Abstract: The present application relates to a system for removal of nitrate from water. The system includes a first reactor comprising a porous oxide-derived silver electrode (OD-Ag) for electrocatalytic reduction of nitrate (NO3?) to nitrite (NO2?) and a second reactor comprising a Pd-based catalyst for catalytic reduction of nitrite (NO2?). Also disclosed is a method of removing nitrate from water.

Abstract: The process of the present invention creates a sustainable and closed water loop allowing inherent recycles of all liquid streams generated in the process. The liquid streams generated during the process of the invention are inherently recycled completely, making the process of the present invention a zero liquid discharge process which is environmentally friendly and sustainable. This invention further relates to a sustainable chemical process of reduction of R—NO2 or R—NO into corresponding R—NH2 that produces environmentally friendly R—NH2 in good yields and selectivity with large of mother liquor recycle. The process has a wide scope in that it can be applied to a number of molecules.

Abstract: The present invention relates to a method of reducing the total organic carbon (TOC) content of waste water in the course of the preparation of concentrated solutions or suspensions of anionic organic compounds, which method comprises increasing the concentration of an aqueous solution or suspension of an anionic organic compound in the form of its free acid or its alkali metal salt, having a salt content of less than 5% of extraneous salt by weight based on the total solution or suspension, by microfiltration, ultrafiltration and/or nanofiltration, a) the membrane pore size being so selected that compounds having molecular weights in the range from 300 to 1000 Daltons or higher are retained, and b) the content of anionic compound in the concentrate being so adjusted to from 10 to 50% by weight that the total organic carbon (TOC) content of the permeate is less than 0.

Abstract: An aromatic amino sulfonic acid compound is purified by a process including steps of:(a) dissolving the aromatic amino sulfonic acid compound in aqueous medium having a basic pH;(b) acidifying the aqueous medium with acetic acid to precipitate the aromatic amino sulfonic acid compound; and(c) removing the precipitated aromatic amino sulfonic acid compound from the aqueous medium.Using acetic acid in the process results in removal of more impurities and undesirable sulfate and chloride salts to provide an improved material for synthesizing dyes and pigments.

Abstract: One object of the invention is a process for the catalytic hydrogenation of aromatic nitro compounds in solution or in melt in the presence of hydrogen and at least one noble metal catalyst, nickel catalyst or cobalt catalyst, in which process a catalytic amount of at least one vanadium compound is present, wherein the vanadium has the oxidation state 0, II, IV or V. It has been found that in the catalytic hydrogenation of aromatic nitro compounds the accumulation of hydroxylamines can be almost completely prevented by the addition of catalytic amounts of vanadium compounds, which usually results in concentrations of <1% hydroxylamine. The resulting hydrogenated products are whiter (purer) than those obtained without the addition of the vanadium compound because almost no azo or azoxy compounds are obtained. The hydrogenation, in particular the final phase, proceeds faster than without said addition. Accordingly, substantial advantages with respect to quality constancy and economy are obtained.

Abstract: The new process for preparing 4,4'-dinitrostilbene-2,2'-disulphonic acid and salts thereof by oxidation of 4-nitrotoluene-2-sulphonic acid with an oxidant in the presence of strong bases is characterized in that the oxidation is carried out in a mixture of water and an organic solvent selected from the group consisting of alcohols, ethers and mixtures thereof.

Abstract: The preparation of 4,4'-dinitrostilbene-2,2'-disulphonic acid by oxidation of 4-nitrotoluene-2-sulphonic acid with oxygen in alkaline medium in aqueous ether alcohol makes possible a simplified work-up.

Abstract: The object of the invention is a process for the preparation of the trans(-) (2R,3S) diastereoisomer of the glycidic esters of general formula: ##STR1## wherein a chlorohydrin of general formula: ##STR2## is reacted with a strong organic base in a suitable solvent and at a temperature between -10.degree. C. and room temperature.Another object of the invention is intermediate compounds cis(+) (2S,3S) 1,5-benzothiazepin-4-one.

Abstract: A process is described for the preparation of 4,4'-dinitrostilbene-2,2'-disulfonic acid by oxidation of 4-nitrotoluene-2-sulfonic acid by using liquid, anhydrous ammonia, a liquid alkyl derivative of ammonia or a mixture of ammonia and/or the alkyl derivatives of ammonia with water as the solvent.

Abstract: The present invention relates to an improved process for the preparation of 4,4'-dinitrostilbene-2,2'-disulfonic acid and its salts.

Abstract: A process for the preparation of 4-nitrotoluene-2-sulfonic acid by sulfonating 4-nitrotoluene with oleum or liquid SO.sub.3 is described. The sulfonation is carried out continuously with oleum of at least 50% concentration or liquid 100% SO.sub.3 while keeping the conversion of 4-nitro-toluene in the reaction mixture at .gtoreq.90% during the entire reaction course.The process is inherently non-polluting, and provides the product in high yield and low sulfuric acid content in a form usable for 4,4'-dinitrostilbene-2,2'-disulfonic acid production without further purification.