2,6-Ditert-butylphenol

Synonym 4-[[4,6-bis(octylsulfanyl)-1,3,5-triazin- 2-yl]amino]-2,6-ditert-butylphenol ... 

With the exception of 2,6-ditert-butylphenol, which remained unreac-tive under the used experimental conditions, the reaction of benzoxazine with phenols and were shown to follow second order kinetics. 

From Table 2 it appears that the reaction takes place preferentially at the phenol s ortho rather than the para position. The nature of the phenol s substituents plays an essential role in reactivity, even preventing reaction occuring, as mentioned before in the case of 2,6-ditert-butylphenol, 2d. 

The unreactive nature of 2,6-ditert-butylphenol, may be explained by this mechanism, since it is quoted in the literature as having very low acidic characteristics. 

As initiator we have employed 2,4-ditert-butylphenol, which, as we have demonstrated above, is highly reactive towards 3,6,8-trimethyl-3,4-dihydro-2H-1,3-benzoxazine ( non-polymerizable benzoxazine"). 

Figure 2. Polymerization of benzoxazine lb in the presence of various amounts of 2,4-ditert-butylphenol. Fraction of unreacted benzoxazine versus reaction time at 140 C. 

Benzoxazine Ic Polymerization Kinetics. A kinetic study of the polymerization of benzoxazine Jx was carried out at 140 C in the presence of 1%, 5%, and 10% by weight of 2,4-ditert-butylphenol (Figure 3). Table 4 summarizes the variation of the average molecular weight with time during this reaction. 

Discussion. The above results suggest the following mechanism for this pol3nnerization, where B represents the benzoxazine and P the phenol initiator, e.g. 2,4-ditert-butylphenol. 

Figure 4 shows the plot of this relationship in the case of benzoxazine lb and for three different concentrations of 2,4-ditert-butylphenol. The rate law is perfectly verified at 10% phenol. However, the observation that the straight lines do not pass through the origin at lower phenol concentration may imply a second reaction, i.e. a thermal degradation of benzoxazine which could lead to the pol3rmerization of benzoxazine in the absence of phenol, or at least loss of some of the initiator species. 

Table 5. Propagation Rate Constants kp for Pol3nnerization of Benz-oxazine lb at 140 C (using Various Amounts of 2,4-Ditert-butylphenol)... 

The sulfonation of 2-tert-butylphenol with chlorosulfonic acid has been studied kinetically the reaction mixture was demonstrated to contain 13 acids (derivatives of phenol, 2-tert-butylphenol, 4-tert-butylphenol and 2,4-ditert-butylphenol). The majority of the reactions gave first order rate constants and the operation of a two-phase reaction mechanism was discussed with reference to direct sulfonation, sulfate ester rearrangement and ipso sulfonation. 

Cl 3-15 alkyl esters 2,2 -isobutylidenebis(2,4-dimethylphenol) 1,1,3-tris(2 methyl-4 -hydroxy-5 tert-butylphenyl)butane Phosphite bis-(2,4-di-t-butylphenol) pentaerythritol diphosphite tris (2,4-di-tert-butylphenyl)phosphite trinonylphenol phosphite distearyl pentaerythritol diphosphite trilauryl trithiophosphite Thiosynergist didodecyl-3,3 -thiodipropionate dioctadecyl 3,3 -thiodipropionate 2,2 -thiodiethylene bis(3-(3,5-ditert-butyl-4-hydroxyphenyl)propionate] 4,4 -thiobis(2-t-butyl-... 

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