Drying silica-alumina

Fig. 15. (4) Spectrum of NH3 chemisorbed on dried silica-alumina (B) and (( ) after rehydration.

Fio. 15. 1,1-Diphenylethylene vapor adsorbed in vacuo. Curve 1 on dry silica-alumina catalyst curve 2 on a hydrated silica-alumina. Transmission spectra, from Webb (92). Band 1 is that of the carbonium ion, band 2 is that of the cation radical. 

Perfluoro(methylcyclohexane) [355-02-2] M 350.1, b 76.3", d 1.7878. Refluxed for 24h with saturated acid KMn04 (to oxidise and remove hydrocarbons), then neutralised, steam distd, dried with P2O5 and passed slowly through a column of dry silica gel. [Glew and Reeves J Phys Chem 60 615 1956.] Also purified by percolation through a Im neutral activated alumina column, and H-impurities checked by NMR. 

As shown in Fig. 17, the number of protons from a series of silica-alumina samples with differing BET surface areas is a nearly linear function of surface area, indicating that essentially all of the protons are situated in the surface phase of the solid. The samples corresponding to the data of Fig. 17 were prepared by steam sintering of the above-mentioned 425 meterVgram sample at various temperatures above 500° so as to reduce the surface area to the values given and then soaked in water for 4 hours, oven-dried at 110° and evacuated at 500° for 16 hours. A plot somewhat similar to Fig. 17 has been obtained for silica gel. The slope of the best straight line repre-... 

By achieving random dispersion of the Kaolin in the sodium silicate solution prior to formation of the silica-alumina gel, it was possible to disperse the clay crystals. They condensed somewhat perpendicular to each other and were bound together by silica-alumina gel. I therefore speculated that spray drying, during which the gel system contracts, might create a dual structure. An analogy would be a house built of cards (Kaolin), cemented together with silica-alumina gel. 

In its dry state, alumina exhibiting basicity reacts with silica, forming aluminum silicate... 

Thin layer chromatography is in principle similar to paper chromatography when used in the ascending method, i.e. the solvent creeps up the stationary phase by capillarity. The adsorbent (e.g. silica, alumina, cellulose) is spread on a rectangular glass plate (or solid inert plastic sheet). Some adsorbents (e.g. silica) are mixed with a setting material (e.g. CaSC>4) by the manufacturers which causes the film to set on drying. The adsorbent can... 

In oxychlorination. ethylene reacts with dry HC1 and either air or pure oxygen to produce EDC and water. While commercial oxychlorination processes may differ from one another to some extent because they were developed independently by many different vinyl chloride producers, in each case the reaction is carried out in the vapor phase in either a fixed- or fluidized-bed reactor containing a modified Deacon catalyst. Cupnc chloride is usually the primary active ingredient of the catalyst, supported on a porous substrate such as alumina, silica-alumina, or diatomaceous earth. The oxychlorination reaction is highly exothermic (AH = —239 kJ/mol for eq. 3) and requires heat removal for temperature control. 

In Figure 10 the experimental ZPCs of hydrous silica-alumina coprecipitates (64) are compared with those of dried and ignited silica-alumina catalysts (49), some of the previously discussed aluminosilicate minerals, and the composition dependence derived from Equation 18 assuming ... 

Fig. 6. Infrared spectra of silica-alumina catalyst A, unheated B, dried at 500°C under vacuum C, dried catalyst with chemisorbed ammonia (35). (Reprinted with permission of the American Chemical Society.)...

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