Methyltetrahydrofuran, polymerization

Fig. 5-5 Polymerization of styrene by sodium naphthalene in 3-methyltetrahydrofuran at 20°C. After Schmitt and Schulz [1975] (by permission of Pergamon Press and Elsevier, Oxford).

Table 1. Effect of bleaching samples with visible light on the polymerization of nitroethylene in 2-methyltetrahydrofuran glass irradiated to a dose of 2 X 70 rad at 77°...

When the 2-methyltetrahydrofuran and n-butylchloride glasses with about 10 mole-% of styrene in them are irradiated to the dose of 1 X 107 rad, polystyrene is obtained only from the latter glass, though the polymer yield is low (1 2%). This indicates that radiation-induced polymerization occurs in the glass where the cation radicals are formed by the radiation. The experimental results of the polymerization in glass matrices are consistent with the previous report that the radiation-... 

The formation of ion radicals from monomers by charge transfer from the matrices is clearly evidenced by the observed spectra nitroethylene anion radicals in 2-methyltetrahydrofuran, n-butylvinylether cation radicals in 3-methylpentane and styrene anion radicals and cation radicals in 2-methyltetrahydrofuran and n-butylchloride, respectively. Such a nature of monomers agrees well with their behavior in radiation-induced ionic polymerization, anionic or cationic. These observations suggest that the ion radicals of monomers play an important role in the initiation process of radiation-induced ionic polymerization, being precursors of the propagating carbanion or carbonium ion. On the basis of the above electron spin resonance studies, the initiation process is discussed briefly. 

Uses. Furfural is primarily a chemical feedstock for a number of monomeric compounds and resins. One route produces furan by decarbonylation. Tetrahydrofuran is derived from furan by hydrogenation. Polytetramethylene ether glycol [25190-06-1] is manufactured from tetrahydrofuran by a ring opening polymerization reaction. Another route (hydrogenation) produces furfuryl alcohol, tetrahydrofurfuryl alcohol, 2-methylfuran, and 2-methyltetrahydrofuran. A variety of proprietary synthetic resins are manufactured from furfural and/or furfuryl alcohol. Other... 

A recent study of the radiation-induced polymerization of nitro-ethylene (38) indicates that the predominant propagating species in this monomer is an anion. This is based on scavenger studies utilizing HBr, substantiated by a study of the electron-trapping capabilities of this monomer in irradiated 2-methyltetrahydrofuran glass (38). 

Tabata and coworkers studied extensively the radiation-induced polymerization of vinylcarbazole (VC) in various solvents27-32. In one paper27 they studied the initial species formed in the polymerization of VC in benzonitrile solutions. To identify the products, they used the optical spectrum obtained for glassy solutions of vinylcarbazole in butyl chloride and 2-methyltetrahydrofuran irradiated at 77 K with y-rays. Irradiation in butyl chloride matrix is known, similarly to that in other organic chlorides, to give... 

Ring strain of 5-membered cyclic ethers is relatively low, thus even the polymerization of unsubstituted monomer, tetrahydrofuran, is highly reversible. The substitution further decreases the thermodynamic polymeri-zability, thus 2-methyltetrahydrofuran does not polymerize [125], while 3-substituted monomer undergoes polymerization, however ceiling temperature is low (4° C) [126]. Thus, the only monomer of this group which has been studied in great detail is tetrahydrofuran. 

THF may also be polymerized in the presence of 30% oleum, chlorosulfonic acid and silver salts (e.g. silver carbonate but not silver halides) to give a good yield of polytetramethylene glycol. Chlorosulfonic acid also catalysed the polymerization of 3-methyltetrahydrofuran at 0 C to give a low molecular weight polymer, demonstrating that, in spite of the hindrance of the methyl group, polymerization was still possible. ... 

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