Edited phthalic

Thermal reaction of allenyl azines , derived from propargylphosphonium salts with ketenes, isocyanates, CS2 or phthalic anhydride to form bi- and tricyclic fused pyrazolo heterocycles (see 1 st edition). 

Gibson, S.B., 1976. The design of new chemical plant using hazard analysis. Process Industry Hazards, Symposium Series No. 47. 135 (IChemE. Rugby. UK). HSE, 1992, Tolerability of Risk from Nuclear Power Stations, revised edition. Pantony, M.F.. Scilly. N.F. and Barton. J.A.. 1989. Safety of exothermic reactions a UK strategy, Int Symp on Runaway Reactions. 504—524 (CCPS, AIChE. USA). Kauffman, D. and Chen, H-J.. 1990, Fault-dynamic modelling of a phthalic anhydride reactor, J Loss Prev Process hid. 3 386-394. 

As the first reported low bandgap polymer, PITN is still of considerable interest and a significant number of publications covering its preparation and derivatives have appeared since the second edition of this handbook. While the majority of these reports have dealt with various PITN derivatives, new methods for the preparation of the parent PITN have also been investigated. Before 1995, the preparation of PITN had focused primarily on the oxidative polymerization of either isothianaphthene or dihydroisothia-naphthene. Starting in 1995, however, Vanderzande and coworkers reported a significantly different preparation method for PITN [33,34]. This method involved the reaction of phthalic anhydride (30) or phthalide (31) with P4S10 at temperatures above 120°C (Scheme 12.1). 

FIGURE 5.12 Multitubular reactor for the oxidation of o-xylene to phthalic acid anhydride. (Data from Froment, G. and Bischoff, K., Chemical Reactor Analysis and Design, 2nd Edition,Wiley, New York, 1990.)... 

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