Study of the Metal Phosphate Gatalysts for Selective Oxidation of Lower Alkanes

1. 从工业角度看，丙烯氧化法合成丙烯醛和氨氧化法合成丙烯腈具有重要意义。近年来，人们在用丙烷代替丙烯合成丙烯腈方面做出了努力。本文研究了正磷酸盐正方型M^<5+>OPO_4催化剂上富丙烷的氧化和氨氧化反应。丙烷氧化脱氢制丙烯催化剂的选择性依次为V > Mo > Nb > Ta。M^<5+>OPO_4的催化活性取决于晶体中M^<5+>=0的强度。根据这些结果，提出了以N^<5+>OPO_4.2的劈裂面（001）为表面反应模型。（VO）_2P_2O_7是一种独特的催化剂，对正丁烷氧化成马来酸酐具有惊人的高选择性。本文报道了（VO）_2P_2O_7与二价金属正磷酸盐混合可选择性和活性地由正丁烷氧化合成马来酸酐。（VO）_2P_2O_7与M^<2+ bbb_3 (PO_4)_2 （M^<2+>=Fe, Ni, Co, Zn）混合的催化剂对正丁烷氧化制马来酸酐具有很高的活性。M^<2+>_3 (PO_4) _2晶粒容易被（VO）_2P_2O_7覆盖。混合催化剂中（VO）_2P_2O_7的（100）面比简单的（VO）_2P_2O_7具有更规则的结构。（100）平面的这种规律性导致了正丁烷氧化的高活性和选择性。金属磷酸盐对（VO）_2P_2O_7的促进作用依次为M^<2+>_3 (PO_4)_2 > M^<2+>_2P_2O_7 > M^<3+>PO_4。不同结构的金属磷酸盐对表面的规整程度决定了其促进效果的不同。

1. The synthesis of acrolein through propylene oxidation and acrylonitrile through ammoxidation are important from an industrial viewpoint. In resent years, efforts have been made to synthesize acrylonitrile using propane insted of propylene. We studied oxidation and ammoxidation of rich propane over orthophosphates of the tetragonal type M^<5+>OPO_4 catalysts. The selectivity of catalyst for oxivativedehydrogenation of propane to propylene decreases in the order of V > Mo > Nb > Ta. The catalytic activities of M^<5+>OPO_4 depends on the M^<5+>=0 strength in the crystal. From these results a surface reaction model is suggested which refers to the clevage (001) surface plane of N^<5+>OPO_4.2. (VO)_2P_2O_7 is a unique catalyst possessing a surprisingly high selectivity for the oxidation of n-butane to maleic anhydride. We reports that (VO)_2P_2O_7 mixed with a divalent metal orthophosphate can be used to synthesize maleic anhydride from n-butane oxidation with high selectivity and activity. The catalyst of (VO)_2P_2O_7 mixed with M^<2+>_3 (PO_4)_2 (M^<2+>=Fe, Ni, Co, Zn) has extremly high activity for n-butane oxidation to maleic anhydride. The M^<2+>_3 (PO_4) _2 grains are easly covered by the (VO)_2P_2O_7. The (100) plane of (VO)_2P_2O_7 in mixed catalysts has a more regular configuration compared to the simple (VO)_2P_2O_7. This regularity of the (100) plane causes the high activity and selectivity for n-butane oxidation. The promotion effect of the metal phosphate for (VO)_2P_2O_7 is in the order of M^<2+>_3 (PO_4)_2 > M^<2+>_2P_2O_7 > M^<3+>PO_4. The different promotion effects come from the degree of surface regularity by intercaleted metal phosphates with different structure.