Dibutyl Citrate Synthesis, Physicochemical Characterization, and Px Data in Mixtures with Butanol

• Published in: Journal of chemical and engineering data 2018-06, Vol.63 (6), p.1946-1954
• Main Authors: Suaza, Andrea, Santaella, Miguel A, Rincón, Luz A, Alarcón, Ángela L, Orjuela, Alvaro
• Format: Article
• Language: English
• ISSN: 0021-9568; 1520-5134
• DOI: 10.1021/acs.jced.7b01064

Dibutyl citrate (DBC) was synthesized via partial esterification of citric acid (CA) with n-butanol (BuOH) and characterized for the first time. Then, the monoacid diester was isolated from the reactive mixture by using a pH-controlled solvent extraction procedure. The identity of the obtained product was verified by NMR spectroscopy, finding that it corresponds to a mixture of asymmetric and symmetric isomers. The obtained product was characterized by thermogravimetric and differential scanning calorimetry analysis and by density and viscosity measurements. As per the calorimetric analysis, DBC exhibited a crystallization point below 213 K, a decomposition temperature of 541 K, and an average heat capacity of 2.461 kJ/kg K in the evaluated temperature range (320–375 K). The average liquid density and viscosity in the studied temperature interval (298–313 K) were 1.122 g/cm3 and 2.03 Pa·s, respectively. Additionally, isothermal vapor–liquid equilibrium data (P–x) in mixtures containing the obtained DBC and BuOH were measured at 313, 323, and 333 K. Experimental data were used to fit UNIQUAC interaction parameters for the binary DBC–BuOH. The regressed model showed good agreement with experimental results, making it suitable for further process design and simulation. The obtained data can be used in the development of processes for citrate plasticizer production and in the development of separation processes for DBC.