In the present study, N-methyldiethanolamine (MDEA) is demonstrated to be a multifunctional structure-directing agent for the synthesis of aluminophosphate-based molecular sieves. Four types of molecular sieves, including SAPO-34, -35, AlPO-9 and -22, are for the first time acquired with MDEA as a novel template. The phase selectivity of the present synthesis is found to be condition-dependent. SAPO-34 (CHA) crystallizes from a conventional hydrothermal system with a higher MDEA concentration. When using MDEA as both the template and solvent, pure SAPO-35 (LEV) is obtained from the synthetic gel with a high P2O5/Al2O3 ratio of (2-3), in which the concentration of MDEA could be varied in a wide range. AlPO-9 and AlPO-22 (AWW) are synthesized under the similar conditions to SAPO-35, except without the addition of Si source. The physicochemical properties of the obtained samples are investigated by XRD, XRF, SEM, N-2 physisorption. TG-DSC, and various NMR spectra (C-13, Si-29, Al-22 and P-31). Both SAPO-34 and SAPO-35 show good thermal stability, large surface area, and high pore volume. The catalytic performance of SAPO-34 is evaluated by the methanol-to-olefins (MTO) reaction and a good (C2H4 + C3H6) selectivity of 82.7% has been achieved. (C) 2014 Elsevier Inc. All rights reserved.
1.Chinese Acad Sci, Dalian Inst Chem Phys, Natl Engn Lab Methanol Olefins, Dalian 116023, Peoples R China 2.Chinese Acad Sci, Dalian Inst Chem Phys, Dalian Natl Lab Clean Energy, Dalian 116023, Peoples R China 3.Chinese Acad Sci, Grad Univ, Beijing 100049, Peoples R China
Recommended Citation:
Wang, Dehua,Tian, Peng,Fan, Dong,et al. N-methyldiethanolamine: A multifunctional structure-directing agent for the synthesis of SAPO and AlPO molecular sieves[J]. JOURNAL OF COLLOID AND INTERFACE SCIENCE,2015,445:119-126.
