Laponite synthetic

SCPX2231 Laponite synthetic clay now from Southern Clay Co. with 2M2HT... 

The first examples of cationic exchange of bis(oxazoline)-metal complexes used clays as supports [49,50]. Cu(II) complexes of ligands ent-6a, 6b, and 6c (Fig. 15) were supported on three different clays laponite (a synthetic clay), bentonite, and montmorillonite KIO. The influence of the copper salt from which the initial complexes were prepared, as well as that of the solvent used in the cationic exchange, was analyzed. 

Vaccari (1983,1999) has given a state-of-the-art account of the preparation and catalytic properties of cationic and anionic clays. Some examples of industrial importance have also been reported. Clays exhibit many desirable features, such as low cost, wide range of preparation variables, ease of set-up and wOrk-up, high selectivity, and environmental friendliness. Cationic clays are widespread in nature, whereas anionic clays are rarely found in nature, but they can be synthesized cheaply. Cationic clays are prepared from the minerals but industrial anionic clays are generally synthetic. Smectite clays exhibit both Brpnsted and Lewis acid sites on the edges of the crystals. Hammet s acidity function values are as follows Na -montmorillonite (M), -3 to t- 1.5 NH4VM -3 to 1.5 H M -8.2 to -5.6 acid activated clay less than -8.2. Laporte also has a synthetic version of cationic clays, Laponite. The acid... 

There are many other forms of clay including synthetic clays such as laponite, a synthetic hectorite. Suitable tuning of the properties of these systems can produce similar structures. These systems have the advantage of small particle size and a relatively improved level of particle monodispersity over their naturally occurring counterparts and are being increasingly used as rheology modifiers. 

Exchange of organic ammonium cations. Exchange selectivity of monovalent alkyl ammonium cations in montmorillonites (40-41) and octahedrally substituted synthetic clay minerals (laponite) increases with their chain length (42) and along the series... 

Plaizier-Vercammen JA. Viscous behaviour of laponite XLG, a synthetic hectorite and its use in pharmaceutical dispersions. [In Dutch]. Farmaceutisch Tijdschrift voor Belgie 1994 71(4—5) 2—9. 

Chiral (Salen)Mn complex Synthetic Laponite Ion-exchange... 

KIO montmorillonite and NaY zeolite were purchased from Aldrich, bentonite from Fluka and silica gel from Merck (silica gel 60), iron free synthetic laponite was generously provided by Chimie Labessor. 

Laponite, a synthetic hectorite clay, when suspended in water, forms disclike particles with a thickness of 1 nm, a diameter of about 25 nm, and a negative surface charge density stabilizing dispersions in water. Formation of a cross-linked polymer network using a small amount of Laponite indicates that these nanoparticles act as a multifunctional cross-linker with a large effective functionality (Okay and Oppermann 2007). 

The major elass of plate-like colloids is that of clay suspensions [21]. Many of these swell in water to give a stack of parallel, thin sheets, stabilized by eleetrieal eharges. Natural elays tend to be quite polydisperse. The synthetic clay laponite is comparatively well defined, eonsisting of dises of about 1 nm in thiekness and 25 nm in diameter. It has been used in a number of studies (e.g. [22]). 

In these derivatives, the substituted bipyridyl ligand has a mesogenic character. The derivative (rac)-(6.30) is obtained by the zinc reduction of Ru (acac)3 followed by addition of the bipyridyl ligand (L). The two enantiomers (A)-(6.30) and (A)-(6.30) are separated by chromatography on a column of synthetic laponite doped with [Ru(phen)3] " (Scheme 6.1). 

Stanionary phase Synthetic Laponite + (A)-[Ru(phen)3] Eluent 1/4 chloroform methanol... 

Fig. 2 Intensity of the second harmonic signal versus the amount of PDDA offered in solution (Cpdda in moles/L) for the film glass/clay/PDDA/NAMO. Lap= laponite Hec= hectorite Sme= synthetic saponite APTS=3-aminopropyltrimethoxysilane and TMSPA=trimethoxysilylpropyltrimethymammonium.

For instance, Herrera et al. recently conducted a series of experiments on Laponite [280-283]. Laponite is a synthetic clay that is similar in structure to MMT, except for the nature of the interlayer cation (Mg + for Laponite and Al + for MMT) and the clay dimensions. Each elementary Laponite disk has a thickness of around 1 nm and a diameter of 30 0 nm. In addition, Laponite also has the advantage over natural clays of being chemically pure and free from external contaminations. All these properties make Laponite a valuable candidate for use in PCN synthesis. 

Since the initial absorption (i.e. color) of the nanocomposite increases with montmorillonite addition, future investigations should focus on examining synthetic aluminosilicates that do not contain isomorphic substitution from transition metals such as Fe. Alternative types of inorganic fillers include laponite, fluorohectorite or synthetic silicic acids (31). Note that the UV exposure is not only an on-orbit concern, but will drastically affect life-cycle and long-term environment stability and performance of nanocomposites used in external terrestrial environments. 

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