(381x) Physicochemical and Thermodynamic Property Determination & Modeling of Aqueous 3-Aminoproyl Triethoxysilane+Mdea/DEA within the Temperature Range of (298.15 to 333.15) K

Carbon dioxide is considered to be one of the major
contributing agents for the global greenhouse gas emission. In this regard,
absorption-regeneration technology aided with various improved solvents is an
effective approach towards mitigation of this issue. The conventional solvents
such as monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine
(MDEA) poses various drawbacks such as high solvent loss and degradation,
equipment corrosion and higher regeneration energy requirement, making the
process inefficient and economically unfavorable [1]. In order to cut down
these limitations, physical solvents such as ionic liquids (IL) can be
considered as a potential solvent for gas sweetening technology. Ionic liquid
possesses many favorable features such as negligible vapor pressure which
reduces the solvent losses to the environment. Other unique properties of IL
includes its high thermal stability, higher conductivity, non-flammability as
well as ease of separation since it require very less regeneration energy, and
it possesses reversible and phase changing behaviors [2]. Despite its various
advantages the applicability of ionic liquids as a solvent for acid gas
separation is limited because of its high cost and lower CO₂
absorption rate. Hence, application of hybrid solvent such as mixture of
(Alkanolamine + Ionic Liquid) or functionalized ionic liquid can be explored as
an alternative solvent since it combines the advantages of both the system
[3,4]. While functionalized ionic liquids have better capacities in comparison
to the pure ionic liquids or mixture of ILs+ amine, but its application is
limited because of advance purification steps required in the synthesis process
which makes the overall process of CO₂ capture to be economically
less favorable. Recently, reversible solvents have been explored as an
alternative to these hybrid solvents. Since, they function both as physical and
chemical absorbent for CO₂ capture. The advantage of using
reversible ionic liquids includes the high capacity of CO₂
absorption over nitrogen (N₂) in dilute flue gas streams. In
addition, the total quantity of solvent required can be drastically reduced
compared to conventional alkanolamine solvents. Vittoria et al [5] has
investigated the efficiency of 3-aminoproyl triethoxysilane (TESA) as a
reversible solvent for CO₂ capture processes. Various thermo
physical properties such as solvent densities,
viscosities, thermal stability as well as total CO₂ capture
capacities (14.76 mol of CO₂/kg of amine) at 35 ^oC and
62.5 bar has been reported. The
present work reports the density, viscosity; sound velocity and refractive
index data of two silane–amine blend systems viz. (1) 3-aminoproyl
triethoxysilane (TESA) + methyldiethanolamine (MDEA) and (2) 3-aminoproyl
triethoxysilane (TESA) + diethanolamine (DEA). The temperature range
for which all the
measurements were conducted is (298.15 to 333.15) K. For all two ternary
aqueous mixture of (TESA+MDEA) and (TESA+DEA), TESA mass fraction was varied
from (0.2 to 0.7). The density and viscosity results were further correlated as
a function of temperature and concentration of ionic liquid with Redlich Kister
and Grunberg - Nissan model, respectively. Two new models have been proposed
for correlation of sound velocity and refractive index i.e. Model M₁and Neural network model. Various other
properties such as diffusivity of CO₂ in the solvents under study,
enthalpy of activation, entropy of activation, Gibb’s free energy of activation
for the viscous flow and isentropic compressibility are evaluated using the
available models in the literature.

References:

1.     
B. Sreenivasulu, D.V.Gayatri, I.Sreedhar, K.V.Raghavan Renewable and
Sustainable Energy 41(2015)1324–1350

2.     
P.T. Anastas, J.C. Warner, Green Chemistry: Theory and practice, Oxford.
University Press,New York,1998

3.      A. Haghtalab , A.Shojaeian, J. Chem.
Thermodynamics 81 (2015) 237–244

4.     
J. Aboudi, M. Vafaeezadeh, 
J. Adv. Res.  6 (2015) 571–577

5.      B. Vittoria, R. Hart, V. L. Mestre,
D. J. H., M. Burlager, H. Huttenhower, B. J. R. Thio, P. Pollet, C. L. Liotta,
C. A. Eckert,  Fuel 89 (2010) 1315-1319