Pyrex glass capillary tubing

An efficient oxidation of glucose to gluconic acid was performed using a porous gold catalyst in a low-cost microreactor designed from Pyrex glass capillary tubing [161]. 

This value is obtained in a Pyrex capillary tube the solid remains yellow until about 2540 when it suddenly decomposes to a red melt with vigorous evolution of gas. When a soft-glass capillary tube is used, the solid assumes a red color at about 180-200° and melts between 240° and 250°. 

Of course, the solubilities of AY, BX, and BY have to be considerably larger than that of AX. As is shown in Fig. 1, the double-infusion crystallizer consists of a thermostated (filled with oil) Pyrex vessel containing the saturated solution and eventually some seed crystals mounted on a stirrer. The solutions AY and BX are introduced through glass capillary tubes by means of a micropump t... 

Apparatus. The apparatus is made of Pyrex glass, in one piece. It consists of a shaped bulb A (Fig. 89 of about 30 ml. capacity in which the reaction takes place, provided with an inclined inlet B at the side and a vertical ascension tube D. B serves not only as an inlet for the admission of the carrier gas but also as the route by which the reagents and test sample are introduced into the apparatus. B ends in a small ground-glass joint into which fits ajoint carrying a capillary-tube which projects well down into the bulb A (the end of the capillary should be just above the liquid level when the apparatus is charged for the determination). The upper extension of this capillary beyond the joint is provided with a tap C to control the rate of flow of the carrier gas. 

Pyrex glass is preferable, but this requires an oxy-coal gas blowpipe for manipulation. Suitable melting point tubes may be purchased from dealers in scientific apparatus or chemicals. It is, however, excellent practice, and an essential part of his training, for the student to learn to prepare bis own capillary tubes. 

Joints, borosilicate to soda glass, 25 Joints in closed systems, 168 Joints, Pyrex to Phoenix, 25 Joints, tungsten-sealing to Xovar-seal-ing glasses, 24 Joints, Vitreosil, 175 Joints with capillary tube, 69 Junctions, 4 and 5 way, 68... 

The first approach to monolithic columns formed from beads can be assigned to Knox and Grant [15] who prepared a particle-embedded continuous-bed CEC column. They packed beads into a Pyrex glass tube of 1 - 2 mm i.d. and then drew the packed column to create a capillary. The particles were partly incorporated in the glass wall and the column was stable unless the column-to-particle diameter exceeded a value of 10. The success of this procedure was very sensitive to the presence of water in the original packing material. 

In order to get a Raman spectrum, a sample is located in the sample cell. Then, a laser light is focused on the sample using a lens. Usually, the sample cell is a capillary tube, normally made of Pyrex glass, where liquids and solids are sampled in [57], Or another appropriate sample holder system where is given the possibility that the light scattered during its interaction with the sample is accumulated using an additional lens and is then focused at the entry slit of the monochromator [32,62],... 

Figure 3-27 Schematic drawing of matrix-isolation apparatus for resonance Raman measurements. 1, glass envelope 2, aluminum sleeve 3, refrigerator 4, gas line 5, steel screen 6, cold tip 7, aluminum radiation shield 8, Pyrex cup 9, spectroscopic-grade spark graphite rod 10, Pyrex capillary tube with sample 11, small mirror 12, cylindrical lens 13, collecting lens. 5 is placed to prevent sample deposition in the optical path. It must be removed from the path by using an external magnet once sample deposition on 6 is completed.

Unless otherwise directed, place a 5.0-g sample and 30 mL of water in a 125-mL Pyrex distillation flask having a side arm and trap. The flask is connected with a condenser and carries a thermometer and a capillary tube, both of which must extend into the liquid. Slowly add, with continuous stirring, 10 mL of 70% perchloric acid, and then add 2 or 3 drops of a 1 2 solution of silver nitrate and a few glass beads. Connect a small dropping funnel or a steam generator to the capillary tube. Support the flask on a flame-resistant mat or shielding board, with a hole that exposes about one-third of the flask to the low, clean flame of a Bunsen burner. 

Fuse, Liquid-Metal, Self-Healing. When mercury replaces the filament of an exploding-wire fuse, it. will break contact by vaporizing upon application of an overvoltage, then make contact by condensing when (he overload disappears. This happens within a heavy-walled capillary tube connecting two reservoirs (see sketch). Evaporation forces mercury from the capillary to break the. circuit Experimental quartz glass and pyrex tubes exhibit da-... 

Gas thermometer bulb a. This is a Pyrex bulb with a volume Fof about 100 cm, with an attached glass capillary passing through a large rubber stopper. The upper end of this capillary tube is connected, by a length of flexible stainless-steel capillary tubing, to the manometer. 

Fig. 13. Ultramicro manometric gasometer (Nl). A, 0.5-nun bore Pyrex capillary tube joined to 1-nnn bore Pyrex capillary tube B, 10-ml syringe and side tube sealed on, as shown C, metal blank (from electric junction box) D, ball bearing for rotating screw without turning coupling E, machined screw tach diameter, 20 threads per inch, recessed and tapped at one end to receive machine screw F, vacuum stopcock G, ball and socket ground-glass joint.

The capillaries are made either of borosilicate glass or fused quartz. Pyrex glass has a cutoff at about 280 nm, so fused silica is often used. The capillary tube is coated with a polyimide to enhance flexibility by preventing the hydration of strained siloxy bonds. The columns vary in internal dia-meter from 10 to 100 pm and in length from 30 to 100 cm, with 50 to 100 cm being common. The capillary side wall is usually thick by comparison, 300 to 600 pm, to act as a heat sink. A small portion (1 to 2 mm) of the coating is burned away if a photometric detector is used. Figure 31-6 shows typical dimensions. 

---