- Formation constants and composition of Ga3+ and In3+ complexes with iminodisuccinic acid in aqueous solutions according to potentiometric data
-
The complexation of Ga3+ and In3+ with iminodisuccinic acid (H4L) at 25 C in 0.1, 0.4, 0.6, and 0.8 M KNO3 supporting solutions was studied by potentiometry and mathematical modeling. The thermodynamic constants of formation of neutral, protonated, and hydroxo complexes were calculated by extrapolating the concentration constants to the zero ionic strength using an equation with one individual parameter.
- Tolkacheva,Nikol'Skii
-
-
Read Online
- Low-ammonia synthesis method of imino-disuccinate
-
The invention relates to a synthesis method of imino-disuccinate, in particular to a low-ammonia synthesis method of imino-disuccinate. The raw materials comprise maleic anhydride, ammonia water, sodium hydroxide and sodium nitrite; wherein the molar ratio of maleic anhydride to ammonia is 1: (0.45-0.6). The synthesis method comprises the following steps: 1) adding maleic anhydride into water to completely dissolve maleic anhydride, slowly adding a sodium hydroxide solution, then adding ammonia water, and finally adding sodium nitrite; 2) heating the reaction solution to 90 DEG C or above, keeping the temperature for 3.5-4.5 hours, then stopping heating, and reducing the temperature to 80-90 DEG C; and 3) adding solid sodium hydroxide in batches to ensure that the reaction is finished as soon as possible under the condition that the solution is not boiled, continuously heating to a boiling state, distilling out part of water, increasing the solid content to 50% or above, maintaining the reaction temperature for 15-24 hours, finishing the reactions, and cooling to the room temperature. Sodium nitrite is added, the safety is high, and the raw material conversion rate is high.
- -
-
Paragraph 0023-0054
(2020/07/15)
-
- CATALYST RECOVERY PROCESS
-
The present invention relates to a method for recovering lanthanoid catalyst from the preparation of aspartic acid diethoxy succinate comprising contacting a carbonate source with a solution containing lanthanoid ions derived from said preparation and a chelating agent different from aspartic acid diethoxy succinate to precipitate lanthanoid carbonate followed by separating the precipitated lanthanoid carbonate from the solution.
- -
-
Paragraph 0043; 0044
(2015/01/18)
-
- Process for preparing D,L-aspartic acid from ammonium salts of the maleic acid
-
A process is disclosed for preparing D,L-aspartic acid by beating aqueous solutions of ammonium salts of the maleic acid. The molar ratio of maleic acid to ammonia ranges from 1:1 to 1:50. The process is carried out at temperatures from 60° to 250° C. and pressures of at least 1 bar. The pressure applied during the reaction is adjusted to ensure that the reaction mixture is almost completely present in liquid phase. Excess ammonia is removed and the reaction solution is acidified so as to release D,L-aspartic acid, which is then isolated.
- -
-
-