Acrylic acid is one of the simplest representatives of carbon unsaturated monobasic acids. Its formula is as follows: CH2 = CH-COOH. It is a colorless liquid with a sharp and unpleasant odor. Soluble in water, chloroform, diethyl alcohol and ethanol, easily polymerizes with the further formation of polyacrylic acid. Acrylic acid has other names: ethenic acid and propenic acid.
How is acrylic acid produced (or synthesized)?
1. At present, acrylic acid is produced by vapor-phase oxidation of propylene with oxygen (O 2) on molybdenum, cobalt or bismuth catalysts. An example is the following reaction:
CH2 = CH-CH3 (propylene) + O2 (oxygen) = CH2 = CH-COOH (acrylic acid)
2. In the past, a reaction was used in which carbon monoxide II (CO), acetylene (CH≡CH) and water (H2O) reacted. The chemical reaction will be as follows:
CHNCH (acetylene) + CO (carbon monoxide II) + H2O (water) → CH2 = CH-COOH (acrylic acid).
Another formaldehyde reaction with ketene was used:
CH2 = C = O (ketene) + H2C = O (formaldehyde) → CH2 = CH-COOH (propenic acid).
3. Now the company Rohm and Haas is creating a special technology for the synthesis of ethenic acid from propane.
Chemical properties of acrylic acid
The acid we are considering can form salts, esters, anhydrides, amides, acid chlorides and other compounds. It can also enter the addition reactions that are characteristic of ethylene carbons. The addition of water, protonic acids and NH3 occurs not according to Markovnikov's rule. In this case, substituted derivatives are formed. Acrylic acid is involved in the synthesis of dienes. It also condenses with various salts of aryldiazonium. With ultraviolet irradiation, it forms polyacrylic acid.
Application of acrylic kilo
- is used as raw material in the production of a wide range of polymer products with various chemical and physical properties (for example, plastics and coatings);
- used in the manufacture of dispersions for acrylic water-based paintwork materials; While the scope of such paints will depend on the chemical properties of the copolymer - from the final coloration of vehicles to the painting of ceilings;
- Acrylic acid and its derivatives are used to create impregnation for leather and fabrics, emulsions for paintwork materials, as a raw material for acrylate rubbers and polyacrylonitrile fibers, building adhesives and mixtures; Esters of methacrylic and acrylic acids (in most cases methyl methacrylate and methyl acrylate esters are used) are used in the production of polymers;
- often acrylic acid is used in the creation of superabsorbents.
Proper storage of acrylic acid
When storing this substance, an inhibitor-hydroquinone is added to avoid polymerization. Before use, the acid must be distilled with caution, since it is possible to develop explosive polymerization.
Safety in use
When working with acrylic acid, it should be noted that this substance has an irritant effect on the skin and mucous membranes. The threshold of the irritating action of the acid is 0.04 mg / liter. When exposed to the mucous membrane of eyeballs, as a rule, causes severe burns to the cornea, it can lead to irreversible changes (damage that can not be cured). The inhalation of vapors of acrylic acid can cause headache, irritation of the respiratory tract, and in excessive doses - the development of pulmonary edema. In rooms where work is being done with acrylic acid, constant air control is necessary. The maximum permissible concentration for this acid is 5 mg / m 3. Safety measures must be followed when working with other derivatives. As an example, you can bring nitrile acrylic acid.