TY - JOUR
T1 - Energetic Insights into the Role of Quaternary Ammonium Cations in Zeolite Synthesis
AU - Jayanthi, K.
AU - Zones, Stacey I.
AU - Navrotsky, Alexandra
N1 - Publisher Copyright:
© 2023 American Chemical Society.
PY - 2023/8/2
Y1 - 2023/8/2
N2 - The thermodynamics of partitioning of an organic structure-directing agent (OSDA) between water and an organic solvent such as chloroform or trichloroethane serve as a proxy for energetic interactions during zeolite synthesis. Using several newly synthesized OSDAs, we have extended our earlier calorimetric and partitioning studies of the thermodynamics of transfer to separate effects of charge (C/N+ ratio) and structure in a series of structurally related OSDAs. The Gibbs free energies of transfer are close to zero, resulting from a balance of strongly exothermic and relatively similar enthalpies and strongly negative and relatively similar entropies of transfer. There is no obvious correlation between the thermodynamics of transfer and the efficacy of a given OSDA in the zeolite synthesis. One must conclude that with bulk energetics of transfer being similar in most cases studied, the critical factors in OSDA function in zeolite synthesis are kinetically rather than thermodynamically controlled and arise from differences in activation energies related to details of OSDA structure and interactions during nucleation of possible zeolite precursors.
AB - The thermodynamics of partitioning of an organic structure-directing agent (OSDA) between water and an organic solvent such as chloroform or trichloroethane serve as a proxy for energetic interactions during zeolite synthesis. Using several newly synthesized OSDAs, we have extended our earlier calorimetric and partitioning studies of the thermodynamics of transfer to separate effects of charge (C/N+ ratio) and structure in a series of structurally related OSDAs. The Gibbs free energies of transfer are close to zero, resulting from a balance of strongly exothermic and relatively similar enthalpies and strongly negative and relatively similar entropies of transfer. There is no obvious correlation between the thermodynamics of transfer and the efficacy of a given OSDA in the zeolite synthesis. One must conclude that with bulk energetics of transfer being similar in most cases studied, the critical factors in OSDA function in zeolite synthesis are kinetically rather than thermodynamically controlled and arise from differences in activation energies related to details of OSDA structure and interactions during nucleation of possible zeolite precursors.
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U2 - 10.1021/acs.cgd.3c00238
DO - 10.1021/acs.cgd.3c00238
M3 - Article
AN - SCOPUS:85165906954
SN - 1528-7483
VL - 23
SP - 5583
EP - 5588
JO - Crystal Growth and Design
JF - Crystal Growth and Design
IS - 8
ER -