Interlayered clays

New Adsorbent Materials. SihcaUte and other hydrophobic molecular sieves, the new family of AlPO molecular sieves, and steadily increasing families of other new molecular sieves (including stmctures with much larger pores than those now commercially available), as well as new carbon molecular sieves and pillared interlayer clays (PILCS), will become more available for commercial appHcations, including adsorption. Adsorbents with enhanced performance, both highly selective physical adsorbents and easily regenerated, weak chemisorbents will be developed, as will new rate-selective adsorbents. 

The hydroamination of alkenes has been performed in the presence of heterogeneous acidic catalysts such as zeolites, amorphous aluminosilicates, phosphates, mesoporous oxides, pillared interlayered clays (PILCs), amorphous oxides, acid-treated sheet silicates or NafioN-H resins. They can be used either under batch conditions or in continuous operation at high temperature (above 200°C) under high pressure (above 100 bar). 

Pillared interlayer clays (PILCs), 1 655 Pill-box cell, 13 417-419 Pilling, reduced, 11 211 Pillow cases, number produced from one bale of cotton, 8 133t Pilot plant(s), 19 457-471... 

More recently, polyoxocations have been used to prepare pillared forms of interlayered clays that are related to the hydroxy-interlayered analogs found in... 

Figure 2. Structure of a typical chlorite-like hydroxy-interlayered clay in which the galleries of a 2 1 smectite structure are filled, or nearly so, with brucite-like sheets of mainly edge-shared Mg(OH) octahedra. Aluminum occasionally substitutes for magnesium in the brucite sheet to provide the charge balance necessary for electrical neutrality.

Future EXAFS studies of the local structure of reactive sites in pillared clay derivatives and related hydroxy-interlayered clay minerals should help elucidate the reactivity of these materials as catalysts for synthetic organic chemical conversions, as well as for reactions occurring in the natural soil environment. 

Pillared interlayered clays (PILCs), nanostructured adsorbents, 120 Platinum, dendrimers, 14-15 Polarizability... 

Cheng J, Yu SM, Zuo P (2006) Horseradish peroxidase immobilized on aluminum-pillared interlayered clay for the catalytic oxidation of phenolic wastewater. Water Res 40 283-290... 

The success of the HZSM-S catafyst is no doubt linked to the low coke forming tendency of this particular zeolite. Other acidic zeolites such as HY are initia% active but deactivate very r idly due to coke depo on. Bradley and Kydd [116] investigated the performance of seve pillar interlayered clay miner and although the Ga pillared montmorihonite was found to be the most effective it had a nnich lower activity than Ga/HZSM-5. 

Pillared interlayered clays (PILC) can be regarded as nanocomposites, in which oxide particles of nano- and subnanometer scales are incorporated into the interlayer space of two-dimensional aluminosilicates [1]. In recent years, much attention has been focused on this new type of materials with large heights of pillars, because they provide larger pores in comparison to conventional zeolites. Smectites pillared with transition metal oxides (e.g. Cr, Fe, Ti) are of particular interest because the incorporated phases have themselves catalytic properties. Such solids are claimed to possess a remarkable activity in a notable number of reactions [2,3]. 

In a survey of U.S. stream sediments, Kennedy (1965) concluded that the makeup and properties of the stream sediments essentially equaled that of local soils. In the eastern states (50 to 150 cm precipitation), dominant clays in the <4 jum (0.004 mm) fraction were illite, kaolinite, ver-miculite, and interlayered clays, with a CEC of 14 to 28 meq/lOOg. In central and west-central states (25 to 100 cm precipitation) Kennedy found dominant smectite, vermiculite, mixed-layer illite, kaolinite, quartz, and feldspar in the <4 /zm fraction, with a CEC range of 25 to 65 meq/100 g. In California and Oregon, because of the wide range of wet and dry conditions (<25 to >200 cm precipitation), clays were highly variable, and had a range of CEC s from 18 to 65 meq/l(X) g for the <4 /um fraction. 

Hsu, Pa Ho, 1968. Heterogeneity of montmorillonite surface and its effect on the nature of hydroxy-aluminum interlayers. Clays Clay Miner., 16 303—311. 

Since the first commercial announcements of Pillared Interlayered Clays (PILC) in 1979 (11. much interest has focused on these materials as potential sources of new materials in sorption, separations and catalysis. In this review I will attempt to summarise some of the recent developments that continue to make PILCs an exciting and opportunistic research area for the petroleum oriented industries. These developments can conveniently be divided into the following areas ... 

Cs Sorption to day interlayers Clay content, cation exchange capacity. 

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