## 4 Conclusions
The following supporting information can be downloaded at [[https://www.mdpi.com/article/10.3390/app15020807/s1](https://www.mdpi.com/article/10.3390/app15020807/s1)]([https://www.mdpi.com/article/10.3390/app15020807/s1](https://www.mdpi.com/article/10.3390/app15020807/s1)), Figure S1: N\({}_{2}\) adsorption isotherms of **N**, **N-Zr**, **N-Zr-S1**, **N-Zr-S2**, **Zr-S** and **Zr**; Figure S2: FT-IR spectra for catalysts **Zr** and **Zr-S**; Figure S3: FT-IR spectra for catalysts **N-Zr**, **N-Zr-S1** and **N-Zr-S2**; Figure S4: FT-IR spectra for catalysts **M**, **M-N** and **M-S**; Figure S5: FT-IR spectra for catalysts **N-HT**, **N-HT-S**, **HT** and **HT-S**; Figure S6: Set-up of the continuous flow reactor; Figure S7: Proton NMR spectrum of crude reaction mixture obtained in continuous flow at a temperature of 60 \({}^{\circ}\)C and a residence time of 30 s, after partial evaporation of the solvent; Figure S8: FT-IR spectra for 1,3-dioxolanes **3** (top) and **4** (bottom); Figure S9: \({}^{1}\)H-NMR spectrum (CDCl\({}_{3}\), 500 MHz) of **3**; Figure S10: \({}^{13}\)C-NMR and DEPT spectra (CDCl\({}_{3}\), 125 MHz) of **3**; Figure S11: \({}^{1}\)H-NMR spectrum (CDCl\({}_{3}\), 500 MHz) of **4**; Figure S12: \({}^{13}\)C-NMR and DEPT spectra (CDCl\({}_{3}\), 125 MHz) of **4**; Figure S13: \({}^{1}\)H-\({}^{13}\)C heteronuclear correlation spectrum (HMQC) of **3**; Figure S14: \({}^{1}\)H-\({}^{1}\)H homonuclear correlation spectrum (NOESY) of **3**; Figure S15: \({}^{1}\)H-\({}^{13}\)C heteronuclear correlation spectrum (HMQC) of **4**; Figure S16: \({}^{1}\)H-\({}^{1}\)H homonuclear correlation spectrum (NOESY) of **4**; Figure S17: Rate constants determination for evolution of diol **2** and intermediate **I2-4** corresponding to the acetalization catalyzed by **HT-S** at 40 \({}^{\circ}\)C; Table S1: XPS components of C 1s peaks after deconvolution; Table S2: XPS components of O 1s peaks after deconvolution; Table S3: XPS components of N 1s peaks after deconvolution; Table S4: XPS components of S 2p peaks after deconvolution; Table S5: Recycling experiment with catalyst **N-HT-S**; Table S6: Recycling experiment with catalyst **HT-S**. Conceptualization, R.P.-B., C.J.D.-V. and R.F.M. ; methodology, L.M., R.P.-B., M.A.-P. and L.C. ; software, R.F.M. ; validation, R.P.-B., C.J.D.-V., P.C., D.C. and R.F.M. ; investigation, L.M., R.P.-B., C.J.D.-V., M.A.-P., P.C., L.C., D.C. and R.F.M. ; writing--original draft preparation, C.J.D.-V., P.C., D.C. and R.F.M. ; writing--review and editing, P.C. and R.F.M. ; supervision, R.P.-B., C.J.D.-V. and R.F.M. ; funding acquisition, R.P.-B., C.J.D.-V. and R.F.M. All authors have read and agreed to the published version of the manuscript. This research was funded by the Junta de Extremadura and Fondo Europeo de Desarrollo Regional (Grants IB20026, GR21039, and GR21107). Not applicable. Additional data, as mentioned in this manuscript, are provided in the Supplementary Materials. Further information can be obtained from the authors upon reasonable request. We thank the staff of the Servicio de Apoyo a la Investigacion at the University of Extremadura (SAIUEX) for obtaining some of the analytical data reported in this manuscript. We greatly acknowledge [PERSON] (Twente University, NL) for kindly providing the cavitation-intensifying bags manufactured by BuBClean. The authors declare no conflicts of interest. The funders had no role in the design of this study, in the collection, analyses, or interpretation of data, in the writing of this manuscript, or in the decision to publish the results.