V-Cr-P-O/SiO_2高分散催化剂催化甲基吡啶氨氧化反应

根据甲基吡啶衍生物中3种甲基吡啶脱α氢活性的差别,研制了对3-甲基吡啶(3-MPy)氨氧化反应选择性和收率都较高的V-Cr-P-O/SiO2系流化床氨氧化催化剂,并利用XRD,DTA,BET等技术对催化剂进行了表征。结果表明,该催化剂用于3-甲基吡啶气相氨氧化反应,连续使用210 h后,催化剂的比表面积、孔径分布和催化剂组分的分散度等变化很小,且无积碳现象,说明催化剂稳定性好,寿命较长。采用该催化剂,考察了原料摩尔比、反应温度等条件对产物收率和选择性的影响,得出了适宜的反应条件:n(空气)/n(3-MPy)为32.6、n(氨)/n(3-MPy)为4.6、反应温度360℃,在该条件下,烟腈的摩尔收率可达97.2％。经气相色谱检测,烟腈纯度大于99.0％。

Study of Ammoxidation of 3-Picoline on Well-Dispersed V-Cr-P-O/SiO2 Catalyst

A V-Cr-P-O/SiO2 catalyst of high selectivity for fluidized - bed ammoxidation of 3-picoline was prepared and characterized by XRD,DTA and BET techniques. According to lower activity of methyl-hydrogen in 3-picoline than in 2 and 4-picoline, ratio of active components in catalyst was adjusted. After 210 h of reaction changes in BET surface area, pore diameter distribution and dispersity were not substantial, and no deposition of carbon on the surface of the catalyst was observed. Thermostability of the catalyst was promising. Influence of n(air)/n (3-picoline), n (NH3)/n (3- picoline) and reaction temperature for conversion of 3 -piconine and yield of nicotinonitrile were studied. Suitable n(air)/n(3-picoline),and n (NH3)n (3-picoline) were 32.6, 4.6 respectively. Reaction temperature was 360 ℃ . Under these conditions, the molar yield of nicotinonitrile was 97.2% .The purity was over 99.0% by GC determination.