Montmorillonite clays Subject

Allyl groups are subject to oxidative deprotection with Chromiapillared Montmorillonite Clay, -BuOOH, CH2CI2, isooctane, 85% yield. Allylamines are cleaved in 84—90% yield, and allyl phenyl ethers are cleaved in 80% yield. 

On the subject of montmorillonite clay, the quite interesting reaction reported by Paechthorowitz and Eirich (1988) should be mentioned. The reaction sequence involves the coupling of an amino acid to form a polypeptide-nucleotide compound, as shown in Figure 4.2. 

The DMA of rubber-based nanocomposites has been the subject of recent research. Many literature reports describe the dynamic mechanical behavior of rubber-based nanocomposites [155, 156]. Das et al. have studied the DMA of CR nanocomposites based on montmorillonite clay and LDH [157]. The montmorillonite clay is... 

These simple examples included only polymer and plasticizer. In normal formulations many other components exist and interact. Many studies address this subject in order to determine how to limit plasticizer loss. Montmorillonite clay was used as filler in PVC/ PMMA composite. The filler was used in its original and intercalated form to make polymer hybrid in which filler is dispersed on a molecular level. Totally different behavior was observed when composites were immersed in a solvent plasticizer mixture followed by drying. The sample containing the intercalated filler absorbed 50% less plasticizer than did any other sample studied. Thus plasticizer movement may be restricted by other than chemical interaction. These include physical obstacles in migration pathways that can also influence plasticizer distribution in a matrix. 

Nanofillers are increasingly being used as high-performance additives for plastics and Finegan et / [ 51 ] have used DMA to qualitatively and quantitatively study the fibre-matrix adhesion of various carbon nanofibres that had been subjected to several different types of surface treatments in a polypropylene matrix. Lee, Hsieh and McKinley [52] have characterised a nanocomposite of poly(methylmethacrylate) containing 1-7.5% of modified montmorillonite clay. They established a number of relationships, which included that the storage and loss moduli were strongly dependent upon the clay content, and that the presence of the clay increased the distortion temperature of the plastic. 

Berteau montmorillonite subjected to 2 (i), 5 ( ) and 10 ( ) wetting-drying cycles (101). Jurves re a simulation. Table VI shows these data for the (Ca - Cs ) equilibrium. Reproduced with permission from Ref. 101. Copyright 1985, The Clay Minerals Society. 

Some of the clays that enter the ocean are transported by river input, but the vast majority of the riverine particles are too large to travel fer and, hence, settle to the seafloor close to their point of entry on the continental margins. The most abundant clay minerals are illite, kaolinite, montmorillonite, and chlorite. Their formation, geographic source distribution and fete in the oceans is the subject of Chapter 14. In general, these minerals tend to undergo little alteration until they are deeply buried in the sediments and subject to metagenesis. 

The sol-pillared clay was prepared following the procedures of Yamanaka et al (1). The mixing ratio of Afsi (mol)/A/T,(moI)/CEC equivalent of clay was 30/3/1. SiC -TiCh sol pillared montmorillonite, subjected to a calcination for 4h at 773 K, was labeled as sol-PILM. Portions of the wet cake prepared with bentonite were subjected to SCD or treatment with surfactants as described below. 

To activated montmorillonite K-10 clay (2 g) in a 100-mL Erlenmeyer flask was added a mixture of freshly distilled phenol (0.50 g, 5.3 mmol) and recrystallized p-methoxycinnamic acid (0.94 g, 5.3 mmol) dissolved in CH2CI2 (5 mL) along with one drop of concentrated H2SO4. The solvent was evaporated and the resultant free-flowing solid placed on a silica bath and subjected to microwave irradiation at 640 W for 10 min. Dichloromethane (20 mL) was added, the reaction mixture filtered and the filtrate washed with saturated NaHC03 solution, brine and dried over Na2S04. Evaporation of the solvent in vacuo yielded the product, 1.05 g (82%). 

The a-phenoxy acetophenone 2 (212 mg, 1 mmol) was dissolved in minimum amount of dichloromethane, adsorbed over montmorillonite KSF clay (sub-strate clay=l 2 w/w). It was transferred into a test tube and subjected to micro-wave irradiation (BPL make, BMO 700T, 650 W, high power). The reaction was monitored by TLC. After completion of the reaction (6 min) it was leached with dichloromethane (3x 10 mL). The solvent was evaporated under reduced pressure and purified through column chromatography using ethyl acetate-hexane (9 1) to give 3-phenylbenzofuran (165 mg, 85%). 

In these experiments a commercially available bentonite, marketed under the name Colclay A90 (Ankerpoort, Geertruidenberg, The Netherlands) was used. It is a sodium-montmorillonite with a third of the exchange complex occupied by calcium. 5.0 g of the air-dried powdered bentonite was weighed into a stainless steel mould with an ID of 50 mm between two porous stones of the same diameter. Then the clay was subjected to a compaction pressure of 20.3 MPa for 30 minutes. After compaction, the mould was placed in a bowl of NaCl-solution for five days in which the clay became saturated and swollen. Thus samples were obtained with thickness of 3.8 and 2.8 mm respectively and a diameter of 50 mm. 

The research on the catalytic applications of clay minerals has been the subject of considerable interest for some time [1-2]. On account of their lamellar structure, clays can be excellent host materials for various metals, and thus the precursors of clay intercalated metal catalysts [3]. This paper reports on the catalytic behaviour of novel Pd intercalated montmorillonites. 

Polymer clay nanocomposites have, for some time now, been the subject of extensive research into improving the properties of various matrices and clay types. It has been shown repeatedly that with the addition of organically modified clay to a polymer matrix, either in-situ (1) or by melt compounding (2), exfoliation of the clay platelets leads to vast improvements in fire retardation (2), gas barrier (4) and mechanical properties (5, 6) of nanocomposite materials, without significant increases in density or brittleness (7). There have been some studies on the effect of clay modification and melt processing conditions on the exfoliation in these nanocomposites as well as various studies focusing on their crystallisation behaviour (7-10). Polyamide-6 (PA-6)/montmorillonite (MMT) nanocomposites are the most widely studied polymer/clay system, however a systematic study relating the structure of the clay modification cation to the properties of the composite has yet to be reported. 

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