Acrylic acid is an unsaturated carboxylic acid, with the formula CH2=CHCO2H. This clear and colorless liquid has a characteristic acrid odor. As it contains a polar carboxylic acid functional group, it is able to dissolve in water and is miscible with relatively polar organic compounds such as alcohols, ethers, and chloroform. Acrylic acid is air and water sensitive as it reacts readily with free radicals and electrophilic or nucleophilic agents. It may polymerize in the presence of acids, alkalis, amines, peroxides, and iron salts. Prolonged exposure to heat or exposure of light can also cause polymerization. If confined, the polymerization of acrylic acid can lead to an explosion even at room temperature. It is corrosive to metals and tissues.
Acrylic acid can be used in the form of free acids, ammonium and alkali salts in many different applications such as thickeners, dispersing agents, flocculants, wetting agents, coatings, textile finishes protective colloids for stabilizing emulsions and polymer dispersions. It readily undergoes additional reactions with a wide variety of organic and inorganic compounds, which makes it a very useful feedstock for the production of many low molecular compounds. For instance, acrylic acid can be used to produce derivatives of propionic acid with water, alcohols, amines, halogens, and chlorinated hydrocarbons. It can also react with other substances to produce unsaturated fatty acids, heterocyclic compounds, and Diels-Alder addition products.
As it polymerizes with explosive violence, it can only be shipped after being stabilized by an inhibitor such as hydroquinone. The removal of the stabilizer is not usually necessary since its action can be compensated for by adding an excessive initiator.
The most widely accepted process for making acrylic acid is the vapor phase oxidation of propylene via acrolein, where propylene is a byproduct of ethylene and gasoline production. Typically, Chemical-Grade (CG) propylene is mixed with steam and air to undergo two-step oxidation where propylene is oxidized to acrolein before further oxidizing again to give acrylic acid. These oxidations are done in tubular, fixed-bed reactors where steam is generated by utilizing the heat emitted by the exothermic reactions.
|Synonyms||2-Propenoic acid,79-10-7,Propenoic acid,prop-2-enoic acid,Acroleic acid,Carbomer,Propenoate|
|Mol Weight||72.06 g/mol|