Kondam Madhusudan Reddy

Synthesis of mesoporous molecular sieves : influence of aluminum source on Al incorporation in MCM-41

Three series of mesoporous aluminosilicate molecular sieves, MCM-41, with various Si/Al ratios were synthesized using different aluminum sources (aluminum isopropoxide, pseudo boehmite and aluminum sulfate). XRD analysis, temperature programmed desorption ofn-butylamine,27Al and29Si MAS NMR, and catalytic alkylation test indicated that aluminum isopropoxide is a better source for incorporating aluminum in the framework of MCM-41 type molecular sieves with better crystallinity and acid characteristics.

Synthesis of mesoporous zeolites and their application for catalytic conversion of polycyclic aromatic hydrocarbons

Abstract Three series of mesoporous aluminosilicate (Al-MCM-41) samples were synthesized using different aluminum sources including aluminum isopropoxide, pseudo boehmite and aluminum sulfate. Their catalytic activities were tested in the conversion of aromatic hydrocarbons including hydrocracking of 1,3,5-triisopropylbenzene, alkylation of naphthalene, and hydrogenation of naphthalene and phenanthrene. The three series of Al-MCM-41 samples behaved differently in acting as acidic catalysts and as supports. The Al-MCM-41 synthesized using aluminum isopropoxide was found to be the most promising acidic catalyst and good support for Pt catalyst.

Effect of Al Sources on the Synthesis and Acidic Characteristics of Mesoporous Aluminosilicates of MCM-41 Type

This paper reports the synthesis of four series of mesoporous aluminosilicates (Al-MCM-41) and their acidic characteristics. Four different Al compounds were examined as Al source in the hydrothermal synthesis of Al-MCM-41, including pseudo boehmite, aluminum sulfate, aluminum isopropoxide, and sodium aluminate. Synthesized samples were characterized by XRD, chemical analysis, nitrogen adsorption, and 27A1 MAS NMR. The acidic characteristics of the Al-MCM-41 samples were characterized using temperature- programmed desorption of n-butylamine, and probe hydrocracking reactions of 1,3,5- triisopropylbenzene and 1,3,5-tri-t-butylbenzene. The results clearly indicate that the Al source used for synthesizing Al-MCM-41 samples has a major impact on the Al incorporation in their framework and their acidic properties. Al-MCM-41 prepared with Al isopropoxide and sodium aluminate showed improved acidic properties than those with pseudo boehmite and Al sulfate.

Shape-selective Fe-MFI catalyst for synthesis of 2,6-dimethylnaphthalene by methylation with methanol

The present study deals with shape-selective methylation of naphthalene for synthesis of 2,6-dimethylnaphthalene (2,6-DMN), and focuses on the Fe-MFI (Fe-ZSM-5) catalyst prepared by isomorphous substitution using Fe compounds and ZSM-5, which led to a highly shape-selective catalyst formulation for 2,6-DMN synthesis. Results with modified ZSM-5 by isomorphous substitution with Ti and Co, by ion exchange with Fe as well as acid treatment of ZSM-5 are also shown for comparison. The best Fe-ZSM-5 formulations used under suitable conditions can lead to shape-selective methylation of naphthalene with methanol, with the 2,6-/2,7-DMN ratio and 2,6-DMN/DMNs percentage reaching as high as 2.2 and about 60%, respectively.