Acrylic acid, with the IUPAC nomenclature propenoic acid and chemical formula CH2CHCO2H, is more popularly known as the simplest form of α, β - unsaturated carboxylic acid. If you study its structure, you will notice that a vinyl group is attached to the carbonyl group and owing to that compounds of this acid go through reactions similar to that of carboxylic acids. In its structure, a double bond and the functional carboxylic acid group, play a crucial role in giving it characteristic reactions similar to those of carboxylic acid. In chemistry, acrylic acid forms an important acid for usage in big chemical plants and industries as it has immense use in commercial production. It is not surprising that reports of shortage have been frequently reported in the media, and chemical factories have invested billions in improving their production.
Acrylic acid is a clear and colorless liquid that finds extensive use, owing to its chemical structure that facilitates easier combination with large chain of compounds forming polymers. It's molecular formula is C3H4O2 and its molecular weight is 72. It is miscible in water and has a melting point equal to 14 °C, and boiling point equal to 141 °C. Consistent or even mild exposure to these acids cause irritation to the skin and the respiratory system. While low exposure is generally not harmful to the body, high doses of this acid can be toxic, leading to problems of pulmonary edema. Concentrated solutions of acrylic acid, if swallowed, can cause severe burns in the mouth and the gastrointestinal tracts. Besides that, these acid vapors can cause congestion in the mucous membrane and respiratory tract. Owing to its chemical structure, acrylic acid reacts with quite a large number of inorganic and organic compounds leading to formation of a large number of low and high molecular weight compounds.
The acrylic acid market has grown over the years, as usage of this chemical has increased in various sectors, ranging from cosmetic products, like acrylic nail polish, to use chemical industries. Acrylic acid usage has also run into various controversies as health agencies in US have scrutinized its usage in various products. Traditionally, acrylic acid has been used as a raw material in the industrial preparation of acrylic esters. These acrylic esters like methyl acrylate, ethyl acrylate etc., have been used for preparation of solvent-based resins, however, due to environmental concerns, their production was stopped. Further, water-based acrylics were developed that found extensive use in home coatings, and in various other products, like paintings, paper, adhesives, and polishes. With further research, a class of compounds known as polyacrylates were developed with the help of acrylic acids, that are used in making thickeners and dispersants. Since the last decade, acrylic use has become extremely popular in two specific areas―the production of Superabsorbent Polymers (SAPs) and detergent polymers. These unique SAPs have been reported to contribute nearly 30% of the world's acrylic acid market consumption.
Basically, SAPs have a unique feature to absorb and at the same time retain moisture 100 times more than their own weight. This has made them an integral part in the production of baby diapers, female hygiene products, and in adult incontinence products. Summarized briefly, acrylic acid is a chemical intermediate that is required for preparation of polymers, textiles, ink industries, consumer products, plastics, surfactants chelating agents, water-based coating, and often in food packaging industries, with strict guidelines from health agencies.
Since unstable acrylic acid has a high tendency to form polymers, it is stored in storage tanks made of aluminum, steel, glass, and iron. Fire causes due to this acid can be controlled by fire extinguishers, and any spilling of this acid needs to be covered by sand to avoid the damage that these acids can cause.