Coal tar autoxidation: kinetic studies by viscometric and refractometric methods
The autoxidation of coal tars (boiling point up to 300/sup 0/C) from bituminous coal hydrogenated at 650/sup 0/C and carbonization (at 700/sup 0/C) processes was studied under ordinary storage conditions. Both the viscosity and the refraction of the coal tars increased continuously during autoxidation. Infrared spectra show that double bonds diminish, and oxygen containing functional groups in the tar increase as it is oxidized in air. This result corresponds very well with the decrease of iodine number. At oxygen pressures greater than 50 mm, the rate of oxidation is independent of the oxygen partial pressure. The viscosity increment is linear with the reaction time indicating that the autoxidation of coal tar is a diffusion-controlled reaction. The activation energy of coal tar autoxidation from the hydrogenation process is about 16 kcal/mole. The behavior of coal tars produced by hydrogenation is compared with that for tars produced from carbonization. Neutral oils are also compared with tar acids and tar bases in their autoxidation behavior. A general mechanism is proposed to account for the experimental results.
- Research Organization:
- Univ. of Utah, Salt Lake City
- OSTI ID:
- 7348544
- Journal Information:
- Am. Chem. Soc., Div. Fuel Chem., Prepr.; (United States), Journal Name: Am. Chem. Soc., Div. Fuel Chem., Prepr.; (United States) Vol. 19:5; ISSN ACFPA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
010500* -- Coal
Lignite
& Peat-- Products & By-Products
ALKENES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COAL TAR
HYDROCARBONS
KINETICS
OPTICAL PROPERTIES
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
OXIDATION
PHYSICAL PROPERTIES
REACTION KINETICS
REFRACTIVITY
STORAGE
TAR
VISCOSITY