Alumina, water removal

Adsorbent Applications. One of the earliest uses for activated alumina was removal of water vapor from gases and this remains an... 

Tri-n-octylphosphine oxide [78-50-2] M 386.7, m 59.5-60°, pK jt <0. Mason, McCarty and Peppard [J Inorg Nuclear Chem 24 967 7962] stirred an O.IM solution in benzene with an equal volume of 6M HCl at 40° in a sealed flask for 48h, then washed the benzene solution successively with water (twice), 5% aq Na2C03 (three times) and water (six times). The benzene and water were then evaporated under reduced pressure at room temperature. Zingaro and White [J Inorg Nucl Chem 12 315 7960] treated a pet ether solution with aqueous KMn04 (to oxidise any phosphinous acids to phosphinic acids), then with sodium oxalate, H2SO4 and HCl (to remove any manganese compounds). The pet ether solution was slurried with activated alumina (to remove phosphinic acids) and recrystd from pet ether or cyclohexane at -20°. It can also be crystd from EtOH. 

Most y-alumina powders placed under high vacuum and heated at moderate temperature (373-423 K) undergo complete water removal, and nearly all of the surface aluminum atoms are hydroxylated. Additionally, for hydroxylated alumina thin films prepared via aluminum evaporation/water oxidation cycles, although the surface density of OH groups would be the same as for powders, the specific surface area differs significantly [9]. 

Metallic beryllium is produced by reduction of beryllium halide with sodium, potassium or magnesium. Commercially, it is obtained primarily from its ore, beryl. Beryllium oxide is separated from silica and alumina in ore by melting the ore, quenching the solid solution, and solubilizing in sulfuric acid at high temperatures and pressure. Silica and alumina are removed by pH adjustment. Beryllium is converted to its hydroxide. Alternatively, beryl is roasted with complex fluoride. The products are dissolved in water and then pH is adjusted to produce beryllium hydroxide. 

Ammonium d-a-bromocamphor-n-sulphonate [14575-84-9] M 328.2, m 284-285°(dec), [oc]q +84.8 (c 4, H2O). Passage of a hot aqueous soln through an alumina column removed water-soluble coloured impurities which remained on the column when the ammonium salt was eluted with hot water. The salt was crystd from water and dried over CaCl2 [Craddock and Jones JACS 84 1098 1962]. 

To dried resins 19 and 21 (0.1 g resin, approximately 0.04 mmol with respect to the loading of the phenol) are added Pd(OAc)2 (8.0 mg), 1,3-bis (diphenyl-phosphino)propane (dppp, 17.0 mg), DMF (1.4 ml), and a mixture of HC02H (0.2 ml) and TEA (0.8 ml). The mixture is shaken at 85° for 2 h, and then the resin is filtered and washed several times with diethyl ether. The combined organic phase is washed with aqueous sodium carbonate solution then water and evaporated to dryness. The residue obtained is dissolved in diethyl ether and eluted through a short column of alumina to remove any remaining inorganic residues. The crude products are purified by preparative TLC (or other suitable methods) to give the desired products 20 and 22 in >95% purity. 

J.J. Schoeman, H. Macleod, The effect of particle size and interfering ions on fluoride removal by activated alumina, Water SA 13 (4) (1987) 229-234. 

The dynamic desiccant capacity of the alumina in a TSA process depends on the type of alumina, nature and composition of the feed stream, regeneration temperature, etc. A typical water removal capacity for alumina is 5-15% by weight. The typical total cycle time for a TSA process is 2-8 hours. 

The newer data (106), showing complete restoration of the maximum activity by only about 5 x 10 ev/gm, are harder to reconcile with a water-removal mechanism, although the absolute amount of water to produce the sensitive catalyst cannot be estimated, since this sample was prepared by a 200° evacuation of the raw catalyst rather than by back-addition of water to a thoroughly pumped one. More data on the effect of water content on activity are obviously necessary if we wish to be able to judge the feasibility of water removal as a mechanism for the radiation effect on alumina. 

Materials. Scoured cotton cellulose fibers of the Acala variety supllied by Kanebo Co Ltd. were piirified by extracting with hot benzene-ethanol mixture (l l vol. ratio) for 2kh. Then the cotton fibers were washed with methanol and distilled water and air-dried. Acrylamide (AM) was purified by recrystallization from benzene for several times. Bis-(beta-chloroethyl) vinylphosphonate (Fy) was purified by passing the monomer through a column filled up with activated alumina to remove inhibitors of polymerization. Other chemicals used were reagent grade, and were used without further purification. 

Trimethylpentane (isooctane) [540-84-1] M 114.2, m -107 , b 99.2 , dl 0.693, ng 1.39145, ng 1.38898. Distil isooctane from sodium, pass it through a column of silica gel or activated alumina (to remove traces of olefins), and again distilled from sodium. Extract repeatedly with cone H2SO4, then agitate it with aqueous KMn04, wash it with water, dry (CaS04) and distil it. Purify it also by azeotropic distillation with EtOH, which is subsequently washed out with water, and the trimethylpentane is dried and fractionally distilled. [Forziati et ai. J Res Nat Bur Stand 36 126 7946.] [Beilstein 1IV 439.]... 

Aldehyde (1 mmol), NH2OH HC1 (0.3 g, 0.4 mmol), MeS02Cl (0.075 ml, 1 mmol) and dry alumina (0.5 g, 4.9 mmol, Fluka type 405 acidic, dried in an oven for 5 h) were thoroughly mixed with a mechanical stirrer. The resulting fine powder was transferred to a round-bottom flask (5 mL) and heated in an oil bath at 100 °C for an appropriate time. Then diethyl ether (10 mL) was added to the reaction mixture and alumina was removed by filtration. The filtrate was extracted with water (2 10 mL), dried over Na2S04 and the solvent evaporated in vacuo to give the crude product. If solid this was purified by recrystallization from EtOH and if liquid then by distillation. 

Isolation and Fractionation of Membranes. Mycelia from 48 hr cultures were separated from the growth medium by filtration and the mycelia were washed with several volumes of distilled, deionized H2O at 4°C and the water removed from the mycelia by pressing between paper towels. The mycelia were pulverized at 4°C in 50 mM Tris-HCl, pH 7.5 buffer with AI2O2 ratio of mycelia alumina buffer, 1 0.3 2 (w/w/v). Membranes were isolated from the homogenate essentially as described previously... 

---