Ammonia is frequently an active component in products such as polishes; cleaning solutions; grease-cutters and dissolvers; etchants; rubber and plastic latices; pulping processes for paper manufacture; leaching solutions for metal ores such as copper, molybdenum, and nickel; fertilizers and the like. Because of its volatility, the ammonia tends to evaporate into the atmosphere, thereby losing effectiveness and causing objectionable odors and atmospheric pollution. Likewise, hydrazine has applications as a fuel, propellant and soldering flux wherein control of evaporation is beneficial to its use.
Amines are used as solvents, surfactants, rust inhibitors, caustic cleaning agents and chemical reactants in the preparation of many products. Likewise, they have been used in extraction of metals from ores. Unwanted evaporation causes poluting, caustic and noxious vapors, loss of effectiveness, and decreased control of process concentration.
Evaporation of volatile liquids and vapors can be retarded by use of physical means such as tanks, floating spheres of inert material, or thick layers of foam or light and inert barrier materials such as wax, oil, and the like. However, such approaches are expensive and can be used only for static storage of bulk ammonia or hydrazine.
Cetyl and stearyl alcohol have been found to be effective in retarding the evaporation rate of water, and long chain alkyl amides and hydroxyethylated amides have been claimed to be effective in reducing the evaporation of such materials as methanol and acetone from their aqueous solutions. However, these materials are without effect on the evaporation of ammonia or amines from water solution.
Long chain aliphatic amines have been used to retard the evaporation of ammonia and hydrazine from aqueous solutions as disclosed in U.S. Pat. No. 3,557,007. However these materials are very insoluble in water and are therefore difficult to apply. Also, when used alone, they migrate very slowly through aqueous solutions and therefore are relatively slow to reform an impermeable surface monolayer after agitation of the surface.
USPTO Backgrounds
USPTO Backgrounds