Methyl tertiary butyl ether (MTBE) has been proposed and is being used as an additive to increase the octane of gasoline without the use of tetraethyl lead and alkylbenzenes. The present experiments have been performed to examine the kinetics and mechanisms of the atmospheric removal of MTBE. The kinetics of the reaction of OH with MTBE was examined by using a relative rate technique in which photolysis of methyl nitrite was used as the source of OH. With n‐butane as the reference compound a value of (2.99 ± 0.12) × 10−12 cm3 molecule−1 s−1 at a temperature of 298 K was obtained for the rate constant. The products (and product yields) for the OH reaction with MTBE in the presence of NOx were also determined and found to be t‐butyl formate (0.68 ± 0.05), methyl acetate (0.14 ± 0.02), acetone (0.026 ± 0.003), t‐butanol (0.062 ± 0.009), and formaldehyde (0.48 ± 0.05) in mols/mol MTBE converted. The OH rate constant for the major product formed, t‐butyl formate was also measured and found to be (7.37 ± 0.05) × 10−13 cm3 molecule−1 s−1. Mechanisms to rationalize the formation of the products are presented.

The photochemical aspects of air pollution are reviewed through 1964. The topics covered include: nitric oxide oxidation and inorganic reactions, atomic oxygen and ozone reactions, singlet oxygen and its importance to air pollution, aldehyde and ketone photolysis, sulfur dioxide photolysis, synergistic effects, photooxidation of commercial solvents, product formation with emphasis on hydroperoxides, nitric acid and peroxybenzoyl nitrate, reactivity measurements including hydrocarbon consumption, nitric oxide oxidation, oxidant formation and eye irritation, aerosols, natural pollution, and actinometry. The effects of photochemical pollutants on plants are not covered. Suggestions for future research are also given.

Limestone Slurry Scrubbing. Stack gas is washed with a recirculating slurry (pH of 5.8-6.4) of limestone and reacted calcium salts in water using a two-stage scrubber system for particulates and SO2 removal. Limestone feed is wet ground prior to addition to the scrubber effluent hold tank. Calcium sulfite and sulfate salts are withdrawn to a disposal area for discard.Lime Slurry Scrubbing. Stack gas is washed with a recirculating slurry (pH of 6.0-8.0) of calcined limestone (lime) and reacted calcium salts in water using a two-stage venturi scrubbing. Lime is purchased from "across the fence" calcination operation, slaked, and added to both circulation streams. Calcium sulfite and sulfate are withdrawn to a disposal area for discard.Magnesia Slurry Scrubbing-Regeneration to H2SO4. Stack gas is washed using a two-stage venturi scrubbing. Water is utilized for removal of particulates, and a recirculating slurry (pH 7.5-8.5) of magnesia (MgO) is utilized for removal of SO2. Makeup magnesia is slaked and added to cover only handling losses since sulfates formed are reduced during regeneration. Slurry from the SO2 scrubber is dewatered, dried, calcined, and recycled, during which concentrated SO2 is evolved to a contact sulfuric acid plant producing 98% acid.Sodium Solution Scrubbing-SO2 Reduction to Sulfur. Stack gas is washed with water in a venturi scrubber for removal of particulates and then washed in a valve tray scrubber with a recirculating solution of sodium salts in water for SO2 removal. Makeup sodium carbonate is added to cover losses due to handling and oxidation of sodium sulfite to sulfate. Sodium sulfate crystals are purged from the system, dried, and sold. Water is evaporated from the scrubbing solution to crystallize and thermally decompose sodium bisulfite, driving off concentrated SO2. The resulting sodium sulfite is recycled to the scrubber, and the SO2 is reacted with methane for reduction to elemental sulfur. Catalytic Oxidation. Stack gas is first cleaned of particulates by a high-temperature electrostatic precipitator. Then the SO2 is catalytically converted to SO3, and available excess heat is recovered. The SO3 reacts with moisture in the stack gas to form H2SO4 mist which is scrubbed in a packed tower using a recirculating acid stream to yield 80% acid. The mist is removed by a Brink mist eliminator, and the clean 254°F gas is exhausted to the stack. Acknowledgment I am indebted to T. Y. Yan of Mobil Research and Development Corp. for his help in constructing the material balance tables and A. M. Chung of Drexel University for his valuable suggestions.

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