4-t-Butylphenol

It was found that in the catalytic transformation of 2- and 4-t-butylphenol in the liquid phase on heterogeneous KSF and K10 montmorillonite catalysts under micro-wave and conventional conditions the microwaves affected both the rate and the selectivity of the reaction. 

Transformation of 2- and 4-t-butylphenols in the presence of KSF catalyst [58], Rate enhancement up to 21.6 was recorded. Reaction conditions a stirred multi-mode tank reactor, no solvent or polar and nonpolar solvents. 

Results for endocrine disrupting phenols in house dust as reported by Rudel et al. (2003) and Butte et al. (2001) are compiled in Table 11.1. Rudel et al. (2003) sampled indoor air in 120 homes as well. They analyzed both house dust and air for 89 organic chemicals identified as EDCs. The most abundant compounds in air included 4-nonylphenol and 4-t-butylphenol with typical concentrations in the range of 0.050-1.500ggm 3. Saito, Onuki and Seto (2004) collected air samples from houses, offices, and outdoor points. 4-t-butylphenol, 4-t-octylphenol and 4-nonylphenol were detected in both indoor and outdoor air. Concentrations and detection frequencies were higher in indoor air than outdoor air. The maximum levels of 4-t-butylphenol, 4-t-octylphenol and 4-nonylphenol in indoor air were 0.387, 0.0457 and 0.680 ggm 3, respectively. 4-t-butylphenol and 4-nonylphenol were detected with high frequencies (more than 97%) in the indoor air samples. Wilson, Chuang and Lyu (2001) reported a mean of 0.0007 gg m"3 Bisphenol A in the air of 10 child care centers and a mean of 0.203 gg m 3 for the sum of nonylphenol and its ethoxylates. 

A reactor was charged with 4-t-butylphenol (199.7 mmol) and 100 ml of toluene and then heated to reflux under nitrogen during which time roughly 20 ml of toluene were removed by distillation. The mixture was then cooled to 100°C, treated with the syringe-addition of tetraisopropyl titanate (47.43 mmol), and refluxed 30 minutes. Isopropanol was then removed by distillation at up to 90°C. Thereafter an additional 50 ml of isopropanol was distilled over at 140°C, and a dark red liquid was isolated. Upon cooling the liquid crystallized to a red solid at ambient temperature. The crystals were dried overnight at 80°C, and the product was isolated in 94.8% yield. 

Figure 15.2 Comparison between the structures of the tetrahydropyranyl ethers of 4-t-butylphenol and c s-4-methylcyclohexanol, and those of hydroxy citronellal and Lilial . The structures have been drawn with similar orientation of the polar group to better visualize similarities in size and shape of the hydrocarbon region...

The conventional synthesis of 4-f-butylcalix[4]arene is shown in Figure 3.5. This method requires the initial preparation of a precursor by melting 4-t-butylphenol in the presence of formaldehyde under basic conditions then dissolving... 

Figure 3.6 Synthesis of 4-t-butylcalix[4]arene from bis(hydroxymethyl)-4-t-butylphenol...

These results show an apparent activation energy for the hydrogenation of 4-t-butylphenol of 15kJ/mol, which indicates that the reaction is controlled by liquid/solid mass transfer. 

The chemistry of certain alkylphenols and that of hindered phenols has been discussed in chapter 6 where tabulated material has included introductory reference to compounds considered at length in the present chapter. Alkylphenols possessing longer alkyl chains which are sometimes mono- but usually multi-branched have achieved special industrial interest notably those with Cg and Cg alkyl groups in the 4-position such as 4-t-nonyl- and 4-t-octylphenol. In addition, 4-t-butylphenol has also attained a considerable level of commercial chemical interest and in recognition of the unique position of these types of compound their chemistry is now detailed. 

Let us now return to the question How to interpret or explain the fact that some reactions are affected by microwaves and some reactions are not . A detailed study of this subject has been performed by Hajek et al. [75-77] for heterogeneous catalytic liquid-phase reactions. Transformation of 2-t-butylphenol into phenol, 4-t-butylphenol, 2,4-di-t-butylphenol, and isobutene on montmorillonites as catalysts (KSF, KIO) was chosen as model reaction. Scheme 13.13. Both reactant and catalysts coupled very well with microwaves. KSF and KIO catalysts in the form of a fine powder (10-15 pm) were used to avoid creation of macroscopic hot spots (as in the presence of voluminous catalyst pellets, e.g. 5 mm [46, 47]). The results are summarized below. 

The first hornoazacalixarene was reported by Hultsch, who prepared hexahomotriazacalix[3]arene through direct reaction of 4-t-butylphenol with hexamethylenetetramine, however, his method has yet to be verified. The first practical synthesis was that of tri(4-methyTA -benzyl)hex-ahomotriazacalix[3]arene by Takemura. In the two-step process, 2.6-bis(hydroxymethyl)-4-methylphenol was first refluxed in toluene with benzylamine, solvent was removed, and the residue was thermally dehydrated at 135°C to give the azacalix[3]arene in 38% yield. A convergent synthesis was developed by Hampton based... 

Methylpropanediot MPDiol Glycol interm iate, lacquer/varnish resins 4-t-Butylphenol intermediate, latex coatings Vinyl neopentanoate intermediate, maintenance paints... 

Dimethylethyl 2-methyl-2-propenoate. See t-Butyl methacrylate 4-(1,1 -Dimethylethyl) phenol. See 4-t-Butylphenol... 

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