Abstract: In one embodiment, the present invention relates to a process for recovering an organic hydroxide from waste solutions containing the organic hydroxide and impurities including the steps of precipitating the organic hydroxide from the waste solution as an insoluble salt; removing the salt from the waste solution and placing the salt in a liquid to form a second solution; charging the second solution to an electrochemical cell containing at least two compartments, a cathode, an anode and a divider and passing a current through the cell whereby the organic hydroxide is regenerated; and recovering the organic hydroxide from the cell.

Abstract: A method is disclosed for producing di- and more highly oxidized carboxylic acids from a compound selected from a first group consisting of carbohydrates, carbohydrate derivatives and carbohydrate derivatives having more than one primary alcohol group, comprising oxidizing, in an aqueous solution in a concentration between 0.1% and 60%, the compound selected from said first group and a compound selected from a second group consisting of monooxidized carbohydrates, monooxidized carbohydrate derivatives and monooxidized carbohydrate derivatives having more than one primary alcohol group, with one of oxygen and an oxygen-containing gas, on one of a noble metal catalyst and a mixed metal catalyst; electrodialyzing the oxidized compounds in at least one electrodialysis stage; and removing said di- and more highly oxidized carboxylic acids in said at least one electrodialysis stage.

Abstract: In an electrolyzer provided according to this invention, the polarity of electrodes is periodically inverted at very short intervals. This has the effect of allowing gases to be generated uniformly all over the surface of each electrode in the form of extremely small bubbles instead of being formed in specific positions in the form of large bubbles as is the case with a conventional electrolyzer in which a direct current is allowed to flow without changing the flow direction. Thus the surfaces of electrodes are prevented from being covered with bubbles, and the flow of liquids along the surfaces of electrodes is not disturbed by the bubbles any more.

Abstract: A process is described for producing organic acids such as lactic acid. The process includes the steps of producing lactic acid by fermentation, resulting in an aqueous fermentation broth containing lactic acid, and adding a calcium base, such as calcium carbonate, to the fermentation broth, thereby producing calcium lactate in the broth. Biomass is removed from the broth, thereby leaving an aqueous solution or dispersion of calcium lactate. The calcium lactate is reacted with a source of ammonium ions, such as ammonium carbonate, or a mixture of ammonia and carbon dioxide, thereby producing an ammonium lactate. Contaminating cations can be removed by ion exchange. The free lactic acid or a derivative thereof can be separated from the ammonium ions, preferably by salt-splitting electrodialysis.

Abstract: In one embodiment, the invention relates to a process for purifying solutions containing a hydroxide compound, including the steps of: (A) providing an electrochemical cell containing an anode, a cathode, a cation selective membrane and a bipolar membrane, the bipolar membrane having an anion selective side facing the anode and a cation selective side facing the cathode, wherein the cation selective membrane is positioned between the anode and the bipolar membrane, and the bipolar membrane is positioned between the cation selective membrane and the cathode, thereby defining a feed compartment between the cation selective membrane and the anode, a recovery compartment between the bipolar membrane and the cation selective membrane, and a water compartment between the bipolar membrane and the cathode; (B) charging a solution of an ionic compound at a first concentration to the water compartment, and water to the recovery compartment; (C) charging a solution containing the hydroxide compound at a second concentra

Abstract: In one embodiment, the invention relates to a process for purifying solutions containing a hydroxide compound, including the steps of: (A) providing an electrochemical cell containing an anode, a cathode, a cation selective membrane and an anion selective membrane, wherein the cation selective membrane is positioned between the cathode and the anion selective membrane, and the anion selective membrane is positioned between the cation selective membrane and the anode, thereby defining a feed compartment between the cation selective membrane and the anion selective membrane, a recovery compartment between the cathode and the cation selective membrane, and a water compartment between the anion selective membrane and the anode; (B) charging a solution of an ionic compound at a first concentration to the water compartment, and water to the recovery compartment; (C) charging a solution of the hydroxide compound at a second concentration to the feed compartment; (D) passing a current through the cell to produce the

Abstract: A process for the preparation of ascorbic acid starting from an ascorbate is characterized in that an ascorbate, e.g. sodium ascorbate, dissolved in water is decomposed under the influence of an electric field by means of ion-selective membranes into ascorbate ions and cations and the latter are separated spatially from one another and then, as a result of simultaneous generation of protons and hydroxide ions, the ascorbic acid is prepared from the liberated ascorbate ions and protons and, spatially separated therefrom, the corresponding hydroxide, e.g. sodium hydroxide, is also prepared from the cations and hydroxide ions.

Abstract: The present invention relates to methods and apparatus for reducing the fouling of ion-selective membranes used in the electrodialytic purification of organic acids. More particularly, the present invention relates to the use of nanofiltration and chelating agents for removal of impurities from an organic acid-containing feed material to reduce the fouling of ion-selective membranes used in electrodialysis.

Abstract: A process is described for preparing organic and inorganic hydroxides or alkoxides, or ammonia or organic amines from the corresponding salts in an electrolysis cell which comprises an anolyte compartment containing an anode and an electrolyte solution, a catholyte compartment containing a cathode, and an intermediate compartment containing a liquid wherein said intermediate compartment is separated from the catholyte compartment by an anion selective membrane and from the anolyte compartment by a cation selective membrane, said process comprising the steps of:(A) charging to the catholyte compartment, a mixture comprising an organic or inorganic salt or an amine salt, and a liquid selected from water or organic liquids provided that sufficient water is present in the catholyte mixture to form the desired hydroxide or amine, or sufficient alcohol is present in the catholyte mixture to form the desired alkoxide;(B) passing a current through the electrolysis cell to produce the desired hydroxide, alkoxide or am

Abstract: A process using an electrodialysis system employing cation-selective membranes and anion-selective membranes, particularly monovalent anion-selective membranes is used to separate kraft pulping liquors into two streams; one that is rich in sulphides (to be used in the initial stage of pulping), and another that is poor in sulphides (to be used in the final stage of pulping). By separating pulping liquors in this way, the sulphur balance in the kraft process can be maintained while obtaining the benefits of modified pulping. The same electrodialytic system can be used to separate green and polysulphide liquors into sulphide-rich and sulphide-poor components.