Regular Article
Enthalpy of Interaction and Activation Energy for Thermal Degradation of Modified Forms of Lamellar Titanium Hydrogenphosphate

https://doi.org/10.1006/jssc.1999.8276Get rights and content

Abstract

Crystalline alpha titanium hydrogenphosphate (TPH), the derivatives of potassium (TPK), calcium (TPCa), barium (TPBa), lanthanum (TPLa), and the intercalated forms of n-butylamine (TPBA) and pyridine (TPPy) were prepared. Thermodynamics of ionic exchange and intercalation processes were performed through calorimetric titration. The enthalpic values for potassium, calcium, barium, and lanthanum gave: −0.54±0.04; 5.82±0.24; 1.11±0.09, and 5.85± 0.13 kJ mol-1, respectively. For the intercalation with butylamine and pyridine the values −42.5±0.15 and −66.76± 1.10 kJ mol-1 were obtained. The nonisolthermal Coats-Redfern method was used to calculate the kinetical parameters for thermal degradation of all matrices through thermogravimetric data. The matrices presented two or three mass loss steps. The activation energy (Ea) values for the condensation of the OH groups are 67, 155, 124, 147, 117, 318, and 477 kJ mol−1 for TPH, TPK, TPCa, TPBa, TPLa, TPBA, and TPPy, respectively. The plot of the enthalpic values as function of Ea gave a linear relationship, expressed by the equation: ΔintHθm=−0.212×Ea+31.070, which correlated the thermochemical and kinetical parameters.

References (27)

  • A. Clearfield. et al.

    Appl. Catal.

    (1986)
  • A.L. Blumenfeld et al.

    Solid State Ionics

    (1994)
  • C. Trobajo et al.

    Thermochim. Acta

    (1991)
  • S. Roca et al.

    Thermochim. Acta

    (1996)
  • A. Bortun et al.

    Mater. Res. Bull.

    (1995)
  • V. Vesely et al.

    Talanta

    (1972)
  • A. Airoldi et al.

    J. Mater. Chem.

    (1996)
  • H. Kaneto et al.

    Chromatographia

    (1993)
  • E. Ruiz-Hitzky

    Adv. Mater.

    (1993)
  • M. Saúrez et al.

    Thermochim. Acta

    (1995)
  • M. Ogawa et al.

    Chem. Rev.

    (1995)
  • A. Clearfield

    Inorganic Ion Exchange Materials

    (1982)
  • R. Llavona et al.

    Inorg. Chem.

    (1989)
  • Cited by (7)

    • Chemistry on modified phosphates

      2023, Interface Science and Technology
    • Chapter Seven Chemistry on Modified Phosphates

      2009, Interface Science and Technology
      Citation Excerpt :

      Lamellar α-titanium hydrogen phosphate (α-Ti(HPO4)2. H2O) can be used to obtain, through proton ion exchange processes, other phosphates, such as Ca2+, Ba2+, and La3+ ones, or can be modified with organic species producing intercalation compounds [1,2]. Zirconium phosphate, besides the traditional intercalation processes, has been used to produce pillared compounds, such as those involving mixed Fe–Cr oxides [3].

    • Thermogravimetric study about PVC-polyaniline blends

      2002, Journal of Thermal Analysis and Calorimetry
    View all citing articles on Scopus
    1

    Present address: Instituto de Quı́mica, Universidade Estadual de Campinas, Caixa Postal 6154, 13083-970, Campinas, São Paulo, Brasil. E-mail: [email protected].

    View full text