Sintered filters

Sintered filters A self-supporting sinteted element used in gas cleaning systems. 

After the identification of the suitable compound bands, silica gel is scraped off the plates, placed in short glass columns, Pasteur pipettes, or sintered filter funnels, and fractions are recovered with such volatile solvents as ethyl acetate or dichloromethane. 

Shine, H. J. el ai, Chem. Ind, 1969, 782 J. Org. Chem., 1971, 36, 2925 A 1-2 g portion of the freshly prepared suction-dried material exploded violently during transfer from a sintered filter. Initiation may have been caused by friction of transfer or rubbing with a glass rod. Preparation of 50-100 mg quantities only is recommended. 

Fig. 3.1. Standing burette A with reservoir B. After B has been filled by distillation on a vacuum line, it is sealed off from this at E and sealed onto A at C. A sintered filter F prevents the drying agent G fouling the PTFE tap. After the recipient for the liquid from B, e.g. a reaction vessel, has been attached at D, it is evacuated, together with A, A is then filled from B and the required volume discharged through D. The internal seal there ensures that the liquid does not come into contact with D. Of course, the joint at D can be replaced by a fused-on seal.

Fig. 3.3. Pressure equalisation burette in a device for potentiometric titration. For full details of operation see original publication. A break-seal ampoule containing the titrating solution B which reacts with the contents of break-seal ampoules P in reactor R, C sintered filter, Z) 10 ml burette, E 2 mm capillary, F capillary tip, Pt wires from electrodes leading to potentiometer. T, T, 7 PTFE taps, 7J three-way glass vacuum tap.

The ampoule A was charged with the crystalline monomer, a phial P of initiator (e g. PFj solution), and a magnetic breaker M and then sealed at B to the rest of the rig which was then evacuated. Methylene chloride was distilled in from a reservoir on the vacuum line to dissolve the monomer and was then pumped off slowly, and evacuation was continued for 8 h, which process produced an efficient final drying. The purpose of the two pumping ducts C and D is to circumvent the evacuation obstacle presented by the sintered filter S. The required volume of solvent was then distilled into A, the rig sealed off from the line at E, and the ampoule A brought to the right... 

The sinter filter is removed and dppe (7.32 g, 18.4 mmol), toluene (70 mL), and a magnetic stirrer are added to the filtrate. A Perkin triangle with a 12-cm Vigreux column is attached (Fig. 1). The Perkin triangle is a piece of apparatus which is used to remove volatile fractions from a boiling mixture. It includes a fractionating column to separate the most volatile fraction,... 

Remove DMF from the swollen resin in the glass sinter filter funnel by aspiration using the vacuum pump and add the activated amino acid solution. Stir with a spatula and incubate at room temperature for 30-45 min, stirring occasionally. 

Add p-toluenesulfonyl chloride (57.5 g, 302 mmol) in small portions as a solid over a period of 3 h. Heat and stir the mixture overnight, and then allow the mixture to cool when a colourless precipitate is evident. Filter the solid on a sintered filter funnel, and wash the solids in turn with water (3 x 50 mL), methanol (3 x 50 mL) and finally diethyl ether (3 x 50 mL). Dry the solid under high vacuum (<0.1 mmHg, 60°C) to yield the acyclic tetra-tosylamide (44.8 g, 86%), m.p. 211-212°C. 

Pour the mixture into a conical flask (250 mL) and cool the flask in an ice bath. S/ow/yadd water (20 mL) and carefully add potassium hydroxide pellets, while swirling the flask in the ice bath. Add sufficient pellets so that the pH of the viscous aqueous mixture is greater than 13 (test with pH papers). Add ethanol (150 mL) and filter the mixture under reduced pressure through a sintered filter funnel attached to a Buchner flask. Wash the residue with ethanol (3 x 10 mL), and evaporate the combined aqueous-alcoholic extracts on a rotary evaporator. 

Take up the residue in hot toluene (40 mL), transfer the solution to a warm conical flask (100 mL) and allow it to cool to room temperature. The 18-ring tetratoluenesulfonamide crystallises out first. Collect the product by filtration (warm sintered filter funnel) and dry it under vacuum (0.2 mmHg, 20°C) to yield a colourless solid, 1.06 g, 20%, m.p. 243-4°C. 

The nine-membered ring ditoluenesulfonamide3 may be obtained from the filtrate. Cool the filtrate (4°C) overnight and collect the colourless crystalline solid by filtration (sintered filter funnel) to give the [9]-ring co-product, 2.17 g, 41%, m.p. 161-2°C. 

Filter papers (Whatman No.1) Sintered filter funnel (porosity 2) Erlenmeyer flask (500 mL) Thermostatted hot plate stirrer Oil bath... 

Take up the residue in boiling absolute ethanol (100 mL) and decant the liquid into an Erlenmeyer flask (250 mL). Treat the remaining sediment with an additional volume of ethanol (50 mL) and boil the mixture for 15 min. Decant the liquid into the half-full Erlenmeyer and store the combined fractions in a fridge overnight (5°C). Separate the colourless crystalline solid by filtration (porosity 2 sintered filter funnel), and dry the product under vacuum (40°C, 0.1 mmHg, 3 h) to give the desired cycle, m.p. 119°C, 3.5 g, 66%. 

Transfer the mixture to a separating funnel, separate the organic layer and wash the aqueous layer with chloroform (4 x 50 mL). Combine the organic extracts and dry them over anhydrous sodium sulfate (c. 10 g, 2 h). Filter the mixture using a sintered filter funnel and evaporate the filtrate under reduced pressure. 

Heatley (H4-H5) demonstrated that mucus and pepsin can be separated by filtration through a sinter filter, which would raise doubts as to whether pepsin really becomes adsorbed to mucus. It appears more probable that the layer of visible mucus only makes a barrier between the surface epithehum and the acid-pepsin solution in the gastric lumen, which slows down the gross mixing of the intraluminal materials with the gastric mucosa. According to Heatley (H4-H5), it is unneces-... 

Rigid ceramic sintered filters Cerel, Universal Porosics, Industrial... 

For sampling in the disengagmcnt zone during gasification, a size selective inlet was located inside the reactor to separate coarse particles and increase sampling time for the sintered filter. The inlet consisted of a stainless steel cyclone with both top and bottom outlets ducted outside the reactor wall. The coarse particle fraction was collected from the bottom outlet, while fine particles were collected on the heated sintered filter connected to the top outlet. The fine particle Alter was again maintained at a temperature equal to or above the gas temperature at the extraction point. Coarse and Ane particles were thus separated without cooling. 

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