A new method to prepare Cu/ZrO2 catalysts by reducing CuO/ZrO2 with hydrazine hydrate is reported, and the prepared catalysts were used to synthesize disodium iminodiacetate by diethanolamine dehydrogenation. Hydrazine hydrate can rapidly reduce the CuO/ZrO2 precursor powder in an alkaline environment at a moderate temperature. The ratio of Cu0/Cu+ at the Cu/ZrO2 surface was controlled by the amount of hydrazine hydrate and the reduction reaction time. The formation mechanism of disodium glycine as the main byproduct and iminodiacetate were deduced by investigating the product yield, the reaction time, and the presence of acetaldehyde in the evolved gas. It has been shown that the ratio of Cu0/Cu+ in Cu/ZrO2 significantly affects the dehydrogenation of diethanolamine into disodium iminodiacetate. Cu0 and Cu+ are the catalytic activity centers in the dehydrogenation of diethanolamine which respectively produce intermediate aldehydes and an ester via nucleophilic addition reactions. The formation mechanism of sodium glycinate is related to the tautomerism of intermediate products and Schiff base hydrolysis. The formation mechanism of disodium iminodiacetate and sodium glycine producing by the dehydrogenation of diethanolamine over the Cu/ZrO2 catalysts which were prepared by a new reduction method.

中文翻译：

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Cu/ZrO2催化剂结构及亚氨基二乙酸二钠和甘氨酸钠的形成机理研究

报道了一种用水合肼还原CuO/ZrO2制备Cu/ZrO2催化剂的新方法，所制备的催化剂用于二乙醇胺脱氢合成亚氨基二乙酸二钠。水合肼可以在中等温度的碱性环境中快速还原 CuO/ZrO2 前驱体粉末。Cu/ZrO2表面的Cu0/Cu+比受水合肼用量和还原反应时间的控制。通过考察产物收率、反应时间和放出气体中乙醛的存在，推断了作为主要副产物的甘氨酸二钠和亚氨基二乙酸盐的形成机制。已经表明，Cu/ZrO2 中的 Cu0/Cu+ 比显着影响二乙醇胺脱氢成亚氨基二乙酸二钠。Cu0和Cu+是二乙醇胺脱氢的催化活性中心，通过亲核加成反应分别生成中间体醛和酯。甘氨酸钠的形成机理与中间产物的互变异构和席夫碱水解有关。二乙醇胺在新还原法制备的Cu/ZrO2催化剂上脱氢生成亚氨基二乙酸二钠和甘氨酸钠的生成机理。