Abstract: Diafenthiuron was one new thiourea insecticide and miticide. Diafenthiuron can control and kill Pieris rapae, leafhopper and other pests, mites. Diafenthiuron-urea was an impurity in the preparation of Diafenthiuron. In order to detect Diafenthiuronur-ea in Diafenthiuron better. Prepared high-purity Diafenthiuron-urea as a reference. In this article, Diafenthiuron-urea was synthesized from 2,6–Diisopropylaniline. Prepared 4-bromo-2,6-Diisopropylaniline with bromine; 4-bromo-2,6-Diisopropylaniline was converted to 4-phenol-2,6–Diisopropylaniline by treatment with phenol, cuprous chloride and potassium hydroxide in xylene, and got the pure 4-phenol-2,6–Diisopropylaniline through vacuum distillation; Under the action of triphosgene and tert-butylamine, the pure 4-phenol-2,6–Diisopropylaniline can converted to N-tert-butyl-N’-(2,6-diisopropylphenyl- 4'-phenoxy) urea, also called Diafenthiuron–urea，a purity of 99.4%.
