制备条件对Cu2O结构及甲醛乙炔化性能的影响

以Cu（NO₃）₂·3H₂O为铜源，在液相还原过程中，调变沉淀剂NaOH、还原剂L-抗坏血酸钠的加入顺序制备了Cu₂O，借助X射线粉末衍射（XRD）、傅里叶变换红外光谱（FT-IR）、拉曼光谱（Raman）、俄歇电子能谱（XAES）和H₂程序升温还原（H₂-TPR）等手段研究了制备条件对Cu₂O结构及催化甲醛乙炔化性能的影响.结果表明，调变NaOH及L-抗坏血酸钠的添加方式改变了Cu₂O的结晶度与粒径尺寸，从而使Cu₂O表现出不同的炔化性能.先加入NaOH，后加入抗坏血酸钠，Cu₂O结晶度高，粒径大，难以转化为活性物种炔化亚铜；先加入抗坏血酸钠，后加入NaOH，Cu₂O被过度还原为非活性的金属Cu，两者均造成催化剂活性较低.而NaOH和抗坏血酸钠混合后添加的方式制备出表面Cu₂O结晶完整而体相Cu₂O分散度高的样品，这使得Cu₂O高效转化为炔化亚铜活性物种，表现出最优的炔化性能，在适宜的反应条件下，1，4-丁炔二醇收率达到71.7%，经6次循环后，仍保持在56.5%.

Effect of Preparation Condition on Structure and Catalytic Performance of Cu2 O for Formaldehyde Ethynylation

Cuprous oxide (Cu₂O) samples were prepared by liquid reduction method using copper nitrate (Cu(NO₃)₂) as copper source, sodium hydroxide(NaOH) as precipitant and sodium ascrobate as reducing agent, by adjusting the addition method of precipitant and reducing agent. The effect of addition method on structure and catalytic performance of Cu₂O for formaldehyde ethynylation was investigated, combined with X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy (Raman), Auger electron spectroscopy (XAES) and H₂ temperature-programmed reduction (H₂-TPR). The results showed that the adding sequence of NaOH and sodium ascorbate played an important role in the properties and catalytic performance of Cu₂O. Cu₂O(1), prepared by adding NaOH firstly, exhibited highly crystallinity and large crystal size, which made it difficult to convert into active cuprous acetylene species. Cu₂O(3) prepared by adding sodium ascorbate firstly was excessively reduced to inactive metallic Cu⁰. Neither Cu₂O(1) and Cu₂O(3) exhibited low catalytic performance for the formaldehyde ethynylation. The Cu₂O(2), which was prepared by co-adding of NaOH and sodium ascorbate, showed high surface crystallinity and high dispersion of bulk Cu₂O, which made the Cu₂O efficiently converted into active species cuprous acetylide. The Cu₂O(2) sample showed the optimal catalytic performance for formaldehyde ethynylation. Under the suitable reaction conditions, 1,4-butynediol yield reached 71.7%, after 6 cycles, remained about 56.5%.