Atmospheric Reactions of Volatile Organic Compounds from the Optoelectronic Industry

in International Symposium (poster summary), 國際研討會(摘要海報發表)
標題Atmospheric Reactions of Volatile Organic Compounds from the Optoelectronic Industry
AuthorsJia-Twu Lee, 李嘉塗
出版日期Aug 28 2014 12:0

Atmospheric Reactions of Volatile Organic Compounds from the Optoelectronic Industry

Jia-Twu Lee*, Mu-En Luo and Chih-Hung Huang

Department of Environmental Science and Engineering, National Pingtung University of Science and Technology, Pingtung, Taiwan
*Corresponding author:

Keywords: Optoelectronic industry, Volatile organic compounds, TFT.

In the last two decades, high-tech industries, including the optical communication, semiconductor, and photovoltaic industries, have developed rapidly in Taiwan. Although the economic benefits are undeniable, manufacturing in such industries has increased emissions of Volatile Organic Compounds (VOCs), which pollute the environment and adversely affect human health. In short, manufacturing processes that produce VOCs must use closed vent systems to collect and treat emissions before they are released into the air.
The many sources of VOCs in the optoelectronics industry include cleaning and chemical treatments that use acetone and isopropanol (IPA). Photolithography and other development processes use photo resist, (HMDS), IPA, xyleneacetate, butyl acetate, and other similar chemicals. The main pollutants emitted by the Thin Film Transistor-Liquid Crystal Display, (TFT-LCD) processes include VOCs, inorganic acid gases, and toxic explosive gases, including IPA, iso-acetone (PGME), propylene glycol, and ether acetate (PGMEA) (Fig. 1).

Figure 1. PGMEA

Pollutant emissions
According to literature, optical processes primarily emit substances that contain acetone, methyl ethyl ketone, methanol, PGME, PGMEA, Dimethyl sulfoxide (DMSO) and N-methylpyrrolidone (NMP). In this study were the estimated organic compounds.
After organic photochemical reactions in the atmosphere generate various complex compounds, mainly due to organic photochemistry under sunlight, the formed free radicals are unstable, and are mainly present in the air contained in the radical groups (O ˙), hydroxyl (OH ˙), methyl groups (CH3 ˙), the nitrogen groups (NO ˙). In the air and other organic radical groups (CH3CH2˙), to form a different nature form, are converted into toxic organic compound with an organic matter contains a double bond, a highly polar functional groups and weaker bond energy of the material.

Volatile organic compounds in reactions in air
Ether acetate (PGMEA), commonly used in photoelectric processes, is PG compound CH3C (O) OCH (CH3) CH2OCH3 in photochemical reactions will produce CH3COH (acetaldehyde), and acetaldehyde in further photochemical reaction produces CH2O (formaldehyde); with the addition of nitric oxide in air or via ozone oxidation, oxidation of acetic acid peroxide CH3C (O) O2, the reaction is
Peroxide and acetic acid in the synthesis of NO in air generates CH3C (O) O2NO2 (peroxy acyl nitrate (PAN)). The main material for used to generate optical smoke. In the photovoltaic industry, due to the manufacturing process uses a large number of strong acids, hydrochloric acid, which also includes hydrofluoric acid. The acid gas in the air to escape readily and react with organic compund, including Cl ˙ (or F ˙) and ClO ˙ (or FO ˙). After the oxidation of hydrochloric acid. For instance, VOCs may be formed CH3C (O) OCl, CH3C (O) Cl, CH3C (OCl)2, CH3CCl2 other substances.
In addition to PGMEA, after the photochemical reaction of a peroxide CHO2 (CH3) CH2OCH3, due to the unstable chemical nature of peroxide, the air immediately reacts with substances that may contain NO reaction CHO2NO2 (CH3) COH2CH3 matter. This matter is also one derivative of photochemical smog. While the hydroxyl radical formation CH3OCH2 (CH3) COOH, according to the chemical structure in which different compounds should from propionic acid methyl ether. Photochemical oxidation and dissociation, is formed CHOO (CH3) CH2OO, the substance has two radicals groups, which may be more complex forming substances, comprising the formation of NO CHOONO (CH3) CH2OONO, CHOONO (CH3) CH2OH, CHOH (CH3) CH2OONO, COOH (CH3) CH2OONO, and CHOONO (CH3) CHOOH, then produce CHOOCl (CH3) CH2OOCl, CHOCl (CH3) CH2OCl, C (O) OCl (CH3) CH (O) OCl, C (OCl) 2 (CH3) CH (OCl) 2, CHCl (CH3) CH2Cl and other substances.
By chemical reaction, the complex reactions of VOCs in air are identified. Although the above reaction is not considered the feasible reaction constant, the derivation is likely to select a number of reactions. The complex compunds formed by the reaction in the air is toxic, the pollution control system is required for optoelectronic industry.

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