Abstract:

Tall oil acid is a renewable biomass material. In this work, the effects of different types of catalysts such as 3, 4, 5-trifluorophenylboronic acid, phosphoric acid, and potassium hydroxide on the conversion rate to tall oil aminoxyethyl imidazoline （TON100） were investigated, in which diethylenetriamine and tall oil acid were used as raw materials. The structure of TON100 was characterized by FT-IR and ES-MS. Its corrosion inhibition performance to A₃ steel sheets in hydrochloric acid solution and sulfuric acid solution was investigated by static weight loss method. The results showed that when the reaction temperature was 230 ℃, 3,4,5-trifluorophenylboronic acid was used as a catalyst and its amount was 0.3 wt% of the total amount, the conversion rate of tall oil acid was 99.4%. In a 4 wt% hydrochloric acid solution, the best dosage of TON100 for corrosion inhibition was 25 mg/L at 30 ℃ and 60 ℃. In contrast, at the experimental temperature of 90 ℃, the best dosage of TON100 was 50 mg/L and the highest corrosion inhibition rate was obtained as 95.1%; at 30 ℃, in a 4 wt% sulfuric acid solution, when the amount of TON100 added was 100 mg/L, the corrosion inhibition rate was 85.1%. Therefore, TON100 had good corrosion inhibition effects against both hydrochloric acid and sulfuric acid.

Key words: tall oil acid, imidazoline, corrosion inhibitor