1.Coatings
Artificial leather: PVC or polyurethane spread-coating
systems contain THF alone or in blends with other solvents. Magnetic tapes: The
abrasion resistance of video, computer or audio tapes can be improved by
applying coatings derived from polyurethane or PVC in which the solvent phase
is a blend of THF and toluene. Cellophane: The mechanical strength, impermeability
to water vapor, heatsealability and printability of cellophane can be improved
by applying coatings formulated from poly(vinylidene chloride) (PVDC), in which
the solvent phase is a blend of THF and toluene.
2.Adhesives
Tetrahydrofuran
is suitable for the production of PVC adhesives for rigid PVC.It is used as a
swelling agent for bonding plasticized PVC film and for fabricating PVC pipe
systems. In both cases, the evaporation rate can be regulated by blending the
THF with another solvent, such as cyclohexanone.
3.Specialty
Coating Systems
By
virtue of its excellent solvent power, THF allows the preparation of highly
concentrated solutions of various polymers. These solutions can be diluted to
the appropriate final concentration by adding thinners. Although THF evaporates
rapidly, films formed from its solutions have very minimal tendency toward
blushing during drying.
4.Reaction
Medium
Tetrahydrofuran
is a reaction medium, used primarily by the pharmaceutical industry, e.g., in
Grignard syntheses or lithium aluminum hydride reductions. In fact, it is the
only medium in which many Grignard compounds can be obtained. By virtue of its
good solvent power for alkali metals, THF is a useful reaction medium for the
production of organometallic compounds. Anionic polymerization reactions can be
carried out in THF as well.
5.Extractant
Some
drugs, e.g., alkaloids, can be obtained in the pure form from their natural or
synthetic precursors by extraction with THF. Also, impurities such as fat, wax
or substances with a high molecular mass can be removed from compounds that are
insoluble in THF.
6.Starting
Material for Syntheses
Tetrahydrofuran
is the starting material for a number of syntheses. For instance, ethers with a
high molecular mass and chains of various lengths can be obtained by
polymerization. The oxygen in the pentagonalring can be replaced by nitrogen or
sulfur to yield other five-membered heterocycles such as tetrahydrothiophene or
pyrrolidine. The ring can be cleaved with halocarbons.
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