| abstract |
Prepn. of urethane comprises reacting an aromatic nitro cpd. (I) with an organic cpd. (II) having >=1 hydroxy gp. and CO, using a catalyst system comprising Pt gp. metal (cpd.) Lewis acid and ammonia as catalyst. Suitable (II) include monohydric alcohol, polyhydric alcohol, monohydric phenol and polyhydric phenol. Pref. Pt gp. metals include Pd, Rh and Ru, and their cpds. Urethane is obtd. in high purity and yield at relatively low temp. and pressure, and prodn. of by-products is minimal. Corrosion of the reactor material is low, catalyst can be recovered simply, and addn. of a small amt. of water increases the reaction velocity. |