The wall paint contains formaldehyde. Except for the wall paint, the formaldehyde content is more or less when it comes to household articles with adhesives.
The introduction of formaldehyde is as follows:
Formaldehyde, chemical formula HCHO or CH2O, molecular formula 30.03, also called formaldehyde. Colorless gas, with a special irritating smell, has a stimulating effect on people's eyes and nose. The relative density of gas is 1.067 (air = 1), and the density of liquid is 0.8 15g/cm3(-20℃). Melting point -92℃, boiling point-65438 09.5℃. Soluble in water and ethanol. The highest concentration of aqueous solution can reach 55%, usually 40%. It is called formaldehyde water, commonly known as formalin, which is a colorless liquid with an irritating smell.
Strong reduction, especially in alkaline solution. Can burn, steam and air form an explosive mixture, and the explosion limit is 7%-73% (volume). The ignition temperature is about 300℃.
Formaldehyde can be produced by dehydrogenation or oxidation of methanol under the catalysis of metals such as silver and copper, and can also be separated from hydrocarbon oxidation products. Used as pesticides and disinfectants, raw materials for preparing phenolic resin, urea-formaldehyde resin, vinylon, urotropine, pentaerythritol and dyes.
Industrial formaldehyde solution generally contains 37% formaldehyde and 15% polymerization inhibitor methanol, and its boiling point is 10 1℃.
2065438+0710127 October, the list of carcinogens published by the International Agency for Research on Cancer of the World Health Organization was preliminarily sorted out for reference. Formaldehyde is in the list of Class I carcinogens. [ 1]
Chinese name
formaldehyde
English name
formaldehyde
Another name
Formaldehyde and formalin
chemical formula
formaldehyde
molecular weight
30.03
physical features
Carbon atoms form three σ bonds through three sp2 hybrid orbitals. One of them is to form a σ bond with oxygen. These three keys are on the same plane. A p orbit of carbon atom and a p orbit of oxygen overlap each other to form a π bond, which is perpendicular to the plane formed by three σ bonds. Bond angles ∠ HCH =11.5, ∠ HCO = 12 1.8. Bond length: carbon-hydrogen bond: 120.3pm, carbon-oxygen double bond: 1 10pm. The dipole moment is 7.56× 10-3? C m .
Colorless aqueous solution or gas, with irritating smell. Can be mixed with water, ethanol, acetone and other organic solvents in any proportion. Liquid is easy to be turbid when it is stored for a long time in cold, and paraformaldehyde precipitates at low temperature. Some formaldehyde escapes during evaporation, but most of it becomes trioxymethylene. This product is a strong reducing agent, which is more reducing when it is slightly alkaline. It can be slowly oxidized into formic acid in air.
The relative density of steam is1.081-1.085g/ml (air = 1), the relative density is 0.82g/mL (water = 1) and the refractive index (ND20) is/ Boiling point-19.5℃ (gas), 98℃(37% aqueous solution), melting point -92℃, auto-ignition temperature 430℃, vapor pressure 13.33kPa(-57.3℃), explosion limit in air 7%-73%, v/v.
Octanol-water partition coefficient is 0.35, critical temperature is137.2 ~141.2℃, critical pressure is 6.784~6.637MPa, and viscosity is 0.242 MPa s (-20℃). [2]
Soluble in water and ether, the highest concentration of aqueous solution can reach 55%. Can be mixed with water, ethanol and acetone at will. It can be gradually oxidized into formic acid in air and is a strong reducing agent. Its steam and air form an explosive mixture, which will cause combustion and explosion when exposed to open fire and high heat energy. In general commodities, 10% ~ 12% methanol is added as polymerization inhibitor, otherwise polymerization will occur. [2]
PH value: 2.8 ~ 4.0, flash point: 60℃
chemical property
Pure formaldehyde has a strong reducing effect, especially in alkaline solution. Formaldehyde itself can slowly undergo condensation reaction, especially prone to polymerization.