Additive for inhibiting acid corrosion and method of using the new additive

An additive for inhibiting high temperature naphthenic acid corrosion comprising an ethylene oxide derivative of polymeric thiophosphate ester formed by reacting polymeric thiophosphate ester with ethylene oxide, wherein said polymeric thiophosphate ester is a reaction product of reaction of hydroxyl terminated polyisobutylene or polybutene succinate ester with phosphorous pentasulphide.

An additive for inhibiting high temperature naphthenic acid corrosion comprising an oxide derivative of polymeric thiophosphate ester formed by reacting polymeric thiophosphate ester with an oxide selected from the group consisting of butylene oxide and propylene oxide, wherein said polymeric thiophosphate ester is a reaction product of reaction of hydroxyl terminated polyisobutylene or polybutene succinate ester with phosphorous pentasulphide.

A method of making an additive for inhibiting high temperature naphthenic acid corrosion, wherein said additive comprises polymeric hydroxyl terminated polyisobutylene thiophosphate ester, and is prepared by a process comprising the steps of:

• (a) reacting high reactive polyisobutylene with maleic anhydride to form polyisobutylene succinic anhydride;
• (b) reacting said polyisobutylene succinic anhydride of step (a) with a compound selected from glycols or polyols or polymeric alcohols to form hydroxyl-terminated polyisobutenyl succinate ester;
• (c) reacting resultant reaction compound of step (b) with phosphorous pentasulphide to form thiophosphate ester of polyisobutylene succinate ester, which is high temperature naphthenic acid corrosion inhibiting additive.