Document 0JyK1MkBj0ppKR06znzDMerLn

i Et h y l Ga s o l in e Co r p o r a t io n Ch e mc a j l Re s e a r c h La b o r a t o r y 7 6 00 We s t Eig u t Mil e Ro a d Dr. Robert A. Kehoe College of Medicine University of Cincinnati Eden Avenue Cincinnati, Ohio De t r o it , Mic h io a x May 25, 1940 Dear Dr. Kehoe: Your letter of May 13 to Dr. Edgar, with respect to study of lead in the dust and atmosphere, has been referred to this laboratory and -will be brought to' Dr, Calingaert's attention on his return June 3. I am sorry to say that a search of our files and questioning of the various people in the different laboratories here has failed to provide much in the way of information in this connection. The follow ing points may be of more or less value; 1 Mr. Heron says that Dr. Edgar has information regarding work done some time ago by the Bureau of Standards to make a Cottrell precipi tation of the exhaust gas, which failed to remove more than a small fraction of the lead content. 2. The Engineering Laboratory reports that in an automobile engine us ing 2 cc. TEL per gallon, 12$ of the lead is removed in the lubri cating oilj with 3 cc., 8% is so removed. 3. The carbon monoxide content of exhaust gas under normal conditions is about 1.5-2$. 4. Information is available as to the coiroosition of the aqueous con densate from the exhaust pipe. However, the amount of such con densate in automobile operation is nil except under special condi tions of cold weather and idling. 5. Information is available as to the composition of the solid deposits in the engine, etc. However, it is believed that the amount of such deposits formed insndbbwn out of the exhaust pipe is, relatively speaking, negligible compared with the total throughput of lead. 6. Although no data are available, our guess is that the relative pro portions of lead bromide and lead chloride in the exhaust gas are about the same as the proportions of bromide and chloride in the fuel. .Dr, R. ' Page 2 &eh6e May 25 1940 7. The boiling points of 1 ead bromide and chloride are, respectively, 916C. and 95GC. Both, of course, are soluble in water. tie calcu late that the vapor,pressure of lead bromide at room temperature- is of the order of 10~ 'ima,, probably correct within a factor of ICO, A rough calculation from this figure shows, that it is quite impossible for the salt to be disbursed as a true vapor by evaporation into the air; therefore, it must precipitate, and settle out sooner or later as a dust. 8. Tie do not see much likelihood of being able to identify the lead salts as such in a mixture of dust taken from the air or surface of the ground However, an indirect analysis for the water soluble lead salts should be obtainable by extraction of such dusts with a limited quantity of water in the complete absence of oxygen and carbon dioxide, 9. It has been suggested that analysis of the water from sewers and drain pipes, immediately following a rainfall, would he in order. 10. It has been suggested that effective removal of all metals, salts and acids from engine exhaust gas will be obtained most easily by passing gas directly through a scrubber packed with suitable material, such as glass cotton wet with water. 11. It is believed to be very doubtful whether any tetraethyllead ever is present in exhaust gas, even at the time of starting the engine,- since the temperature reached on compression should be quite sufficient to decompose the TEL. Very sincerely yours. HAB :AMC cc; Dr. G. Edgar Ik. G. Calingaert Harold A. Beatty nr ooisoas