Morpholine has been employed as a catalyst for thecondensation of aldehydes and ketones which containactive methyl or methylene groups. The condensates maybe hydrogenated to polyhydroxy compounds which can besulfated to form surface-active agents.Small quantities of morpholine are used in the emul-sion polymerization of monomers, such as butadiene andisoprene, as well as their copolymerization with styrene,acrylonitrile, and the like.Morpholine has been used as a temperature sensitivepolymerization inhibitor. Small amounts permit completeimpregnation of porous materials with molten vinylpyrrole-type monomers just above their melting points, but stillallow complete polymerization at slightly higher tempera-tures.Morpholine has also been used as a gelling agent inthe preparation of alumina catalysts for the treatment ofhydrocarbons. Catalysts of fine particle size suitable forfluidized solid techniques result from this procedure.
Morpholine is widely used as a neutralizing amine incombating carbonic acid corrosion in condensate return lines of steam boiler systems. The morpholine volatilizes with the steam from the boiler and condenses when the steam does, thereby affording protection to the lines,which otherwise would be subjected to corrosion by thecarbonic acid present in the steam condensate.Morpholine vapors protect silver and other metalsagainst corrosion and tarnish by acid fumes, such assulfur dioxide and hydrogen sulfide. The morpholine is
supplied by evaporation from solution in a solid, such ascamphor, or by sublimation from morpholiniumN,N’-oxydiethylenecarbamate.Morpholine is a component of a corrosion inhibitorsystem that prevents decomposition of a chlorinatedhydrocarbon in a composition containing the chlorinatedhydrocarbon and a large amount of water.Corrosion of metal aerosol containers and valves canbe prevented by the use of low levels of morpholine.Morpholine is one of several amines employed asphosphates for inhibiting the corrosive action of grease-proof paper on steel and other metals. Di-4-morpholinylpolysulfides have been claimed as corrosion inhibitors tobe added to mineral lubricating oils. Turbine oils, espe-cially, are quickly contaminated with water, and to protectthe machinery against rusting, 4,4′-alkylidenedimorpho-lines and poly (4-morpholinylmethyl) phenols have beenused. Storage tanks, pipes, and other devices for handlingpetroleum distillates must be protected against corrosion,and for this purpose 4,4’butylmercaptomorpholine,morpholinium mahogany sulfonates, and morpholine inconjunction with ammonium mahogany sulfonates havebeen suggested.