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Brian F. Woodfield – One of the best experts on this subject based on the ideXlab platform.

  • acid site properties of thermally stable silica doped Alumina as a function of silica Alumina Ratio and calcination temperature
    Applied Catalysis A-general, 2014
    Co-Authors: Maryam Khosravi Mardkhe, Kamyar Keyvanloo, Calvin H. Bartholomew, William C. Hecker, Todd M. Alam, Brian F. Woodfield

    Abstract:

    Abstract Acid site properties of silica-doped Aluminas prepared by a simple solvent deficient hydrolysis of the alkoxides was investigated. The total acid concentRation (Bronsted and Lewis sites) of silica-doped Aluminas (SDAs) calcined in the range of 700–1200 °C with Si/Al Ratios of 5, 15, 27 wt% was determined using temperature-programmed desorption of ammonia (ammonia-TPD). 27 Al solid state MAS NMR (Al SS MAS NMR) was used to measure the intrinsic Lewis acid site concentRation, and FTIR was also used as a separate measure of the Bronsted and Lewis acid site concentRation. Results indicate that removing hydroxyl groups in the form of water molecules through calcination result in a lower concentRation of Bronsted acid sites. Calcination at higher temperature also results in the transformation of unsaturated 5-coordinated aluminum (a strong Lewis acid) to higher concentRations of 6 and 4-coordinated aluminum in 5, 15 and 27% silica-doped Alumina samples. Therefore, the total acid site concentRation (Bronsted and Lewis sites) decreases by increasing the calcination temperature. In addition, the data show that increasing the silica/Alumina Ratio increases both the Bronsted and Lewis acid site concentRations. Based on these results, the acid site concentRations can be controlled by altering the Si/Al Ratio and calcination temperature while maintaining high surface areas, large pore volumes, and large pore diameters.

  • Acid site properties of thermally stable, silica-doped Alumina as a function of silica/Alumina Ratio and calcination temperature
    Applied Catalysis A: General, 2014
    Co-Authors: Maryam Khosravi Mardkhe, Kamyar Keyvanloo, Calvin H. Bartholomew, William C. Hecker, Todd M. Alam, Brian F. Woodfield

    Abstract:

    Abstract Acid site properties of silica-doped Aluminas prepared by a simple solvent deficient hydrolysis of the alkoxides was investigated. The total acid concentRation (Bronsted and Lewis sites) of silica-doped Aluminas (SDAs) calcined in the range of 700–1200 °C with Si/Al Ratios of 5, 15, 27 wt% was determined using temperature-programmed desorption of ammonia (ammonia-TPD). 27 Al solid state MAS NMR (Al SS MAS NMR) was used to measure the intrinsic Lewis acid site concentRation, and FTIR was also used as a separate measure of the Bronsted and Lewis acid site concentRation. Results indicate that removing hydroxyl groups in the form of water molecules through calcination result in a lower concentRation of Bronsted acid sites. Calcination at higher temperature also results in the transformation of unsaturated 5-coordinated aluminum (a strong Lewis acid) to higher concentRations of 6 and 4-coordinated aluminum in 5, 15 and 27% silica-doped Alumina samples. Therefore, the total acid site concentRation (Bronsted and Lewis sites) decreases by increasing the calcination temperature. In addition, the data show that increasing the silica/Alumina Ratio increases both the Bronsted and Lewis acid site concentRations. Based on these results, the acid site concentRations can be controlled by altering the Si/Al Ratio and calcination temperature while maintaining high surface areas, large pore volumes, and large pore diameters.

Shilun Qiu – One of the best experts on this subject based on the ideXlab platform.

  • fast synthesis of submicron aluminosilicate low silica Alumina Ratio zeolites under solventless microwave radiation
    RSC Advances, 2015
    Co-Authors: Shangjing Zeng, Runwei Wang, Yongcun Zou, Zhongtao Zhang, Shilun Qiu

    Abstract:

    A promising strategy for synthesis zeolites has been reported in this paper. The method combines the advantages of both microwave heating and solventless synthesis. This method can generate zeolites under atmospheric pressure and is safe, highly efficient and environmentally benign.

  • Fast synthesis of submicron aluminosilicate (low silica/Alumina Ratio) zeolites under solventless microwave radiation
    RSC Advances, 2015
    Co-Authors: Shangjing Zeng, Runwei Wang, Yongcun Zou, Fu Jingru, Zhongtao Zhang, Shilun Qiu

    Abstract:

    A promising strategy for synthesis zeolites has been reported in this paper. The method combines the advantages of both microwave heating and solventless synthesis. This method can generate zeolites under atmospheric pressure and is safe, highly efficient and environmentally benign.

Maryam Khosravi Mardkhe – One of the best experts on this subject based on the ideXlab platform.

  • acid site properties of thermally stable silica doped Alumina as a function of silica Alumina Ratio and calcination temperature
    Applied Catalysis A-general, 2014
    Co-Authors: Maryam Khosravi Mardkhe, Kamyar Keyvanloo, Calvin H. Bartholomew, William C. Hecker, Todd M. Alam, Brian F. Woodfield

    Abstract:

    Abstract Acid site properties of silica-doped Aluminas prepared by a simple solvent deficient hydrolysis of the alkoxides was investigated. The total acid concentRation (Bronsted and Lewis sites) of silica-doped Aluminas (SDAs) calcined in the range of 700–1200 °C with Si/Al Ratios of 5, 15, 27 wt% was determined using temperature-programmed desorption of ammonia (ammonia-TPD). 27 Al solid state MAS NMR (Al SS MAS NMR) was used to measure the intrinsic Lewis acid site concentRation, and FTIR was also used as a separate measure of the Bronsted and Lewis acid site concentRation. Results indicate that removing hydroxyl groups in the form of water molecules through calcination result in a lower concentRation of Bronsted acid sites. Calcination at higher temperature also results in the transformation of unsaturated 5-coordinated aluminum (a strong Lewis acid) to higher concentRations of 6 and 4-coordinated aluminum in 5, 15 and 27% silica-doped Alumina samples. Therefore, the total acid site concentRation (Bronsted and Lewis sites) decreases by increasing the calcination temperature. In addition, the data show that increasing the silica/Alumina Ratio increases both the Bronsted and Lewis acid site concentRations. Based on these results, the acid site concentRations can be controlled by altering the Si/Al Ratio and calcination temperature while maintaining high surface areas, large pore volumes, and large pore diameters.

  • Acid site properties of thermally stable, silica-doped Alumina as a function of silica/Alumina Ratio and calcination temperature
    Applied Catalysis A: General, 2014
    Co-Authors: Maryam Khosravi Mardkhe, Kamyar Keyvanloo, Calvin H. Bartholomew, William C. Hecker, Todd M. Alam, Brian F. Woodfield

    Abstract:

    Abstract Acid site properties of silica-doped Aluminas prepared by a simple solvent deficient hydrolysis of the alkoxides was investigated. The total acid concentRation (Bronsted and Lewis sites) of silica-doped Aluminas (SDAs) calcined in the range of 700–1200 °C with Si/Al Ratios of 5, 15, 27 wt% was determined using temperature-programmed desorption of ammonia (ammonia-TPD). 27 Al solid state MAS NMR (Al SS MAS NMR) was used to measure the intrinsic Lewis acid site concentRation, and FTIR was also used as a separate measure of the Bronsted and Lewis acid site concentRation. Results indicate that removing hydroxyl groups in the form of water molecules through calcination result in a lower concentRation of Bronsted acid sites. Calcination at higher temperature also results in the transformation of unsaturated 5-coordinated aluminum (a strong Lewis acid) to higher concentRations of 6 and 4-coordinated aluminum in 5, 15 and 27% silica-doped Alumina samples. Therefore, the total acid site concentRation (Bronsted and Lewis sites) decreases by increasing the calcination temperature. In addition, the data show that increasing the silica/Alumina Ratio increases both the Bronsted and Lewis acid site concentRations. Based on these results, the acid site concentRations can be controlled by altering the Si/Al Ratio and calcination temperature while maintaining high surface areas, large pore volumes, and large pore diameters.