Dawson结构杂多磷钨酸钠催化氧化噻吩脱硫

Thiophene Oxidative Desulfurization Catalyzed by Sodium Phosphotungstate with Dawson Structure

以钨酸、磷酸二氢钠为原料,通过水热法合成了 Dawson 结构杂多磷钨酸钠(P_2W_(18))。以 P_2W_(18)为催化剂、无水乙醇为助催化剂、质量分数30%的过氧化氢水溶液为氧化剂,在温和条件下将模拟燃油中的噻吩氧化为砜类:亚砜类等极性较强的物质,并以 N,N-二甲基甲酰胺为萃取剂将其萃取出来,考察了反应温度、反应时间、过氧化氢水溶液用量、萃取剂用量和萃取级数对脱硫率的影响。在模拟燃油(硫含量500 mg/L)20 mL、P_2W_(18)0.030 g、无水乙醇1.2 mL、过氧化氢水溶液0.12 mL、反应温度310 K、反应时间60 min、萃取剂与油相的体积比1.0、萃取3次的优化条件下,脱硫率达96.7%。反应结束后,可通过简单的倾倒将模拟燃油与催化剂分离,催化剂可重复使用5次,稳定性较好。

Sodium Phosphotungstate（ P2W18 ）with Dawson structure were synthesized from H2WO4 and NaH2PO4 under conventional hydrothermal conditions in acidic solution. The P2W18 catalyst was applied in catalytic oxidative desulfurization and characterized by means of IR. Using PEW18 with Dawson structure and C2H5 OH as amphiphilic catalyst,30% （w） hydrogen peroxide as oxidant, under mild conditions, thiophen in model fuel was converted into sulfones which was extracted by N, N- dimethylformamide （DMF）. Effects of reaction temperature, reaction time, hydrogen peroxide dosage, DMF dosage and extraction times on desulfurization rate were investigated. Under optimal reaction conditions： 20 mL model fuel with 500 mg/L sulfur, 0. 030 g P2W18, 1.2 mL C2H5OH, 0.12 mL 30% （w） hydrogen peroxide solution, reaction temperature 310 K and reaction time 60 rain, extraction for three times with DMF（ V（DMF） ： V（oil） = 1.0）, desulfurization rate is 96.7%. Model fuel and catalyst were separated by decantation after reaction. The catalyst can be reused for five times without obvious change in catalytic activity.