TY - JOUR

T1 - Contrasting structure-property relationships in amorphous, hierarchical and microporous aluminophosphate catalysts for Claisen-Schmidt condensation reactions

AU - Annath, Hamza

AU - Manayil, Jinesh C.

AU - Thompson, Jillian

AU - Marr, Andrew C.

AU - Raja, Robert

N1 - Author was employed at another UK HEI at the time of submission and was deposited at Queens University Belfast Repository, see link https://pure.qub.ac.uk/en/publications/contrasting-structure-property-relationships-in-amorphous-hierarc

PY - 2021/10/25

Y1 - 2021/10/25

N2 - Amorphous aluminophosphates are industrial catalysts that are active in aldol-type condensations, dehydration and alkylation. The intrinsic nature of the active sites present in these materials is poorly understood. Herein we report a comparative investigation of the catalytic active sites in amorphous and crystalline aluminophosphates (AFI topology) and their corresponding iron-containing analogues, employing Claisen-Schmidt condensation of acetophenone and benzaldehyde as the test reaction. Secondary porosity generated via the soft-templating approach in hierarchically-porous HP FeAlPO-5, and the presence of large mesopores in amorphous Am FeAlPO resulted in improved mass-transport and high conversion of carbonyls. The nature and concentration of the active acidic sites within these materials were characterized by pyridine-DRIFTS and propylamine-TPD studies and was shown to play a crucial role in the activation of carbonyl groups and better catalytic performance. Am FeAlPO(5) nearly outperformed HP FeAlPO-5, thus providing a promising alternative for expanding scope in industrial and pharmaceutical applications.

AB - Amorphous aluminophosphates are industrial catalysts that are active in aldol-type condensations, dehydration and alkylation. The intrinsic nature of the active sites present in these materials is poorly understood. Herein we report a comparative investigation of the catalytic active sites in amorphous and crystalline aluminophosphates (AFI topology) and their corresponding iron-containing analogues, employing Claisen-Schmidt condensation of acetophenone and benzaldehyde as the test reaction. Secondary porosity generated via the soft-templating approach in hierarchically-porous HP FeAlPO-5, and the presence of large mesopores in amorphous Am FeAlPO resulted in improved mass-transport and high conversion of carbonyls. The nature and concentration of the active acidic sites within these materials were characterized by pyridine-DRIFTS and propylamine-TPD studies and was shown to play a crucial role in the activation of carbonyl groups and better catalytic performance. Am FeAlPO(5) nearly outperformed HP FeAlPO-5, thus providing a promising alternative for expanding scope in industrial and pharmaceutical applications.

KW - Aluminophosphate

KW - Amorphous and crystalline catalysts

KW - Chalcones

KW - Claisen-Schmidt condensation

KW - Hierarchically porous

U2 - 10.1016/j.apcata.2021.118376

DO - 10.1016/j.apcata.2021.118376

M3 - Journal article

AN - SCOPUS:85116942985

VL - 627

JO - Applied Catalysis A: General

JF - Applied Catalysis A: General

SN - 0926-860X

M1 - 118376

ER -