A process is described for improving the purity of quaternary ammonium hydroxides. In one embodiment, the process of the present invention comprises the steps of (a) charging an aqueous solution containing the quaternary ammonium hydroxide to the anolyte compartment of an electrolysis cell which comprises an anolyte compartment and a catholyte compartment containing water separated from each other by a cation-exchange membrane, (b) passing a direct current through the electrolysis cell to produce a high purity quaternary ammonium hydroxide in the catholyte compartment, and (c) recovering the high purity quaternary ammonium hydroxide from the catholyte compartment. In a preferred embodiment, the aqueous solution containing the quaternary ammonium hydroxide charged to the anolyte compartment is heated to an elevated temperature for a given period of time prior to subjecting the quaternary ammonium hydroxide to the electrolytic process of the present invention. The process of the present invention results in the formation of quaternary ammonium hydroxide solutions containing significantly reduced amounts of halogen (both ionic and latent), carbonates and/or metals, and the solutions also are characterized by improved color.

Method for producing high purity quaternary ammonium hydroxides

A method of manufacturing quarternary ammonium hydroxide by electrolyzing a quarternary ammonium salt in an electrolytic cell whose diaphragm is prepared from a cation exchange membrane, wherein said quarternary ammonium salt is represented by an organic acid salt expressed by the general structural formula: ##STR1## where R 1 to R 4 =methyl radical or ethyl radical (at least R 1 to R 3 denote the same radical; X represents formic acid).

Method of manufacturing tetramethyl ammonium hydroxide

The disclosed process for rejuvenation treatment of a photoresist development waste mainly containing a photoresist and tetraalkylammonium (TAA) ions comprises at least a simple membrane separation step of treating the photoresist development waste or a treated solution derived from the photoresist development waste with a nanofiltration membrane (NF membrane) to obtain a concentrate (NF concentrate) mainly containing impurities such as the photoresist and a higher-purity permeate (NF permeate) mainly containing TAA ions. The NF concentrate and/or the NF permeate, preferably the NF permeate, is desirably subjected to a step of concentration and refining by electrodialysis or electrolysis and/or a step of refining by ion exchange treatment, for example, with an anion exchange resin and/or a cation exchange resin in one of the H form and the TAA form. The NF permeate may advantageously be passed through the concentrating cells of an electrodialysis unit while passing the NF concentrate through the desalting cells of the electrodialysis unit to further recover TAA ions remaining in the NF concentrate, whereby the amount of wastewater discharged as the desalted waste can be decreased. The NF membrane separation step is preferably effected in multiple stages.

Process and equipment for rejuvenation treatment of photoresist development waste

A process is described for reducing the latent halide content of a solution of quaternary ammonium hydroxide containing latent halide which comprises the steps of (A) providing an electrolytic cell comprising an anode and a cathode, (B) charging a solution containing at least one quaternary ammonium hydroxide which contains latent halide into said electrolytic cell, (C) passing a current through the electrolytic cell to lower the latent halide content in the solution, and (D) recovering the quaternary ammonium hydroxide solution from the electrolytic cell. A process also is described for reducing the latent and ionic halide content of quaternary ammonium hydroxides prepared from the corresponding halide.

Method for purifying quaternary ammonium hydroxides

A process is described for preparing quaternary ammonium hydroxides of improved purity. In one embodiment, the present invention relates to a process of preparing quaternary ammonium hydroxides from the corresponding quaternary ammonium salts in an electrolytic cell which comprises an anolyte compartment containing an anode and a catholyte compartment containing a cathode and water, said anolyte and catholyte compartments being separated from each other by a cation-exchange membrane, said process comprising the steps of (a) providing the catholyte compartment with a cathode of zinc, cadmium, tin, lead, or alloys thereof, mercury, or mercury amalgam, (b) charging an aqueous solution containing a quaternary ammonium salt to the anolyte compartment, (c) passing a current through the electrolytic cell to produce quaternary ammonium hydroxide in the catholyte compartment, and (d) recovering the quaternary ammonium hydroxide from the catholyte compartment.

Process for preparing quaternary ammonium hydroxides

PURPOSE: To manufacture organic ammonium hydroxide of extra high purity, by electrolyzing the organic ammonium salt of specified composition in an electrolyzing cell which makes a cation exchange membrane as a diaphragm. CONSTITUTION: The inside of an electrolytic cell 1 is partitioned by a cation exchange membrane 2 into an anode chamber 3 and a cathode chamber 4, and an anode 5 and a cathode 6 are provided in each chamber. The aqueous solution of organic ammonium salt of tetramethylammoniumchloride etc. represented in the formulaIof which concentration is 5W30wt% is circulated through the anode chamber 3 via an outlet 8, a liquid bath 9, being supplied from an inlet 7. And the dilute water of organic ammonium hydroxide such as ca. 1% concentration of tetramethylammoniumhydroxide etc. represented in the formula II as the product is circulated through the cathode chamber 4 via an outlet 13, a solvent bath 14, being supplied from an inlet 12. Electrolysis is done at the temperature 10W40°C and at the current density of 1W50A/dm 2 in the both electrode chambers and it is continued until the concentration of tetramethylammoniumhydroxide rises to 2W30wt%. COPYRIGHT: (C)1982,JPO&Japio

Shiro Oota

Papers

Manufacture of organic ammonium hydroxide using ion exchange membrane