Fritted glass apparatus

Filtration. One of the most convenient aspects of the cannula techniques is that filtration does not require the use of fritted glass equipment. Small scale filtrations are simply carried out by transferring the liquid to be filtered from one Schlenk tube to another through a filter stick as shown in Figure 5. When the filtration is complete the filter paper is discarded, and the cannula washed with acetone to prepare it for the next filtration. The advantages of filter stick filtration over filtration through fritted glass apparatus maybe summarized as follows ... 

The Ba(CN)2 used contains metal cation impurities limited to sodium, aluminum, strontium, and 0.05% potassium, plus traces of iron, magnesium and lithium. Each platinum electrode is a 90-100 cm2 heavy sheet with purity > 99%. During the electrolysis, half of each electrode is submerged in the solution. All water used is distilled, and all filters are medium-pore fritted-glass filters. The electrolysis apparatus consists of a variable ac voltage supply with an ac ammeter included in the circuit. 

The hygroscopicity of a propellant is detd rapidly in an apparatus consisting of 2 identical gas washing bottles provided with fritted glass plates near the bottom. The outlets at the bottom are connected through a diaphragm pump... 

The apparatus used is shown in Fig. 2 (Note 1). A solution of sodium ethoxide prepared by dissolving 2.5 g. of clean sodium metal (0.11 gram atom) in 230 g. (292 ml., 5 moles) of absolute ethanol under anhydrous conditions is added to the reaction tube C. The tube C thus charged is weighed, and placed in position with the gas inlet tube, fitted with fritted-glass dispersion cylinder D, extending nearly to the bottom. Several inches of ethanol is placed in the tube G, which serves as a flow indicator. The... 

The apparatus consists of a flow through extraction system that can be operated at pressures up to 400 bar and temperatures up to 200°C. This apparatus was described elsewhere (2). Its main piece is a 19 cm3 reactor, where 4-5 g of 40-60 mesh milled cork were placed between two G3 fritted glass discs. The reaction mixture is expanded into a series of three 35 cm3 precipitation traps. A dual-head high pressure liquid pump was used to compress the solvent. One pump head was cooled with ice to pump liquid C02 while the other pump head was used for 1,4-dioxane. 

The wood specimen is ground to pass a 0.4 mm (40-mesh) screen. A sample of the wood meal equivalent to about 5 g on an oven-dry basis is placed in a coarse porosity alundum or fritted glass extraction thimble and extracted successively in a Soxhlet apparatus with ethanol-benzene for 6-8 h and 95% ethanol for 4h. Between extractions the wood meal is transferred to a Buchner funnel, where the excess solvent is removed by suction and washing with ethanol. 

Groundwood and high-yield pulps containing a significant amount of resins are extracted with ethanol-benzene a sample equivalent to 10 g of oven-dry pulp is cut into pieces approximately 10 mm square and placed in a coarse porosity alundum or fritted glass extraction thimble and extracted with ethanol-benzene in a Soxhlet apparatus for 4-5 h (minimum of 24 siphoning cycles). The pulp is filtered on a Buchner funnel and washed with ethanol and hot water. The moisture content of an air-dried sample is determined as described above. 

Considerably improved filtration may be accomplished when the fritted-glass filter is covered with a 1-1.5 cm layer of powdered aluminum (or dried Celite filter aid). Before starting the filtration, the whole apparatus is evacuated. Then the reaction mixture is poured into the fritted-glass filter while nitrogen is introduced slowly into the space above the filter. The solids are washed with 15 ml of benzene and the filtrates are combined to give 262 g of clear yellowish solution. The yield with respect to the initial amount of 2-methoxyethanol is 98.1%. Anal. Calcd. for Na[AlH2(0CH2CH20CH3)2] Na, 11.37 Al, 13.35 H, 0.997%. Found Na, 6.04 Al, 6.94 H, 0.537%, Na Al H = 1.02 1 2.07. 

In the course of these studies the most convenient apparatus in which to run these reactions was found to be a flask with a stirrer which has a gas inlet through it. This gives as good a dispersion of the gas in the liquid as does a fritted glass diffuser, and greatly simplifies the manipulations accompanying the reaction. It has the additional advantage that an insoluble product, if formed, does not interfere with the continuation of the reaction. 

A. 9,10-Dihydro-trans-9,10-phenanthrenediol (1). Phenan-threnequinone (6 g., 0.029 mole) (Note 1) is placed in a fritted-glass (coarse porosity) extraction thimble of a Soxhlet apparatus over a 1-1. flask containing a suspension of 3 g. of lithium aluminum hydride in 500 ml. of anhydrous ethyl ether (Note 2). Extraction of the quinone over a period of 16 hours affords a green solution (Note 3). The reaction is quenched by the cautious addition of water (Note 4) and neutralized by the addition of glacial acetic acid. The ether layer is separated, and the aqueous layer is extracted with two 200-ml. portions of ethyl ether. The combined ether extracts are washed consecutively with aqueous sodium bicarbonate and water, and then dried over magnesium sulfate. Evaporation of the solvent under reduced pressure gives the crude product (Note 5), which is recrystallized from benzene to... 

Figure 34-11. Schematic diagram of the foam fractionation apparatus. (A) air cylinder (B) gas rotameter (C) gas saturator (HjO) (D) Hg U tube (E) liquid trap (F) fritted glass gas dispenser (G) constant temperature water jacket (H) foam fractionating column (I) foam receiver (J) tap for withdrawing foamed solution (K) tap for draining foam fractionating column. (Courtesy - Skomoroski, R.M.,y. Chem. Ed., 40 (9), 470, 1963)...

Water Uptake Measurements. The water absorption capability of films was determined by measurements of water rising by capillary action. The experimental device, also called Baumann apparatus is shown in Figure 1. The samples were cut in order to expose their inner structure to water rising. They were then coated on each of their faces (except the contact surface) with epoxide resin to prevent their swelling and put on fritted glass in contact with distilled water. The absorbed water volume versus time data is then recorded as water penetrates into the sample. 

Fig. 69. Apparatus for reactions in liquid ammonia I) reaction tube II) condensation equipment 2 and 6) pressure release valves 3) condensation, drying and storage of NHa 4) protection against spray and fog—fritted glass or glass wool.

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