P-Methoxy styrene

A large number of alkyl-substituted styrene and p-methoxy-styrene oxidra have been ieomerizod in various laboratories, notably those of Tiffeneau, ElieL and Cope. Among the catalysts found to be effective in this connexion are magnesium bromide, aluminum chloride, and boron trifluoride. Only a few illustrative examples are cited in tbe text, although a larger compilation may be found in Table 10. 

Thus, the intermediate resulting from addition of HBr to the methoxyl-substituted styrene is more stable, and reaction of p-methoxy styrene is faster. 

We have already discussed the work of Sawamoto and Higashimura with p-methoxy-styrene and methanesulphonic acid (Sect. III-E-10). In those same three papers iodine was also tried as catalyst a value of the propagation rate constant was cal-... 

It is believed that the free positive and negative species annihilate each other immediately on contact. This is borne out by the strict square root relationship which is found between the rates of polymerization and the dose rate of the radiation. The growing chain ends are therefore free in nature, i.e., with no ion-pair component. This makes radiation initiated ionic polymerization an excellent method for studying free ion polymerization examples of the power of this method have been presented for p-methoxy styrene (1 9) and the vinyl ethers (16,20,21). 

A two-step 1,3-cycloaddition may have been found in the case of p-anisyl-diazomethane reacting with p-methoxy-styrene . While with other substituents only /rfl/ii-3,5-diaryl-pyrazolines are produced, p-methoxy-substituents on both 1,3-dipole and dipolarophile give rise to a mixture of cis and trans isomers in roughly equal amounts. Overberger et suggest a dipolar... 

Interestingly, the use of the more nucleophilic iodide (I or I3 ) as a counteranion allows the formation of bimodal MWD polymers from p-methyl- and p-methoxy-styrenes in CH2CI2 or CH2CI2/CCI4 mixed solvent (Polymerizations of styrene and p-chlorostyrene by iodine have not been studied in detail because of the rather low molecular weight and complex structure of the products.)... 

Halogen-capped PSt and poly(p-methoxy styrene) (PMOSt) were modified with Ph2l PF, and the resultant cationic species was subsequently used to initiate cationic ring-opening polymerization of cyclohexene oxide to produce CLB-5 and CLB-6, respectively [103],... 

PMDETA N,N,N ,N ,N -pentamethyldiethylenetriamine PMOSt poly (p-methoxy styrene)... 

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