ChemicalBook CAS DataBase List Pyromellitic Dianhydride

Pyromellitic Dianhydride synthesis

12synthesis methods

Product Name:Pyromellitic Dianhydride
CAS Number:89-32-7
Molecular formula:C10H2O6
Molecular Weight:218.12

Pyromellitic Dianhydride is prepared by gas-phase oxidation of 1,2,4,5-tetramethylbenzene (or related tetrasubstituted benzene derivatives). An idealized equation is:
C6H2(CH3)4 + 6 O2 → C6H2(C2O3)2 + 6 H2O
In the laboratory, it can be prepared by dehydration of pyromellitic acid using acetic anhydride.

89-05-4 Synthesis

89-05-4
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89-32-7
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Yield:89-32-7 90%

Reaction Conditions:

2,6-bis[(2,2,6,6-tetramethylpiperidin-1-yl)methyl]phenylboronic acid in butryonitrile; for 12 h;Reflux;

Steps:

28

Examples 28 to 32Synthesis of a tetracarboxylic dianhydride used as a raw material for polyimide resin synthesis was investigated. In particular, in accordance with Examples 21 to 27, the dehydrative condensation reaction of a tetracarboxylic acid (2.5 mmol) shown in Table 5 was performed in butyronitrile (10 mL) in the presence of the boronic acid compound E (0.025 mmol, 1 percent by mole). After the reaction mixture was cooled to room temperature, 50 mL of pentane was added, and a precipitated solid was collected by filtration, so that a target tetracarboxylic dianhydride was obtained. In addition, in Example 32, instead of the isolated yield, the conversion yield was obtained by analysis using ¹H NMR. The results are shown in Table 5. Each tetracarboxylic acid showed excellent reactivity, and a carboxylic dianhydride corresponding thereto was obtained in high yield (85% to 99%). Although the results obtained by reaction performed under no catalyst conditions were also shown in Table 5, the reaction hardly progressed under no catalyst conditions.

References:

US2011/319620,2011,A1 Location in patent:Page/Page column 10-11