Pd(Ni)对铜基催化剂的调变及对顺酐选择性加氢产物的调控

Effects of Adding Pd or Ni in Cu-Ti-Al-O Catalyst on Regulating Products in Selective Hydrogenation of Maleic Anhydride

考察了在Cu Ti Al O催化剂中添加Pd(或Ni)对活性中心Cu的调变作用及对顺酐加氢产物的调控 .结果表明 ,Cu Ni Ti Al O是优良的顺酐选择性加氢制γ 丁内酯 (GBL)反应的催化剂 ,催化剂中Cu和Ni含量的改变会影响加氢深度 .当Cu含量较Ni含量高时 ,可以得到第三步加氢产物 1,4 丁二醇和四氢呋喃 ,在 2 70℃下其选择性为 17 3% ;当Ni含量较Cu含量高时 ,GBL选择性可达到 10 0 % .添加微量的Pd后 ,可加速活性组分Cu的还原 ,使Cu的还原更加彻底 ,获得纳米尺寸更小和晶格畸变率更大的Cu0 晶粒 ,使顺酐第三步加氢产物的选择性显著提高 .使用Cu Pd Ti Al O(n(Pd) /n(Cu) =0 0 8% )催化剂 ,在 2 40℃下顺酐转化率为 10 0 % ,1,4 丁二醇与四氢呋喃选择性为 38 5 % .

The selective hydrogenation of maleic anhydride over copper-based catalyst supported on TiO 2-Al 2O 3 was studied at 200～280 ℃ and atmospheric pressure, and palladium or nickel as the promoter was added in the catalyst. In the reaction, there are many products, such as 1,4-butanediol, tetrahydrofuran, γ-butyrolactone and so on. Cu-Ni/TiO 2-Al 2O 3 exhibits excellent catalytic performance for hydrogenation of maleic anhydride, and the change of the loading of CuO or NiO affects the product distribution. When the loading of CuO is higher than that of NiO, 1,4-butanediol and tetrahydrofuran are obtained with ～17.3% total selectivity at 270 ℃; When the loading of NiO is higher than that of CuO, the selectivity for γ-butyrolactone reaches 100% with 100% conversion of maleic anhydride. Adding Pd into Cu/TiO 2-Al 2O 3 catalyst makes the selectivity for 1,4-butanediol or tetrahydrofuran increase remarkably, such as at 240 ℃ using Cu-Pd/TiO 2-Al 2O 3 ( n(Pd)/ n(Cu)=0.08%) catalyst, 38.5% selectivity for 1,4-butanediol and tetrahydrofuran with 100% conversion of maleic anhydride is obtained, but using Cu/TiO 2-Al 2O 3 catalyst, the selectivity for 1,4-butanediol and tetrahydrofuran is zero. The presence of Pd in CuO/TiO 2-Al 2O 3 can promote the reduction of Cu + and Cu 2+ to Cu 0 obviously, which enable the crystallite size of Cu 0 in the catalyst to decrease from 9.1 nm to 2.4 nm and the micro-strain value of Cu 0 to increase from 0.32×10 -3 to 5.8×10 -3. This leads that the catalyst with Pd behaves much higher activity than that without Pd.