催化学报

催化学报 ›› 2011, Vol. 32 ›› Issue (3): 405-411.DOI: 10.1016/S1872-2067(10)60188-X

• 研究论文 • 上一篇    下一篇

碱土金属修饰 NaY 分子筛催化乳酸脱水制丙烯酸: 碱性位对催化活性的影响

闫婕 1, 余定华 1,2, 孙鹏 1, 黄和 1,2   

  1. 1南京工业大学生物与制药工程学院, 江苏南京 210009; 2南京工业大学材料化学工程国家重点实验室, 江苏南京 210009
  • 收稿日期:2010-10-28 修回日期:2010-11-22 出版日期:2011-03-04 发布日期:2014-08-01

Alkaline Earth Metal Modified NaY for Lactic Acid Dehydration to Acrylic Acid: Effect of Basic Sites on the Catalytic Performance

YAN Jie1, YU Dinghua1,2, SUN Peng1, HUANG He1,2,*   

  1. 1College of Biotechnology and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing 210009, Jiangsu, China;  2State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, Nanjing 210009, Jiangsu, China
  • Received:2010-10-28 Revised:2010-11-22 Online:2011-03-04 Published:2014-08-01

PDF

1145

被引次数

31

摘要： 采用碱土金属 (Mg, Ca, Sr, Ba) 对 NaY 分子筛进行改性, 并采用氮气物理吸附、X 射线衍射、氨气及二氧化碳程序升温脱附等技术对样品进行了表征, 考察了阳离子物种对 NaY 结构、表面酸碱分布等的影响, 以进一步甄别影响催化剂活性的关键因素. 结果表明, 阳离子物种所引入的碱性位尤其是中强碱性位控制着丙烯酸的生成, 而表面酸性位则影响乙醛的生成. 当以钡含量为 2% 的 NaY 分子筛为催化剂, 在乳酸进料浓度为 38%, 进料空速为 3 h-1 及 325 °C 反应条件下, 丙烯酸收率最高, 为 44.6%. 这归结于该催化剂表面具有最多的中强碱性位, 且表面 Ba2+ 簇具有合适的 Ba–O 键长及碱度.

关键词: 碱土金属, 碱性位, NaY 分子筛, 乳酸, 脱水, 丙烯酸

Abstract: Various NaY zeolites modified by alkaline earth metals (Mg, Ca, Sr, and Ba) were synthesized and used as catalysts for the dehydration of lactic acid to acrylic acid to investigate the effects of cationic species on the structure and surface acid/base distribution of the NaY zeolites. The important factors that affect their catalytic performance were also identified. The catalysts were characterized by N2 physical adsorption/desorption, X-ray diffraction, temperature-programmed desorption of NH3, and temperature-programmed desorption of CO2. The results show that the basic sites that are induced by modified metallic species, particularly the medium basic sites, are mainly responsible for the formation of acrylic acid. The generation of acetaldehyde was affected by the acidic sites. Among the catalysts, 2%Ba/NaY showed the highest yield of acrylic acid at up to 44.6% (38% solution, LHSV = 3 h–1, 325 °C) because it contained the most medium basic sites and a suitable Ba2+ cluster character.

Key words: alkaline earth, basic site, NaY zeolite, lactic acid, dehydration, acrylic acid