Vycor glass tubes

Porous Vycor glass tube (in double pipe configuration), wall thickness 3 mm, length 600 mm, outer diameter 15 mm, mean pore diameter 45 A. Feed enters the reactor at shell side, permeate at tube side. ... 

The membrane used was a Vycor glass tube (Corning Inc., code 7930), the dimensions of which were dinner = 7.8 mm, douter = 10 mm, and L = 100 mm. Vycor glass possesses a narrow pore size distribution, with a mean pore diameter of approximately 4 nm. 

The Vycor glass tube used in the membrane reactor experiments was filled with 3.2 g of catalyst. As the accessible area was ca. 30 cm2, the ratio of membrane area to catalyst mass is in the range specified by Eq. (35). Consequently, there should be sufficient membrane area available to remove significant amounts of hydrogen and, therefore, to have an effect on the reaction process. 

Hu and Bautista used a fluidized-bed electrochemical reactor to recover chromium from dilute solutions [20]. The particulate cathode bed contained chromium particles (20-mesh, 450-600 pm diameter) and carbon rod current feeders which projected into the center of the fluidized bed. The lead tube anode was separated from the cathode by a porous Vycor glass tube which was selective to hydrogen ions. Current effieiency for chromium deposition varied from 8 to 22% and increased with increasing chromium concentrations and current density. The conversion ratio (the ratio of the amount of Cr(III) formed to Cr(VI) consumed) was 0.77. 

Dehydrogenation of cyclohexane Pd-impregnated Vycor glass tube 288-345 136... 

Methane steam-reforming Pd layer on Vycor glass tube Ni 350-500 149... 

A solution of 1.00 g (3.9 mmol) of 9-diazothioxanthene-S,S-dioxidet l was irradiated using a Hanovia lamp (450 W) in 20 mL of styrene, placed in a 25 mL-size Vycor glass tube with a side arm, until the photolysis was complete and the red color of the solution turned yellow. The excess styrene was distilled at 0.01 Torr and the residue was separated by colunm chromatography (silica gel) with petrolether (bp 60 - 80 °C)/ ether (1 4). After evaporation of solvent and recrystallization from ether 1.05 g (82%), mp 171 °C were obtained. 

A solution of 0.30 g (1.5 mmol) of 9-diazo-4,5-diazafluorene 2.10f vide supra) in 20 mL of a-methylstyrene was irradiated with a Hanovia lamp (450 W) for six hours in a 25 mL Vycor glass tube while stirring. The reaction mixture was distilled under vacuum and the residue chromatographed on a silica gel column (ethyl acetate/methanol, 25 2). Solvent removal and recrystallization from ether yielded 0.23 g (54%) of 2.10h, mp 178 °C. 

The tubing containing the coupon samples were placed inside a Vycor glass tube (2.2 cm. I. D. and 85 cm.long) that was positioned horizontally in an electrical furnace controlled at either 700 or 900°C. For inorganic gas treatments Incoloy 800 and polished Incoloy 800 coupons were positioned side by side 4. 5 cm. upstream of the reactor midpoint polished and unpolished aluminized Incoloy 800 coupons were likewise positioned side by side except 2.0 cm. upstream... 

Porous membranes used for reactant feed are typically mesoporous or macro-porous. Two problems arise control of the rate of addition and distribution of reactant B, and back-diffusion of reactant A. To control the uniformity of the distribution of B, we want the membrane to present enough resistance to equalize pressure on the reactant B side, giving a constant transmembrane pressure drop along the tube. This may mean modification of thin y-alumina mesoporous membranes or use of Vycor glass tubes.A higher pressure drop also helps reduce the driving force for back-diffusion, which was exploited in the pneumatic... 

Stoichiometric amounts of Cu and red P are heated for 20 hours at 640°C in an evacuated, sealed Vycor glass tube. The reaction product is homogenized, melted in a sealed quartz tube, and heated for five hours at 1000°C. 

Pyrolysis conducted in vertically-mounted, externally-heated, 49 cm Vycor glass tube containing a 30 cm bed of 1/8 Pyrex helices. 

Dimethyl 3-methylenecyclobutane-l,2-dicarboxylate passed during 3 hrs. at 300-600°/25 mm through a vertical N2-flushed Vycor-glass tube packed with glass ringsmethyl butadienoate (Y 40-44%) and methyl acrylate (Y 48-55%). H. B. Stevenson and W. H. Sharkey, Org. Synth. 43, 71 (1963). 

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