**High Catalytic E** ffi**ciency of a Layered Coordination Polymer to Remove Simultaneous Sulfur and Nitrogen Compounds from Fuels**

#### **Fátima Mirante 1, Ricardo F. Mendes 2, Filipe A. Almeida Paz 2,\* and Salete S. Balula 1,\***

1 REQUIMTE/LAQV & Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal; fatimaisabelmirante@gmail.com

2 CICECO-Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, Campus UniversitáriodeSantiago,3810-193Aveiro,Portugal;rfmendes@ua.pt

 **\***Correspondence:filipe.paz@ua.pt (F.A.A.P.);sbalula@fc.up.pt(S.S.B.)

Received: 1 June 2020; Accepted: 24 June 2020; Published: 2 July 2020

**Abstract:** An ionic lamellar coordination polymer based on a flexible triphosphonic acid linker, [Gd(H4nmp)(H2O)2]Cl2 H2O (1) (H6nmp stands for nitrilo(trimethylphosphonic) acid), presents high e fficiency to remove sulfur and nitrogen pollutant compounds from model diesel. Its oxidative catalytic performance was investigated using single sulfur (1-BT, DBT, 4-MDBT and 4,6-DMDBT, 2350 ppm of S) and nitrogen (indole and quinolone, 400 ppm of N) model diesels and further, using multicomponent S/N model diesel. Di fferent methodologies of preparation followed (microwave, one-pot, hydrothermal) originated small morphological di fferences that did not influenced the catalytic performance of catalyst. Complete desulfurization and denitrogenation were achieved after 2 h using single model diesels, an ionic liquid as extraction solvent ([BMIM]PF6) and H2O2 as oxidant. Simultaneous desulfurization and denitrogenation processes revealed that the nitrogen compounds are more easily removed from the diesel phase to the [BMIM]PF6 phase and consequently, faster oxidized than the sulfur compounds. The lamellar catalyst showed a high recycle capacity for desulfurization. The reusability of the diesel/H2O2/[BMIM]PF6 system catalyzed by lamellar catalyst was more e fficient for denitrogenation than for desulfurization process using a multicomponent model diesel. This behavior is not associated with the catalyst performance but it is mainly due to the saturation of S/N compounds in the extraction phase.

**Keywords:** layered coordination polymer; oxidative desulfurization; denitrogenation extraction; hydrogen peroxide; lanthanides
