Carbon Precursors from Anthracene Oil. Insight into the Reactions of Anthracene Oil with Sulfur Adela L. Ferna ´ ndez, Marcos Granda, Jenaro Bermejo, and Rosa Mene ´ndez* Instituto Nacional del Carbo ´ n, CSIC, Apartado 73, 33080 Oviedo, Spain Pablo Bernad Departamento de Quı ´mica Organometa ´ lica, Universidad de Oviedo, 33071 Oviedo, Spain Received February 5, 1998. Revised Manuscript Received June 24, 1998 An anthracene oil with a boiling point of 250-370 °C was reacted with sulfur (5-20 wt %) at 250-300 °C for 2 h. The extent of anthracene oil conversion to a carbon precursor (pitch-like material) was monitored from the weights of the residues obtained by thermogravimetric analysis at 350 °C (R 350 ), the temperature at which the anthracene oil residue is zero. Anthracene oil readily reacts with sulfur, the initial concentration of sulfur being the main controlling parameter of the reaction. The anthracene oil components showed different reactivities with sulfur, as determined by gas chromatography of the toluene-soluble fraction, and also followed different mechanisms because of their different structures. Studies by probe mass spectrometry of the pure compounds revealed the type of reaction mechanisms involved in the process. The amount of sulfur incorporated into the reaction products determined the optical texture of the resultant cokes. Introduction Anthracene oil is a tar fraction that distills between 250 and 370 °C. It is mainly composed of polycyclic aromatic hydrocarbons (PAH) with 2-4 aromatic rings. The major constituent compounds are phenanthrene, anthracene, fluoranthene, and pyrene. Conversion of the molecules of anthracene oil to larger-sized molecules offers the possibility of using anthracene oil as a precursor for carbon materials, with the subsequent economic upgrading of the anthracene oil. Pitch-like materials can be prepared by polymerizing the constituents of anthracene oil. The process of polymerization can be either thermal or chemical. Results obtained with model compounds 1,2 show that thermal polymerizations of PAH occur at temperatures near to 500 °C and at high pressures. Russian research- ers 3 have obtained needle coke from anthracene oil by thermal treatment at 455 °C and 7 MPa for 4 h. This treatment requires expensive facilities and a high energy consumption, with a subsequent increase in the price of the final product. Chemical polymerization of anthracene oil could be possible under less severe conditions by means of Friedel-Crafts type catalysts, 4-7 air-blowing, 8,9 or addition of sulfur. The reaction of sulfur with aromatic compounds has not been studied in depth. Its oxidizing effects on toluene have been known since the beginning of this century. 10 Sulfur reacts principally with alicyclic and hydroaromatic structures. This reaction was used in the 1960s to measure the amounts of such structures in coals 11,12 and later to measure the hydrogen-donor capability of coals, as well as coal- and petroleum- derived liquids. 13,14 Elemental sulfur has been exten- sively used as a dehydrogenation reagent in the syn- thesis of polycyclic aromatic hydrocarbons and their derivatives. 15 However, Van Krevelen et al. 16 and other researchers 17 have shown that at temperatures above 200 °C, sulfur extracts hydrogen from aromatic com- pounds. Mazumdar et al. 18 stated that sulfur reacts with aromatic compounds to give Ar-S-Ar-type com- * To whom correspondence should be addressed. (1) Lewis, I. C. Carbon 1980, 18, 191-196. (2) Greinke, R. A.; Lewis, I. C. Carbon 1984, 22, 305-314. (3) Cheshko, F. F.; Pityulin, I. N.; Pyrin, A. I.; Shustikov, V. I. Coke Chem. 1995, 7, 36-44. (4) Rey Boero, J. F.; Wargon, J. A. Carbon 1981, 19, 333-340. (5) Otani, S.; Oya, A. Bull. Chem. Soc. Jpn. 1972, 45, 623-624. (6) Mochida, I.; Kudo, K.; Fukuda, N.; Takeshita, K. Carbon 1975, 13, 135-139. (7) Mochida, I.; Shimizu, K.; Korai, Y.; Otsuka, H.; Fujiyama, S. Carbon 1988, 26, 843-852. (8) Belkina, T. V.; Privalov, V. E.; Stepanenko, M. A. Coke Chem. 1979, 8, 53-57. (9) Yamaguchi, C.; Mondori, J.; Matsumoto, A.; Honda, H.; Kumagai, H.; Sanada, Y. Carbon 1995, 33, 193-201. (10) Aronstein, M. M. L.; von Nierop, S. A. Recl. Trav. Chim. Pays- Bas 1902, 21, 448. (11) Mazumdar, B. K.; Chakrabartty, S. K.; Lahiri, A. Fuel 1959, 38, 115-119. (12) Dicker, P. H.; Flagg, M. K.; Gaines, A. F.; Martin, T. G. J. Appl. Chem. 1963, 13, 444-454. (13) Aiura, M.; Masunaga, T.; Moriya, K.; Kageyama, Y. Fuel 1984, 63, 1138-1142. (14) Rahimi, P. M.; Dawson, W. H.; Kelly, J. F. Fuel 1991, 70, 95- 99. (15) Fu, P. P.; Harvey, R. G. Chem. Rev. 1978, 78, 317-361. (16) van Krevelen, D. W.; Goedkoop, M. L.; Palmen, P. H. G. Fuel 1959, 38, 256. (17) Iyengar, M. S.; Dutta, S. N.; Banerjee, D. D.; Banerjee, D. K.; Rai, S. K. Fuel 1960, 39, 189-192. (18) Mazumdar, B. K.; Chakrabartty, S. K.; Ganguly, S.; Lahiri, A. Fuel 1962, 41, 121-128. 949 Energy & Fuels 1998, 12, 949-957 S0887-0624(98)00025-5 CCC: $15.00 © 1998 American Chemical Society Published on Web 08/26/1998