Effects of corrosion inhibitors on protective properties of preservative oil film in the course of aging

Autor: I. A. Prokop'ev, L. P. Maiko, N. M. Maryakhin, A. B. Énglin
Rok vydání: 1985
Předmět:
Zdroj: Chemistry and Technology of Fuels and Oils. 21:511-512
ISSN: 1573-8310
0009-3092
DOI: 10.1007/bf00726698
Popis: To this end, we tested the protective properties of mineral oil base stocks with corrosion inhibitors differing in their mechanism of action. The electrical properties of the base stocks had the following parameters: dielectric constant 2.26, conductivity 25 pS/m. The content of inhibitor in the oil base Stock was 5% by weight. The following corrosion inhibitors were used: calcium alkylbenzenesulfonate (Sab ca), isododecenylsuccinic acid (KAP-25), alkenylsuccinimide of urea (SIM), alkylbenzenesulfonate of urea (BMPA), pentaerythritol ester of fatty acids (EPZhK), oxidized petrolatum (OP), and alkeny!succinic anhydride (AYaA). The test results given in Table 1 are expressed in terms of the protective effect and the relative change in protective properties of the oil. The protective effect is defined as the ratio of the corrosion rate of metal protected with the uninhibited oil base stock to the corrosion rate of metal protected by the base stock with the corrosion inhibitor, under identical conditions [3]. The relative change in protective properties is defined as the ratio of the specific weight losses of metal when protected by the oxidized on unoxidized oil film [i]. According to modern concepts of the mechanism of action of oil-soluble corrosion inhibitors [4], the inhibitors in this group can be classified as follows: Sab Ca and KAP-25 are chemisorption type inhibitors with a donor action; SIM and BMPA are chemisorption type inhibitors with an acceptor action; EPZhK, OP, and AYaA are adsorption type inhibitors with a shielding action. It should be noted that for all of the chemisorption type inhibitors (with the exception of the SIM), the protective properties in the gas/air corrosive medium proved to be considerably better than in the aqueous electrolyte solution. For the adsorption-type corrosion inhibitors, the protection in the gas/air corrosive medium was approximately the same as in the electrolyte solution. The studies of stability of protective properties of these corrosion inhibitors showed the following: For the shielding inhibitors, the protective properties did not change or even improved slightly as a result of oxidation of the oil in a thin film on the metal surface (steel i0); the corrosion inhibitors with a donor or acceptor action, in a number of cases dropped in protective efficiency under analogous conditions. From these results, we canconclude tentatively that the changes in protective properties of films of preservative and operational/preservative oils in the course of aging can be
Databáze: OpenAIRE
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