9/25/2015 PhysicochemicalPropertiesEvonikisoneoftheworld'slargestproducersofhydrogenperoxideH2O2

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Hydrogen Peroxide | HOMEABOUT HYDROGEN PEROXIDE PRODUCTS APPLICATION AREAS SERVICES CONTACT

Physicochemical PropertiesHydrogen peroxide (H O ) is a colorless watersoluble liquid. The molecule of hydrogen peroxide is asymmetrical andstrongly polarized. A high tendency to form hydrogenbond networks causes higher viscosity than water. Because offree electron pairs on both oxygen atoms, the H O molecule tends to form donoracceptor compounds. Pure hydrogenperoxide is primarily of scientific interest only. Its aqueous solutions, however, are widely used in many industrialbranches for various applications. Important physical properties of hydrogen peroxide and its aqueous solutions assummarized in the table on the left side.The molecular structure as well as oxygen's oxidation state define the chemical properties of hydrogen peroxide. The oxygenatom, being in the oxidation state I, allows hydrogen peroxide to participate in both oxidation as well as reduction reactions.Although hydrogen peroxide is well known as a strong oxidizing agent, its reduction properties play an important role insome applications. Typical chemical reactions, in which hydrogen peroxide is involved, are oxidation and reductionreactions, formations of other peroxygen or adduct compounds. In contrast to many other redox agents, hydrogen peroxideintroduces no additional substances other than water into the reaction system and an excess can be easily decomposed intowater and oxygen, not interfering thereby with subsequent reaction steps. Hydrogen peroxide is often regarded as a true"green chemical".

Despite its high reactivity, pure hydrogen peroxide is a stable substance and, if kept under optimal conditions, can be storedfor years. The most important factors increasing the rate of decomposition are high pH value, high temperatures, UVirradiation, presence of transition metal salts and all kinds of impurities.

The decomposition of hydrogen peroxide into oxygen and water is a quite complex process, which involves formation ofvarious free radicals. In some applications (soil remediation) the induced instability is intentionally caused and used.

Important physicochemical properties of aqueous solutions of hydrogen peroxide (1)

H O concentration(2)

%(wt.) 0 30 35 50 60 70 100

g(H O ) /kg

300 350 500 600 700

g(H O ) /l

332 395 596 742 899

mol/ l l 9,8 11,6 17,5 21,8 26,4 mol% 18,5 22,2 34,6 44,3 55,3 Active oxygencontent

%(wt.) 0 14,1 16,5 23,5 28,2 32,9 47,1

Molecular weight g/mol 18,015 34,015Density at 20 C g/ml 0,998 1,111 1,131 1,195 1,241 1,289 1,450Freezing point C 0 26 33 52 56 40 0,4Boiling point at 1013mbar.

C 100 106 108 114 119 125 150

Boiling point at 2026mbar.

C 132 135 145 152 158

Boiling point at 3039mbar.

C 147 150 161 168 176

Total vapor pressure(30 C)

mbar 42 33 32 24 19 15 8

mm. Hg. 31,6 25 24 18 14 11 6HO partial vapor mbar 0,3 0,4 0,8 1,2 1,7 pressure at 30 C mm. Hg. 0,25 0,3 0,6 0,9 1,3 Specific heat at 25C J*g/K 4,2 3,6 3,5 3,3 3,2 3,1 2,6

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9/25/2015 PhysicochemicalPropertiesEvonikisoneoftheworld'slargestproducersofhydrogenperoxideH2O2

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Refractive index,n25D at 25C

1,3325 1,3519 1,3554 1,3661 1,3734 1,3814 1,4067

Viscosity at 20C mPa*s 1,00 1,11 1,12 1,18 1,21 1,23 1,25Surface tension at20C

mN/m 72,8 74,2 74,5 75,7 76,4 77,3 80,4

1) The tabulated values, which are given above, describe physicochemical properties of salt freepure aqueous solutions of hydrogen peroxide in water.

2) Hydrogen peroxide concentration can be expressed in weight percent, gram of 100%age hydrogenperoxide in 1 kg solution, gram of 100%age hydrogen peroxide in 1L solution and as molarconcentration or molar fraction of hydrogen peroxide in solution. The tabulated values for g(H O )/land mol/l are given for the temperature of 25C.

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