The adsorption and photochemical behavior of 5,10,15-triphenyl-20-mono(N-Methyl-4-pyridyl)porphyrin (MMPyP) were examined onto the clay surface in MeOH/water=1/9 (v/v). Absorption and fluorescence spectra were observed for MMPyP–clay complexes. MMPyP adsorbs on the clay surface in the manner where porphyrin ring is parallel to the clay surface and absorbs up to 25% vs. CEC of the clay. Fluorescence of MMPyP was strongly quenched as its adsorption density increased on the clay surface.

In order to clarify a specific intercalation behavior of layered double hydroxide (LDH) in methanol, the intercalation reaction of LDH in water and methanol was investigated for carboxylic acids and their sodium salts. The LDHs used are carbonate MgAl-layered double hydroxide (CO₃-LDH) and nitrate MgAl-layered double hydroxide (NO₃-LDH). Carboxylic acids reacted with CO₃-LDH in methanol and with NO₃-LDH in water. In contrast, sodium carboxylates reacted with NO₃-LDH in both solvents. The lack of reaction between sodium carboxylate and CO₃-LDH in methanol indicated that protons from the carboxyl group were largely responsible for decarbonation of CO₃-LDH. Because the intercalation reaction with NO₃-LDH proceeds by ion-exchange, the proportion of anionic guest compound in solvent affected the success of intercalation. Sodium carboxylates with a large number of alkyl carbons, which are insoluble in water, were incorporated into NO₃-LDH through the use of methanol. The basal spacing of the product increased linearly with number of alkyl carbons of carboxylic acid.

Three different kinds of montmorillonites (Benclay SL, Benclay KK, and Kunipia F) were evaluated as “Support-Activators” for metallocene-catalyzed propylene polymerization. The respective clay materials were acid-treated to alter their physico-chemical properties, and used for the preparation of metallocene catalysts. The catalyst systems were subsequently characterized and their efficacy in facilitating the polymerization of propylene was evaluated. It was observed that polymerization activities were specifically influenced by the kind of clay mineral used. Based on our study, the level of catalytic activity is proportionally related to the surface areas of the small-size pores (pore diameter<6 nm), where strong acid sites are present.

A porous material with smectite-type structure was prepared from natural clay (surface area of 13 m² g⁻¹ and pore volume of 0.12 cm³ g⁻¹) and silicate synthesized by hydrothermal method using water glass and magnesium chloride, and dimethyldistearyl ammonium chloride. The hydrothermally treated sample had large surface area (272 m² g⁻¹) and pore volume (0.55 cm³ g⁻¹) values because pores were formed between the stacking structure of clay and synthetic silicate fragments.

Transparent clay-based coating materials with high He-gas barrier property were developed using synthetic stevensite and methoxymethyl nylon. The coated film can be used in a roll installation and is resistant to humidity. The high He-gas barrier property was achieved by using clay nanosheets with a high aspect ratio and improved film formability. However, the haze of the coated film increased with increasing aspect ratio of the clay nanosheets.

The attempt of optical resolution by use of smectite clays is reviewed. The first clue was given by the discovery that the pure enantiomer of [Ru(1,10-phenanthroline)₃]²⁺ was adsorbed by sodium montmorillonite within the CEC of a clay, while the racemic mixture was adsorbed to two times excess of CEC. It was proposed that a vacant space capable of chiral discrimination was generated when a clay surface was modified with the enantiomeric chelates. This model lead to the method of optical resolution using an ion-exchange adduct of a smectite clay and chiral chelates as an adsorbent. A clay column prepared for high performance liquid chromatography is now commercially available and has been applied for separating a wide range of chiral organic and inorganic compounds. Further improvement is now under progress.