High temperature corrosion inhibitor.

摘要

Corrosion of the internal metal surfaces of equipment used in the processing of crude oil at 400-790 deg.F is inhibited by adding to the oil a compsn. (I) comprising (a) a trialkyl phosphate containing a 1-12C moiety; and (b) an alkaline earth metal phosphonate-phenate sulphide in which 20-40% of the phenol hydroxy groups have been phosphonated. Wt. ratio (a):(b) is pref. 1:10 to 2:1, esp. 1:5 to 1:1. (a) pref. is tributyl phosphate, (a') and (b) is calcium phisphonate-phenate sulphide pref. (b'). (I) is added at 1-5000, esp. 100-1500 ppm to the crude oil.