formaldehyde

English name: formaldehyde

Nicknames: formaldehyde, formalin

Chemical formula: HCHO

Melting point: -92℃

Boiling point:-19.5℃

Water solubility: Soluble in water.

Appearance: colorless gas

Introduction:

Formaldehyde, chemical formula HCHO or CH? O, the molecular formula is 30.03, also known as ant aldehyde. Colorless gas, irritating smell, irritating to people's eyes, nose, etc. The relative density of gas is 1.067 (air = 1), and the density of liquid is 0.8 15g/cm? (-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℃.

Governance misunderstanding:

1. Soak in water, vinegar and black tea to remove formaldehyde.

Many people on Amethyst say that because formaldehyde is soluble in water, you can put more pots at home to absorb formaldehyde or soak it in vinegar or black tea. It is a fact that formaldehyde is soluble in water, water, alcohol and ether. Free formaldehyde in the air will dissolve into it when it meets water during movement, which is similar to the adsorption principle of activated carbon. The contact area between a basin of water and air is only the size of a basin, while the specific surface area of internal pores of 1g activated carbon can reach the size of a football field. Even if you put a hundred pots of water in the room, the adsorption effect will not be much stronger than a small bag of activated carbon. Therefore, it is obviously unrealistic to use water, black tea and vinegar to adsorb formaldehyde. The release of formaldehyde is closely related to indoor temperature and humidity. With the increase of temperature, the release of formaldehyde will greatly increase. The experimental results show that when the relative humidity in the air increases 10%, the indoor formaldehyde emission will increase by about 5%.

2. Plants have limited ability to purify air.

We must note that this is only an outbreak of plant resistance. In addition to formaldehyde is the last resort for plants. Harmless treatment, but also a lot of detours, far less effective than photosynthesis to absorb carbon dioxide.

Moreover, in this process, plants themselves will also be hurt, and many plants will be injured or even killed in an environment with high formaldehyde concentration. Oxalis rubra is particularly sensitive. As long as it is placed in the environment with formaldehyde concentration of 0. 1 mg/m3 for 3 hours, 95% of its leaves will be damaged (calculated by area ratio). And the greater the concentration of formaldehyde, the faster the damage. They can only persist for 3 hours in the environment with formaldehyde concentration of 0.4 mg/m3, and then the whole leaves turn yellow-brown, wither after losing water and become hay.

3. Fruits such as oranges and pineapples cannot adsorb formaldehyde.

This is a method that many people like to use in the past, and it can be said to be a folk law. Many folk indigenous laws are the summary of long-term life experience and the truth that has been tested by time and practice. But this method is completely absurd. CCTV Financial Channel "Is it true? There was once a program, grapefruit peel and pineapple were formaldehyde-free. Is it true? The experiment was specially done in the program. The experimental results showed that the formaldehyde content of the experimental warehouse with grapefruit peel was ten times that of the blank warehouse in the same sealed warehouse. Because after putting grapefruit peel, the temperature of the experimental warehouse rises, and the amount of formaldehyde released greatly increases. Pomelo peel and pineapple can not only remove formaldehyde, but also increase indoor formaldehyde content. In the past, many people thought that after using grapefruit peel and pineapple, the taste of interior decoration was small, because the taste of fruit masked the smell of formaldehyde. There are some "assembly lines" in these factories to remove formaldehyde, which will make formaldehyde react with certain chemicals to produce amino acids (such as serine). Or directly converted into carbonic acid and carbon dioxide, so as to enter the material cycle and be used for manufacturing new sugar, fat or protein. Therefore, this process undoubtedly reduces the damage of formaldehyde to plant cells, on the other hand, it also increases the "nutrients" of plants. After all, there is no difference between carbon and carbon dioxide in formaldehyde. This is a good way to kill two birds with one stone.

The main reason is that formaldehyde will combine with superoxide dismutase in plant cells, inactivate these key proteins, further destroy the cell membrane structure, and finally tear down this wall. That is the key part of strictly controlling the entry and exit of nutrients, moisture and waste. At this point, the fate of plants can be imagined.