CuNiAl类水滑石的合成及其在催化氧化苯甲醇中的应用

采用水热法制备了CuNiAl类水滑石催化剂;运用电感耦合等离子体原子发射光谱、X射线衍射、傅里叶变换红外光谱和透射电子显微镜等方法对其进行表征,并用于催化苯甲醇氧化合成苯甲醛。表征结果显示,催化剂中Cu,Ni,Al的配比明显影响类水滑石的晶型结构,层间阴离子的结构决定着层间通道的大小和空间位阻。在催化苯甲醇氧化合成苯甲醛反应中,以层间阴离子为CO_3~(2-)的CuNiAl类水滑石为催化剂,且催化剂中n(Cu):n(Nj):n(Al)=0.86:0.84:1.00,在催化剂用量(占苯甲醇的质量分数)0.46%、反应温度50℃、n(H_2O_2):n(苯甲醇)=2.6、反应时间1 h的适宜条件下,苯甲醇的转化率为55.6%,苯甲醛的选择性为98.0%。该催化剂重复使用6次后仍保持较优的催化性能。

Synthesis of CuNiAl Hydrotalcites and Its Application in Catalytic Oxidation of Benzyl Alcohol

CuNiAl hydrotalcite-like compounds(CuNiAl-HT) were synthesized by hydrothermal method and were characterized by the means of ICP-AES,XRD,FTIR and TEM.CuNiAl-HTs were used as catalysts in selective oxidation of benzyl alcohol to benzaldehyde.The crystalline structures of the catalysts varied obviously according to n(Cu):n(Ni):n(Al) ratios of the catalysts.The size of interlayer space and related steric hindrance in reaction significantly depended on the structure of intercalated anions.In catalytic oxidation of benzyl alcohol to benzaldehyde,when n(Cu):n(Ni):n(Al) ratio of CuNiAl-HTs catalyst was 0.86:0.84:1.00 with CO_3~(2-) as intercalated anions and reaction was carried out under optimal conditions: catalyst dosage 0.46%(based on mass of benzyl alcohol),mole ratio of H_2O_2 to benzyl alcohol 2.6,reaction temperature 50 ℃ and reaction time 1 h,conversion of benzyl alcohol was 55.6% and selectivity to benzaldehyde was 98.0%.The catalytic activity remained after being reused 6 times.