Ethanol dehydration activity on hydrothermally stable LaP sub(x)O sub(y) catalysts synthesized using CTAB template

• Published in: Journal of porous materials Vol. 19; no. 4; pp. 423 - 431
• Main Authors: Ramesh, Kanaparthi, Goh, Yi Ling Eileen, Gwie, C G, Jie, Chang, White, Timothy John, Borgna, Armando
• Format: Journal Article
• Language: English
• Published: 01-08-2012
• Subjects: Catalysis; Catalysts; Dehydration; Ethanol; Ethyl alcohol; Ethylene; Nuclear magnetic resonance; Sol gel process
• DOI: 10.1007/s10934-011-9490-9
• EISSN: 1573-4854
• ISSN: 1380-2224

Nanocrystalline LaP sub(x)O sub(y) with various starting P to La ratios from 0.5 to 2.0 catalysts were prepared by a sol-gel method using cetyl trimethylammonium bromide (CTAB) as template. The catalysts were thoroughly characterized by N sub(2) physisorption, powder X-ray diffraction (XRD), temperature programmed desorption (TPD) of NH sub(3), solid state super(31)P and super(1)H nuclear magnetic resonance (NMR), and transmission electron microscopy (TEM) techniques. XRD results indicate the presence of predominantly monazite LaPO sub(4) with minor amounts of ( less than or equal to 3.0 wt%) rhabdophane LaPO sub(4) phase in the samples with starting P/La ratios of 1.0 and 1.5. NH sub(3)-TPD results show an increasing trend in the total acidity with increase in P/La ratio. These catalysts were tested in the selective ethanol dehydration in the temperature range between 250 and 400 degree C. The catalyst activity ( mu mol/h/m super(2)) is increased with P/La ratio and the catalyst with highest P/La ratio of 2.0 exhibiting the highest ethanol dehydration activity. The ethanol conversion increased with reaction temperature, reaching 100% at 350 degree C and remains unchanged at higher temperatures. On the other hand, the ethylene selectivity is also increased up to 350 degree C and then decreased with further increase of reaction temperature. At a P/La ratio of 2, the CTAB templated LaP sub(x)O sub(y) catalyst showed higher catalytic activities compared to the LaP sub(x)O sub(y) by hydrothermal method without any template.