Liquid purification or separation – Processes – Ion exchange or selective sorption
Reexamination Certificate
1998-04-06
2001-04-10
Cintins, Ivars (Department: 1724)
Liquid purification or separation
Processes
Ion exchange or selective sorption
C210S694000
Reexamination Certificate
active
06214235
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a process for the removal of quaternary ammonium salts (QS) from a brine solution.
BACKGROUND OF THE INVENTION
Many processes used to manufacture polymers, plastics, and other chemicals generate brine solutions as byproducts. In some cases, the byproduct brine solution contains one or more quaternary ammonium salts (QS) as an impurity. Such quatemary ammonium salts can form in the chemical manufacturing process by reactions between an aliphatic amine, which is often employed as a catalyst, and a chlorinated hydrocarbon, which is often used as a solvent (Gunnar O. Nevstad and Jon Songstad Acta Chem. Scand., Ser. B, B38(6), 469-77, (1984)). In recycle processes in which the product brine solution is utilized as feedstock to a chlor-alkali plant that uses membrane electrolyzer technology, it is important to remove quaternary ammonium salts (QS) from the brine before feeding the brine to the electrolyzers because even small quantities of quaternary ammonium salts (QS) in the feed brine causes elevated cell voltage and foaming in the caustic solution, which is a product of the membrane cell electrolyzer.
Existing brine purification technology is ineffective for removing quaternary ammonium salts from the brine solution. Brines that contain quaternary ammonium salts (QS) are therefore not suitable to be recycled to membrane electrolyzer chlor-alkali plants. There is thus a need for a process that will remove the quatemary ammonium salts from brine solution, before it is recycled to membrane electrolyzers.
SUMMARY OF THE INVENTION
The present invention addresses the above discussed needs by providing a process for removing quaternary ammonium salts (QS) from brine solution generated during the manufacture of polymers, plastics, polycarbonates, and other chemicals, which utilize brine solution and an organic solvent phase.
The present invention provides a process to remove quaternary ammonium salts (QS) from brine solution comprising contacting the quaternary ammonium salts (QS) containing brine solution with an adsorbent at a temperature ranging from about −10° C. to about 90° C., at a pH from about 1 to about 13, and at a feed rate from about 2 to about 40 bed volumes per hour.
REFERENCES:
patent: 4297220 (1981-10-01), Meitzner et al.
patent: 4303704 (1981-12-01), Couduvelis et al.
patent: 4450057 (1984-05-01), Kelly
patent: 5759406 (1998-06-01), Phelps et al.
patent: 3115937 (1982-11-01), None
patent: 0697396 (1996-02-01), None
G. O. Nevstad et al., “Solvent Properties of Dichloromethane. II. the Reactivity of Dichloromethane Toward Amines”, Acta Chemical Scandinavica, vol. B38, 1984, pp. 469-477, XP002109466.
Pecsok et al., Journal of the American Chemical Society, vol. 77, Mar. 20, 1955, pp. 1489-149.
Cintins Ivars
General Electric Company
Johnson Noreen C.
Stoner Douglas E.
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