ISSN 0036-0244, Russian Journal of Physical Chemistry A, 2020, Vol. 94, No. 3, pp. 659–661. © Pleiades Publishing, Ltd., 2020.
Russian Text © The Author(s), 2020, published in Zhurnal Fizicheskoi Khimii, 2020, Vol. 94, No. 3, pp. 478–480.
SHORT
COMMUNICATIONS
Retention Indices and Enthalpies of Sorption of Esters
of Neopentyl Glycol on DB-1 Stationary Phase
O. D. Lukinaa, E. L. Krasnykha,*, S. V. Portnovaa, and S. V. Levanovaa
aSamara State Technical University, Samara, 443001 Russia
*е-mail: kinterm@samgtu.ru
Received April 18, 2019; revised April 18, 2019; accepted September 10, 2019
Abstract—The logarithmic retention indices and the enthalpies of sorption at the average temperature of an
experiment and 298.2 K are determined via gas–liquid chromatography using DB-1 stationary phase for
esters of neopentyl glycol and С2–С6 monobasic carboxylic acids of linear and branched structure at 423.2–
523.2 K. The temperature dependences of the studied compounds’ retention indices are obtained, and the
linearity of these dependences in the investigated range of temperatures is demonstrated. The values obtained
for the enthalpies of sorption are analyzed.
Keywords: esters, neopentyl glycol, retention times, logarithmic retention indices, enthalpy of sorption
DOI: 10.1134/S0036024420030188
INTRODUCTION
gas–liquid chromatography on DB-1 nonpolar
phase [2–4].
Esters of neopentyl glycol and carboxylic acids are
characterized by reduced oxidation and hydrolysis
potential, compared to natural esters. They can be
used as plasticizers and viscosity modifiers for poly-
mers. The special interest in these compounds is due
to the possibility of using them as the basis for syn-
thetic lubricants [1].
EXPERIMENTAL
Esters of neopentyl glycol were obtained via azeo-
tropic esterification. Carboxylic acids of linear and
branched structure containing 2–6 carbon atoms per
molecule were used as precursors. The neopentyl gly-
col : acid molar ratio was 1 : 4. Synthesis was per-
formed in the presence of benzene (for the esters of
This work continues a series of studies on the
sorption of esters of carboxylic acids and poly- C2–C5 acids) or toluene (for the esters of С6–С7
atomic alcohols characterized by different contents
of ester and hydroxyl groups under conditions of added as a catalyst.
acids); 1 wt % of orthophosphoric acid (72.5%) was
O
C
CH3
O
R
OH
OH
HO CH2
C
CH2
O
C R + H2O
CH3
CH3
HO CH2
C
CH2 OH
+
Neopentyl glycol monoesters
CH3
CH3
Neopentyl glycol
O
C
O
C
2R
R
C
O
O CH2
C
CH2
CH3
Neopentyl glycol diesters
O
R + 2H2O
where R = CH3, C2H5, n-C3H7, n-C4H9, n-C5H11, the mixture was neutralized with an aqueous solution
n-C6H13, iso-C3H7, iso-C4H9, tert-C4H9.
Excess acid was removed from the reaction mixture
via distillation using a water-jet vacuum pump, and cation under vacuum to isolate the target ester.
of sodium bicarbonate. Once purified of the residues
of acid, the reaction mixture was separated via rectifi-
659