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本文采用吡啶中毒脉冲色诏技术,在440～500℃范围的反应条件下,考察了 Ni—Y 分子筛的甲苯脱烷基反应表面活性中心及其催化作用.结果表明:Br(?)nsted 酸和 Lewis 酸均有催化作用.但活性规律不尽一致,它们对脱烷基反应的贡献又随温度的变化出现相反结果,在465℃以下时 B酸中心起主要作用.而在490℃以上 L 酸中心的作用占主导地位,在480℃左右二者的作用相当.催化剂再生实验指出,吡啶在 Ni—Y 上的吸附具有一定可逆性.对脉冲中毒催化剂进行红外光谱检测,发现1450.4Cm~(-1)和1536.3Cm~(-1)处有吡啶分子与 L 酸和 B 酸作用的特征吸收带,给出了L 酸和 B 酸含量之比 C_L/C_B=1.68,相对含量 C_L%=62.69%,C_B%=37.31%.
In this paper, pyridine poisoning pulse Chao technique was used to study the catalytic activity of toluene dealkylation reaction of Ni-Y molecular sieves under the reaction conditions of 440 ~ 500 ℃. The results showed that Br (?) Nsted acid and Lewis acids all catalyzed, but the activity rules were not consistent, and their contribution to dealkylation reaction had the opposite result with the change of temperature. The B acid center played a major role below 465 ℃, whereas the L acid The central role played a dominant role at about 480 ° C. The catalyst regeneration experiment indicated that the adsorption of pyridine on Ni-Y was reversible.Fluorescence spectroscopy of pulsed poisoning catalysts showed that 1450.4Cm ~ (- 1) and 1536.3cm -1, the ratio of L-acid to B-acid is C_L / C_B = 1.68 and the relative content C_L% is 62.69% , C_B% = 37.31%.