Lab 6 Nitration of Salicylic Acid Name Ramali Gunatilake Lab Partner Kevin Hsu TA Vamsee Date Handed 3rd April 2014 Abstract The purpose of this lab was to convert salicylic acid into nitro salicylic acid Recrystallization is performed on the final product and the percent yield was calculated Introduction Electrophilic Aromatic Substitution is a reaction in which an atom usually a hydrogen atom on the aromatic structure is replaced with an electrophile In this specific reaction a nitronium ion replaces a hydrogen atom on a salicylic acid ring to form nitro salicylic acid The nitronium ion is generated by combining sulfuric acid with nitric acid The weak nitric acid breaks down into a nitronium atom and a water molecule after it is protonated by the sulfuric acid The pi bond in the salicylic acid ring then attacks the positively charged nitronium ion A hydrogen atom is given off which is picked up by the HSO4 ion to reform the sulfuric acid and a nitro salicylic acid molecule Mechanism Procedure Refer to lab hand out and or lab manual for experimental procedure Results Reactant Product Sulfuric Acid Nitric Acid Salicylic Acid Ethanol Nitro salicylic Acid Theoretical Yield Actual Yield Crude Actual Yield Recrystallized Calculation Molecular Weight g mol MPt C BPt C Density g ml XXX XXX XXX XXX XXX XXX 183 12 229 XXX XXX Color XXX Weight g Amounts Moles mmol Discussion When 1 ml of acid mixture was mixed with 6g of salicylic acid the semisolid mixture turned burgundy When crushed ice was added to the reaction mixture the burgundy color lightened and 2 layers were formed with the water being on the top When vacuum filtered 50 yield of crude nitro salicylic acid was obtained This low yield is probably due to impurities in the crude product Possible Major Product The nitro salicylic acid that is formed is probably a 5 nitrosalicylic acid This is due to the carboxyl group being a deactivating group meta director and the hydroxyl group being an activating group ortho para director 2 nitrosalicylic acid can also be formed but it would be formed as the minor product due to steric hindrance from the hydroxyl group Conclusion The purpose of this experiment was to convert salicylic acid into nitro salicylic acid Melting point analysis was then carried out on the experimental salicylic acid and found to be 184 189 C The high melting point is probably due to some remaining impurities in the product