A high-purity aqueous urea solution for the application as NOx reducing agent for SCR (Selective Catalytic Reduction) exhaust gas after treatment of vehicles with a diesel engine.

AdBlue® has a small alkaline reaction. The pH of a newly prepared solution is between and inclusive of 9.0 to 9.5. During its life span, a pH value of approximately 10 may be reached. Dissolved urea decomposes ever so slowly at ambient temperature releasing ammonia & Co2. Should the solutionbe heated, the rate of this reaction will increase. Should temperatures of 70ºc be exceeded, biuret will be additionally formed at an escalating rate.