The most efficient method for synthesizing 2,4-dinitrophenol from phenol and nitric acid with a high yield is through a two-step nitration process.1. First Nitration: In this step, phenol is nitrated to form 2-nitrophenol or 4-nitrophenol. To carry out this reaction, mix phenol with a mixture of concentrated nitric acid HNO3 and concentrated sulfuric acid H2SO4 . The sulfuric acid acts as a catalyst and helps in controlling the reaction rate. The reaction should be carried out at a temperature between 0-5C to avoid over-nitration. The molar ratio of phenol to nitric acid should be around 1:1.5 to ensure a high yield.2. Second Nitration: In this step, the mono-nitrophenol either 2-nitrophenol or 4-nitrophenol is further nitrated to form 2,4-dinitrophenol. To carry out this reaction, mix the mono-nitrophenol with a mixture of concentrated nitric acid and concentrated sulfuric acid. The reaction should be carried out at a temperature between 0-5C to avoid over-nitration. The molar ratio of mono-nitrophenol to nitric acid should be around 1:1.5 to ensure a high yield.After the second nitration, the reaction mixture should be poured into cold water to precipitate the 2,4-dinitrophenol. The precipitate can be filtered, washed with water, and recrystallized from a suitable solvent e.g., ethanol to obtain pure 2,4-dinitrophenol.It is important to note that 2,4-dinitrophenol is a hazardous substance and should be handled with care. Proper safety measures, including wearing gloves, goggles, and a lab coat, should be taken while performing this synthesis.