Etude de la télomérisation de l'acide acrylique par les mercaptans, 1 Télomérisation de l'acide acrylique par l'acide thioglycolique; Influence de la nature du solvant sur la valeur de la constante de transfert et dekp/√kte

Autor: Cédric Loubat, Azarang Javidan, Bernard Boutevin
Rok vydání: 2000
Předmět:
Zdroj: Macromolecular Chemistry and Physics. 201:2845-2852
ISSN: 1521-3935
1022-1352
DOI: 10.1002/1521-3935(20001201)201:18<2845::aid-macp2845>3.0.co;2-7
Popis: The telomerization of acrylic acid (AA) with thioglycolic acid (TGA) initiated with 2,2'-azoisobutyronitrile (AIBN) was first investigated in organic medium (THF, 65°C). The kinetic study of this telomerization led to the determination of the TGA transfer constant (C T =3.2) and to the ratio k p /√k te equal to 0.48 L 1/2 -mol -1/2 . Then, the same study was performed both in aqueous medium and in water/THF mixture in order to investigate the solvent effect on the transfer constant. From these works it is emphasised that the nature of the solvent plays an important role on the kinetics parameters. First, this research underlined an increase of the K p /√k te value by raising the water proportion in water THF/ mixtures. Then, the kinetic study showed the highest value for the k p /√k te constant, equal to 2,48 L 1 /2.mol- 1 /2.s 1 /2 when the telomerization proceeded in water. Consequently, the value of C f , which is directly influenced by the k p /√k te constant , presented a decrease from C T = 3.2 in THF to a value equal to 0.5 in water. By this way, the ideal case of telomerization (C T = 1) was reached for a mixture of solvents; 80% water/20% THF (v/v). Formula maths. Mecanisme reactionnel de la reaction de telomerisation de l'acide acrylidique par l'acide thioglycolique.
Databáze: OpenAIRE
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