| Research Abstract |
Samples of alumina pillared fluoro-tetrasilicic mica, one of the pillared clay minerals. with different amounts of pillar were prepared. Changing the CEC (cation exchange capacity) of the starting mica by the ion-exchange and sintering of Al^<3+> ion, samples with 1.00 to 4.51 mmol-Al/g-mica were obtained, and the pore structures of the resultant porous materials were analyzed by XRD, adsorption of nitrogen, and the adsorption of some bulky dye molecules. Methylene blue could be adsorbed onto all the samples prepared, but some molecular sieving effects were observed in the adsorption behavior of crystal violet. From these results, it is concluded that the interpillar distance could be predicted by the simple model.
Samples of alumina pillared mica were used as catalysts for the alkylation of naphthalene with t-butyl alcohol. and their catalytic activity and selectivity for the formation of 2,6-di-t-butylnaphthalene were studied. Selectivity for the formation of 2,6-di-t-butylnaphthalene
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is correlated well with selectivity for adsorption of 2,6-di-t- butylnaphthalene, indicating that selective formation of 2,6-isomer may be attributed to molecular sieving effect of alumina pillared mica.
It is known that thiourea selectively forms crystal adducts with 2,6-dialkylnaphthalenes (DAN). In connection with the application of thiourea adduct for the separation of 2,6-DAN from the relevant mixtures, equilibrium constants for the formation of thiourea adducts of diisopropylnaphthalene (DIPN) isomers and di-t-butylnaphthalene (DtBN) isomers were determined at temperatures from 273 to 293 K.Both recovery and purity of 2,6-DAN isomers were used to evaluate the separation process. Equilibrium constants for 2,6-DIPN were determined to be 0.0138 at 273 K and 0.0400 at 292 K, while those for other isomers of DIPN were found to be more than unity. The order of adduct forming tendency of the DIPN isomers was as follows : 2,6-DIPN>2,7-DIPN>1,7-DIPN>1,3-DIPN〜1,4-DIPN〜1,6-DIPN.In addition, equilibrium constants for 2,6-DtBN were also determined to be 0.00428 at 273 K and 0.00813 at 293 K.while those for 2,7-DtBN were 0.33 at 273 K and 0.51 at 293 K.These equilibrium constants can be used to evaluate both the yield and the purity of 2,6-DAN recovered in the adduct which agree well with the observed values with standard deviations of 4.8% for recovery and 3.6% for purity. under the conditions in which studies were conducted. The separation of 2,6-DAN isomers from the relevant mixtures by multistage thiourea addtucts was simulated by the equilibrium model, providing the relationship between the conditions of formation of addtuct and the extent of separation of 2,6-DNA isomers. Less
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