Precipitate carbonate group precipitates

The nanotubes were first oxidized in nitric acid before dispersion as the acidic groups on the sidewalls of the nanotubes can interact with the carbonate groups in the polycarbonate chains. To achieve nanocomposites, the oxidized nanotubes were dispersed in THF and were added to a separate solution of polycarbonate in THF. The suspension was then precipitated in methanol and the precipitated nanocomposite material was recovered by filtration. From the scanning electron microscopy investigation of the fracture surface of nanotubes, the authors observed a uniform distribution of the nanotubes in the polycarbonate matrix as shown in Figure 2.3 (19). 

Any thallium not precipitated in Group I as T1C1, will ultimately be found in the precipitate of Group IIIB. It is best to dissolve the Group IIIB precipitate in dilute nitric acid, boil to expel H2S, add a few drops of sulphurous acid and boil to expel excess S02. The resulting solution is then poured into excess sodium carbonate solution when the carbonates of cobalt, nickel, manganese, and zinc are precipitated. The thallium remains in solution as thallium(I) carbonate and can be precipitated as thallium(I) sulphide, T12S, by the addition of ammonium sulphide solution. 

According to the above reactions, removal of carbonate groups from the mineral surface should result in the reduction of the intensity of carbonate peak as shown in Fig. 4.33. On the other hand, adsorption and surface precipitation of oleate can take place on the dolomite surface leading also to similar reductions. A new peak at 1351 cm when the oleate concentration reaches about 10 mol/1 can be clearly seen in Fig. 4.33b and the intensity of this peak increases with the increase in the oleate concentration, where precipitation of calcium and magnesium oleates is likely to occur both on the particle surface and in the bulk. The peak heights of both the carbonate and the oleate (7co and 7oi) in the spectra were measured. Bulk precipitation using a common tangent baseline method (Willis et al., 1987) and the ratio Ico/Ioh is plotted in Fig. 4.34. This plot also... 

The existence of competitive precipitation phenomena have a direct influence on the film composition which is presently a matter of increasing attention [44]. Cyanamide and hydroxide groups have been found as major impurities in CdS films at levels which can reach 20% [140]. Carbonate groups have been recently evidenced too... 

For the precipitation from copper nitrate in the above experiments, Fujita et al. have also reported that intermediates or precursors were altered depending on the feed rate. MA was formed by slow addition but, while using fast or medium feeding rate, the initial precipitates are amorphous. These amorphous precipitates were found to have hydroxyl and carbonate groups by FTIR measurement and they decomposed to CuO at elevated... 

Because the group 14 elements bond covalently, they do not lend themselves to identification through flame tests. The exception is lead, which produces a light-blue color. The carbon group elements can be identified through analysis of their physical properties (melting point, boiling point, density), emission spectra, or reactions with other chemicals. For example, tin and lead form precipitates when added to specific solutions. 

As expected, the addition of barium hydroxide results in a somewhat higher retention of all components this effect is more pronounced with lactose and cellobiose. The retention increase is attributed to the complete removal of carbonate, which precipitates in the eluent reservoir as low-soluble barium carbonate. The improved peak shape for ribose that Angyal [225] attributes to the complexation of sugar molecules by alkaline-earth metals, especially by Sr(II) and Ba(II), is remarkable. Sugar molecules with a six-membered ring and a sequence of an axial (ax), an equatorial (eq), and an axial (ax) hydroxide group bind alkaline-earth metals very strongly. Ribose has such a structure as shown here ... 

The chemistry of derivatives of laudanosine where the methylene carbon of the benzyl group is oxygenated has been the subject of several studies. The known isomeric a- and (8-hydroxylaudanosines 147) have been resolved 148). The -isomer (LXXXVII) can be oxidized to ketolaudanosine (LXXXVIII) by the action of potassium /-butoxide in the presence of benzophenone and, in turn, the keto base can be easily reduced to the original product with sodium borohydride. Ketolaudanosine (mp 56°-58.5°) was first obtained by reduction of papaveraldine methosulfate with sodium borohydride in aqueous solution in the presence of sodium carbonate which precipitates the initially reduced base. When methanol is used as a solvent the ketolaudanosine does not precipitate and /3-hydroxylaudanosine (LXXXVII) is the end product of the reaction 135). 

According to the Colour Index (1971), synthetic calcite can be produced industrially in two ways (1) from conversion of calcium oxide, and (2) as a precipitate of calcium chloride with sodium carbonate. The resultant compound was often used as a base for lake pigments and as an extender for others. However, see calcium carbonates group for a fuller discussion of synthesis. The Colour Index designation for this pigment is Cl 77220/Pigment White 18. The term whiting also may refer to a synthetic calcimn carbonate. 

Precipitated calcium carbonate is treated prior to precipitation with sodium stearate, generating a calcium carbonate-stearate precipitate. Since stearate groups are not compatible with the calcite (or aragonite) crystal, they appear at the particle surface. 

Kea.tlte, Keatite has been prepared (65) by the crystallisation of amorphous precipitated silica ia a hydrothermal bomb from dilute alkah hydroxide or carbonate solutions at 380—585°C and 35—120 MPa (345—1180 atm). The stmcture (66) is tetragonal. There are 12 Si02 units ia the unit cell ttg = 745 pm and Cg = 8604 pm the space group is P42. Keatite has a negative volumetric expansion coefficient from 20—550°C. It is unchanged by beating at 1100°C, but is transformed completely to cristobahte ia three hours at 1620°C. 

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