Application

Adipic Acid
Adipic Acid is a white, crystalline compound with a slight acid taste and a nil to very faint odor. Slightly soluble in water and soluble in alcohol and acetone. It is mainly as a precursor for the production of nylon. Adipic acid is a white crystalline powder (monoclinic system)
Adipic acid occurs rarely naturally in the environment. Large amount is produced by oxidation of cyclohexane (which is produced from the petroleum product benzene or butadiene) with air, nitric acid and metal catalyst.

 

Preparation
Adipic acid was prepared by the oxidation of various fats. Nowadays adipic acid is produced from a mixture of cyclohexanol and cyclohexanone called “KA oil”, the abbreviation of “ketone-alcohol oil.” The KA oil is oxidized with nitric acid to give adipic acid, via a multistep pathway. Early in the reaction the cyclohexanol is converted to the ketone, releasing nitrous acid:
HOC6H11 + HNO3 → OC6H10 + HNO2 + H2O
HNO2 + HNO3 → NO+NO3- + H2O
OC6H10 + NO+ → OC6H9-2-NO + H+

Chemical applications
Adipic acid can also polymerise with polyalcohol such as ethylene glycol to polyester which often reacts further with ioscyanates to form polyurethanes.
Different types of polyesters are produced with the help of adipic acid and they are used as a binder in paint, adhesives and for paper chemicals.

Medical uses:

Adipic acid is used in the field of medicine incorporated for the formulation matrix tablets to obtain pH-independent release for both weakly basic and weakly acidic drugs. It is also been incorporated into the polymeric coating of hydrophilic monolithic systems to modulate the intragel pH, resulting in zero-order release of a hydrophilic drug. When this acid was used as a pore-forming agent without affecting release in the acidic media.

Adipic Acid uses in food

Significant amounts of adipic acid is used as a food ingredient as a flavorant and gelling aid. It is used in some calcium carbonate antacids to make them tart.

Other applications of Adipic Acid
• Polyamide polymers
• polyurethane systems
• organic synthesis
• plasticizers
• adhesives
• paints
• flexible and rigid foams
• detergency.

Other Uses
Adipic acid is approved as a food additive; however, the dominating use is for polymerisation. Different types of polyesters are produced with the help of adipic acid and they are used as a binder in paint, adhesives and for paper chemicals.
Adipic acid can also polymerise with polyalcohol such as ethylene glycol to polyester which often reacts further with ioscyanates to form polyurethanes.
Smaller esters of adipic acid are produced with alcohols with 8-10 carbon. These are called adipates. These are used as softeners in plastic (such as PVC) and as synthetic grease base oils (“synthetic esters”). In the latter use branched carbon chains are preferred since it gives better floating properties.

Toxicity
Adipic acid has very low acute toxicity in rats with an LD50 > 5000 mg/kg. Adipic acid produced mild to no skin irritation. It was not a skin sensitizer. Adipic acid dust may irritate the mucous membranes of the lungs and nose. Adipic acid is not genetically active in a wide variety of assay systems. Adipic acid is partially metabolized in humans; the balance is eliminated unchanged in the urine. Adipic acid is slightly to moderately toxic to fish, daphnia, and algae in acute testsH2S odours generated during sludge processing can cause community complaints and make plant working conditions unpleasant. Furthermore, damage to equipment and concrete structures caused by H2S initiated corrosion can be substantial. Typical areas where H2S problems occur include gravity thickeners, mix tanks, and dewatering presses.