TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The process comprises recovering substituted alkyl phenol from the organic phase by rectification, and recycling the effluent phase to the (i) and (ii) steps. The effluent phase is recycled infinite times without any pretreatment. The step of treating the substituted amino compound with an acid is carried out at a temperature of 40-60 degrees C. The step of treating the amine salt with a diazotizing agent is carried out at a temperature of 0-5 degrees C. The step of hydrolyzing the diazonium salt with the solvent is carried out at a temperature of 70-105 degrees C. The various steps include a salt formation, diazotization and hydrolysis. The effluent phase is generated during hydrolysis. Preferred Components: The effluent phase includes acid and water. A ratio of the substituted amino compound and acid is 1:1.5 to 1:5. The concentration of the acid is 10-40%. The substituted amino compound consists of alkyl substituted aniline, halo substituted aniline, and/or naphthylamines. The acid consists of sulfuric acid, hydrochloric acid , sulfuric acid and/or phosphoric acid. The diazotizing agent consists of nitrogen oxide component, sodium nitrite and hydrogen chloride, sodium nitrite and sulfuric acid, sodium nitrite and mixture of sulfuric acid and phosphoric acid, nitrosyl sulfuric acid and sulfuric acid, nitrosyl sulfuric acid and acetic acid, and nitrosyl chloride. The nitrogen oxide component is a mixture of nitric oxide and nitrogen dioxide. The solvent is nonpolar solvent and nonprotic solvent, preferably consists of toluene, benzene, chlorobenzene, xylene and cumene. EXAMPLE - 1015 g of 35% Aqueous solution of sulfuric acid was charged to a round bottom flask with scrubber system. 121 g of 2,4-Xylidine was added slowly into the flask at 60 degrees C under stirring to obtain aqueous solution of 2,4-xylidine sulfate. Nitrogen oxide component (nitrogen oxide 200 ml/minute and nitrogen dioxide 600 ml/minute) was passed into chilled aqueous solution of 2,4-xylidine sulfate at a temperature of 2 degrees C to form diazonium salt solution. The solution was tested with starch potassium iodide paper. The reaction was stopped when the color of the paper changed to blue. Simultaneously 5 g of sulfamic acid was added to eliminate excess of nitric oxide component. 353 g of 35% Aqueous solution of sulfuric acid and 453 g of toluene was added to another round bottom flask and heated to 80 degrees C. The diazonium salt solution was added slowly to the round bottom flask within 2 hours at 80 degrees C under stirring. The temperature was maintained at 80 degrees C for 30 minutes after complete addition of diazonium salt solution to obtain an organic phase comprising 2,4-xylenol and an effluent phase comprising of sulfuric acid and toluene. The reaction mixture was cooled to 35 degrees C. The organic phase was separated from the effluent phase. The effluent layer was recycled back to the salt formation and hydrolysis step. The organic phase was distilled and toluene was recovered which was recycled to the hydrolysis step to obtain 107 g of 2,4-xylenol.