Pyrophosphonic acids

If the ratio is 2.5—3, the product is a mixture of phosphonic and pyrophosphonic acids ... 

Additional phosphonic acid is derived from by-product streams. In the manufacture of acid chlorides from carboxyUc acids and PCl, phosphonic acid or pyrophosphonic acid is produced, frequentiy with copious quantities of yellow polymeric LOOP. Such mixtures slowly evolve phosphine, particularly on heating, and formerly were a disposal problem. However, purification of this cmde mixture affords commercial phosphonic acid. By-product acid is also derived from the precipitate of calcium salts in the manufacture of phosphinic acid. As a consequence of the treatments of the salt with sulfuric acid, carbonate is Hberated as CO2 and phosphonic acid goes into solution. 

The potassium salts of the pyrophosphonic acids gave FAB spectra free from matrix interferance.238 Chemical ionisation induced competing and consecutive heterolytic ring cleavage in the mass spectra of the oxides (88).239 The base peaks of imphos and cyclophane were guite different and base peaks appeared at m/z 131 and 21 respectively.240 The mass spectra of phenylphosphonates and phosphates such as (89) have been reviewed.24 ... 

Ring opening of the iV-methylated 1,3,2-oxaza- and 1,3,2-diaza-phospholidine rings with phosphoric and phosphonic acids yields 2-aminoethyl derivatives of pyrophosphoric and pyrophosphonic acids (9) 2-dimethylamino-l,3,2-dioxa-... 

Pyrophosphoric and pyrophosphonic acid esters from acylphosphoric and acylphosphonic acid esters... 

Diphosphonic acids and esters Pyrophosphonic acids and esters 20... 

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