biostudies-literatureChen TAir Force Equipment Military Scientific Research ProjectNational Natural Science Foundation of ChinaAir Force Logistics AcademyNatural Science Foundation of Jiangsu Province7957-7962https://www.ebi.ac.uk/biostudies/studies/S-EPMC8908365biostudies-literatureUnknown7(9)Evaluation of the acidic characteristics of a jet fuel, especially for the total acid number (TAN), is of great significance to ensure flight safety. Methylbenzene is commonly used as the titration solvent; however, it is poisonous and harmful to the environment. It is highly desirable to develop an alternative solvent for methylbenzene to extract the acidic compounds from the jet fuel during the determination of the TAN. Here, we develop a desirable alternative solvent of a mixed ethanol-water solution with the volume ratio of ethanol to water of 99:1, which exhibits a value of TAN similar to that of the solvent of methylbenzene in potentiometric titration and acid-base titration methods. The TAN value derived from the different titration solvents was in the order of 2.96 μg KOH g<sup>-1<ACS omegaStudy on the Alternative Solvent of Methylbenzene in the Total Acid Number Titration of Current Jet Fuels.PMC890836551705530KQQNJ21-007KJ2020C018-4BK20180180Hao JTong LMa JFei YXu XYan HSun YChen TfalseStudy on the Alternative Solvent of Methylbenzene in the Total Acid Number Titration of Current Jet Fuels.Evaluation of the acidic characteristics of a jet fuel, especially for the total acid number (TAN), is of great significance to ensure flight safety. Methylbenzene is commonly used as the titration solvent; however, it is poisonous and harmful to the environment. It is highly desirable to develop an alternative solvent for methylbenzene to extract the acidic compounds from the jet fuel during the determination of the TAN. Here, we develop a desirable alternative solvent of a mixed ethanol-water solution with the volume ratio of ethanol to water of 99:1, which exhibits a value of TAN similar to that of the solvent of methylbenzene in potentiometric titration and acid-base titration methods. The TAN value derived from the different titration solvents was in the order of 2.96 μg KOH g<sup>-1<2022-01-01T00:00:00Z2022 Mar2026-03-27T16:41:49.486Z2025-04-04T20:50:56.521ZS-EPMC89083653528475310.1021/acsomega.1c07015