Nitration of Aromatic Compounds without Using Sulfuric Acid

摘要

Green Chemistry is becoming the worldwide term used to describe clean,rnenvironmentally friendly, sustainable chemical technology; the core principlernbeing to eliminate the generation of hazardous substances during chemicalrnmanufacture and use. It has been tried to apply the same approach here for thernnitration process.rnNitration is one of the most important reactions in synthesis of organicrncompounds because of their wide range of applications like solvents, dyes,rnpharmaceuticals & explosives. Nitration development is a complex, lengthy andrnexpensive process.rnThe majority of organic nitration requires the use of sulfuric acid or oleum in thernnitric acid because sulfuric acid is present as catalyst, solvent and dehydratingrnagent. Also, in about 94% sulfuric acid, the nitric acid practically completelyrnionized to nitryl ion.rnUtilization of sulfuric acid produce contaminated and diluted spent acid stream.rnAs environmental legislation become more stringent, this spent acid must berntreated and recovered.rn1. Discharge without treatment of spent acid is not an acceptable solution. 2.rnNeutralization of spent acid stream with lime is still practiced, particularly in casesrnin which the quantity of acid is relatively small. However in many cases therngypsum is not of saleable quality and must be stockpiled leading to concerns thatrncontaminants in the gypsum may be leached into the ground water. 3. Direct usernof nitration spent acids in other industries is rarely possible due to the presencernof residual nitricitrous species and organic contaminants.rnConsidering above explained disadvantages associated with nitration inrnpresence of sulfuric acid, the study has been performed with objective to findrnalternate routes to carry out nitration without the use of sulfuric acid.rnIn this work, various experiments were carried out on p-toluidine (aromaticrnamine). P-Toluidine nitro product is used for dyeing cotton, viscose and thernchromogenic agent for printing. P-Toluidine is aromatic amine and nitration ofrnaromatic amine is to be done in three steps as: 1. Protection of amine group byrnacylation, 2. Nitration of amide and 3. Removal of acetyl group.