Study of SAPO acidity variation by controlling silicon islands formation

• Grant number: 07/00088-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): May 01, 2007
• Effective date (End): January 25, 2009
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Principal Investigator: Heloise de Oliveira Pastore
• Grantee: Darlene Luzia Felix
• Host Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

The use of zeolites and molecular sieves as catalysts for hydrocarbon conversion is an important tool in modern Chemistry and on the Petrochemical Industries, since the use of acid microporous materials in the conversion of gasoline and other hydrocarbons presents important advantages in terms of yield, safety and reduction of pollution. These processes are only possible because of the Bronsted acidity present in molecular sieves. The object of the study presented here is a siliconaluminophosphate known as CAL-2, whose structure is the chabazite one (CHA). It is prepared from the lamellar aluminophosphate and a versatile silicon source. The means by which this silicon source is introduced in the synthesis may create Bronsted acid sites with different acidities. It is widely known that the acidity of these molecular sieves is related to the neighborhood of the silicon atoms. The discussion on the results will be based on the characterization of the prepared material through X-rays diffraction, nuclear magnetic resonance of the Si-29 nucleous, differential thermogravimetry, and infrared spectroscopy with adsorption of probe molecules. (AU)