The article presents the results of laboratory determination of the partition coefficient between the aqueous and petroleum phases of two corrosion inhibitors (CI) CI-1 and CI-2. These inhibitors were industrially used in Kondaneft Oil Company JSC when organizing inhibitory protection of oil and gas pipelines. The composition of CIs was determined by gas chromatography-mass spectrometry (GC-MS). As a result of laboratory studies, it was determined that CI-1 at concentration up to 150 mg/dm3 is not distributed into water, due to its probable concentration at the interface of the «oil-water» phases. The analysis of CI-2 showed that at concentrations of 50, 100, 150 and 200 mg/dm3, its migration into the aqueous phase occurs. The partition coefficients of this inhibitor were calculated, ranging from 1,2 to 4,9 depending on the different water-oil ratio, as well as on the initial concentration of the inhibitor introduced into the mixture. It was found that at the concentration of 20 mg/dm3, the partition of CI-2 into the aqueous phase did not occur. It was recorded that with an increase in the concentration of the introduced CI into the mixture, the partition coefficient decreases, i.e. its more efficient distribution into water begins at all values of water content. According to the industrial application of these CIs and to the results of corrosion monitoring, it was confirmed that CI-2 begins to show some effectiveness only after overcoming the threshold concentration of activation of partition and the effectiveness increases systematically with an increase in the administered dosage.
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