Abstract: An improved process for preparing ammonium salts from fumaric or succinic acid, is described. The method consists of neutralizing the corresponding acid carbonate or ammonium bicarbonate at a molar stoichiometric or greater than the stoichiometric ratio of 4-5% in a saturated aqueous solution of the synthesized salt at a temperature not exceeding 40° C., followed by separation of the product and drying at a temperature not exceeding 70° C. After separation of the ammonium salts, the filtrate can be re-used. Isolation of the product is usually carried out by cooling the reaction mixture to a temperature of 15-18 C.°. The product comes out in almost crystalline form. Saturated aqueous solution of the synthesized salt is formed by the interaction of carbonate or ammonium bicarbonate with the appropriate acid at a temperature not exceeding 40° C. It is possible to obtain cleaner salt concentration weighing more than 99% and not yielding lower than 98%.

Abstract: A method for preparing succinic acid, including producing a modified palladium-containing catalyst by using an acid and liquid-phase hydrogenation of unsaturated acid compounds on the modified catalyst at an increased temperature and pressure; separating the catalyst from the succinic acid; wherein the modification of the catalyst is performed on a substrate having the palladium-containing catalyst delivered thereon, the delivery being performed in an oxygen-free atmosphere; the delivery being performed in an aqueous medium of succinic, maleic or fumaric acids and/or their mixtures at a Pd2+/acid ratio of 1:1-1:100; hydrogenating the liquid-phase unsaturated acid compounds selected from maleic, fumaric acids or their anhydrides or their mixtures; and crystallizing the succinic acid from an aqueous solution containing 0.001-0.01 wt. % succinic acid seed.

Abstract: An improved process for preparing ammonium salts from fumaric or succinic acid, is described. The method consists of neutralizing the corresponding acid carbonate or ammonium bicarbonate at a molar stoichiometric or greater than the stoichiometric ratio of 4-5% in a saturated aqueous solution of the synthesized salt at a temperature not exceeding 40° C., followed by separation of the product and drying at a temperature not exceeding 70° C. After separation of the ammonium salts, the filtrate can be re-used. Isolation of the product is usually carried out by cooling the reaction mixture to a temperature of 15-18C°. The product comes out in almost crystalline form. Saturated aqueous solution of the synthesized salt is formed by the interaction of carbonate or ammonium bicarbonate with the appropriate acid at a temperature not exceeding 40° C. It is possible to obtain cleaner salt concentration weighing more than 99% and not yielding lower than 98%.