Cu/CeO_2催化剂催化二乙醇胺脱氢制亚氨基二乙酸

Dehydrogenation of Diethanolamine to Iminodiacetic Acid over Cu/CeO_2 Catalysts

以硝酸铜和硝酸铈为原料,采用共沉淀法制备系列Cu/CeO_2催化剂。并用物理吸附(BET)、X射线衍射(XRD)、H2程序升温还原(H2-TPR)对催化剂的结构和还原性进行了表征,考察了其在二乙醇胺脱氢制亚氨基二乙酸反应中的催化性能。结果表明,经500℃焙烧、铜铈物质的量比为3∶1的Cu_3Ce_1催化剂还原温度最低,为230℃,且Cu_3Ce_1还原后表面有适量Cu活性中心,Cu_3Ce_1催化剂在二乙醇胺(DEA)脱氢制亚氨基二乙酸的反应中具有较好催化活性。该催化剂最适宜的反应条件为:m(DEA)∶m(Na OH)∶m(H2O)=1.15∶1.00∶2.42,催化剂用量6 g,反应温度180℃,反应压力1.1 MPa,反应时间4 h,搅拌转速600 r/min,Cu_3Ce_1催化剂上二乙醇胺的转化率为99.63%,亚氨基二乙酸选择性为95.73%,Cu_3Ce_1催化剂重复使用9次,无明显失活。

A series of Cu/CeO_2 catalysts were prepared by co-precipitation method using copper（ Ⅱ）nitrate hydrate and cerium（ Ⅲ） nitrate hexahydrate as raw materials. The structure and reduction properties of the catalysts were characterized by Brunauer-Emmett-Teller（ BET） nitrogen adsorptiondesorption,X-ray diffraction（ XRD） and hydrogen temperature programmed reduction（ H2-TPR）. The catalytic performance of Cu/CeO_2 catalysts for the dehydrogenation of diethanolamine（ DEA） to iminodiacetic acid was investigated. The results showed that Cu_3Ce_1 catalyst calcined at 500 ℃ with copper and cerium mole ratio of 3 ∶ 1 had the lowest reduction temperature of 230 ℃. There were appropriate Cu0 active centers over the reduced Cu_3Ce_1 catalyst,and this catalyst exhibited higher catalytic performance for the synthesis of iminodiacetic acid from diethanolamine via dehydrogenation.The optimum synthesis conditions for iminodiacetic acid over Cu_3Ce_1 catalyst were obtained as follows：m（ DEA） ∶ m（ Na OH） ∶ m（ H_2O） = 1. 15 ∶ 1. 00 ∶ 2. 42,dosage of catalyst 6 g,reaction temperature 180℃,reaction pressure 1. 1 MPa,reaction time 4 h,and agitation speed 600 r/min. Under the abovementioned conditions,the conversion of diethanolamine reached 99. 63%,and the selectivity of iminodiacetic acid was 95. 73%. The deactivity of Cu_3Ce_1 catalyst was not observed as the catalyst was reused 9 times.