Contact Process

• Contact process is used to make sulfuric acid
• Raw materials used to make sulfuric acid are S (from oil or coal - desulfurization), O2 (from the air - fractional distillation), and H2O
• Reaction 1: S + O2 -- SO2 (blue flame produced)
• Reaction 2: 2SO2 + O2 -- 2SO3 (Reversible Reaction)
• Reaction 3: SO3 + H2O -- H2SO4 (highly exothermic - releases a lot of heat and would cause acid to boil)
• Reaction 4: SO3 + H2SO4 -- H2S2O7 (oleum)
• Reaction 5: H2S2O7 + H2O -- 2H2SO4 (reaction is less exothermic - temp does not increase)
• Conditions for the reaction are 1-2 Atm of pressure, 450 c, and vanadium (v) oxide catalyst
• An environmental problem of this process is that sulfur oxides contribute to acid rain

  SO2 + H2O -- H2SO3

  SO3 + H2O -- H2SO4
• An environmental problem of this process is that it kills fish and damages their gills
• An environmental problem of this process is that it kills trees/plants because the acid rain is absorbed through the roots
• An environmental problem of this process is that it damages limestone buildings
• An environmental problem of this process is that acid rain contributes to smog which damages lungs
• A method to reduce the pollution produced would be the removal of SO2 and SO3 from exhaust fumes by reacting them with CaO (Lime)
• CaO + SO2 -- CaSO3

  CaO + SO3 -- CaSO4

  (used to make plaster)
• A method to reduce the pollution produced would be to use low sulfur oil