The effect of pressure up to 12,000 kg/cm2 on reactions in solution

In a previous publication it was shown that pressure was capable of exerting a considerable influence on the rate of reactions in solution. Two reactions were studied; the first, the interaction of sodium ethoxide and ethyl iodide in alcohol solution, was a typical example of the “normal” class, in which the number of molecules reacting is approximately equal to the number of collisions with the requisite activation energy, while the second, the interaction of pyridine and ethyl iodide in acetone solution, was a typical “slow" reaction, in which the number o f molecules reacting is several powers of 10 less than the number of collisions with the requisite activation energy. The rates of both reactions were increased by pressure, but while the first was accelerated 1.6 times at 3000 kg/cm2, the second was accelerated 7.2 times at 3000 kg/cm2, and much more at higher pressures. It seemed desirable to investigate other reactions falling into these two classes, to see whether this behaviour was general. With this end in view, the hydrolysis of sodium monochloracetate by aqueous caustic soda, another typical “normal” reaction, has been studied up to 12,000 kg/cm2, and the work on the sodium ethoxide and ethyl iodide reaction has also been extended to this pressure.