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

1.丙烯氧化法合成丙烯醛和氨氧化法合成丙烯腈具有重要的工业应用价值。近年来，以丙烯为原料的丙烷合成丙烯腈的研究取得了很大进展。研究了四方晶系M^&lt；5+&Gt；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按V&GT；Mo&GT；Nb&GT；Ta顺序递减。M^&lt；5+&gt；OPO_4的催化活性取决于晶体中M^&lt；5+&gt；=0的强度。根据这些结果提出了一个表面反应模型，该模型指的是N^&lt；5+&gt；OPO_4.2的(001)面。(VO)_2P_2O_7是一种独特的催化剂，对正丁烷氧化制顺丁烯二酸酐具有极高的选择性。本文报道了(VO)_2P_2O_7与二价金属正磷酸盐混合后用于正丁烷氧化合成顺丁烯二酸酐，具有较高的选择性和活性。(VO)_2P_2O_7/M^&lt；2+&gt；_3(PO_4)_2(M^&lt；2+&gt；=Fe，Ni，Co，Zn)催化剂对正丁烷氧化制顺丁烯二酸酐具有极高的催化活性。混合催化剂中的(VO)_2P_2O_7较单一的(VO)_2P_2O_7具有更规整的(100)晶面，这种(100)晶面的规整性使得正丁烷氧化具有较高的活性和选择性。金属磷酸盐对(VO)_2P_2O_7的促进作用大小顺序为：M^&lt；2+&gt；_3(PO_4)_2&gt；M^&lt；2+&gt；_2P_2O_7&gt；M^&lt；3+&gt；PO_4。

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.