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Structuring and Phase Formation in Silica Gel in Water Fluids of Different Densities

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Abstract

The effect of the density of water fluid in the range of ~10–3–0.25 g cm–3 on the structuring of amorphous silica gel was studied at 380°C that exceeds the temperature of critical point of water. It was shown that a decrease in the specific surface area (Ssp) is observed already at the lowest density. As the latter increases, Ssp decreases further, and starting from the density of ~0.01 g cm–3, the formation of crystalline silica phases (cristobalite, keatit) was observed in the sample. Based on the observed regularities in the change in the morphology and crystallinity of SiO2, as well as on the data on the variations in the properties of the water fluid with temperature and pressure below and above the critical point, it was concluded that the increase in the structuring rate with an increase in the density of the water fluid is more likely due to the kinetic factor (mass action law) than with a change in the physical state of water (intermolecular interaction forces action). Using the obtained samples of treated silica gel as a support for the NaWMn/SiO2 catalysts it was shown that their efficiency in the oxidative coupling of methane decreases with increasing degree of crystallinity of the support. However, when supports that have undergone processing in the water fluid of relatively low densities (<0.05 g cm3) were used, the catalysts were more active and selective than the one prepared using the untreated silica gel.

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REFERENCES

  1. NIST Chemistry WebBook, NIST Standard Reference Database No. 69 (2018). https://webbook.nist.gov/chemistry/. https://doi.org/10.18434/T4D303

  2. A. A. Galkin and V. V. Lunin, Russ. Chem. Rev. 74, 24 (2005).

    Article  Google Scholar 

  3. A. Cabanas, J. A. Darr, E. Lester, and M. Poliakoff, J. Mater. Chem. 11, 561 (2001).

    Article  CAS  Google Scholar 

  4. M. N. Danchevskaya, S. N. Torbin, Y. D. Ivakin, and G. P. Muravieva, J. Phys.: Condens. Matter 16, S1187 (2004).

    CAS  Google Scholar 

  5. M. N. Danchevskaya, Y. D. Ivakin, S. N. Torbin, and G. P. Muravieva, J. Supercrit. Fluids 46, 358 (2008).

    Article  CAS  Google Scholar 

  6. Y. D. Ivakin, M. N. Danchevskaya, O. G. Ovchinnikova, G. P. Muravieva, and V. A. Kraisberg, Sverkhkrit. Flyuidy: Teor. Prakt., No. 4, 11 (2008).

  7. M. N. Danchevskaya, G. P. Panasyuk, and V. B. Lasarev, Ross. Khim. Zh. 36, 706 (1991).

    Google Scholar 

  8. M. N. Danchevskaya, V. A. Kraizberg, V. R. Rakchev, G. P. Muravieva, G. P. Panasyuk, G. P. Panasyuk, G. P. Budova, V. I. Privalov, and A. G. Panasuyk, Russ. J. Inorg. Chem. 35, 1243 (1999).

    Google Scholar 

  9. M. N. Danchevskaya, Y. D. Ivakin, S. N. Torbin, and G. P. Muravieva, J. Supercrit. Fluids 42, 419 (2007).

    Article  CAS  Google Scholar 

  10. M. Yu. Sinev, Yu. D. Ivakin, D. P. Shashkin, Z. T. Fattakhova, E. A. Ponomareva, Yu. A. Gordienko, and V. Yu. Bychkov, Sverkhkrit. Flyuidy: Teor. Prakt., No. 3, 45 (2019).

  11. A. Saul and W. Wagner, J. Phys. Chem. Ref. Data 18, 1537 (1989).

    Article  CAS  Google Scholar 

  12. W. Wagner and A. Pruss, J. Phys. Chem. Ref. Data 31, 387 (2002).

    Article  CAS  Google Scholar 

  13. I. R. Krichevskii, Phase Equilibria in Solutions at High Pressures (Goskhimizdat, Moscow, Leningrad, 1952) [in Russian].

    Google Scholar 

  14. M. G. Gonikberg, Chemical Equilibrium and Chemical Reaction Rate at High Pressure, 2nd ed. (Izd. Akad. Nauk USSR, Moscow, 1960) [in Russian].

    Google Scholar 

  15. L. P. Phillipov, Affinities in Properties of Substances (Mosk. Gos. Univ., Moscow, 1978) [in Russian].

    Google Scholar 

  16. M. Yu. Sinev, Yu. A. Gordienko, E. A. Ponomareva, and Yu. A. Ivakin, Sverkhkrit. Flyuidy: Teor. Prakt., No. 2, 116 (2019).

  17. V. I. Lomonosov, Yu. A. Gordienko, M. Yu. Sinev, V. A. Rogov, and V. A. Sadykov, Russ. J. Phys. Chem. A 92, 430 (2018).

    Article  CAS  Google Scholar 

  18. V. I. Lomonosov, Yu. A. Gordienko, and M. Yu. Sinev, Kinet. Catal. 54, 474 (2013).

    Article  Google Scholar 

  19. M. Yu. Sinev, E. A. Ponomareva, I. M. Sinev, V. I. Lomonosov, Yu. A. Gordienko, Z. T. Fattakhova, and D. P. Shashkin, Catal. Today 333, 36 (2019).

    Article  CAS  Google Scholar 

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ACKNOWLEDGMENTS

Authors are deeply grateful to Prof. S.Ya. Umanskii and Dr. Yu.A. Chaikina (FC “Chemical Physics” RAS) for the fruitful discussion of the obtained results and their theoretical interpretation.

Funding

This work was financially supported by the Russian Foundation for Basic Research (project no. 18-29-06055).

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Correspondence to M. Yu. Sinev.

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Lagunova, E.A., Ivakin, Y.D., Sinev, M.Y. et al. Structuring and Phase Formation in Silica Gel in Water Fluids of Different Densities. Russ. J. Phys. Chem. B 14, 1163–1171 (2020). https://doi.org/10.1134/S199079312007009X

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