration that used ethanol instead of ether. The original procedure along with the revised procedure was run in the Organic Chemistry Lab course this year in block six, in order to see how the yields and quality of the crystals compare to each other.
Jesse Sackett, ’16
Sponsor: Charles Liberko