NH4F modification of microspherical CrOx/Al2O3 catalyst for isobutane dehydrogenation

The effect of NH₄F modification on the physicochemical characteristics, active component state, and catalytic performance of microspherical CrO_x/Al₂O₃ during isobutane dehydrogenation to isobutylene was studied using X-ray diffraction (XRD), X-ray fluorescence (XRF), low-temperature nitrogen adsorption, UV-Vis and Raman spectroscopy, NH₃-TPD, and chemical analysis. It was found that after NH₄F application and thermal treatment of the catalyst, fluorine is distributed and adheres to the surface, altering the phase composition, textural characteristics, and acidic properties of the surface. Furthermore, phases of α-Cr₂O₃, the aluminum and chromium oxyfluorides, (Cr_xAl_2-x)O₃ solid solution are formed in the catalysts. Surface fluoride ions increase the overall concentration of acidic sites, form strong acidic sites, and increase the conversion of isobutane, the rate of isobutylene formation, and the selectivity for isobutylene during dehydrogenation. When the aluminum and chromium oxyfluorides are formed, the catalyst activity decreases, but selectivity remains high. When (Cr_хAl_2-х)O₃ phase are formed, the catalyst is deactivated.

1. Sanfilippo D., Miracca I. // Catalysis Today. 2006. V.111. P. 133-139. https://doi.org/10.1016/j.cattod.2005.10.012

2. Nawaz Z. // Revives in Chemical Engineering. 2015. V.31. № 5. P. 413-436. https://doi.org/10.1515/revce-2015-0012

3. Sanfilippo D. // Catalysis Today. 2011. V.178. № 1. P. 142-150. https://doi.org/10.1016/j.cattod.2011.07.013

4. Sanfilippo D., Miracca I. // Catalysis Today. 2006. V.111. P. 142-150.P. 133-139. doi:10.1016/j.cattod.2005.10.012.

5. Fridman V.Z., Xing R., Severance M. // Applied Catalysis A: General. 2016. V. 523. P. 39-53. https://doi.org/10.1016/j.apcata.2016.05.008

6. Grzybowska B., Słoczyński J., Grabowski R., Wcisło K., Kozłowska A., Stoch J., Zieliński J. // Journal of Catalysis. 1998. V. 178. № 2. P. 687-700. https://doi.org/10.1006/jcat.1998.2203

7. Sattler J.J.H.B., Ruiz-Martinez J., Santillan-Jimenez E., Weckhuysen B.M. // Chemical Reviews. 2014. V. 114. № 20. P. 10613-10653. https://doi.org/10.1021/cr5002436

8. Li C., Wang G. // Chemical Society Reviews. 2021. V. 50. Р. 4359-4381. https://doi.org/10.1039/d0cs00983k

9. Botavina M., Barzan C., Piovano A., Braglia L., Agostini G., Martra G., Groppo E. // Catalysis Science & Technology. 2017. V. 7. P. 1690-1700. https://doi.org/ 10.1039/c7cy00142h.

10. Kopaˇc D., Jurkovi´c D.L., Likozar B., Huˇs M. // ACS Catalysis. 2020. V.10. P. 14732-14746. https://doi.org/10.1021/acscatal.0c03197.

11. Salaeva A.A., Salaev M.A., Mamontov G.V. // Chemical Engineering Science. 2020. V.215. P. 115462. https://doi.org/10.1016/j.ces.2019.115462

12. Kopas D., Likozar B., Hus M. // Applied Surface Science. 2022. V. 575. P. 151653. https://doi.org/10.1016/j.apsusc.2021.151653

13. Li X., Li J., Yuan M., Li J., Wang G., Li Ch. // Applied Catalysis A: General. 2023. V. 2023. P. 119322. https://doi.org/10.1016/j.apcata.2023.119322

14. Баулин А.А., Кудряшов В.Н., Бобров Б.Н. // Высокомолекулярные соединения, Серия А. 2008. Т. 50. № 12. Р. 2082-2089.

15. Egorova S.R., Tuktarov R.R., Boretskaya A.V., Laskin A.I., Gizyatullov R.N., Lamberov A.A. // Molecular Catalysis. 2021. V.509. P.111610 https://doi.org/10.1016/j.mcat.2021.111610

16. ГОСТ 33501-2015. Топливо твердое минеральное. Определение содержания общего фтора сжиганием в калориметрической бомбе с последующим определением в растворе с помощью ион-селективного электрода // М.: Стандартинформ, 2019.

17. ASTM E1941-10. Standard Test Method for Determination of Carbon in Refractory and Reactive Metals and Their Alloys by Combustion Analysis // ASTM Int. 2016.

18. Hossani Md., S., Ahmed S. // Results in Materials. 2023. V. 20. P. 100492. https://doi.org/10.1016/j.rinma.2023.100492

19. Ющенко В.В. // Журнал физической химии. 1997. Т. 71, № 4. С. 628-632. 34. 35. 20. Раков Э.Г., Мельниченко Е.И. // Успехи химии. 1984. Т. LII. Вып. 9. С. 1463-1492.

20. Ballhausen С.J., Introduction to Ligand Field Theory, Mac Graw‐Hill Book Company, INC., New Yorkn. NY. USA. 1962. 208 p.

21. Weckhuysen B.M., De Ridder L.M., Schoonheydt R.A. // Journal of Physical Chemistry. 1993. V. 97. P. 4756-4763. https://doi.org/10.1021/j100120a030

22. Vuurman M.A., Wachs I.E., Stufkens D.J., Oskam A. // Journal of Molecular Catalysis. 1993. V. 80. P. 209–227. https://doi.org/10.1016/0304-5102(93)85079-9

23. Vuurman M.A., Hardcastle F.D., Wachs I.E. // Journal of Molecular Catalysis. 1993. V. 84. P. 193–205. https://doi.org/10.1016/0304-5102(93)85052-U

24. Mentasty L.R., Gorriz O.F., Cadus L.E. // Industrial & Engineering Chemistry Research. 1999. V. 38. P. 396–404. https://doi.org/10.1021/ie9802562

25. Vuurman M.A., Stufkens D.J., Oskam A., Moulijn J.A., Kapteijn F. // Journal of Molecular Catalysis. 1990. V. 60. P. 83–98. https://doi.org/10.1016/0304-5102(90)85070-X

26. Oskam A., Stufkens D.J., Vuurman M.A. // Journal of Molecular Structure. 1990. V. 217. P. 325–334. https://doi.org/10.1016/0022-2860(90)80371-P

27. Saniger J.M., Sanchez N.A., Flores J.O. // Journal of Fluorine Chemistry. 1998. V. 88. P. 117-125. https://doi.org/10.1016/S0022-1139(98)00106-7

28. Bedghiou D., Rehab M.N., Benali-Cherif R., Djelloul A., Boumaza A.// Acta Materialia. 2024. V. 281. P. 120450. https://doi.org/10.1016/j.actamat.2024.120450

29. Старостин А.Г., Островский С.В. // Химия и химическая технология. 2022. V. 65, № 3. C. 43-51. https://doi.org/10.6060/ivkkt.20226503.6514

30. Дьяченко А.Н., Крайденко Р.И., Петлин И.В., Травин Б.М. // Известия Томского политехнического университета. 2010. № 3. С. 69-72.

31. Hope E.G., Peter J.J., William L., Steven O.J, Mahmoud T., Turff J.W. // Journal of Chemical Society, Dalton Transactions. 1985. № 3. P. 529-533. https://doi.org/10.1039/DT9850000529

32. Крайденко Р.И. Фтороаммонийное разделение многокомпонентных силикатных систем на индивидуальные оксиды: Диссертация на соискание ученой степени кандидата химических наук. Томск, 2008. С. 140.

33. Мельниченко Е. И. Оксифториды и фторометаллаты аммония в химии и технологии редких металлов: Диссертация на соискание ученой степени доктора химических наук. Владивосток, 1999. С. 364.

34. Gerberich H.R., Lutinski F.E., Hall K.W. // Journal of Catalysis. 1966. V. 6. № 2. .P. 209-219. https://doi.org/10.1016/0021-9517(66)90051-0

35. Reitsma H. J., Boelhouwer C. // Journal of Catalysis. 1974. V. 33. № 1. P. 39-46. https://doi.org/10.1016/0021-9517(74)90241-3

36. Davis S.M., Meitzner G.D., Fischer D.A., Gland J. // Journal of Catalysis. 1993. V. 142. № 2. P. 368-372. https://doi.org/10.1006/jcat.1993.1214

37. Накамото К. ИК спектры и спектры КР неорганических и координационных соединений. М.: Мир, 1991. 536 с.

38. Сontescu A., Schramm C., Sato R., Schwartz J.A. // Journal of Colloid and Interface Science. 1994. V. 1. № 1. P. 66-71. https://doi.org/10.1006/jcis.1994.1206

39. Ahrem L., Scholz G., Gutmann T., Calvo B., Buntkowsky G., Kemnitz E. // The Journal of Physical Chemistry C. 2017. V. 121. P. 12206-12213. https://doi.org/10.1021/acs.jpcc.7b02535

40. ZangW., Sun M., Prins // Journal of Physical Chemistry. 2003. V. 106. P. 11805-11809.

41. Fridman V.Z., Xing R. // Applied Catalysis A: General. 2017. V. 530. P. 154-165. https://doi.org/10.1016/j.apcata.2016.11.024

42. Rodemerck U., Kondratenko E.V., Otroshchenko T., Linke D. // Chemical Communications. 2016. V.52. P. 12222. DOI: 10.1039/c6cc06442f.