[CAS No.] 7400-08-0 [Formula] C9H8O3 [Molecular weight] 164.16 [No.] 231-000-0 [EINECS] white or pale appearance yellow powder. [Relative density (d435)] 1.07 [melting point] 218-221 ℃ dissolved] dissolved in hot ether, hot alcohol, slightly soluble in benzene, insoluble in petroleum ether, insoluble in water. [Use] 1 medicine: expectorant drugs can be used to prime the synthesis of cuckoo in the pharmaceutical industry for the production of coronary heart disease treatment Kexin be intermediates, and for the manufacture of local anesthetics, fungicides, and hemostatic and so on; with the role of inhibition of cervical cancer; can also be used to synthesize the anti-adrenergic drug esmolol 2, agriculture: in the pesticide industry for the production of plant growth-promoting agents, fungicides, and long-lasting fresh fruit and vegetable preservative. In addition, the hydroxy acid can also be used for the determination of uranium and hunger of the chemical reagents used in the production of the main raw material ethylene photosensitive resin plug oil Suspended 4. 3, chemical aspects: 1)-hydroxy acid is very important flavor and fragrance, allows the use of spices, primarily used to configure the spicy cherry, apricot, honey and other spices. In the Japanese chemical industry for the preparation of soap and cosmetic fragrances. 2)-hydroxy acid or a strong effect of conductive material, liquid crystal display industry in recent years, extensive research. By hydroxyl polyimide with the grafting reaction of hydroxy acid synthesis of hydroxy with photosensitive polyimide, and by IR, NMR to determine the photosensitivity of the hydroxyl polyimide structure. The synthesis of hydroxy polyimide liquid crystal alignment layer as used in liquid crystal display devices, the demonstrated good thermal stability. 4, cosmetics: hydroxy cinnamic acid on the tyrosinase enzyme and two single-phenol phenol activity was inhibited, leading to a single enzyme and two phenol phenol enzyme activity decreased by 50%, used in cosmetics which inhibit melanin production. 5-hydroxy cinnamic acid new research direction: In recent years, many scientists working abroad will be extended to hydroxy acid of microorganisms and medicine - cell differentiation and telomerase activity; cervical cancer inhibition. Hydroxy acid in the future will be more and more into our lives.