ASTM D4310 Method for Sludging and Corrosion Tendencies of Inhibited Mineral Oils
9. Preparation of Apparatus
9.1 Cleaning Catalyst - Immediately prior to winding a catalyst coil, clean a 3.00 ± 0.01-m length of iron wire and an equal length of copper wire with wads of absorbent cotton wet with n-heptane and follow by abrasion with abrasive cloth until a fresh metal surface is exposed. Then wipe with dry absorbent cotton until all loose particles of metal and abrasive have been removed. In subsequent operations handle the catalyst wires with clean gloves (cotton, rubber, or plastic) to prevent contact with the skin.
9.2 Preparation of Catalyst Coil - Twist the iron and copper wires tightly together at one end for three turns and then wind them simultaneously alongside each other on a threaded mandrel (see Fig. 2), inserting the iron wire in the deeper thread. Remove the coil from the mandrel, twist the free ends of the iron and copper wires together for three turns, and bend the twisted ends to conform to the shape of the spiral coil. The overall length of the finished coil should be 225 ± 5 mm (8.9 ± 0.2 in.). If necessary, the coil may be stretched to give the required length (Note 4 and Note 5).
NOTE 5 - The finished catalyst coil is a double spiral of copper and iron wire, 225 ± 5 mm (8.9 ± 0.2 in.) overall length and 15.9 to 16.5 mm (0.625 to 0.650 in.) inside diameter. The turns of wire are evenly spaced, and two consecutive turns of the same wire are 3.96 to 4.22 mm (0.156 to 0.166 in.) apart, center to center. The mandrel shown in Fig. 2 is designed to produce such a coil. Using this mandrel, the iron wire is wound on a thread of 14.98 mm (0.590 in.) diameter, while the copper wire is wound on a thread of 15.9-mm (0.625-in.) diameter. The smaller diameter is to allow for "springback" of the steel wire after winding, so as to give 15.9-mm consistent inside diameter. Use of a very soft annealed steel wire may allow use of identical thread diameters for the two wires. Any arrangement that leads to the coil configuration described above is satisfactory.
9.3 Catalyst Storage - The catalyst coil may be stored in a dry, inert atmosphere prior to use. A suitable procedure for catalyst storage is given in Appendix X1. Before use it should be inspected to assure that no corrosion products or contaminating materials are present. For overnight storage (less than 24 h) the coil may be stored in n-heptane.
9.3.1 n-heptane used for catalyst storage must be free of traces of water and corrosive materials. Redistilled n-heptane conforming to 7.5 and stored in a tightly sealed bottle is suitable.
9.4 Cleaning New Glassware - Wash new oxygen delivery tubes, condensers, and test tubes with a hot detergent solution and rinse thoroughly with tap water. Clean the interiors of the test tubes, exteriors of the condensers, and both interiors and exteriors of the oxygen delivery tubes with a cleaning reagent. Rinse thoroughly with tap water until all cleaning solution is removed. Rinse all parts with reagent water and allow to dry at room temperature or in an oven. The final reagent water rinse may be followed by an isopropyl alcohol rinse, or acetone rinse optionally followed by dry air blowing to hasten drying at room temperature.
9.5 Cleaning Used Glassware - Immediately following termination of a test, drain the oil completely from the test tube. Rinse all the glassware with n-heptane to remove traces of oil, wash with a hot detergent solution using a long-handled brush, and rinse thoroughly with tap water. If deposits still adhere to the glassware, a method that has been found useful is to fill the test tubes with detergent solution, insert the oxygen delivery tubes and condensers, and place the tubes in the bath at test temperature. Several hours soaking in this manner often serves to loosen all adhering deposits except iron oxide. Subsequent rinsing with hot (50°C) hydrochloric acid will serve to remove iron oxide. After all deposits are removed, rinse all glassware with a cleaning reagent. Rinse thoroughly with tap water until all cleaning reagent is removed. Rinse all parts with reagent water and allow to dry at room temperature or in an oven. The final reagent water rinse may be followed by an isopropyl alcohol rinse, or acetone rinse optionally followed by dry air blowing, to hasten drying at room temperature. Store glassware in a dry dust-free condition until ready to use.
