**4. Conclusions**

The catalytic isomerization process applying Pt/Al2O3/Cl and Pt/H-Mordenite/Al2O3 catalysts at favorable process parameters (respectively: temperature = 125–135 ◦C, LHSV = 1.0–1.33 h<sup>−</sup>1; and temperature = 260 ◦C; LHSV = 1.0–1.5 h<sup>−</sup>1; P = 30 bar; H2/feedstock molar ratio = 0.15:1.0) is suitable to enhance the octane number of light biogasoline fractions containing benzene and oxygenates. The increase in octane number compared to the feedstock was ca. 32 and ca. 27 units, respectively. The yield of liquid products was high (ca. 98% and ca. 93%) and contained only paraffin hydrocarbons, primarily i-paraffins depending on the extent of recirculation of components having a low octane number. The thermodynamic equilibrium concentration values of these i-paraffins was around 75–95% and 56.1–92.7%. These light biogasoline blending components produced from renewable feedstocks by the presented catalytic hydroisomerization process with Pt/Al2O3/Cl and Pt/H-Mordenite/Al2O3 catalysts have lower pollutant emissions during their application. Unlike Pt/H-Mordenite/Al2O3, the Pt/Al2O3/Cl catalyst is very sensitive to water, sulfur, and oxygen-containing compounds; thus, feedstock needs to be pre-treated. However, the isomerization process at lower temperatures is energy and feedstock efficient (cracking reactions take place to a lesser extent). Moreover, the octane number of the products is higher by ca. 5 units. These factors more than compensate for the costs of the feedstock pre-treatment.

**Author Contributions:** Conceptualization, J.H.; methodology, J.H. and O.V.; validation, J.H. and T.K.; formal analysis, O.V.; investigation, J.H., T.K. and O.V.; resources, T.K.; data curation, O.V.; writing—original draft preparation, J.H. and O.V.; writing—review and editing, J.H., T.K. and O.V.; visualization, O.V.; supervision, J.H.; funding acquisition, J.H. All authors have read and agreed to the published version of the manuscript.

**Acknowledgments:** The authors acknowledge the financial support of the project of the Economic Development and Innovation Operative Programme of Hungary, GINOP-2.3.2-15-2016-00053: Development of liquid fuels having high hydrogen content in the molecule (contribution to sustainable mobility) and the project of Széchenyi 2020 under the EFOP-3.6.1-16-2016-00015: University of Pannonia's comprehensive institutional development program to promote Smart Specialization Strategy. The Project is supported by the European Union and co-financed by Széchenyi 2020.

**Conflicts of Interest:** The authors declare no conflict of interest.
