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Title: Extraction of coal tar pitch using a mixture of compressed CO[sub 2] and toluene

Abstract

The removal of low-molecular-weight components from commercial pitches is a critical step in the production of suitable precursors for isotropic carbon fiber formation. A unique extraction process employing a one-phase binary mixture of carbon dioxide and toluene has been developed to remove low-molecular-weight components from coal tar pitch, with an ultimate goal of increasing the softening point of the pitch. The mass fraction of coal tar pitch extracted was determined as a function of extraction temperature (25--75 C), pressure (8.7--14.9 MPa), and extractive solvent composition (40--70 wt % toluene) using a factorial experimental design. As much as 44 wt % of the coal tar pitch was removed at these extraction conditions, and softening points greater than 250 C were achieved. The separation is controlled by the temperature and composition of the extractant solvent. This compressed gas/organic solvent extraction process removes low-molecular-weight material from the coal tar pitch using significantly milder solvents and reduced temperatures relative to traditional extractive processes.

Authors:
; ;  [1]
  1. (Univ. of Kentucky, Lexington, KY (United States))
Publication Date:
OSTI Identifier:
6106546
Resource Type:
Journal Article
Journal Name:
Industrial and Engineering Chemistry Research
Additional Journal Information:
Journal Volume: 38:9; Journal ID: ISSN 0888-5885
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; CARBON DIOXIDE; CARBON FIBERS; COAL TAR; FABRICATION; PITCHES; SOLVENT EXTRACTION; TOLUENE; ALKYLATED AROMATICS; AROMATICS; CARBON COMPOUNDS; CARBON OXIDES; CHALCOGENIDES; EXTRACTION; FIBERS; HYDROCARBONS; ORGANIC COMPOUNDS; OTHER ORGANIC COMPOUNDS; OXIDES; OXYGEN COMPOUNDS; SEPARATION PROCESSES; TAR; 010402* - Coal, Lignite, & Peat- Purification & Upgrading; 010500 - Coal, Lignite, & Peat- Products & By-Products

Citation Formats

White, K.L., Knutson, B.L., and Kimber, G. Extraction of coal tar pitch using a mixture of compressed CO[sub 2] and toluene. United States: N. p., 1999. Web. doi:10.1021/ie990119k.
White, K.L., Knutson, B.L., & Kimber, G. Extraction of coal tar pitch using a mixture of compressed CO[sub 2] and toluene. United States. doi:10.1021/ie990119k.
White, K.L., Knutson, B.L., and Kimber, G. Wed . "Extraction of coal tar pitch using a mixture of compressed CO[sub 2] and toluene". United States. doi:10.1021/ie990119k.
@article{osti_6106546,
title = {Extraction of coal tar pitch using a mixture of compressed CO[sub 2] and toluene},
author = {White, K.L. and Knutson, B.L. and Kimber, G.},
abstractNote = {The removal of low-molecular-weight components from commercial pitches is a critical step in the production of suitable precursors for isotropic carbon fiber formation. A unique extraction process employing a one-phase binary mixture of carbon dioxide and toluene has been developed to remove low-molecular-weight components from coal tar pitch, with an ultimate goal of increasing the softening point of the pitch. The mass fraction of coal tar pitch extracted was determined as a function of extraction temperature (25--75 C), pressure (8.7--14.9 MPa), and extractive solvent composition (40--70 wt % toluene) using a factorial experimental design. As much as 44 wt % of the coal tar pitch was removed at these extraction conditions, and softening points greater than 250 C were achieved. The separation is controlled by the temperature and composition of the extractant solvent. This compressed gas/organic solvent extraction process removes low-molecular-weight material from the coal tar pitch using significantly milder solvents and reduced temperatures relative to traditional extractive processes.},
doi = {10.1021/ie990119k},
journal = {Industrial and Engineering Chemistry Research},
issn = {0888-5885},
number = ,
volume = 38:9,
place = {United States},
year = {1999},
month = {9}
}