Joints, glass standard taper

Metal ball joints, metal standard taper joints, and O-ring joints with a step tooled into Ihe groove are available from Kontes Glass Co., P.O. Box 729, Vineland, NJ 08360. The first two items are also available from Ace Glass Co., P.O. Box 688, Vineland, NJ 08360. 

E. Miscellaneous Tubing Connectors. The variety of tubing couplers is enormous and a comprehensive list would be out of place in this book, but several additional types will be mentioned here which are useful in the laboratory. Metal standard taper and metal ball joints are available, and these will mate with corresponding ground-glass joints to provide one means of connecting parts made of dissimilar materials.4 As with glass standard taper joints, the seal is... 

Fig. 1.13. Variation on the cannula technique. The glass lube with fritted filter and the glass delivery tubes are attached to the glass standard taper joints by means of plastic adaptors (e.g., Kontes K-179800). The flexible plastic tubing connecting the two parts should be impervious to solvents. Teflon tubing is best and. to prevent contamination of the filtrate, Tygon tubing should be avoided when organic solvents are used.

A Pyrex reaction vessel with a volume of approximately 390 mL is constructed from a 350-mL round-bottomed Pyrex flask with a 29/42 standard taper male joint connected to the neck, and a Teflon/glass stopcock that has a 29/42 standard taper outer joint. The standard taper joints are lubricated with Fluorolube grease... 

Connect a short length (12 cm.) of glass tubing equipped with a male standard-taper joint to the flask and immerse flask in a boiling water bath until the volume of the liquid is reduced to about 5 ml. Avoid prolonged heating after the alcohol has evaporated and run the next step as soon as possible. It is undesirable to hold this alcoholic solution overnight. 

The lower part of the barrel of the dropping funnel should be bent in such a way as to offset it from the path of the thermocouple to permit adjustment of the latter. The checkers used a 8-mm. glass tube bent for offset and fitted at the upper end with a nitrogen inlet and a standard-taper ground joint to permit at-tachment of funnels of various sizes. 

Graduated cylinders of various sizes with 24/40 standard taper joints are available from Ace Glass, Inc. appropriate septa were obtained from Aldrich Chemical Company, Inc. 

The reaction vessels as shown in Figure 1 were cylindrical borosili-cate glass vessels, with i.d., 25 mm. and internal height, 36 mm. A standard-taper joint permitted connection to a stopcock. These two sections could be filled in a nitrogen atmosphere box. Then the sealed vessel could be connected to the vacuum system at the ball joint. 

Specifically, the glass connection between the Schlenk tube receiver (C) and stopcock (D) should extend about 130 mm below the top of the 24/40 standard taper inner joint and approximately 50 mm into Dewar flask (E) to prevent loss of the especially volatile V(CO)e to the vacuum line during the reaction and sublimation. The Schlenk tube receiver is cooled to about —70°C with dry ice/acetone or dry ice/isopropyl alcohol. The level of coolant should be near the top of the Dewar so that the glass connection between the stopcock (D) and the Schlenk tube is entirely covered. The apparatus is evacuated very slowly and cautiously... 

The gas-washing cylinders are preferably without flanges. Those used by the submitters were prepared from 45-mm. Pyrex tubing, measured 28 cm. in length, and were fitted with 29/42 standard taper ground-glass joints. The inlet tubes extended two-thirds of the way into the cylinders. 

Fig. 1.21. Typical assemblies of Schlenk ware. Commercial apparatus is illustrated similar apparatus with O-ring joints in place of standard taper joints is preferred by the authors. (

Fig. 1.26. Sublimation apparatus. Solids are introduced under inert-gas flush, and a loose plug of glass wool is introduced. The oil bath should extend above the glass wool. High vacuum may be applied through the standard taper joint. A lower vacuum may be applied through the sidearm.

A. Standard Taper and Ball Joints. These joints (Fig. 8.1) have been used for many years on vacuum and inert-atmosphere systems, and the availability of a variety of synthetic greases and waxes has extended their utility. Of the two, the ball-and-socket joint permits more flexibility in the orientation of the two halves. When this flexibility is important, this type of joint is obviously to be preferred, even though the ball joint is somewhat more prone to leak than a standard taper joint. Both metal ball joints and metal standard taper joints are available,1 and these items provide one means of joining metal and glass apparatus. 

Fig. 6.1 Two-electrode assembly (A) platinum wire (B) mercury-filled glass tube (C) thermometer adapter, 10/18 standard taper joint, Teflon (D) platinum electrodes 25 mm x 30 mm. Reprinted with permission [20],...

Two hundred seventy-five grams of phosphorus(III) chloride (2 mols) is weighed into a 500-ml., round-bottomed, three-necked flask equipped with standard-taper ground-glass joints and cooled by means of an ice-salt or Dry Ice bath. The necks of the flask are fitted, respectively, with a dropping funnel, a mercury-sealed, motor-driven stirrer, ... 

One hundred four milliliters of phosphorus(V) sulfochlo-ride (1.0 mol) is placed in a 500-ml. three-necked flask. The flask is fitted with a mercury-sealed stirrer, a water-cooled condenser to which a drying tube containing barium oxide is attached in a horizontal position, and a 250-ml. dropping funnel containing 58 ml. of anhydrous ethanol (1.0 mol). All joints may be rubber stoppers or, preferably, nonlubricated standard-taper ground-glass joints. 

The apparatus is constructed of pyrex glass and is assembled as shown in Fig. 15. Reaction tube A (1.6 by 41 cm.) is inserted in tube B (5 by 53 cm.), which leads to the condensing chamber C (6 by 35 cm.). A 35/25 standard-taper joint E connects the condensing chamber to the collection... 

Some thermometers have standard taper joints or ridges on the body of the glass to fit specific equipment such as distillation or melting point apparatus. These thermometers provide two types of position control. They set the bulb at just the right height within specialized equipment and ensure that the liquid column is sufficiently immersed in the heated sample. However, most thermometers do not have built-in controls and the user must not only select the right thermometer, but also adjust the thermometer to its proper level within the equipment. 

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