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Acylation of aromatic compounds by acid anhydrides using Preyssler's anion [NaP5W30O110]14- and heteropolyacids as green catalysts

Gharib A., Jahangir M., Scheeren J.(H.)W.

Polish Journal of Chemical Technology

2011

Vol. 13, nr 2

11-17

The Preyssler, Wells-Dowson and Keggin heteropolyacids are efficient and eco-friendly solid acid catalysts for the acylation of electron-rich aromatic compounds with acid anhydrides. The performance of different forms of heteropolyacids was compared. In all the cases, the best results were obtained using the Preyssler heteropolyacid as the catalyst. In the presence of 25 mol% (with respect to H+ equivalency) Preyssler catalyst, highly para-selective acetylation of anisole occurs using two equivalents of acetic anhydride, in 15 min at room temperature. The isolated yield of the p-methoxyacetophenone product is 98%.

Investigations of electrochemical method of chromic acid anhydride production

Kowalski Z., Krystek A.

Polish Journal of Applied Chemistry

1999

Vol. 43, nr 3-4

177-189

The electrochemical process and the results of the laboratory and semi- technical investigations of the sodium chromate transformation to chromic acid using cation-exchangeble membranes are discussed. In comparison with the traditional chemical process of chromic acid anhydride production, the new electrochemical method can be characterised with advantages enables production of high purity crystalline product and leads to elimination the troublesome by-product -acid chromic sodium sulphate.