J. W. Pafton and I. D. Johnson
Morathon Oil Co. Littleton, Colorodo 80121
Magnetic Gas Circulation Pump for Pressure Reactors
In many autoxidation reactions, carbon dioxide is liberated in sufficient amounts to smother the oxidation unless removed. This can be accomplished in flow-through systems, but this makes the measurement of the amount of oxygen consumed difficult. I t is more convenient to be able to circulate the gases through an ahsorbant, such as Mallcosorb, to remove the carbon dioxide. If the reactor is maintained a t a constant pressure by means of a pressure regulator, then the pressure drop in an oxygen reservoir is a measure of the amount of oxygen consumed in the oxidation. We have previously described' a magnetic stirring device for glass pressure reactors. A similar device has been designed for a gas circulation pump that works well under pressure. A bifilar solenoid was wound directly on a section of stainless steel tubing. A sketch of the solenoid assembly is shown in Figure 1. The bifilar winding was
Figure 1. Solenoid valve orsembly for gas circulation pump. A, ttoinleu steel tubing; 8, soft iron rings, silver-soldered in place; C,center tropped biRlorwound coil; D, magnetic shielding.
described previously for the magnetic stirrer, and the solenoid wiring is again the same. A diagram for the entire pressure reactor system is shown in Figure 3. A TMT tee compression fitting, Swagelok or Gyrolok, was used to connect t,he stainless steel tubing of the circulation system to the FischerPorter aerosol compatibility tube.2 A press-fit of in.-tubing was made into the incoming '/,tubing in the TblT tee. Thus, gases can gc into the Fischer-Porter tube through the in.-tubing, and leave through the tee side arm. Water jacketed condensers were used to minimize the loss of volatile substances. The gases from the side arm of the TnlT tee pass through the condenser and then through a carbon dioxide trap containing Mallcosorb. From there they pass through the magnetic gas circulation pump and on through a needle valve and rotameter, then return to the oxygen inlet tube. In connecting the magnetic circulation pump to the '/
