HZSM-5沸石分子筛上苯酚与甲醇的烷基化反应  

Study on Methylation of Phenol with Methanol over HZSM-5 Zeolite

作　　者：张悝[1] 项寿鹤[2] 张怀彬[2] 刘上垣[2] 李赫咺 

机构地区：[1]天津大学化工学院一碳化学与化工国家重点实验室,天津300072 [2]南开大学化学院,天津300071

出　　处：《催化学报》2001年第6期545-549,共5页

摘　　要：在n(PhOH) /n(CH3OH) =1,WGSV =0 5h-1,T =6 73K的反应条件下 ,研究了HZSM 5 ,HZSM 2 3和改性HZSM 5分子筛上苯酚与甲醇烷基化反应的规律 .结果表明 ,分子筛外表面的酸中心对苯酚烷基化反应的贡献较大 .用 4 甲基喹啉使分子筛外表面的酸中心中毒后 ,影响反应产物选择性的主要因素是分子筛的孔径 .孔径较小的HZSM 2 3分子筛对提高芳香醚的选择性 ,抑制二甲酚的生成和提高对甲酚的选择性有利 .间甲酚和二甲酚可以在HZSM 5沸石的孔道内生成 ,但在HZSM 2 3的孔道内受到抑制 .用P2 O5,MgO和Sb2 O3 对HZSM 5改性都可以提高芳香醚的选择性 ,降低甲酚和二甲酚的选择性 .随着氧化物负载量的增加 ,邻甲酚选择性升高 .适度的氧化物改性可以提高对甲酚的选择性 ,改性效果为Sb2 O3>P2 O5>The methylation of phenol with methanol over HZSM-5, HZSM-23, and modified HZSM-5 with P2O5, MgO, and Sb2O3 was investigated under the reaction conditions of n (PhOH)/n(CH3OH) = 1, WHSV = 0.5 h(-1) and T = 673 K. The results revealed that the acid sites on the external surface of HZSM-5 and HZSM-23 played an important role in the reaction. When the zeolite was treated with 4-methylquinoline, the pore size of the zeolite was the key factor affecting the product selectivity. The HZSM-23 zeolite with smaller pore size than HZSM-5 zeolite was beneficial to enhancement of the selectivity for anisole plus methylanisole, as well as p-cresol. Xylenol and m-cresol could be formed in the pores of HZSM-5, while their formation in the pores of HZSM-23 was strongly inhibited. The modification of HZSM-5 with P2O5, MgO and Sb2O3 could increase the selectivity for anisole plus methylanisole. However, the modification of HZSM-5 decreased the selectivity for xylenol and cresol. Increasing the amount of those oxides could enhance the selectivity for o-cresol. Moderate impregnation of HZSM-5 zeolite with the oxide solution could improve the selectivity for p-cresol, and the modification effect had the sequence: Sb2O3 > P2O5 > MgO.

关 键 词：HZSM-5沸石 HZSM-23沸石 五氧化二磷 氧化镁 三氧化二锑 苯酚 甲醇 甲酚 烷基化反应 分子筛催化剂 改性 

分 类 号：O643.3[理学—物理化学]