Studies on commercial octamethyl-pyrophosphoramide. IV—The decomposition of pyrophosphoric acid tetra(dimethylamide) and orthophosphoric acid tri(dimethylamide) in the living plant

1952 ◽  
Vol 3 (2) ◽  
pp. 69-73 ◽  
Author(s):  
D. F. Heath ◽  
D. W. J. Lane ◽  
Margaret Llewellyn
Keyword(s):  
Orthophosphoric Acid ◽  
Living Plant ◽  
Pyrophosphoric Acid

The Mechanical Properties and Microstructures of Cement Formed from Pyrophosphoric and Orthophosphoric Acids

2005 ◽  
Vol 284-286 ◽  
pp. 125-128 ◽  
Author(s):  
Liam M. Grover ◽  
Uwe Gbureck ◽  
David Farrar ◽  
J.E. Barralet
Keyword(s):  
Mechanical Properties ◽  
Acid Solution ◽  
Tricalcium Phosphate ◽  
Orthophosphoric Acid ◽  
Marked Change ◽  
Solution Set ◽  
Liquid Ratio ◽  
Setting Times ◽  
Pyrophosphoric Acid ◽  
Orthophosphoric Acid Solution

In this study the setting times, compressive strengths and microstructures of cements formed using pyrophosphoric acid solution and b-tricalcium phosphate (β-TCP; Ca3(PO4)2) were compared with those of cement formed using orthophosphoric acid solution and b-TCP. It was found that cement formed using pyrophosphoric acid solution set more slowly than that formed using orthophosphoric acid and could be mixed to a higher powder to liquid ratio, facilitating the production of cement exhibiting compressive strengths, without pre-compaction, as high as 25 MPa. The use of pyrophosphoric acid as opposed to orthophosphoric acid resulted in a marked change in the microstructure of the cement.

System ammonia-potassium monoxide-orthophosphoric acid-pyrophosphoric acid-water at 25.deg.

1973 ◽  
Vol 21 (4) ◽  
pp. 700-704 ◽  
Author(s):  
A. William Frazier ◽  
Ewell P. Dillard ◽  
Raymond D. Thrasher ◽  
Kjell R. Waerstad
Keyword(s):  
Orthophosphoric Acid ◽  
Acid Water ◽  
Pyrophosphoric Acid

System ammonia-zinc oxide-orthophosphoric acid-pyrophosphoric acid-water at 25.deg.

1975 ◽  
Vol 23 (2) ◽  
pp. 330-334
Author(s):  
A. William. Frazier ◽  
Ewell F. Dillard ◽  
James R. Lehr
Keyword(s):  
Zinc Oxide ◽  
Orthophosphoric Acid ◽  
Acid Water ◽  
Pyrophosphoric Acid

On-Line In-Situ Diagnostics of Processes Within HT-PEM Fuel Cells Membrane by Raman Microscopy

2013 ◽  
Author(s):  
Hans Bettermann ◽  
Martin Labus ◽  
Anne Majerus ◽  
Carsten Korte ◽  
Werner Lehnert
Keyword(s):  
Fuel Cell ◽  
Polyphosphoric Acid ◽  
Orthophosphoric Acid ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Current Consumption ◽  
Pyrophosphoric Acid ◽  
On Line ◽  
Concentration Changes

This contribution describes how Raman spectroscopy can be applied to investigate the distribution of molecular species inside an ABPBI membrane of a running PEM fuel cell. For the in-situ measurements an experimental setup was first developed and then used to identify phosphoric acid species and to record how they change their concentrations when the current consumption of the fuel cell was changed. The observation port to look inside the membrane was placed next to the cathode. At that location among orthophosphoric acid, H3PO4·H2O, a lot of oligophosphoric acid species are present where pyrophosphoric acid could unambiguously be identified. In comparison to all identified species pyrophoshoric acid and polyphosphoric acid undergo largest concentration changes when the current was changed.

THE COMPOSITION OF THE STRONG PHOSPHORIC ACIDS

1956 ◽  
Vol 34 (6) ◽  
pp. 785-797 ◽  
Author(s):  
Anna-Liisa Huhti ◽  
Phoebus A. Gartaganis
Keyword(s):  
Room Temperature ◽  
Orthophosphoric Acid ◽  
Dynamic Equilibrium ◽  
Free Water ◽  
Phosphorus Pentoxide ◽  
Mole Percent ◽  
Pyrophosphoric Acid ◽  
Set Up ◽  
Phosphoric Acids

The composition of the strong phosphoric acids was studied in the range 68.8 to 86.3% phosphorus pentoxide by weight. Improved filter-paper chromatography made possible the quantitative determination of the nine lower members of the series, and occasionally up to the twelfth member. It was found that when the strong phosphoric acids are prepared by heating at 350 °C, a dynamic equilibrium between the component acids is set up which persists when the mixtures are cooled to room temperature. Only linear condensed polyphosphoric acids were present in the range studied. The composition corresponding to 100% orthophosphoric acid contains about 6 mole percent each of pyrophosphoric acid and “free water”. As the mole ratio of water to phosphorus pentoxide decreases, the number of component acids increases. Orthophosphoric acid is present to an appreciable extent in the stronger phosphoric acids. “Hexametaphosphoric acid” is not a separate chemical entity, but a mixture of higher linear polyphosphoric acids.

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