Abstract
For the first time, the synthesis of new scaling inhibitors – esters of phosphoric acids, based on the reactions of phosphorylation of hydroxyethylterephthalamide with polyphosphoric acid, was theoretically substantiated and experimentally carried out. The esterification with polyphosphoric acid of bishydroxyethyterephthalamide was carried out at a temperature of 130-140°C for 4-6 hours. Bishydroxyethyl terephthalamide is a product of the aminolysis of polyethylene terephthalate, including in the form of production waste or recycling of polyethylene terephthalate. Using 1 H-, 31P spectroscopy the structure and composition of new reagents were proved. The inhibitory activity of phosphoric acid esters of bishydroxyethyl terephthalamide was studied on model water-salt solutions. It has been established that inhibitors have complex actions in relation to carbonate and sulfate deposits. An effective amount to inhibit sulfate scale is 2-10 ppm, carbonate scale 10-30 ppm. The degree of inhibition reaches 100%. Inhibitors can be recommended to protect pipelines from scale deposits during oil transportation.