Sodium aluminosilicate

Table 3. Some Synthetic Zeolites Prepared from Sodium Aluminosilicate Gels...

Type 4A sieves. A crystalline sodium aluminosilicate with a pore size of about 4 Angstroms, so that, besides water, ethane molecules (but not butane) can be adsorbed. This type of molecular sieves is suitable for drying chloroform, dichloromethane, diethyl ether, dimethylformamide, ethyl acetate, cyclohexane, benzene, toluene, xylene, pyridine and diisopropyl ether. It is also useful for low pressure air drying. The material is supplied as beads, pellets or powder. 

Type 13X sieves. A crystalline sodium aluminosilicate with a pore size of about 10 Angstroms which enables many branched-chain and cyclic compounds to be adsorbed, in addition to all the substances removed by type 5A sieves. 

Other anticaking ingredients include ferric ammonium citrate, silicon dioxide, sodium ferrocyanide, magnesium silicate, magnesium carbonate, propylene glycol, aluminum calcium silicate, sodium aluminosilicate (also called sodium silicoaluminate), and calcium phosphate. 

By using 10 mol% of 51, MS4A, and t-BuSH, the desired product 52 was obtained in up to 98% ee in 80% yield. A complementary role by two metals (Ga and Li) in activating and positioning both of the substrates has been proposed. The MS4A (sodium aluminosilicate) accelerated the reaction however, the actual role of this additive was not clearly defined, although the possibilty that MS4A delivers Na ions was pointed out. Tomioka et al. reported the asymmetric Michael addition of an aromatic thiol to a,P-unsaturated esters in the presence of 8 mol% of 53 to provide 54 in up to 97% ee in 99% yield (Eq. 7.40) [47]. 

Molecular sieves (zeolites) are artificially prepared aluminosilicates of alXali metals. The most common types for gas chromatography are molecular sieve 5A, a calcium aluminosilicate with an effective pore diameter of 0.5 nm, and molecular sieve 13X, a sodium aluminosilicate with an effective pore diameter of 1 nm. The molecular sieves have a tunnel-liXe pore structure with the pore size being dependent on the geometrical structure of the zeolite and the size of the cation. The pores are essentially microporous as the cross-sectional diameter of the channels is of similar dimensions to those of small molecules. This also contrilsutes to the enormous surface area of these materials. Two features primarily govern retention on molecular sieves. The size of the analyte idiich determines whether it can enter the porous... 

Park, H "Thermodynamics of Sodium Aluminosilicate Formation in Aqueous Alkaline Solutions Relevant to Closed-Cycle Kraft Pulp Mills", PhD Thesis, Dept, of Chemical and Bio-Resource Engineering, University of British Columbia, Vancouver, BC, Canada, 1999. 

All the silica present in the bauxite was converted to insoluble sodium aluminosilicate, which represented a loss of sodium and aluminum. The aluminum hydroxide was calcined to the oxide, and the sodium carbonate solution was concentrated for re-use. The process was developed by H. E. St-Claire Deville in the 1860s the carbon dioxide stage had been invented earlier by H. L. Le Chatelier. It was superseded by the Bayer process. 

Figure 11.1 Batch reactors (a) schematic representation showing some features (b) pilot plant reactor for production of sodium aluminosilicate (Courtesy of National Silicates Ltd.)...

Sodium aluminate, 2 345t, 358-359 analysis, 2 275-276 economic aspects, 2 275 health and safety factors, 2 276 manufacture, 2 274-275 neutralization, 2 424 physical and chemical properties of, 2 273-274 uses of, 2 276-277 in water treatment, 26 111 Sodium aluminosilicate gels, synthetic zeolites prepared from, 16 831t Sodium aluminosilicates, 12 578 Sodium aluminum hydride, 13 621, 623-624... 

Barrer, R.M. and White, E.A.D. (1952) The hydrothermal chemistry of silicates. Part 11. Synthetic crystalline sodium aluminosilicates./. Chem. Soc., 1561-1571. 

Flanigen monitored the changes in the IR spectra that occur during the synthesis of NaX zeolite from a sodium aluminosilicate gel. The appearance of absorption bands due to the formation of structural units in the zeoUte as the crystallization of NaX proceeded were observed [93]. In particular, the growth of a band around 575 cm indicated the formation of double six-rings which is one of the structural sub-units of X zeolite. 

The present study deals with the application of RDF to the sodium aluminosilicate hydrogels, which were formed by mixing, aging and heating of sodium silicate solution with sodium aluminate solution under stirring, in order to produce NaA-zeolite crystal. 

Since the main peaks are 3.25A, 4.2-4.6A and 7.0A, the most reasonable unit structure of the sodium aluminosilicate hydrogel is the 4-member chain illustrated in Fig, 11. Many 4-member chains easily form sodalite cages as shown in Fig. 12. In the case of a simpler silica structure, the double 4-member ring (cube) was recognized by Sakka et al C5). 

TABLE 2. SOME SYNTHETIC ZEOLITES PREPARED FROM SODIUM ALUMINOSILICATE OELS... 

Many complex silico-aluminates or aluminosilicates are formed in nature. Of these, clay in more or less pure form (pure clay, kaolinite kaolin, china clay. HrjSiiA Oc) or AI2O3 2SiC>2 2H2O) is of great importance. Clay is formed by the weathering of igneous rocks, and is used in the manufacture of bricks, pottery, porcelain, Portland cement. Sodium aluminosilicate is used in water purification to remove dissolved calcium compounds. 

Aluminosilicate Sodium aluminosilicate is used as a water softener for the removal of dissolved calcium compounds. 

Zeolite Na-A was synthesized in our laboratory. After crystallization from the sodium aluminosilicate gel, the zeolite was carefully washed with deionized water in order to remove occluded impurities without causing H30+ ion exchange. It was then stored in a desiccator containing saturated NH4CI solution. 

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