Sorption properties of crystalline molecular sieve AlPO/sub 4/-5

Journal Article · Sun May 01 04:00:00 EDT 1988 · J. Catal.; (United States)

OSTI ID:7201504

Choudhary, V R; Akolekar, D B; Singh, A P; Sansare, S D

The sorption capacity of a number of sorbates, viz. alcohols and hydrocarbons, and the isotherms of sorption of methanol, n-hexane, and benzene in AlPO/sub 4/-5 at 313 K were measured by gravimetric technique. The isotherms of sorption of n-hexane, cyclohexane, benzene, and pyridine in the AlPO/sub 4/-5, at higher temperatures (523-673 K) were determined by the GC peak maxima method. The isosteric heats of sorption of these sorbates at different sorbate loadings were obtained from the isotherm data. The heat of sorption near zero sorbate loading was determined separately by the GC pulse technique in the temperature range 523-673 K. The sorption capacities of AlPO/sub 4/-5 for the sorbates, differing widely in their dipole moments and critical molecular sizes, have been found to be nearly the same (about 0.14 cm/sup 3//g). The sorption of methanol, n-hexane, and benzene at 313 K occurs by the volume filling mechanism and the total volume of the sorption space in AlPO/sub 4/-5 has been found to be about 0.14 cm/sup 3//g. The sorption of n-hexane, cyclohexane, benzene, and pyridine at the higher temperatures follows the Freundlich isotherm. The influence of sorbate loading on the isosteric heat of sorption of benzene is very weak but the influence in the case of the other sorbates is very strong, particularly at the higher sorbate loadings. With the increase in the sorbate loading, the heat of sorption of n-hexane and pyridine increases and that of cyclohexane decreases. The heat of sorption of pyridine is much higher than that of the other sorbates. The values of the heat of sorption of n-hexane, cyclohexane, and benzene at near zero sorbate loading, obtained by the two methods, are very close to each other, and there is very good agreement between the heats of sorption obtained by the two methods.

• Research Organization: National Chemical Lab., Pune (India)
• OSTI ID: 7201504
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 111:1; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ADSORBENTS
ADSORPTION HEAT
ALCOHOLS
ALKANES
ALUMINIUM COMPOUNDS
ALUMINIUM PHOSPHATES
AROMATICS
AZINES
BENZENE
CHROMATOGRAPHY
COMPARATIVE EVALUATIONS
CYCLOALKANES
CYCLOHEXANE
ENTHALPY
GAS CHROMATOGRAPHY
HETEROCYCLIC COMPOUNDS
HEXANE
HYDROCARBONS
HYDROXY COMPOUNDS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MATERIALS
METHANOL
MINERALS
MOLECULAR SIEVES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS COMPOUNDS
PHYSICAL PROPERTIES
PYRIDINE
PYRIDINES
QUANTITY RATIO
SEPARATION PROCESSES
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
ZEOLITES