Kaolinitic clay

Dihydropyran, K-10 clay, CH2CI2, it, 63-95% yield. Kaolinitic Clay is... 

MeO)3CH, Montmorillonite Clay K-10, 5 min to 15 h, > 90% yield. Diethyl ketals have been prepared in satisfactory yield by reaction of the carbonyl compound and ethanol in the presence of Montmorillonite Clay. Kaolinitic clay has also been used. ... 

Due to the TO structure of the clay, the interlayer H-bonding is very strong. This hinders the intercalation of any molecule or chain into the gallery. Hence, the kaolinite clay cannot be used for nanocomposite preparation. 

FIGURE 2.1 The layered structure of kaolinite clay. (From http /jan.ucc.nau.edu/doetqp/courses/env440/ env440 2/lectures/lecl9/Figl9 3.gif, access date 4.11.06.)... 

Adsorption of nonionic and anionic polyacrylamides on kaolinite clay is studied together with various flocculation properties (settling rate, sediment volume, supernatant clarity and suspension viscosity) under controlled conditions of pH, ionic strength and agitation. Adsorption and flocculation data obtained simultaneously for selected systems were correlated to obtain information on the dependence of flocculation on the surface coverage. Interestingly, optimum polymer concentration and type vary depending upon the flocculation response that is monitored. This is discussed in terms of the different properties of the floes and the floe network that control different flocculation responses. Flocculation itself is examined as the cumulative result of many subprocesses that can depend differently on system properties. 

At the boundary between uplands and wetlands there is, in some circumstances, an interaction between organic matter accumulation in sediments and the development of wetland conditions. Some level of organic matter accumulation is required to drive anaerobic metabolism. But also, because, in general, well-decomposed organic matter improves the water holding capacity of mineral soils, particularly in medium to coarse texmred sediments, and particularly if the clay mineralogy is dominated by low activity kaolinitic clays, there is a feedback between organic matter accumulation and the extent and duration of water saturation. 

In acids soils, particularly those with kaolinite clay minerals, soluble Fe + concentrations tend to rise to high levels because of low CEC and because conditions do not favour precipitation of Fe(II) oxides or carbonates or synthesis of silicates. 

Gehring AU, Fry IV, Luster J, Sposito G. 1993. The chemical form of vanadium(IV) in kaolinite. Clays and Clay Minerals 41 662-661. 

Ozone and UV light alone cannot oxide parathion. However, in the presence of ozone (300 ppb) and UV light, dry kaolinite clays were more effective than the montmorillonite clays in the oxidation of parathion. The Cu-saturated clays were most effective oxidizing parathion to paraoxon and the Ca-saturated clays were the least effective (Spencer et al., 1980). 

Biological. Under aerobic and anaerobic conditions, the rate of diquat mineralization in eutrophic water and sediments was very low. After 65 d, only 0.88 and 0.21% of the applied amount (5 mg/mL) evolved as carbon dioxide (Simsiman and Chesters, 1976). Diquat is readily mineralized to carbon dioxide in nutrient solutions containing microorganisms. The addition of montmorillonite clay in an amount equal to adsorb one-half of the diquat decreased the amount of carbon dioxide by 50%. Additions of kaolinite clay had no effect on the amount of diquat degraded by microorganisms (Weber and Coble, 1968). 

Mingelgrin, U., Saltzman, S., and Yaron, B. A possible model for the surface-induced hydrolysis of organophosphorus pesticides on kaolinite clays. Soil Sol. Soc. Am. J., 41 519-523, 1977. 

Weber, J.B. and Coble, H.D. Microbial decomposition of diquat adsorbed on montmorillonite and kaolinite clays, J. Agric. 

Saltzman et al. (1974) compare the persistence of parathion on a glass surface and adsorbed on an oven-dried Ca " -kaolinite clay (Fig. 16.13). Parathion is relatively stable on a glass surface, but it breaks down partially in an aqueous solution with pH 8.5 and degrades much more when adsorbed on dry Ca -kaolinite. The differences in degradation of parathion in water and on the clay surface suggest a strong catalytic activity of the Ca " -kaolinite. 

Kaolinite is the main constituent in china clay used to make porcelain. The layers are largely held together by van der Waals forces. Bentonite is used in cosmetics, as a filler for soaps, and as a plasticizer, and it is used in drilling-muds as a suspension stabilizer. Bentonite and kaolinite clays are used, after treatment with sulfuric acid to create acidic surface sites, as petroleum cracking catalysts. Asbestos also has a layered structure (Section 12.13). 

Isatoic anhydride undergoes a one-step conversion to o-aminophenyloxazolines 2 with amino alcohols via elimination of carbon dioxide. The reaction is carried out in the presence of kaolinitic clay in refluxing chlorobenzene. These o-aminophenyloxazolines, in particular, those derived from chiral amino alcohols,... 

A common and effective direct approach to unsubstituted or multiply substituted oxazolines is the Lewis acid catalyzed reaction of nitriles with amino alcohols in an alcoholic or aromatic solvent (chlorobenzene) at reflux. The most common Lewis acids employed include ZnCl2, ZnBr2, NiBr2, CuCl2, and kaolinitic clay. Microwave irradiation has also been reported to facilitate the transformation. Alternatively, the condensation can be carried out in the presence of catalytic amounts of potassium carbonate. The method works well for both aliphatic and aromatic nitriles, with retention of stereochemistry. Some representative examples from the recent literature are listed in Table 8.16 (Scheme 3 40),2 35.2oi-2i3... 

Keywords 2-hydroxybenzaldehyde, 2-hydroxyacetophenone, Meldrum s acid, kaolinitic clay, microwave irradiation, 3-carboxycoumarin... 

Prange JA, Gaus C, Papke O, Muller JF (2002) Investigations into the PCDD Contamination of Topsoil, River Sediments and Kaolinite Clay in Queensland, Australia. Chemosphere 46 1335... 

Wang, M. C., and Huang, P. M. (1989c). Pyrogallol transformations as catalyzed by nontronite, bentonite and kaolinite. Clays Clay Miner. 37, 525-531. 

Fruhstorfer, P., R.J. Schneider, L. WeU, and R. Niessner (1993). Factors inUuencing the adsorption of atrazine on montmoriUonite and kaolinitic clays. Sci. Total Environ., 138 317-328. 

Weber, J.B. and S.B. Weed (1968). Adsorption and desorption of diquat, paraquat, and prometone by montmorillonitic and kaolinitic clay minerals. Soil Sci. Soc. Am. Proc., 32 485 -87. 

In an effort to establish basic differences between Georgia soft kaolinites (clay feels soft and friable) and Georgia hard kaolinites (breaks with a conchoidal fracture and crumbles with difficulty between thumb and finger) Hinckley (1961) analyzed over three hundred samples. Although this is an empirical division it effectively divides... 

McLaughlin, R.J.W., 1959. The geochemistry of some kaolinitic clays. Geochim. Cosmochim. Acta, 17 11-16. 

Worrall, W.E. and Cooper, A.E., 1966. Ionic composition of a disordered kaolinite. Clay Miner., 6 341-344. 

In carrier flotation, small-sized (several pm diameter) particles become attached to the surfaces of larger particles (perhaps 50 pm diameter, the carrier particles) [630]. The carrier particles attach to the air bubbles and the combined aggregates of small desired particles, carrier particles, and air bubbles float to form the froth. An example is the use of limestone particles as carriers in the flotation removal of fine iron and titanium oxide mineral impurities from kaolinite clays [630]. The use of a fatty acid collector makes the impurity oxide particles hydrophobic these then aggregate on the carrier particles. In a sense, the opposite of carrier flotation is slime coating, in which the flotation of coarse particles is decreased or prevented by coating their surfaces with fine hydrophilic particles (slimes). An example is the slime coating of fine fluorite particles onto galena particles [630],... 

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