Patent EA-003752-B1 (EA)
Title: Method for separating hydroxymethylthiobutyric acid
Inventor: CARENCOTTE FREDERIC
IPC: C07C319/28
Filed: 1999-07-07
Abstract: 1. A process for extracting 2-hydroxymethylthiobutane acid from aqueous solution, obtained after neutralization of sulphuric hydrolyzate 2-hydroxy-4-methylthiobutyronitril hydrate by hydrate of ammonium oxide, and decanting, characterized in that the extracting is made by organic solvent, weakly mixable with water, in quality which is sufficient for extracting of almost whole available in solution 2-hydroxy-4-methylthiobutanic acid. 2. A process as claimed in claim 1, characterized in that organic solvent is selected from ketones, aldehydes, ethers, esters, carbonates and alcohols. 3. A process as claimed in claim 2, characterized in that the solvent is selected from methylethylketone, methylisobutylketone, ethers, such as methyltretbutyl ether or diisopropyl ether, or carbonates, such as diethylcarbonate. 4. A process as claimed in claim 3, characterized in that the solvent is selected from methylethylketone, methylisobutylketone and ethylcarbonate. 5. A process according to any of preceding claims, characterized in that the weight ratio of applicable solvent to aqueous solution, obtained after sulphuric hydrolyze and neutralization exceeds 0.05 and, presumably, equal to 0.1-0.5. 6. A process of salting-out of salts, containing in organic solution, obtained after neutralization by hydrate of ammonium oxide and decanting of sulphuric hydrolyzate 2-hydroxy-4-methylthiobutyronitril, characterized in that the salting-out of this solution is made by organic solvent, weakly mixable with water, in quantity which is sufficient for extracting of almost whole available in solution 2-hydroxy-4-methylthiobutanic acid. 7. A process as claimed in claim 6, characterized in that organic solvent is selected from ketones, aldehydes, ethers, esters, carbonates and alcohols. 8. A process as claimed in claim 7, characterized in that the solvent is selected from methylethylketone, methylisobutylketone, ethers, such as methyltretbutyl ether or diisopropyl ether, or carbonates, such as diethylcarbonate. 9. A process as claimed in claim 8, characterized in that the solvent is selected from methylethylketone, methylisobutylketone and ethylcarbonate. 10. A process according to one claims 7-9, characterized in that the weight ratio of applicable solvent to organic solution, obtained after sulphuric hydrolyze and neutralization exceeds 0.03 and, presumably, equal to 0.3-1. 11. A process according to claims 1and 6 of extracting of organic phase and salting-out from aqueous solution, obtained after neutralization by hydrate of ammonium oxide and decanting of sulphuric hydrolyzate 2-hydroxy-4-methylthiobutyronitril, characterized in that the processes of extracting and salting-out of each phase is made with help of sufficient quantity of organic solution, weakly mixable with water. 12. A process as claimed in claim 11, characterized in that the processes of extracting and salting-out of each phase is made simultaneously and continuously by sufficient for each phase quantity of organic solvent, weakly mixable with water. 13. A process as claimed in claim 11, characterized in that after extracting and salting-out, the applicable solvent is evaporated and recycled on new operation, the organic phase is taken to commercial concentration by adding of water, and extracting water phase is crystallized, with the following obtaining of salt crystals. 14. Use of salt crystals recuperated from aqueous phase as claimed in claim 13 as fertilizer or for the industrial use. 15. A process of crystal treatment, recuperated from aqueous phase as claimed in claim 13, by electrodialysis for regeneration, from one side, of ammonia, which is recycling on neutralization stage, and, from other side, of sulphuric acid, which is, after concentration, recycled on stage of hydrolysis of 2-hydroxy-4-methylthiobutyronitril. 16. A process of crystal treatment, recuperated from aqueous phase as claimed in claim 13, by thermal method in sulphuric regeneration unit to obtain sulphuric acid solution, which is recycled on stage of hydrolysis of 2-hydroxy-4-methylthiobutyronitril.