Ind. Eng. Chem. Res.It should also be noted that anisole did not show any significant direct demethoxylation under corresponding reaction conditions (Vuori et al., 1984).Effect of Tetralin. As can be seen from Figure 2, for example, tetralin decreases the decomposition rate of each of the model compounds studied. The presence of tetralin was also found to prevent the formation of higher products, excluding experiments with p-hydroxyanisole at 673 K. Obviously this is due to the quenching effect tetralin has on free-radical reactions. The formation of higher products from p-hydroxyanisole, even in the presence of tetralin, can be explained by steric reason.
ConclusionsThe reactivity of guaiacol is much greater than the reactivity of any other of the hydroxy-or methoxyanisoles. The reason for this is the hydroxy group at the ortho position, since the reactivity of anisole is also low.Two major primary pathways can be distinquished for d three hydroxyanisoles: the first leading to the formation of the correspondingly substituted dihydroxybenzenes and the second leading to the formation of the correspondingly substituted cresols. For guaiacol, the former pathway may be, in addition to a homolytic bond scission, partly concerted. A concerted mechanism cannot, however, be visualized for m-and p-hydroxyanisoles. The latter pathway is thought to take place via a spiranic oxiran intermediate. Neat m-hydroxyanisole shows, in addition, some formation of methyl-m-hydroxyanisoles. Direct breaking of the aromatic C-0 bonds in the hydroxyanisoles occurs only to a minor extent under mild thermolysis conditions. The o-and p-methoxyanisoles follow a reaction pattern of the same type as the hydroxyanisoles, while m-methoxyanisole gives more ring-methylated products with two oxygen atoms. There is, however, no indication of a concerted mechanism for o-methoxyanisole. The formation of anisole by direct demethoxylation is significant for all three methoxyanisoles, while the presence of a hydroxy group in the hydroxyanisoles seems to prevent this demethoxylation.The decomposition rate of all the model compounds studied is decreased by the presence of tetralin.
AcknowledgmentThis work has been funded in part by grants from the Ministry of Education and Neste Oy Foundation. We are 1987,26, 365-369 365 grateful to Eija Kinnunen and Tim0 Karinen for their contributions to the experimental part of this work. Literature Cited Avni, E.; Coughlin, R. W.; Solomon, P. R.; King, H. H. Prepr. Pap.-Am. Chem. SOC., Diu. Fuel Chem. 1983, 28(5), 307-318. Bredenberg, J. B.; Ceylan, R. Fuel 1983, 62, 342-344. Bredenberg, J. B.; Huuska, M.; Toropainen, P. Actas Simp. Iberoam. Ceylan, R.; Bredenberg, J. B. Fuel 1982, 61, 377-382. Connors, W. J.; Johanson, L. N.; Sarkanen, K. V.; Winslow, P. Deglise, X.; Lede, J. Znt. Chem. Eng. 1982, 22, 631-646. Iatridis, B.; Gavalas, R. Ind. Eng. Chem. Prod. Res. Dev. 1979, 18, Jegers, H. E.; Klein, M. T. Ind. Eng. Chem. Process Des. Deu. 1985, Kislitsyn, A. N.; Rodionova, Z. M.; Savinykh, V. I.; Il'ina, E. I.; Abakhumo...
