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Formation of nonvolatile particulates from organic vapors.
Keng-EY; Chu-RR; Knight-JA Jr.; Orre-C Jr.
Engineering Experiment Station, Georgia Institute of Technology, Atlanta, Georgia, Final Technical Report, Project 13-358, 1972 Jan; :1-65
Report on the photochemical experiments conducted to study the mechanism involved in the formation of particulates when organic vapors in air are irradiated with ultraviolet light. The study also aims at measuring experimentally the important factors such as the concentrations of the original and newly formed gaseous components, particulate concentration, and particulate size distribution. The chemical structures of the particulate substances are also examined to some extent. The report has three major sections: aerocolloid formation from semisolid materials exposed to sunlight; aerocolloids produced in ultraviolet light; and aerocolloids produced by X-rays. Methods employed and results obtained are discussed in detail with the help of tables, diagrams, and graphs. Photochemical reactions of organic vapors in air were studied in a reactor using an ultraviolet lamp. The amount of aerocolloids formed was increased substantially by adding either water vapor or nitrogen-oxides (10024972). Small proportions of organic vapors in air produce aerocolloids under the influence of X-rays. The particulates are generally spherical in shape and less than a micron in diameter. Those formed from acetylene (74862) and benzene (71432) vapor appear yellow and brown, respectively, and are essentially nonvolatile at room temperature and stable even when exposed to the high vacuum of an electron microscope. The size and quantity of the particulates formed under x-radiation depend on the organic vapor, its concentration, the humidity of the air, the intensity of the X-rays, irradiated time, and aging time after exposure. Infrared spectrum analysis provides information on the chemical structure of the particulates.
Photochemistry; Organic-vapors; Chemical-structures; Colloids; Ionizing-radiation; Non-ionizing-radiation
10024-97-2; 74-86-2; 71-43-2
Final Grant Report
NTIS Accession No.
Engineering Experiment Station, Georgia Institute of Technology, Atlanta, Georgia, Final Technical Report, Project 13-358, 65 pages, 43 references
Micromeritics Engineering Experiment Station 225 North Avenue, NW Atlanta, GA 30332
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division