Acrylic Acid Overview

Acrylic acid or 2-propenoic acid is a chemical compound (formula C3H4O2) and it is the simplest unsaturated carboxylic acid with both a double bond and a carboxyl group linked to its C3. In its pure form, acrylic acid is a clear, colorless liquid with a characteristic acrid odor. It is miscible with water, alcohols, ethers and chloroform. Acrylic acid is produced from propylene, a gaseous product of oil refineries.

Acrylic acid undergoes the typical reactions of a carboxylic acid and, when reacted with an alcohol, it will form the corresponding ester. The esters and salts of acrylic acid are collectively known as acrylates (or propionates). The most common alkyl esters of acrylic acid are methyl-, butyl-, ethyl- and 2-ethylhexyl-acrylate.

Acrylic acid and its esters readily combine with themselves or other monomers (e.g. amides, acrylonitrile, vinyl, styrene and butadiene) by reacting at their double bond, forming homopolymers or copolymers which are used in the manufacture of various plastics, coatings, adhesives, elastomers as well as floor polishes and paints.

Carboxylic acids can be produced by oxidation of primary alcohols and aldehydes with strong oxidants such as Jones reagent, potassium permanganate, or sodium chlorite. They may also be produced by the oxidative cleavage of olefins by potassium permanganate or potassium dichromate. In particular, any alkyl group on a benzene ring will be fully oxidized to a carboxylic acid, regardless of its chain length. This is the basis for the industrial synthesis of benzoic acid from toluene.

Carboxylic acids can also be obtained by the hydrolysis of nitrates, esters, or amides, with the addition of acid or base. They can also be prepared from the action of a Grignard reagent on carbon dioxide, though this method is not used industrially.

Acrylic acid is a commonly used, yet extremely valuable, chemical intermediate used to produce polymers, textiles, and numerous other industrial and consumer products. Because of the lucrative market for this product, this design project focuses on the optimization of an acrylic acid plant. Due to the simplicity of the initial design of the plant, this optimization involved more investigation of native reaction kinetic characteristics rather than extra pieces of equipment. By lowering the reaction temperature from 310 ° C to 190 ° C the three reactions in competition allow the desired product to have its highest conversion (94% versus the original 69%), thereby generating much higher process revenue. To aid in this aggressive cooling effort, a molten salt stream similar to the original specifications should be satisfactory in forming nearly isothermal conditions inside the reactor. Beyond this, it has been determined that the last 5 meters of the reactor do not produce enough acrylic acid to overcome the operating and capital costs involved. Therefore, by decreasing the reactor length by 50% and lowering the temperature, this optimized process has the capability of increasing its revenue by 37% over the older design – a truly competitive alternative to the current design.

Acrylic acid is used as a chemical intermediate for the production of Acrylic esters like ethyl acrylate, butyl acrylate, methyl acrylate,ethyl hexyl acrylate and super absorbent polymers (glacial acrylic acid). Global capacity is just over 3.5 million tpa. Major markets for esters include coatings, adhesives, textiles, paper coatings and additives. MMA is used in polymers in various forms such as cast sheets, lattices and molding and extrusion polymers. Applications include advertising signs, aircraft windows, desk tops, lighting fixtures, building panels and plumbing/bathroom fixtures.

Acrylic acid’s chemical nature makes it a highly desirable component in a polymer system. Besides polymer applications, the molecule also follows the characteristics of both a carboxylic acid and acrylate ester, making it suitable for chemical intermediates as well. The largest application for acrylic acid is in the industrial coatings area. And, because it is miscible with water, alcohols, and ethers, the wetting ability can be enhanced based on the specific employment.

An area of growth for acrylic acid is with acrylic acid homopolymers and acrylic acid/starch grafts. These combinations provide a high rate of absorption, perfect for use in hygiene products. Other minor uses include viscosity modifiers for rubber lattices and adhesives, detergents, fiber sizing, and soil conditioners.

PRODUCT IDENTIFICATION
CAS NO. : 79-10-7
EINECS NO. : 201-177-9
FORMULA. : CH2=CHCOOH
MOL WT. : 72.06
SYNONYMS. : Acroleic acid; 2-Propenoic acid; Acrylate; Ethylenecarboxylic acid; propene acid;
PHISICAL PROPERTIES
PHYSICAL STATE. : Clear Liquid
MELTING POINT. : 12 C
BOILING POINT. : 141 – 142 C
SPECIFIC GRAVITY. : 1047 – 1051
SOLUBILITY IN WATER. : Soluble
SOLUBILITY IN WATER. : Polymerization will occur under light and heat
SALES SPECIFICATION
APPEARANCE. : Clear liquid
PURITY (G.C). : 99.0% min
COLOR, APHA. : 10 Max
INHIBITOR. : 0.3% Max
INHIBITOR. : 200ppm (Monomethyl Ether Hydroquinone)
 
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