The purpose of this investigation was to obtain definite quantitative data on the optimum conditions for the production of ethylene oxide by the catalytic vapor phase oxidation of ethylene. This data was to cover the effects of temperature, ethylene concentration, and velocity of flow through the catalyst bed. The catalyst chosen was metallic silver, known to be effective in promoting the reaction. The experimental data obtained was to be used in making preliminary engineering studies on the design of a commercial plant for the production of ethylene glycol by first forming ethylene oxide and then hydrolyzing it to the glycol.

The reactor used in oxidizing ethylene to the oxide consisted of an iron reactor tube 0.824 inches in diameter and 11.7 inches long, surrounded by a diphenylamine constant temperature bath. The tube was filled to a depth of 10 inches with the metallic silver catalyst. Rates of flow of the air and ethylene streams were controlled by means of needle valves and indicated by water filled manometers. The reactant gas mixture was pre-heated prior to passage through the reactor tube.

A series of runs was made to determine the effect of ethylene concentration on the oxidation reaction. The temperature was held at approximately 260°C. and the gas flow rate was set at 25 liters/cm.²/hr. for each run. The ethylene concentration was varied from one per cent to 9.8 per cent. It was found that the highest yield of the oxide was obtained with an ethylene concentration of one per cent. An increase in the ethylene concentration was found to result in lower yields of the oxide.

The effect on ethylene oxide production of the rate of gas flow through the catalyst bed was deter:nined by making three series of runs at gas flow rates of 12.5, 25 and 50 liters/cm²/hr. respectively. Temperatures were varied from 200°C. to 265°C., while the ethylene concentration was held at 2.2 per cent. It was found 2 that a rate of flow of 25 liters/cm. /hr. gave uniformly highest yields of ethylene oxide. A rate of flow of 50 liters/cm²/hr. gave the lowest yields, while a gas flow rate of 12.5 liters/cm²/hr. gave yields intermediate between the other two rates.

The results of a series of runs made for the purpose of determining the effect of temperature on the yield of ethylene oxide indicated that the yield of oxide increased as the temperature was increased from 200°C. to 240°C. As the temperature was further increased from 240°C. to 265°C., the yield of ethylene oxide decreased with the increasing temperatures. The optimum temperature for the reaction was found to be 240°C. for gas flow rates of 12.5, 25 and 50 liters/cm²/hr. through the catalyst bed.

The commercial plant, designed on the basis of the data obtained, is designed to produce 6,451,352 pounds of antifreeze mixture per year. The capital investment required is $3,900,054. The gross annual income would be $967,703 on the basis of a selling price of $0.15 per pound for the antifreeze mixture. The yearly cost of production would be $883,256, giving a net yearly income of $84,447.