Apparent molar heat capacity of aqueous hydrolyzed and non-hydrolyzed AlCl[sub 3] between 50 and 150[degree]C

Journal Article · Tue Dec 01 04:00:00 EST 1992 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(92)90255-H· OSTI ID:7030950

Conti, G; Gianni, P ^[1]; Matteoli, E ^[2]

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1. Dipartimento di Chimica e Chimica Industriale, Pisa (Italy)
2. Istituto di Chimica Quantistica ed Energetica Molecolare, Pisa (Italy)

By means of a flow calorimeter, the specific heats of aqueous solutions containing AlCl[sub 3] with and without added HCl have been measured at 50, 100, and 150[degree]C. The apparent molar heat capacity C[sub p,[phi]] of the HCl-containing solutions have allowed the calculation of the standard molar heat capacity of AlCl[sub 3], C[sup [minus]0][sub p,AlCl[sub 3]]. These data satisfactorily link together with those of Hovey and Tremaine in the range 10-55[degree]C, afterwards reassessed by Barta and Hepler, 1986. The treatment of the C[sup p,[phi]] data with the ionic interactions model of Pitzer has provided the values of [beta][sup (0)J] and [beta][sup (1)J] for the calculation of C[sup AlCl[sup 3]][sub p,[phi]] in the concentration range 0.03-0.75 mol kg[sup [minus]1] at the temperatures studied. Experimental values of the apparent molar heat capacities obtained for hydrolyzed solutions have been compared with the analogous quantities calculated accounting for the C[sub p,[phi],i] of all species present at equilibrium, as well as for the chemical relaxation term, C[sup rel][sub p,[phi]], which is due to the energy absorbed by the hydrolysis shift induced by the heating inherent in the specific heat measurement. The calculation has been carried out on the basis of some hydrolytic schemes proposed in the literature and has provided useful insights on the hydrolysis reaction at temperatures where the extent of reaction is quite marked.

• OSTI ID: 7030950
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Journal Name: Geochimica et Cosmochimica Acta; (United States) Vol. 56:12; ISSN GCACAK; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360606 -- Other Materials-- Physical Properties-- (1992-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALUMINIUM CHLORIDES
ALUMINIUM COMPOUNDS
AQUEOUS SOLUTIONS
CALORIMETRY
CHEMICAL REACTIONS
CHLORIDES
CHLORINE COMPOUNDS
DECOMPOSITION
DISPERSIONS
HALIDES
HALOGEN COMPOUNDS
HYDROLYSIS
LYSIS
MIXTURES
PHYSICAL PROPERTIES
RELAXATION
SOLUTIONS
SOLVOLYSIS
SPECIFIC HEAT
THERMODYNAMIC PROPERTIES