| Iminodiacetic acid, namely IDA, is an important fine chemical product. IDA has a widely use and was used mainly to produce glyphosate, a pesticide. Currently, IDA is demanded more and more greatly in home, but methods, such as chloroacetic acid method, used to manufacture IDA in domestic companies were traditional, with a low yield and lack of quality competition, greatly environment polluting, falling short of the demand of clear manufacture. Dehydrogen oxidating diethanolamine to prepara -tion IDA, one of many methods to generate IDA, with a high yield, purity and pollut -antlessness, has a great potential to put into industrial production. But this method has a deadly disadvantage, that is catalyst Raney Cu used in this method had a bad repeatedly use performance and used in great amount. And this disadvantage impedes its production in industry.Glyphosate, first invented by Monsanto (U.S. Co.) in 1971, is herbicide and uses world widely. And nowadays its worldwide output is amount to 300,000 tons, one third of worldwide herbicide total output. Glyphosate manufactured through IDA method is used overwhelming in abroad companies. Compared with abroad companies, most our domestic companies take Glycine method as choice to manufacture glyphosate. Glycine method has many disadvantages, such as long industrial flow, lower product quality competition and great pollution. So it is emergent to popularize IDA method to produce glyphosate in home companies.In order to popularize IDA method producing Glyphosate, new method manufacturing IDA should be found. In this study, a new method to prepare IDA with hydroxynitrile was presented and IDA was successfully synthesize by using this new method,. By adding an inhibitor, ammonia and hydroxynitrile were ammonolyzed at -7℃ to produce a intermediate iminodiacetonitrile. After 20min heat preservation reaction (HPR), iminodiacetonitrile was hydrolyzed by alkali at 102℃ to produce a salt of disodium iminodiacetic acid. Sulfuric acid was added to the solution to neutralize to the isoelectric point of iminodiacetic acid (IDA), and IDA crystallizedfrom the solution. The product IDA was achieved after decolorizing, recrystallizing, filtering and drying. The rough yield and content of IDA are 85% and 89.3%, respectively. And the content attains 99.3% after refiningAt the same time, method to produce IDA by diethanolamine dehydrogen oxidating was also studied. The influence of systemic pressure, amount of catalyst and manner of adding catalyst Raney Cu were investigated and more attention were paid to the regeneration of catalyst Raney Cu. The results show that the activity of catalyst Raney Cu would be ultimately recovered by three steps, which are washing with 1% sulfuric acid, resolving coke with refluxing benzene and reduce with 40% formic acid. Raney copper regenerated by this method can be used repeatedly for 15 times with an average rough yield 92.3% of IDA. Also technical and economical evaluations were carried, compared with the new method presented above.In the end, we did research on the synthesis of glyphosate with disodium iminodiacetic acid. The results show that N-phosphonomethyliminodiacetic acid, namely PMIDA, would get higher yield by a manner of adding 20% overuse of phosphorus trichloride with half amount of disodium iminodiacetic acid at the same time, 30% overuse of formaldehyde and 20min HPR. Using this method, the rough yield of PMIDA can be amount to 97.4%. And also the results show that glyphosate would achieve better yield by a way of adding 20% overuse of hydrogen peroxide, oxidating at 65 ℃ and 1.5hrs HPR. The rough yield 90% and the content of glyphosate is 93.5% after refining. |
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