Activation of tertiary amine

Another mechanism of copolymerization was reported by Feltzin et al.73). These authors also considered activation of tertiary amine by a compound with active hydrogen but with the formation of a quaternary ammonium base (Eq. (45)), being regarded as the real initiator of copolymerization. Initiation, propagation and termination reactions according to Feltzin are illustrated by schemes (46)-(49). 

TABLE 1. Substrate activity of tertiary amines for cytochrome P-450 using microsomes from phenobarbital-induced rabbits. 

The catalytic activity of tertiary amines in the phenyl isocyanate-butanol reaction falls off as the size of the substituent groups in tertiary amines increases [140]. The base strengths (pKa) of trimethylamine, ethyldimethylam-ine, diethylmethylamine, triethylamine, and triethylenediamine are 9.9, 10.2, 10.4, 10.8, and 8.2, respectively, whereas the relative catalytic activities of those are 2.2, 1.6, 1.0. 0.9, and 3.3, respectively [140]. 

Knight AW, Greenway GM. Relationship between structural attributes and observed ECL activity of tertiary amines as potential analytes for the tris(2,2-bipyridine)ruthenium(II) ECL reaction. Analyst 1996 121 101-6. 

Y Endo, T Tani, and M Kodama, Antimicrobial activity of tertiary amine covalently bonded to a polystyrene fibre , Appl Environ Microbiol. 1987 53(9) 2050-2055. 

Table 14.2. Catalytic activity of tertiary amines in the phenyl isocyanate-hutanol reaction [3].

The phase transfer activity of tertiary amines is believed to occur because of the formation of a quaternary ammonium ion pair through reaction with hydrogen chloride eliminated during reaction of the alcohol and acid chloride. 

With microwave-assisted technology, Porcheddu and colleagues [11] prepared benzimidazoles via one-pot C-H activation of tertiary amines/oxidative cycliza-tion with 1,2-phenylenediamine in the presence of Pd/C (Scheme 14.10). To ascertain the heterogeneous character of the catalytically active species in this process, further leaching studies were performed. Both Sheldons hot filtration test and atomic absorption spectroscopy analysis (ICP-MS) of the filtrate detected no significant quantities of leached Pd in solution, suggesting that the reaction was a heterogeneous process. 

Curing of PU resins is often carried out in the presence of catalysts. The nature of the catalyst used varies, depending upon whether it is moisture-cured (NCO-H2O reaction) or if the curing involves reaction between —NCO and—OH groups. Tertiary amines have been found to be the most effective catalysts for NCO-H2O reactions, whereas metal catalysts function as the most efficient catalysts for — NCO and —OH reactions. However, tertiary amines have also been found to be effective, in some cases, for the latter type of reaction. Such catalytic reactions have been comprehensively reviewed by several workers. Catalytic activity of tertiary amines increases with... 

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