Cresol, cationic polymerization

Note Moderately polar solvent, ethereal odor soluble in water and most organic solvents flammable moderately toxic incompatible with strong oxidizers can form potentially explosive peroxides upon long standing in air see the relevant tables in the chapter on laboratory safety commercially, it is often stabilized against peroxidation with 0.5 to 1.0% (mass/mass) p-cresol, 05 to 1.0% (mass/mass) hydroquinone, or 0.01% (mass/mass) 4,4 -thiobis(6-ferf-butyl-m-cresol) can polymerize in the presence of cationic initiators such as Lewis acids or strong proton acids. Synonyms THF, tet-ramethylene oxide, diethylene oxide, 1,4-epoxybutane, oxolane, oxacyclopentane. 

A number of years ago triphenylmethyl cation, Ph3C, formed in situ by dissociation of triphenylmethyl chloride, was shown [73] to initiate the polymerization of 2-ethylhexyl vinyl ether in m-cresol solvent. More recently certain stable carbonium ion salts, notably hexachloroantimonate (SbCls) salts of cycloheptatrienyl (tropylium, C7H7) and triphenylmethyl cations have been shown [74, 50] to be very efficient initiators of the cationic polymerization of many reactive monomers [27, 29, 75]. Since the discovery of the effectiveness of the SbClg salt, triphenylmethyl salts with different anions have also been used [76—78]. The most detailed kinetic studies using these initiators have been carried out on alkyl vinyl ethers [27, 30] and A-vinylcarbazole [39] in homogeneous solution in methylene chloride. 

Pyrrole is dried with CaH2 for 24 h, followed by distillation under reduced pressure. Ammonium persulfate is used as an oxidant and dodecylbenzene sulfonate as the codopant. 0.15 mol of dodecylbenzene sulfonic acid and 0.3 mol of pyrrole are dissolved in 500 mL of distilled water with vigorous stirring. 0.06 mol of ammonium persulfate in 100 mL of distilled water are slowly added to the above solution whose temperature is maintained at 0 °C. The reaction is carried out for 40 h and terminated by pouring methanol. The resultant PPy powder is filtered and washed sequentially with distilled water, methanol and acetone several times, followed by filtering and drying in a vacuum oven at 25 °C for 12h. The apparent polymerization yield is 42%. This PPy can be dissolved by soni-cation into m-cresol in reasonable amounts. Another report describes the use of sodimn di(2-ethylhexyl)sulfosuccinate in analogous conditions. 

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