2.6- Di-f-butyl-4-methylphenol

SFC-FID is widely used for the analysis of (nonvolatile) textile finish components. An application of SFC in fuel product analysis is the determination of lubricating oil additives, which consist of complex mixtures of compounds such as zinc dialkylthiophosphates, organic sulfur compounds (e.g. nonylphenyl sulfides), hindered phenols (e.g. 2,6-di-f-butyl-4-methylphenol), hindered amines (e.g. dioctyldiphenylamines) and surfactants (sulfonic acid salts). Classical TLC, SEC and LC analysis are not satisfactory here because of the complexity of such mixtures of compounds, while their lability precludes GC determination. Both cSFC and pSFC enable analysis of most of these chemical classes [305]. Rather few examples have been reported of thermally unstable compounds analysed by SFC an example of thermally labile polymer additives are fire retardants [360]. pSFC has been used for the separation of a mixture of methylvinylsilicones and peroxides (thermally labile analytes) [361]. 

A GC-IR-MS system with library search capability has been used to effectively identify the pyrolysis products of polybutadiene and the antioxidant additive 2,6-di-f-butyl-4-methylphenol [199]. Paper for food packaging was analysed by P T (at 100 °C) combined with /i-GC-UV. No specific applications of /rGC-UV to poly-mer/additive analysis have as yet been reported. 

Figure 1. Degree of ionization of various phenols in aqueous DMSO as a function of solvent composition ( ) 2,6-di-isopropylphenol, (o) 2-t-butylphenol, (half-shaded circle) 2,4-di-f-butylphenol, ( ) 2,6-di-f-butylphenol, ( ) 2,6-di-f-butyl-4-methylphenol, (half-shaded square) 2,4,6-tri-f-butylphenol. (Albagli et al., 1973.)...

A wide range of trialkylaluminum with different bulkiness and Lewis acidity was investigated They influenced differently the PMMA tacticity. EtsAl and i-BusAl led to syndiotactic PMMA, whereas atactic PMMA was formed in the presence of f-BusAl. Ballard and coworkers successfully polymerized MMA in toluene at 0 °C in the presence of a mixture of f-BuLi and (2,6-di-f-butyl-4-methylphenoxy)diisobutylaluminum, that was prepared by reaction of triisobutylaluminum with 2,6-di-f-butyl-4-methylphenol. In order to shed light on the origin of the polymerization control, a mechanistic study was undertaken by NMR techniques. In the f-BuLi/EtsAl system, the actual polymerization initiator is a f-butyl carbanion. Actually, f-BuLi forms an ate complex with EtsAl. Later on, Muller and coworkers analyzed the unimeric model in the presence of EtsAl and MMA, and they confirmed the formation of a bimetallic ate complex It was accordingly proposed that the propagating species is an ate complex, which exhibits a decreased nucleophilicity compared to the uncomplexed species. 

Alkadienoic esters. Ketenes are generated from unsaturated esters of 2,6-di-f-butyl-4-methylphenol on reaction with RLi-SnCl. An immediate Emmons- Wadsworth reaction provides the allenes. 

The palladium complex, [Pd(PPh3)4], was found to catalyze the decomposition of r-BuOOH in chlorobenzene at 35 °C [337], The rate of oxygen evolution was found to be directly proportional to the catalyst concentration. The rate of radical production (R ) was measured by the inhibition method [338] using 2,6-di-f-butyl-4-methylphenol. The chain length of the reaction [d02ldt/Rr] was found to be 10 in agreement with other studies [339,340]. Thus, decomposition is a normal radical induced reaction as in the case of catalysis by cobalt compounds. 

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