Studies On Cu-zirconia Catalyst For Oxidation Dehydrogenation From Diethanolamine To Iminodiacetic Acid

Iminodiacetic acid(IDA) is a widely used chemical industrial intermediate, which is mainly used for the production of herbicide glyphosate and also applied to water disposal reagents,electroplanting,pharmacy,rubber,metal manufacture and so on.So it has a larger development space in our country. Among many kinds of production of IDA,the process route of oxidation dehydrogen of diethanolamine have realised the greening production because of its simple operation,pollution-free,less equipment investment,low production cost and high yield.For improving production efficiency and marketing competitiveness of IDA,it's the key to choose high efficient and stable catalyst. So the catalyst exhibits scientific research value for oxidation dehydrogenation from diethanolamine to iminodiacetic acid.In this paper,the catalytic performance of Cu/ZrO2 and additives modified Cu/ZrO2 have been studied for oxidation dehydrogenation diethanolamine to iminodiacetic acid.The main contents and results can be summarized as follows:1. Cu/ZrO2 catalyst was prepared by coprecipitation and tested for oxidation dehydrogenation from diethanolamine to iminodiacetic acid.The results showed that the catalytic activity was influenced by the reaction material and temperature. Techniques of X-ray powder diffraction, Scanning electron microscope and N2 adsorption-desorption were used to characterize the structure and surface properties of the catalyst. The results showed that the structual changes of the catalyst was the major factor of deactivation in the reaction process.The sodium hydroxide accelerated the crystallization of catalyst and weakened the interaction between copper and zirconia, which brought about copper particles growing up and catalytic activity decreased.2. A series of CU/ZrO2 catalysts containing additives (Mn, La) were prepared by coprecipitation and tested for dehydrogenation oxidation from diethanolamine to iminodiacetic acid. The structure and surface properties of the catalysts were investegated by X-ray powder diffraction, temperature programmed reduction, N2O titration and N2 adsorption-desorption techniques. The results showed that the additive of Mn could increase the surface area of catalyst from 105 m2·g-1 to 143 m2·g-1 and the dispersion degrees of copper species from 36.5% to 53.6%; La could inhibit Cu particle from growing up and suppress the crystallization of the catalysts; The catalytic performance of La and Mn co-modified catalyst was greately improved, which showed a synergistic effect.3. Different contents additives(Mn and La) modified Cu/ZrO2 were prepared by coprecipitation and tested for dehydrogenation oxidation from diethanolamine to iminodiacetic acid.The modified catalysts were characterized by by X-ray powder diffraction, temperature programmed reduction and N2 adsorption-desorption techniques. The results showed that the CuMn2La3Zr with 2% Mn and 3% La performed the best catalytic activity in recycling process.With the contents of Mn increasing from 2% to 5%, the dispersion degree of copper was obviously increased and the particale size of copper was decreased drastically, the catalytic activity showed high initially, but declined rapidly in the recycling process,the crystallized degree of catalyst was strengthed after the 15th recycling time. With the contents of La increasing from 3% to 5%,it wasn't happened obviously different with the dispersion degree and particale size of copper,the crystallized degree of catalyst after the 15th recycling time, the catalytic performance was no longer obviously improved.