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溶解性
水及びエタノールに溶ける。
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解説
ピロリン酸無色の針状晶またはガラス状の塊。通常の固体はI型(融点54.3℃)で，これを封管中で約50℃に熱するとII型(融点71.5℃)に転移する。
株式会社平凡社 世界大百科事典 第２版について 情報
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用途
触媒、電解研磨剤
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製造
ピロリン酸化学式H4P2O7。二リン酸diphosphoric
acidともいう。オルトリン酸H3PO4が脱水縮合してできる四塩基酸である。オルトリン酸(85％)を減圧下，約180℃で加熱脱水するか，計算量の五酸化二リンを加えてつくる。 4H3PO4＋P2O5―→3H4P2O7
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説明
Pyrophosphoric acid, also known under the name
diphosphoric acid, is colorless, odorless, hygroscopic
and is soluble in water, diethyl ether and ethyl alcohol.
It is produced from phosphoric acid by dehydration.
Pyrophosphoric acid slowly hydrolyzes in the presence
of water into phosphoric acid.
H4P2O7 +H2O?2H3PO4
Upon heating, phosphoric acid loses water, being
converted successively, and to some extent concurrently,
into the pyro- and meta-acids:
2H3PO4?H4P2O7 +H2O
nH3PO4?(HPO3)n + [H2O]n
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化学的特性
White to very pale yellow glassy solid
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物理的性質
Colorless needles or liquid; hygroscopic. Crystallizes in two anhydrous forms: a metastable form melting at 54.3°C and a second and more stable form melting at 71.5°C; extremely soluble in cold water, reacting very slowly to form phosphoric acid; decomposing much faster in hot water; very soluble in alcohol and ether.
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使用
Pyrophosphoric Acid has been shown to enhance the rate of pyrophosphate hydrolysis by nonenzymatic catlysis and by inorganic pyrophoshatase. Pyrophosphoric Acid can be used for the preparation of vanadyl pyrophosphato methoxide cluster anion. Pyrophosphoric Acid is used in anion binding of inorganic phosphates due to is ability to form complexes.
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製造方法
According to early investigators, the pyro-acid is
formed as low as 100 °C, and the conversion is complete
between 255 and 260 °C. Phosphorous oxychloride
reacts with phosphoric acid in the following manner:
5H3PO4 + POC13?3H4P2O7 + 3HC1
A mixture of the ortho- and meta-acids may be
condensed together to form the pyro-acid by heating on the water bath:
nH3PO4 +[HPO3]n?[H4P2O7]n
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定義
ChEBI: An acyclic phosphorus acid anhydride obtained by condensation of two molecules of phosphoric acid.
