Usually used in preparing monodispersed poly (N-isopropylacryamide) (PNIPAM)/AAc microgels.And also used primarily as an intermediate in the production of acrylates.
Air & Water Reactions
Flammable. Soluble in water. The presence of water, due to different solubilities of the acid and inhibitor (partitioning one from the other), may initiate polymerization.
Acrylic acid is a carboxylic acid, of which the primary use is in the production of acrylic esters. It has been traditionally used as the raw material for acrylic esters – methyl acrylate, ethyl acrylate, butyl acrylate and 2-ethylhexyl acrylate which were originally used to produce solvent-based acrylic resins but environmental concerns about solvent use led to the development of water-based acrylics. Acrylic acid can readily react with a wide variety of organic and inorganic compounds which results in it’s considered as a very useful feedstock to manufacture many low molecular compounds, such as propionic acid, unsaturated fatty acids, heterocyclic compounds, and Diels-Alder addition products. As a vinyl compound and a carboxylic acid, acrylic acid is used widely for polymerisation, including production of polyacrylates. It is also a monomer for polyacrylic and polymethacrylic acids and other acrylic polymers.
Acrylic acid and esters are flammable, reactive, volatile liquids based on an alpha-, beta-unsaturated carboxyl structure. Incorporation of varying percentages of acrylate monomers permits the production of many formulations for latex and solution copolymers, copolymer plastics and cross-linkable polymer systems. Their performance characteristics—which impart varying degrees of tackiness, durability, hardness, and glass transition temperatures—promote consumption in many end-use applications. Major markets for the esters include surface coatings, textiles, adhesives, and plastics.
Polyacrylic acid which produced by acrylic acid can be further modified to produce superabsorbent polymers (SAPs) and other polyacrylic acid homopolymers or copolymers used as detergents, dispersants/antiscalants, anionic polyelectrolytes for water treatment, and rheology modifiers.
SAPs are cross-linked polyacrylates with the ability to absorb and retain more than 100 times their own weight in liquid. They have experienced very strong growth, primarily in baby diapers (nappies) and incontinence products.
A new application for SAPs is soaker pads used in food packaging. In 2007, the US Food and Drug Adminstration authorised SAPs in packaging with indirect food contact for poultry, meat, fish, fruit and vegetables.
Crude acrylic acid (CAA) is made by the oxidation of propylene. About 55% of the CAA is converted to acrylate esters. The remaining 45% is purified to 98–99.5% purity to glacial acrylic acid (GAA), which, in turn, is converted to polyacrylic acid, which is used to produce superabsorbent polymers (SAPs) and other polyacrylic acid copolymers. In 2016, global glacial acrylic acid consumption was estimated to account for about 45% of total crude acrylic acid consumption, of which 79% was consumed for superabsorbent polymers. Growth in GAA consumption is forecast at about 5% per year during 2016?21. Growth in demand for crude acrylic acid is forecast at 4.5% per year during 2016?21, driven by growth in superabsorbent polymers at 5.5% and acrylate esters at about 4%. SAP growth will be strongest in China and other areas of Asia, but will be much more moderate in the mature regions of North America, Western Europe, and Japan.
Manhua Mandy Lin. Selective oxidation of propane to acrylic acid with molecular oxygen[J]. Applied Catalysis A:General 207(2001)1-16.
An antibacterial agent.
ACRYLIC ACID may polymerize violently especially when the frozen acid is partially thawed (freezing point 12°C or 53°F). Frozen acid should be melted at room temperature and the process should be well stirred. Do not use heat during the melting process [Kirk-Othmer, 3rd ed., Vol. 1, 1978, p. 330]. Corrodes iron and steel and polymerization may occur on contact with iron salts. The uninhibited acid polymerizes exothermically at ambient temperature and explodes if confined. The inhibitor (usually hydroquinone) greatly reduces the tendency to polymerize. Explosive polymerization can also occur with strong bases, amines, ammonia, oleum, chlorosulfonic acid, and peroxides. Mixing with 2-aminoethanol, 28% ammonium hydroxide, ethylenediamine or ethyleneimine in a closed container causes an increase in temperature and pressure. Can react violently with oxidizing reagents and strong bases [Bretherick, 5th ed., 1995, p. 419].
Health & Safety Hazard
Tests involving acute exposure of rats, mice, and rabbits have demonstrated that acrylic acid has moderate acute toxicity by inhalation or ingestion, and high acute toxicity by dermal exposure. Acrylic acid is a strong irritant to the skin, eyes, and mucous membranes in humans. The liquid may cause blindness if splashed into the eye. Acute (short-term) exposure of rats to acrylic acid by inhalation has been observed to produce nose and eye irritation, lung haemorrhage, and degenerative changes in the liver and kidneys.
Some ill-health effects could happen when people exposed to acrylic acid, while people can be easily exposed to acrylic acid through direct contact with a product containing it or by inhaling it in air contaminated by a nearby plant manufacturing acrylic acid, for example, in the workplace, exposure to acrylic acid occurs primarily via inhalation and dermal contact during its manufacture or use; consumers may be exposed to acrylic acid in polishes, paints, coatings, rug backings, adhesives, plastics, textiles, and paper finishes. In addition, acrylic acid may be released in wastewater and can be also produced naturally by some species of algae. When we do not feel well, we should get medical attention immediately.
Acrylic acid is sensitive to heat and sunlight and also a fire hazard when exposed to heat or flame. The product should be stored in a segregated and approved area away from heat, sources of ignition and the container should be kept in a cool, well-ventilated area, tightly closed and sealed until ready for use. It is also very necessary to keep the product away from incompatibles such as oxidising agents, acids, alkalis, moisture.
It can be purified by steam distillation, or vacuum distillation through a column packed with copper gauze to inhibit polymerisation. (This treatment also removes inhibitors such as methylene blue that may be present.) Azeotropic distillation of the water with *benzene converts aqueous acrylic acid to the anhydrous material. [Beilstein 2 H 397, 2 I 186, 2 II 383, 2 III 1215, 2 IV 1455.]
Acrylates are esters from acrylic acid. Occupational
contact allergies from acrylates have frequently been
reported and mainly concern workers exposed to the
glues based on acrylic acid, as well as dental workers
colourless liquid with an acrid odour
Acrylic acid is a colorless liquid with a distinctive acrid odor. Flash point 130°F. Boiling point 286°F. Freezing point 53°F. Corrosive to metals and tissue. Prolonged exposure to fire or heat can cause polymerization. If polymerization takes place in a closed container, violent rupture may occur. The inhibitor (usually hydroquinone) greatly reduces the tendency to polymerize.
May burn skin or eyes upon short contact. INHALATION: eye and nasal irritation and lacrimation. INGESTION: may cause severe damage to the gastrointestinal tract.
In the manufacture of plastics.
Acrylic acid (AAc, IUPAC: prop-2-enoic acid) is the simplest unsaturated carboxylic acid, consisting of a vinyl group connected directly to a carboxylic acid terminus with the formula CH2=CHCO2H which is a colorless liquid above its freezing point of 13°C ( 56°F) with a distinctive acrid odor. It is corrosive to metals and tissue and prolonged exposure to fire or heat can cause polymerization. If polymerization takes place in a closed container, violent rupture may occur because the polymerizaiton of acrylic acid is exothermic. The inhibitor (usually hydroquinone) can greatly reduce the tendency to polymerize. It is miscible with water, alcohol, ether, benzene, chloroform, and acetone, but incompatible with strong oxidisers, strong bases, strong alkalies and pure nitrogen. It may polymerize (sometimes explosively) when contacting with amines, ammonia, oleum and chlorosulfonic acid, iron salts and peroxides.
Acrylic acid can be prepared in different ways, for example as follows:
The easiest way to prepare pure acrylic acid in the laboratory is to exchange the ester of formic acid and readily available methyl acrylate. Sulfuric acid is a good catalyst.
CH2=CHCOOCH3 +HCOOH → CH2=CHCOOH+HCOOCH3
Acrolein can be oxidized in the liquid phase at 20-40℃ with silver or vanadium as the catalyst and methoxybenzene as the solvent which glacial acetic acid is more commonly used. It has been reported that the yield of acrylic acid can reach 65-90% based on the consumption of acrolein.
CH2=CHCHO+ 1⁄2 O2 → CH2=CHCOOH
A mixture of water and 2,3 dibromopropionic acid is treated with zinc powder can obtain an aqueous solution of acrylic acid with a yield of 90%.
CH2BrCHBrCOOH +Zn → CH2=CHCOOH+ZnBr2
Acrylic acid also can be obtained by pyrolyzing sec-butyl acrylate at 500℃, or pyrolyzing ethyl acrylate at 570℃.
CH2=CHCOOCH(CH3)CH2CH3 → CH2=CHCOOH+CH3CH=CHCH3
At 200-300℃, acrylic acid can be obtained by passing carbon dioxide and ethylene through the silica gel impregnated with iron sulfite.