GRAPHITE CATHODE
t i - C O A L MANIFOLD GRAPHITE ANODE Hz-COAL MANIFOLD
Figure 8. Arc reactor with dual coal feed
(Krukonis et al., 1969) process, in which the coal is injected directly into the arc. I n such a process a large portion of the coal is volatilized in the interelectrode region and the effluent gas mixture consists of acetylene and other hydrocarbon species as well as arc-heated hydrogen. Coal injected into this plasma jet, as shown in Figure 8, should react with the arc-heated hydrogen to form additional acetylene and to quench the high temperature hydrocarbon species t o preserve a high percentage of the acetylene. The combination of the two processes would be analogous to the Huels process (Gladisch, 1962), in which fluid hydrocarbons are injected directly into the arc as well as downstream of the arc. Initial tests in which the combined processes were tried with coal injection showed a 10 to 15cc increase in the acetylene concentration with a corresponding decrease in SER values. A decrease in acetylene yield was also noted. This can be traced to the additional coal, added downstream, which apparently is not converted to acetylene as efficiently as the primary coal charge injected directly into the plasma. Acknowledgment
The technical assistance of Albert Bothe, Thomas Henze, Robert McDonough, and Richard Ruediger in planning and performing the described experiments is gratefully acknowledged. literature Cited
Bond, R. L., Lander, W. R., McConnel, G. I. T., Aduan. Chem. Ser., No. 55, 650-65 (1966).
Curran, G. P., Struck, R. T., Gorin, E., Amer. Chem. SOC., Div. Fuel Chem., Prepr. 10, (2), C-130-C-148 (1966). Eddinger, R. T., Friedman, L. D., Rau, E., Fuel 45, 245-52 (1966). Gladisch, H., Hydrocarbon Process Petrol. Refiner. 41 (6), 159 (1962). Howard, W. B., Wood, B. H., Kaltenbacher, E . J., Cheni. Eng Progr. 57 (ll), 50 (1961). Kavlick, F. J., Lee, B. S., Amer. Chem SOC.,Div. Fuel Chem., Prepr. 10, (4), 131-9 (1966). Kawa, W., Graves, R . D., Hiteshue, R. W., U. S.Bureau of Mines, Rept. Invest. 6829 (1966). Kawana, Y., Mankino, M., Kimura, Tatsuo, Kogyo K q a h u Zmshi 69 (6), 1144-50 (1966). Kozlov, G. I., Inter. Chem. Eng. 8, KO. 2, 289 (April 1968). Krukonis, V. J., Gannon, R. E., Schoenberg, T., 19th Canadian Engineering Conference, Edmonton, Alberta, 1969. Krukonis, V. J., Schoenberg, T., Paper 5-132, 7th International Conference on Coal Science, Prague, 1968. Lefrancois, P. A., Barclay, K. M., Skaperdas, G. T., Amer. Chem. SOC.,n i v . Fuel Chem., Prepr. 10 (4), 198-205 (1966). Littlewood, K., McGrath, I . A., Paper C9, 5th International Conference on Coal Science, Cheltenham, 1963. Newman, J. 0. H., Coldrick, A. J. T., Evans, P. L., Kempton, T. J., O’Brien D. G., Woods, B., 7th International Conference on Coal Science, Prague, 1968. Office of Coal Research, “AVCO Arc-Coal Process,” OCR Contract No. 14-01-0001-493, R & D Rept. 34 (1968). O’Hara, J. B., Chem. Eng. Progr. 63, 61 (1967). Rau, E., Eddinger, R. T., Fuel 43 (3), 246 (1964). Rau, E., Seglin, L., Fuel 43 (2), 147-57 (1964). Sharkey, A. G., Jr., Schultz, J. L., Friedel, R. A,, Adilan. Chem. Ser., No. 55, 560-5 (1966). Wagman, D. D., Kilpatrick, J. E., Pitzer, K . S., Rossini, F. D., J . Res. Nut. Bur. Stand. 35, 467 (1945). RECEIVED for review September 24, 1969 ACCEPTED March 16, 1970 Symposium on Chemicals from Coal, Division of Fuel Chemistry, 158th Meeting, ACS, New York, N. Y., September 1969. Program supported by the Ofice of Coal Research, Contract Number 14-01-0001-493.
Partial Decarboxylation of Coal Aromatic Acids by Transition Metal Complexes Sidney Friedman, Samuel R. Harris, and Irving Wender Pittsburgh Coal Research Center, Bureau of Mines, U . S.Department of the Interior, 4800 Forbes Aue., Pittsburgh, Pa. 15213
CONTROLLED
OXIDATION OF COAL in the presence of alkali produces a mixture consisting largely of aromatic acids (Smith et al., 1939). This work was originally done to obtain product information to be used in deducing the structure of coal. The product proved to be of sufficient interest for a large chemical company to do pilot plant work on oxidizing coal to coal acids (Archer et al., 1960;
Montgomery and McMurtrie, 1964). The mixed acids, as obtained, found no large markets, largely because of the complexity of the product. Though commercialization did not occur, interest in coal acids has remained high, and workers in laboratories around the world have published on this topic in recent years (Benning, 1965; Franke et al., 1952; Germain and Valadon, 1960; Gomez Aranda Ind. Eng. Chem. Prod. Res. Develop., Vol. 9, No. 3, 1970
347
In the presence of carbon monoxide and hydrogen, dicobalt octacarbonyl, C O ~ ( C O ) A , catalyzes the selective partial decarboxylation of phthalic acid or anhydride and substituted phthalic acids or anhydrides to yield the corresponding benzoic acids. In the case of pyromellitic acid, the Co,(CO)i; i s consumed in the decarboxylation, becoming a reactant instead of a catalyst. By using derivatives of Col(CO)8 in which one or two carbonyl groups are replaced by trialkylphosphine ligands, it i s possible to preserve the catalytic activity of the complex. Such a catalyst will selectively decarboxylate benzenepolycarboxylic acids containing carboxyl groups on adjacent carbons to mixtures
of isophthalic and terephthalic acids. By applying this reaction to a mixture of acids obtained by alkaline oxidation of coal, char, or other coal derivatives, it i s possible to obtain a product rich in isophthalic and terephthalic acids.
and Gomez Beltran, 1962; Kamiya, 1961). Analyses indicate that these coal acid mixtures may contain up t o 9 5 5 of benzenepolycarboxylic acid (BPCA), ranging all the way from phthalic acid to mellitic acid (Germain and Valadon, 1960). If it were possible to convert this complex mixture to one with only a few separable components, the oxidation uf coal and its derivatives might become a promising route to valuable chemicals. This second step in the process, conversion of the coal acids to a simple mixture rich in isophthalic and terephthalic acids, is now feasible as a result of a reaction developed a t the Bureau of Mines (Friedman et al., 1967; Wender et al., 1958), in which a selective decarboxylation of BPCA is effected by Co.(COjn and certain of its derivatives. As a result, it is possible to convert coal directly t o a mixture of isophthalic and terephthalic acids.
t o free acids. An aliquot was converted to trimethylsilyl esters (Kaufman et al., 1967) and analyzed by gas chromatography on a 6-foot by ?
