| Autor: |
Pečar, Darja, Goršek, Andreja |
| Jazyk: |
angličtina |
| Rok vydání: |
2017 |
| Předmět: |
|
| Zdroj: |
Acta Chimica Slovenica, vol. 62, no. 1, pp. 237-241, 2015. |
| ISSN: |
1318-0207 |
| Popis: |
The saponification of an aromatic ester with an aqueous sodium hydroxide was studied within a heterogeneous reaction medium in order to determine the overall kinetics of the selected system. The extended thermo-kinetic model was developed compared to the previously used simple one. The reaction rate within a heterogeneous liquid-liquid system incorporates a chemical kinetics term as well as mass transfer between both phases. Chemical rate constant was obtained from experiments within a homogeneous medium, whilst the mass-transfer coefficient was determined separately. The measured thermal profiles were then the bases for determining the overall reaction-rate. This study presents the development of an extended kinetic model for considering mass transfer regarding the saponification of ethyl benzoate with sodium hydroxide within a heterogeneous reaction medium. The time-dependences are presented for the mass transfer coefficient and the interfacial areas at different heterogeneous stages and temperatures. The results indicated an important role of reliable kinetic model, as significant difference in $k_La$ product was obtained with extended and simple approach. Umiljenje aromatskega estra v vodni raztopini natrijevega hidroksida smo preučevali v heterogenem reakcijskem mediju z namenom razvoja kinetičnega modela. Za primerjavo s predhodno uporabljenim preprostim modelom je bil razvit razširjen termo-kinetični model. Proizvodnost v heterogenem tekoče-tekoče sistemu smo opisali z izrazom, ki upošteva tako kemijsko kinetiko, kakor tudi prenos snovi med obema fazama. Konstanta proizvodnosti je bila pridobljena iz poskusov v homogenem mediju, medtem ko je bil koeficient snovnega prenosa določen posebej. Izmerjeni termični profili so bili osnova za določitev proizvodnosti reakcije. Prikazane so časovne odvisnosti koeficienta snovnega prenosa in medfazne površine pri različnih stopnjah heterogenosti in temperaturah. Iz rezultatov je razvidno, da razlika v $k_La$ produktu, dobljenim z razširjenim in enostavnim modelom obstaja, kar potrjuje pomembnost izbire zanesljivega kinetičnega modela. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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