An efficient rhenium oxide-modified H3PW12O40/TiO2 catalyst is found for a new synthesis of dimethoxy dimethyl ether from dimethyl ether oxidation. The effects of Re loading, H3PW12O40 content and different feedstocks on the performance of Re–H3PW12O40/TiO2 were investigated. The results showed that DMM2 selectivity was significantly improved up to 60.0%, with 15.6% of DME conversion over 5% Re–20% H3PW12O40/TiO2. NH3-TPD, NH3-IR, Raman spectra, H2-TPR, XPS and TEM were used to extensively characterize the structure and surface properties of the catalysts. The introduction of H3PW12O40 significantly affected the structure and reducibility of surface rhenium oxide species, in addition to increasing the acidity of the catalyst. The increased number of Lewis acid sites and weak acid sites and the optimal ratio of Re4+/Re7+ of Re–H3PW12O40/TiO2 were favorable for the formation of DMM2 from DME oxidation. The possible reaction pathway of DME oxidation to DMM2 was proposed.
发现了一种高效的
铼氧化物修饰的H3PW12O40/TiO2催化剂,可用于从二
甲醚氧化合成二甲氧基二
甲醚。研究了
铼负载量、H3PW12O40含量及不同原料对Re–H3PW12O40/TiO2催化剂性能的影响。结果显示,5% Re–20% H3PW12O40/TiO2催化剂的二
甲醚转化率为15.6%,而
DMM2选择性显著提高至60.0%。研究使用了NH3-
TPD、NH3-IR、拉曼光谱、H2-TPR、XPS和
TEM等方法对催化剂的结构和表面特性进行了广泛表征。H3PW12O40的引入显著影响了表面
铼氧化物物种的结构和可还原性,同时增加了催化剂的酸度。Lewis酸位点和弱酸位点的数量增加,以及Re–H3PW12O40/TiO2中Re4+/Re7+的最佳比率,有利于二
甲醚氧化生成
DMM2。提出了二
甲醚氧化生成
DMM2的可能反应路径。