Catalysis by Alkali and Alkaline Earth Metal Ion Coordinated with Tetrakis[3,5-bis(trifluoromethyl)phenyl]borate
Date Issued
2004
Date
2004
Author(s)
Chang, Chih-Ching
DOI
zh-TW
Abstract
In this thesis, it was found that Mn+(H2O)m(BArF4-)n {M = Li+, Na+, K+, Mg2+, and Ca2+ ; BArF4- = tetrakis[bis-3,5-(trifluoromethtyl)phenyl]
-borate}could catalyze the polymerization reaction, deprotection of acetal, ring opening reaction of ε-caprolactone and epoxides, and Mannich type reaction.
In aqueous solution, the borate salt forms aggregates particularly with organic materials, which is due to the hydrophobic effect of the aryl group on the borates. This aggregation readily includes the hydrated metal ion into the organic phase. That makes the hydrated metal ion acting as a Brønsted-Lowry acids. Mn+(H2O)m(BArF4-)n produced proton to polymerize vinyl ether and p-methoxystyrene in CH2Cl2. Additionally, BArF4- could make cation that was produced by proton more easily be attacked by another nucleophile, and avoid the termination of the polymerization.
In different reaction conditions, hydrated metal ion could act different roles. In the polymerization of styrene, it was needed that an initator to start the polymerizeion. So, they acted as lewis acids to catalyze the forming of caboncation. In the deprotection of acetal, and Mannich type recation. Thus, Mn+(H2O)m(BArF4-)n promotes the polymerization of vinyl ether and p-methoxystyrene. Under different reaction conditions, the hydrated metal ions can also act as Lewis acid. With a initator, Mn+(H2O)m(BArF4-)n catalyze the polymerization of styrene.
Subjects
四[3,5-雙(三氟甲基)苯基]硼酸離子
Tetrakis[3,5-bis(trifluoromethyl)phenyl]borate
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-93-D89223013-1.pdf
Size
23.31 KB
Format
Adobe PDF
Checksum
(MD5):b02a9cfda9f7e6cb602ea600fdce2e11