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Properties of substance:

methanal

Synonyms:

formaldehyde

Group of substances:

organic

Physical appearance:

colorless gas

Empirical formula (Hill's system for organic substances):

CH2O

Structural formula as text:

HCHO

Molar/atomic mass: 30.03

Melting point (°C):

-92

Boiling point (°C):

-19.2

Solubility (g/100 g of solvent):

1-butanol: 70.6 (20°C) [Ref.]
1-hexanol: 45.8 (20°C) [Ref.]
1-octanol: 28.5 (20°C) [Ref.]
2-pentanol: 56.7 (20°C) [Ref.]
acetone: soluble [Ref.]
benzene: soluble [Ref.]
benzylic alcohol: 64.7 (20°C) [Ref.]
chloroform: soluble [Ref.]
cyclohexanol: 43.1 (20°C) [Ref.]
diethyl ether: soluble [Ref.]
ethanol: soluble [Ref.]
hydrogen fluoride : very soluble [Ref.]
oxygen liquid: 0.000025 (-183°C) [Ref.]
petroleum ether: insoluble [Ref.]
water: soluble [Ref.]

Properties of solutions:

2% (wt.), solvent - water
  Density (g/cm3) = 1.0048 (18°)
10% (wt.), solvent - water
  Density (g/cm3) = 1.028 (18°)
20% (wt.), solvent - water
  Density (g/cm3) = 1.0602 (18°)
30% (wt.), solvent - water
  Density (g/cm3) = 1.0921 (18°)
38% (wt.), solvent - water
  Density (g/cm3) = 1.1173 (18°)

Numerical data:

Year of discovery: 1867

Density:

0.9151 (-80°C, g/cm3)
0.8153 (-20°C, g/cm3)

Reactions:

  1. Yeild 35-95%. [Ref.1aster]
    C10H8 + CH2O + HCl → C10H7CH2Cl + H2O
  2. Yeild 50-60%. [Ref.1]
    CH3OC6H5 + CH2O + HCl → CH3OC6H4CH2Cl + H2O
  3. Yeild 80%. [Ref.1]
    C6H5NHCH3 + CH2O + Zn + 2HCl → C6H5N(CH3)2 + ZnCl2 + H2O
  4. Yeild 60%. [Ref.1]
    C6H5COCH3 + CH2O + HN(CH3)2 * HCl → C6H5COCH2CH2N(CH3)2 + HCl + H2O

Vapour pressure (Torr):

20 (-79.6°C)

Electrode potential:

HCOO- + 2H2O + 2e- → CH2O + 3OH-, E = -1.07 V (water, 25°C)

Dissociation:

pKa (1) = 13.27 (25°C, water)

Standard molar enthalpy (heat) of formation ΔfH0 (298.15 K, kJ/mol):

-115.9 (g)

Standard molar Gibbs energy of formation ΔfG0 (298.15 K, kJ/mol):

-110 (g)

Standard molar entropy S0 (298.15 K, J/(mol·K)):

218.66 (g)

Molar heat capacity at constant pressure Cp (298.15 K, J/(mol·K)):

35.35 (g)

Enthalpy (heat) of vaporization ΔvapH (kJ/mol):

23.3

Heat of combustion (kJ/mol):

561.1

References:

  1. CRC Handbook of Chemistry and Physics. - 95ed. - CRC Press, 2014. - pp. 3-278
  2. Альберт А., Сержент Е. Константы ионизации кислот и оснований. - М.-Л.: Химия, 1964. - pp. 123-124 [Russian]
  3. Вредные вещества в промышленности: Справочник для химиков, инженеров и врачей. - 7-е изд., Т.1. - Л.: Химия, 1976. - pp. 505-509 [Russian]
  4. Некрасов Б.В. Основы общей химии. - Т.1. - М.: Химия, 1973. - pp. 560 [Russian]
  5. Огородников С.К. Формальдегид. - Л.: Химия, 1984 [Russian]
  6. Рабинович В.А., Хавин З.Я. Краткий химический справочник. - Л.: Химия, 1977. - pp. 163 [Russian]
  7. Тюкавкина Н.А., Бауков Ю.И. Биоорганическая химия. - М.: Медицина, 1985. - pp. 190 [Russian]

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    © Collected Ruslan Anatolievich Kiper, burewestnik@mail.ru