Azelaic acid is mainly used to treat acne, melasma and postinflammatory hyperpigmentation. Moreover, azelaic acid is an important intermediates for organic synthesis. It is used to synthesize plasticizers in plastic and rubber industries, low-temperature and high speed bearing lubricants in aviation. Furthermore, it also find applications in electrolytic capacitor manufacturing.Azelaic acid serves as the raw material for azelaic acid dioctyl ester plasticizer, spice, lubricant, oil agent and polyamide. With high plasticizing efficiency, high stability and low volatility, azelaic acid is also used as cold resistance plasticizer for cable, thin-film, artificial leather, etc.
Boiling point: 286℃ 100mmHg (lit.)
Vapor density: 6.5 (vsair)
Vapor pressure: <1mmHg (20℃)
Refractive index: 1.4303
Flash point: 215℃
Storage condition: 2-8℃
Water Solubility: 2.4g/l
Acidity coefficient (pKa): 4.53,5.33 (at25℃)
Shape: Slightly Crystalline Powder or Flakes
Color: White to slightly yellow
PH: value 3.5 (1g/l,H2O)
Azelaic acid is a topical antibacterial agent, having inhibitory and killing effects on various aerobic and anaerobic bacteria on the skin. Topical application of 20% azelaic acid significantly reduces the growth of bacteria and propionibacterium-like bacteria in follicles and decreases the free fatty acid content of lipids on the skin surface. The antibacterial activity and absorption of azelaic acid are pH-dependent. When pH is low, azelaic acid has high antibacterial activity as it can be quickly absorbed by cells and fight against the bacteria that caused kinds of skin diseases. Characteristically, the amount of drug penetrating into abnormal cells is more than normal cells, reversibly inhibiting the activity of major enzymes. Azelaic acid exerts the antibacterial effect, by inhibiting protein synthesis which is the same mechanism that underlies the pharmacological action of other bactericides and bacteriostatic agents.
Azelaic acid has an anti-keratinizing effect on normal skin and skin with acne, as it reduces follicular hyperkeratosis. In addition, azelaic acid also has antiproliferative and anticytotoxic effects, which appears to be mediated by disruption of mitochondrial respiration and cellular DNA synthesis, rather than by inhibition of tyrosinase activity. The ultraviolet structural study has revealed that when melanoma cells from skin or choroid and tissue (obtained by skin biopsy) from patients with malignant moles or skin melanoma are cultured in azelaic acid (≤100nmol/L), their intracellular mitochondria swell and form vacuole and the intracellular cytoplasmic lipid particles accumulate. In terms of alleviating hyperpigmentation and melanosis, 20% AzA is considered to be equally effective as 4% hydroquinone, markedly superior to 2% hydroquinone. Azelaic acid is effective for mild to moderate acne, significantly reducing numbers of comedones, papules and pustules.
The most common way to synthesize azelaic acid involved the use of unsaturated fatty acids such as oleic acid, and corresponding triglycerides such as castor oil and cottonseed oil.
The process for preparing azelaic acid with solid acid catalyst comprises following steps:
The mixture of unsaturated fatty acid or mixed fatty acid generated by hydrolysis of animal fats and vegetable oils, solid acid catalyst, cetyl trimethyl ammonium chloride was well stirred and heated to 50-70℃.
In the presence of a mixture containing 2~10g/L ozone at a flow rate of 500ml/min, 20-40% hydrogen peroxide solution was charged in batches into the mixture in batches, during which the temperature was kept under 70℃. After all the raw material is added, the temperature was increased to 95-110℃ for the following 5-12 h of reaction.
After the reaction reacted completely, the reactant was separated by a separating funnel to gain the solid acid catalyst layer, the oil layer and the water layer. The water layer was crystallized by refrigeration at 3℃ and then white azelaic acid was precipitated, filtrated and dried. The oil layer was extracted by boiling water and crystallized by refrigeration at 3℃, and azelaic acid was obtained after extraction and filtration.
The purified azelaic acid is obtained by recrystallization with hot water after combining the resulting azelaic acid. The amount of said solid acid catalyst is 5-20% of the weight of unsaturated fatty acid or mixed fatty acid; the amount of hydrogen peroxide solution is 2-5 times the volume of unsaturated fatty acid or mixed fatty acid; the amount of cetyl trimethyl ammonium chloride is 1%-5% of the weight of unsaturated fatty acid or mixed fatty acid.