Study On The Dehydrogenating Of Diethanolamine To Iminodiacetic Salt

Dehydrogenating diethanolamine (DEA) to iminodiacetic salt by one step is a promising method which applied widely in the glyphosate industry since it has a simplified process, less equipment investment, more quickened reaction speed and it can perform efficiently under mild reaction condition. The present paper was carried out by researching the catalysts used in the reaction which two kind of catalysts Cu-Zr series and Cu-Co series was developed. We have then optimized the catalysts and made a number of explorations about the reaction condition.About catalysts of these two series, the preparations or the catalysts, the mole ratio of the metal elements, the addition of the assistants and the specified preparation conditions (such as temperature, precipitation pH value, calcinations, and reduction etc.) were investigated in detail. By all of these researchs it showed that Cu-Co series catalysts possessed a higher activity over Cu-Zr series catalysts, besides, Cu-Co series also shortened the reaction time and more easily to be separated from the product.It showed a great improvement by mixing the Cu-Co catalyst with Fe element, and by study this Cu-Fe-Co tri-component catalyst we have concluded that there was a sequence of influencing ability about the catalytic performance prepared by precipitation method that about the selectivity of product:Cu/Fe/Co mole ratio> reuction temperature>Cu2+ initial concentration> precipitation pH> calcinations temperature. About the yield:reduction temperature> Cu/Fe/Co mole ratio> precipitation pH>Cu2+ initial concentration> calcinations temperature.Different reaction conditions were studied to testify the influence upon catalytic performance in this paper, and a conclusion was drawn that the various reaction conditions mainly impacted the reaction time and then the yield and selectivity in order. At all the optimized preparation methods and reaction conditions mentioned above the best result was gained:the selectivity of iminodiacetic sodium salt 98.1%; and the yield 96.4%. With 10 times repeated reaction, the average yield was 86.5%, and the average reaction time was 2.73 h.TG/DTA, XRD, BET, ICP, H2-TPR and other analytical methods were utilized to characterize the catalysts which showed that:copper is the active centre of the catalyst; with the doping of Fe, catalyst gained a better modified surface structure, a finer redox performance, and finally it promote the copper dispersion on the surface and boost the formation of Cu-Co-O solid solution.