Banca de DEFESA: ROSANGELA PEDROSA CARVALHO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : ROSANGELA PEDROSA CARVALHO
DATE: 27/05/2022
TIME: 14:00
LOCAL: Ambiente Virtual
TITLE:

Boron incorporation in silicoaluminophosphate SAPO-11 and SAPO-5 molecular sieves.

KEY WORDS:

Boron; incorporation; SAPOs; AFI; AEL.

PAGES: 87
BIG AREA: Engenharias
AREA: Engenharia Química
SUMMARY:

The silicoaluminophosphates SAPO-5 and SAPO-11 are microporous molecular sieves of economic, industrial and academic interest due to their architecture and properties. SAPO-5 has large pores and moderate acidity, while SAPO-11 has small pores and weak acidity, yet both suffer problems related to lower conversions and coke deactivation when applied in certain reactions. The addition of metallic heteroatoms helps to improve acidic properties by increasing Brønsted sites, but without greater effectiveness in problems with deactivation. Research shows that the addition of boron semimetal in the structure of zeolites and zeotypes can promote an increase in their acidity, maintaining or increasing the conversion of the reactions, at the same time delaying the hydrogen transfer reactions characteristic of coke formation. The present work proposed the addition of boron in crystalline structures of silicoaluminophosphates such as SAPO-5 and SAPO-11 by small modifications in the hydrothermal synthesis process, and in SAPO-11 by ion exchange, seeking to verify an optimal amount of boron to be added, without prejudice to the properties of the materials and the influence that the form of boron addition exerts on them. The physicochemical properties of the samples were determined XRD, FTIR, TG-ATD, TPD-NH3, nitrogen adsorption at -196°C (BET and t-plot). The results obtained show that, regardless of the form of addition, boron resulted in pure and crystalline SAPO-5 and SAPO-11, and when in optimal amounts, with greater crystallinity. The presence of boron kept the samples thermally stable and facilitated TG desorption processes. The IR spectra showed that the amount of boron in the hydrothermal synthesis and the form of addition influence the formation of different functional groups, mainly those related to acidic species, which also resulted in displacement of acidity, mainly in the exchange-modified SAPO-11 ionic. The increase in surface area and volume of micropores was more pronounced in samples where boron was added in the synthesis process. The ion exchanges, when in optimal amounts, resulted in higher conversion in the n-hexane cracking reaction and lower coke formation in the catalyst.

BANKING MEMBERS:
Presidente - 1545506 - ANTONIO OSIMAR SOUSA DA SILVA
Interno - 1797785 - LUCAS MEILI
Externa ao Programa - 1695821 - MARITZA MONTOYA URBINA
Externo à Instituição - ELEDIR VITOR SOBRINHO - UFRN