Acrylic acid and Esters
Acrylic acid and its esters such as Methyl acrylate, Ethyl acrylate, Butyl acrylate and 2-Ethylhexyl acrylate, are known as basic acrylates. Most of the acrylates are flammable, volatile and colourless liquids.
The global market for crude acrylic acid was approximately 5 million metric tons in 2013, from which about 3.5 million metric tons of commodity acrylate esters are produced. The EU production capacity is currently about 1.3 million tons of crude acrylic acid and 850000 tons of acrylate esters [CEH].
Commercial Acrylic acid is produced by selective gas phase oxidation of propene. The crude acrylic acid is further purified to obtain different acrylic acid qualities of standard or ester grade to high purity grade acrylic acid. The purity of the acrylic acid produced usually exceeds 99.5 wt %.
Acrylic acid and its esters are usually stabilized with inhibitors such as hydroquinone monomethyl ether (MeHQ). Because MeHQ is only effective in the presence of oxygen, the acrylic monomers must be stored under air or an atmosphere containing at least 5 Vol.-% of oxygen.
The stabilized monomers are generally stored below 25 °C. Acrylic acid should not be stored below 15 °C because acrylic acid crystallizes.
The primary use of acrylic acid and esters is as an intermediate in the production of polyacrylates. Polyacrylates can be produced by various processes, with emulsion polymerization being the most important industrial polymerisation process. Polyacrylates are produced by exothermic radical polymerization. The variety of the properties of polyacrylates and copolymers gives a large range of products, with their applications and uses. As a result, polyacrylates are used for the manufacture of polymer dispersions (coatings, paints and printing inks), adhesives, binding agents, super absorbent polymers, flocculants, detergents, varnishes, fibres and plastics, as well as chemical intermediates.