改性NaY分子筛上多乙苯和苯烷基转移反应性能  

Study on Transalkylation of Benzene with Diethyl/Triethyl-Benzen over Modified Y Zeolite

作　　者：郭冬冬[1,2] 杨为民[1] 曹锋[3] 宦明耀[1] 张斌[1] 孙洪敏[1] 卢冠忠[2] 

机构地区：[1]中国石油化工股份有限公司上海石油化工研究院绿色化工与工业催化国家重点实验室,上海201208 [2]华东理工大学化学与分子工程学院工业催化研究所,上海200237 [3]华东理工大学化工学院,上海200237

出　　处：《化学反应工程与工艺》2016年第5期423-431,共9页Chemical Reaction Engineering and Technology

摘　　要：为了提高烷基转移催化剂性能性,以不同骨架硅铝比的NaY分子筛为原料,利用"两交-水热-焙烧"后改性工艺得到了一系列USY分子筛。通过X射线衍射(XRD)、N_2-物理吸附、扫描电镜(SEM)、氨气程序升温脱附(NH_3-TPD)、吡啶吸附红外光谱(Py-IR)等表征手段研究了各USY分子筛的骨架硅铝比、孔结构特征以及酸性质,考察了各USY分子筛上苯与多乙苯烷基转移反应性能。结果表明:以骨架硅铝比为5.9的NaY分子筛为原料进行水热处理改性,有利于保持微孔结构且制得的USY分子筛比表面积和介孔量大、所含强B酸中心比例较高(B酸/L酸比为1.01),提高了活性位的可接近性及扩散能力,而且强B酸中心为苯与多乙苯烷基转移反应提供比较充足的活性位。在反应温度170℃、反应压力3 MPa、苯与多乙苯质量比2、质量空速为3.3 h^(-1)的实验条件下,二乙苯转化率和三乙苯转化率分别达到了67%和55%以上,乙苯选择性达到了99%以上。因此进一步调变NaY分子筛的合成工艺,合成具有较高骨架硅铝比的Y型分子筛可提高烷基转移催化剂的活性。In order to improve the performance of the transalkylation catalyst, a series of ultra stable Y（USY） molecular sieves were obtained by the modification process of NaY zeolite with different molar ratios of framework SiO2/Al2O3（5.0, 5.5, and 5.9） and ＂the combination of NH4-＋ ion exchange and hydrothermal-thermal treatments＂. The framework of each USY molecular sieve was characterized by X-ray diffraction（XRD）, N2-physical adsorption, scanning electron microscopy（SEM）, temperature programmed desorption（NH3-TPD）, pyridine adsorption infrared spectroscopy（Py-IR）, and the catalytic performance on the USY molecular sieves was evaluated during diethyl/triethylbenzene-benzene transalkylation. The results showed that the hydrothermal modification of NaY zeolite with SiO2/Al2O3 ratio of 5.9 was beneficial to maintain the microporous structure and the prepared USY molecular sieve had a large specific surface area and mesopore volume and a high ratio of strong Br？nsted acid sites（Brnsted/Lewis ratio of 1.01）, which enhanced the accessibility of the active sites and the diffusion capacity. In addition, strong acid sites can also provide sufficient active sites for benzene and poly ethylbenzene transalkylation reactions. Under the experimental conditions of reaction temperature 170 ℃, reaction pressure 3 MPa, mass ratio of benzene to polyethylbenzene 2 and mass space velocity of 3.3 h^-1, the conversion of diethylbenzene and triethylbenzene reached over 67% and 55%, ethylbenzene selectivity reached 99%. Therefore, further adjustment of the synthetic process of NaY zeolite to synthesize higher ratio Si/Al Y zeolite can improve the activity of the transalkylation catalysts.

关 键 词：水热改性 USY分子筛 酸性 烷基转移 

分 类 号：O643.36[理学—物理化学]