Purified bentonite

Bentonite Purified Bentonite Bentonite Magma Method IV NF (19, pp. 2416, 2417 and 2418)... 

The USPNF 23 describes bentonite, purified benonite, and bentonite magma in three separate monographs. Bentonite is described as a native, colloidal, hydrated aluminum silicate and purified bentonite is described as a colloidal montmorillonite that has been processed to remove grit and nonswellable ore compounds. 

Potassium bisulfite Potassium myristate Potassium propionate Powdered fructose Propan-1-ol (S)-Propylene carbonate Propylparaben potassium Propylparaben sodium Purified bentonite Purified stearic acid Quaternium 18-hectorite Rapeseed oil Refined almond oil Refined olive-pomace oil... 

Figure 2.11. Bentonite purified and spray dried. Courtesy of Rheox, Inc., Hightstown, NJ, USA.

Nltroestrone (2)/ Claylen was prepared from a mixture of Fe(N03)3 H2O (45 g Oil mol), K 10 bentonite clay and MeaCO (750 mL) Freshly prepared Claylen" (2 0 g) was added to estrone 1 (0 54 g 2 mmol) and PhMe (150 mL) The suspension was slirred overnight at 20° and filtered under vacuum The yellow liltraie was purified by column chromatography on sdica gel (n-hexane ElOAc 8 2] Evaporation of the corresponding fraction afforded 0 347 g of 2 (55%) mp 178 180°C... 

The latter two points usually tip the balance in favour of using purified enzymes. Ideally the enzyme should be easy to isolate. The penicillin acylase from Bacillus megaterium is, for example, an extracelluar enzyme and can be readily absorbed into bentonite. 

Recently, greases have been developed in which chemically altered bentonite is used as a thickener instead of soap 10). The bentonite is purified by removal of silica and is altered chemically by reaction with alkyl amines. 

A source of error in chemical analyses of montmorillonites (and in other clays) that is not commonly checked is the presence of amorphous material, particularly Si and Al. Table XXXII lists structural formulas given by Osthaus (1955) for montmorillonites which were purified by size fraction and by extraction with 0.5 N NaOH to remove amorphous Si and Al. In six analyses dissolved silica ranged from 3.6 to 8.4% and alumina from 0.6 to 2.25%. Amorphous silicon dioxide should be expected in most montmorillonites derived from volcanic material. The source glass has more Si than is required for the 2 1 layer and the excess must be leached from the glass. Much of the Si is deposited in the sediments underlying the bentonite bed in the form of chert but it is to be expected that the extraction would not be complete and a portion of the colloidal Si would remain in the bentonite bed. 

Many other materials, including synthetic aluminas, aluminum carbonates, aluminum silicates, magnesium silicates, various forms of attapulgite and sepiolite (81-83), alumina-pillared acid-activated montmorillonite (84), synthetic mica mont-morillonite, HY-zeolite, zirconium phosphate (85), mica, kaolin, and synthetic hectorite (86), have been evaluated for their ability to purify virgin fats and oils, but none were as good as acid-activated bentonite. 

The USPNF 23 also contains specifications for bentonite magma and purified bentonite. See Section 17. 

Bentonite magma kaolin magnesium aluminum silicate magnesium trisilicate purified bentonite talc. 

Comments a 5% w/w suspension of bentonite in purified water appears in some pharmacopeias, such as the USPNF 23. 

Benna, M. et al.. Effect of pH on rheological properties of purified sodium bentonite suspensions, 7. Colloid Interf. Sci., 218, 442, 1999. 

The active compound corresponding to peak 7 was purified in two stages by ion-exchange chromatography on DEAE Sepharose and then affinity chromatography on Concanavaline A (Moine-Ledoux, 1996). The purified product was highly effective for protein stabilization, as only a few mg/1 were sufficient to make a Sauvignon Blanc wine perfectly stable. It would otherwise have required bentonite treatment at a rate of 100 g/hl. 

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