Tetrafluoro-phthalic anhydride

JJ Parlow, W Naing, MS South, DL Flynn. In situ chemical tagging tetrafluoro-phthalic anhydride as a sequestration enabling reagent" (SER) in the purification of solution-phase combinatorial libraries. Tetrahedron Lett 38 7959-7962, 1997. 

Retention of ester groups. Equimolar amounts of startg. nitrile and tetrafluorophthalic acid heated at 135° for 4 days in a heavy-walled glass pressure tube product. Y 56%. Work-up is simple since no solvent is required. F.e.s. W.D. Rounds, G.W. Gribble, Tetrahedron Letters 29, 6557-60 (1988) from carboxylic acid amides with tetrachloro-or tetrafluoro-phthalic anhydride s. ibid. 6553-6. 

Copyrolysis (ca. 650 °C) of tetrafluorophthalic anhydride with tetrafluoro-ethylene or hexafluoropropene provides a route to perfluorobenzocyclobutenes (50 X = F, Y = F or CFs) (some perfluoroindane is also formed in the former reaction) and an analogous reaction occurs with phthalic anhydride itself [to give (50 X = H, Y = F)]. Perfluoro(methylnaphthalenes) are the main products from octafluoronaphthalene and polytetrafluoroethylene at elevated temperatures, but the reaction of octafluoronaphthalene with potassium fluoride at ca. 500 °C gives a mixture containing perfluoro(methylnaphthalenes, indane, and methyl-indanes). Such reactions are believed to involve difluorocarbene, and some... 

As can be deduced from plant purchases, the PRC is still at the formative stage where emphasis is on producing only the most basic petrochemicals. No plants were purchased for producing dibasic acids (phthalic and maleic anhydrides, etc.) and fluro-carbon or tetrafluoro ethylene or some of the advanced engineering plastics like ABS polyacetals, polycarbonates, polyimides or any other unsaturated polyesters. Another important area of low Chinese activity is thermoplastics for space and defense applications. ... 

Cyclic tetrafluoro ethers are also the main or sole products of the sulfur tctrafluoridc fluorination of phthalic and pyromellitic acids, or their anhydrides, possessing two bulky ortho substituents (e.g., CF3. N02, Br. Cl or even Me). These substituents create steric crowding which pushes two neighboring carboxylic acid groups towards each other and forces cyclization acid anhydrides and difluoro lactones are the intermediates and they may be isolated from reactions carried out under sufficiently mild conditions. Thus, reaction of 3,6-bis(trifluoromcthyl)bcn-zcnc-1,2-dicarboxylic acid (4) with sulfur tctrafluoridc at ambient temperature results in dehydration to give exclusively the corresponding cyclic anhydride 5 at 60"C a mixture of the anhydride 5, 3,6-bis(trifluoromethyl)phthaloyI difluoride (6) and 3,3-difluoro-4,7-bis(trifluoro-methyl)isobenzofuran-l(3//)-one (7) is obtained, but at 200"C the final product, 1,1,3,3-tct-rafluoro-4,7-bis(trifluoromethyl)-l,3-dihydroisobenzofuran (8), is formed as the sole product.137... 

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