Study on the Alternative Solvent of Methylbenzene in the Total Acid Number Titration of Current Jet Fuels

Teng Chen; Jingtuan Hao; Hui Yan; Jun Ma; Yuanbao Sun; Xin Xu; Liping Tong; Yiwei Fei

doi:10.1021/acsomega.1c07015

Study on the Alternative Solvent of Methylbenzene in the Total Acid Number Titration of Current Jet Fuels

ACS Omega. 2022 Feb 22;7(9):7957-7962. doi: 10.1021/acsomega.1c07015. eCollection 2022 Mar 8.

Authors

Teng Chen^{1

2}, Jingtuan Hao¹, Hui Yan³, Jun Ma¹, Yuanbao Sun¹, Xin Xu¹, Liping Tong¹, Yiwei Fei¹

Affiliations

¹ Department of Aviation Oil and Material, Air Force Logistics Academy, Xuzhou 221000, China.
² Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
³ College of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, China.

Abstract

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^-1 (V _cyclohexane/V _isopropanol/V _water = 100:99:1) > 2.68 μg KOH g^-1 (V _{methylbenzene}/V _isopropanol/V _water = 100:99:1) ≈ 2.6 μg KOH g^-1 (V _{absolute ethanol}/V _water = 99:1) > 2.34 μg KOH g^-1 (V _isopropanol/V _water = 99:1). The current report presents a nontoxic and eco-friendly alternative solvent for methylbenzene, which may open up an avenue for evaluating the TAN of jet fuels.