化学学报 ›› 2013, Vol. 71 ›› Issue (05): 810-814.DOI: 10.6023/A13010107 上一篇    下一篇

研究论文

甲醇脱水制二甲醚的杂多酸/纳米HZSM-5复合固体酸催化剂

姜春杰a, 孙胜男a, 王旭阳a, 王祥生b, 郭洪臣b, 郭新闻b, 陈立东a   

  1. a 辽宁师范大学功能材料化学研究所 大连 116029;
    b 大连理工大学精细化工国家重点实验室 大连 116024
  • 收稿日期:2013-01-21 出版日期:2013-05-14 发布日期:2013-03-26
  • 通讯作者: 陈立东,lidongchhm0809@163.com; Tel.: 0411-82156915 E-mail:lidongchhm0809@163.com
  • 基金资助:

    项目受中国博士后科学基金面上项目(No. 20080441109)和国家自然科学基金(No. 21171082)资助.

Synthesis of Dimethyl Ether from Methanol over Heteropoly Acid/Nanocrystalline HZSM-5 Complex Solid Acidic Catalyst

Jiang Chunjiea, Sun Shengnana, Wang Xuyanga, Wang Xiangshengb, Guo Hongchenb, Guo Xinwenb, Chen Lidonga   

  1. a Institute of Chemistry for Functionalized Materials, Liaoning Normal University, Dalian 116029, China;
    b State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China
  • Received:2013-01-21 Online:2013-05-14 Published:2013-03-26
  • Supported by:

    Project supported by China Postdoctoral Science Foundation (No. 20080441109) and the National Natural Science Foundation of China (No. 21171082).

开发低温、高活性和良好稳定性的催化剂成为甲醇气相脱水制二甲醚乃至合成气一步法制二甲醚反应的核心.在氧化铝挤条成型的纳米HZSM-5沸石上负载Keggin结构12-磷钨酸制备了复合固体酸催化剂, 通过FT-IR、UV-Raman、31P MAS-NMR和XRD对所制备的样品进行表征. 以甲醇气相脱水制二甲醚为探针反应的研究结果表明, 在选定的操作条件下连续运转超过300 h, 甲醇摩尔转化率大于87%(理论转化率90.9%), 二甲醚摩尔选择性高于99.0%, 是目前该反应非常有效的催化剂之一.

关键词: 12-磷钨酸, 纳米HZSM-5沸石, 甲醇脱水, 二甲醚

Exploiting the catalysts with higher activity and stability for methanol dehydration at low temperature has become the central part of research dimethyl ether from synthesis gas or methanol. The crystal size of HZSM-5 zeolite is 50~100 nm. The nanocrystalline HZSM-5 zeolite is thought to be an ideal material for the encapsulation of heteropoly acid (HPA) molecules having a Keggin or Dawson structure since they have the intergranular secondary pores. A HPA/nanocrystalline HZSM-5 complex solid acidic catalyst was prepared by an impregnation method and characterized by FT-IR, UV-Raman, XRD and 31P MAS-NMR. The 12-phosphotungstic acid (HPW) loaded on nanocrystalline HZSM-5 zeolites was prepared by the following steps. The strip (ф 1 mm×2 mm) nanocrystalline HZSM-5 (Si/Al=4.2) catalyst was prepared by the procedure that reported in the literature. 1.00 g HPW was dissolved in 15 mL deionized water. 10.0 g of the strip nanocrystalline HZSM-5 zeolite were added into the solution and steeped the mixture for 12 h. The slurry mixture was calcined at 350 ℃ for 4 h. This catalyst is denoted HPW-HZSM-5. The FT-IR spectroscopy, UV-Raman spectroscopy and 31P MAS-NMR of HPW-HZSM-5 characterization results show that the Dawson type structure was well preserved after calcination of the catalysts. The reaction was carried out in a continuous flow fixed-bed reactor (diameter 10 mm). Reaction conditions are listed as following: temperature 200 ℃, WHSV=1.6, FRH (methanol flow rate)=0.08 mL/min; FRH (N2 flow rate)=8.0 mL/min; catalyst 2.05 g; system pressure 0.8 MPa. The composition of the products was analyzed by a GC-8820 gas chromatograph equipped with FID and a GDX-403 (2 m×4 mm). The reaction performance results, including methanol conversion and dimethyl ether selectivity were subsequently calculated. Under steady state conditions, the catalyst shows good stability, and the conversion of methanol maintains above 87.0 mol% (90.9 mol%) during 300 h, it also shows the selectivity (99.0 mol%) of dimethyl ether under the experimental conditions.

Key words: 12-phosphotungstic acid, nanocrystalline HZSM-5 zeolite, methanol dehydration, dimethyl ether