固体碱负载酞菁钴硫醇氧化催化剂的研究

将CoPc(SO3Na) 4 或CoPcN(CH3) 3I]4 和CoPc(SO3Na) 4 二元混合物 ,负载在Mg(Al)O载体上制成的催化剂 ,能有效脱除喷气燃料中的硫醇。后者的催化活性和稳定性优于前者。Mg(Al)O负载CoPc(SO3Na) 4 催化剂运转32 4h后活性下降 ,脱硫醇率低于 60 % ,硫醇硫质量分数高于 2× 1 0 - 5;而Mg(Al)O负载二元混合物催化剂在运转4 80h后 ,脱硫醇率仍可达 85% ,硫醇硫质量分数低于 1 4× 1 0 - 5。XRD和ESR表征表明 ,前者活性下降的原因主要是Mg(Al)O载体上酞菁钴分子聚集。用带有正电荷和负电荷基团的二元水溶性酞菁钴混合物制备催化剂可在一定程度上抑制酞菁钴分子的聚集 ,改善催化剂的性能。

Basic Calcined Mg-Al Hydrotalcite Supported Cobaltphthalocyanines Catalysts for Mercaptan Autoxidation

Two catalysts for mercaptan autoxidation have been prepared by supporting cobaltphthalocyanine tetrasodium sulphonate CoPc(SO_3Na)_4 and an equimolar mixture of cobaltphthalocyanine tetrasodium sulphonate CoPc(SO_3Na)_4 and cobaltphthalocyanine tetra(trimethylammonium) iodide CoPcN(CH_3)_3I]_4 on basic mixed Mg-Al oxide (denoted as Mg(Al)O) derived from thermal decomposition of Mg-Al hydrotalcite n(Mg)/n(Al).The resulting catalysts,which possess Co(Ⅱ) oxidation sites and Mg(Al)O basic sites,are effective in sweetening jet kerosene,and clean kerosene with a mercaptan level of less than 2×10~-5 sulfur has been obtained over these two catalysts at 40 ℃.The latter catalyst containing CoPc(SO_3Na)_4 and CoPcN(CH_3)_3I]_4 is much more active and stable than the former one containing only CoPc(SO_3Na)_4.The Mg(Al)O-supported CoPc(SO_3Na)_4 deactivated after being operated in the kerosene flow for 324 h,with less than 60% of the mercaptans being converted to disulfides.However,Mg(Al)O-supported CoPc(SO_3Na)_4 and CoPcN(CH_3)_3I]_4 catalysts,even after being used for 480 h,were still able to oxidize about 85% of mercaptans in kerosene,and clean products containing less than 1.4×10~-5 of mercaptan-sulfur were obtained.The catalysts before and after autoxidation of mercaptan were characterized by means of XRD and ESR.It is shown that the deactivation of Mg(Al)-O-supported CoPc(SO_3Na)_4 catalyst is probably due to the aggregation of CoPc(SO_3Na)_4 molecules on Mg(Al)O.All these results show that it is a better way to prepare the catalysts using an equal amount of the two oppositely charged water-soluble cobaltphthalocyanines:CoPc(SO_3Na)_4 and CoPcN(CH_3)_3I]_4.This prevents to some extent the aggregation of Co(Ⅱ) centers and the formation of less active peroxocomplex:—Co(Ⅲ)—O—O—Co(Ⅲ)—,thus obtaining catalysts with higher activity and stability compared to that using CoPc(SO_3Na)_4 only.