正丁烷氧化制顺酐磷—钒催化剂的制备和活化

用XRD、IR、XPS和ESR等方法,考察了以草酸、盐酸羟氨、盐酸联氨和异丁醇分别作还原剂制备的磷-钒催化剂在不同条件下活化及用于正丁烷氧化制顺酐反应后的相组成和催化剂的性能。实验结果表明,影响顺酐收率的主要因素是催化剂的相组成及钒的氧化态,而不是催化剂的比表面积。在催化剂制备过程中,所用还原剂的种类以及活化条件对催化剂的性能都有重要影响。

THE PREPARATION AND ACTIVATION OF VANADIUM-PHOSPHORUS CATALYSTS FOR n-BUTANE OXIDATION TO MALEIC ANHYDRIDE

Five vanadium- phosphorus catalysts have been prepared and activated. Experimental results of using the catalysts for the oxidation of n -butane to maleie anhydride and the XRD, IR, XPS and ESR studies of the catalysts showed, that hydroxylamine, hydrazine, isobutanol and benzalcohol are better reducing agents than oxalic acid, and activation of the catalysts in nitrogen atmosphere and in a 1.5% n- butane -air mixture excelled that in air. The main factor influencing the yield of maleic anhydride is the phase composition or oxidation state of vanadium in the catalyst, and is not the BET surface area of the catalyst. A good catalyst was composed of well -crystallized (VO)_2P_2O_2 and an amorphous a-VOPO_4 phase. The use of organic solvents can lead to increased surface area but does not always improve catalytic performance.