Main uses of ethyl 4 aminobenzoate
Background and overview
The molecular formula of ethyl 4 aminobenzoate is C7H7NO2. Molecular weight 137.14. Monoclinic prismatic crystals were obtained from dilute ethanol, which turned yellow when exposed to light in the air. Melting point 188～189℃, relative density 1.37425, UVλmax220, 289nm in ethanol. When the solubility in water is 25°C, 1g dissolves in 170ml water, 1g dissolves in 90ml water at 100°C, 1g is also soluble in 8ml ethanol, 50ml ether, soluble in ethyl acetate and acetic acid, slightly soluble in benzene, insoluble Petroleum ether. At 25°C, Ka=1.21×10-5, Kb=2.3×10-12, and the pH of 5% solution is 3.5. It reacts with bromine to generate dibromo derivatives, reacts with HCl and KClO3 to generate chloranil (tetrachlorobenzoquinone), and reacts with HCl at 180°C to generate aniline and carbon dioxide. A complexing factor of alkali widely exists in nature, the mass fraction contained in fermenting yeast is 5×10-6～6×10-6, and the mass fraction contained in Saccharomyces cerevisiae is 10×10-6～100×10 -6. Preparation method: derived from the reduction of p-nitrobenzoic acid by iron powder.
ethyl 4 aminobenzoate is one of the most important aromatic amino acids. It is an important part of the substances necessary for the growth and division of body cells. It has an irreplaceable role in the metabolism of life. It is used in yeast, liver, bran and malt. The content is very high. ethyl 4 aminobenzoate can relieve anemia caused by lack of red blood cells, viral anemia, sprue and anemia during pregnancy. ethyl 4 aminobenzoate is a high-efficiency nutritional product with the main component - vitamin B-100, which can effectively improve the three major metabolisms of the human body, comprehensively combat fatigue and relieve stress. The compatibility of ethyl 4 aminobenzoate with penicillin or streptomycin can effectively improve the bacteriostatic effect. ethyl 4 aminobenzoate is also an important fine chemical raw material. In terms of medicine, it is a key intermediate in the synthesis of blood tonic-folic acid, and a coagulant-p-carboxybenzylamine. It is also used in the manufacture of treatment for rickets, rheumatism, and arthritis. , Tuberculosis drugs. In the cosmetics industry, it is an important intermediate of human sunscreen and hair growth agents; in the organic chemical industry, it is used to prepare various ester products, which can be used as resin modifiers, and can also be used to synthesize reactive dyes, azo Special intermediates for dyes. Examples of its application are as follows:
1) Synthesis of ethyl 4-aminobenzoate, including the following steps: dissolving ethyl 4 aminobenzoate with alcohol to prepare a ethyl 4 aminobenzoate solution with a mass fraction of 5-30%; Add thionyl chloride dropwise to the aminobenzoic acid solution to carry out the esterification reaction, after the dropwise addition, the temperature is raised to reflux, and the reaction is carried out for 4-10 hours; A weak base is added to neutralize to pH 7-8, and the solid matter is separated out and then filtered, washed with water, and dried to obtain ethyl 4 aminobenzoate ethyl ester product. The present invention uses ethyl 4 aminobenzoate as raw material, uses thionyl chloride as dehydrating agent to carry out esterification reaction to prepare ethyl 4-aminobenzoate, has fast reaction speed, high yield and high product purity, and has good industrial performance application prospects.
2) The preparation of an adefovir drug co-crystal using ethyl 4 aminobenzoate as a co-crystal precursor belongs to the technical field of drug co-crystals. The space group of the drug co-crystal is monoclinic system, and one adefovir molecule, two ethyl 4 aminobenzoate molecules and one water molecule are combined through hydrogen bonds to form the adefovir-aminobenzoic acid drug. The basic building block of a co-crystal. The solvent selected in the preparation process of the drug co-crystal of the present invention is water, and the adopted method is the solution co-crystallization method. Since Adefovir is slightly soluble in cold water and easily soluble in hot water, it is heated and stirred to dissolve and then placed in an oven to keep warm for a period of time. After cooling, crystals crystallize out. The drug co-crystal prepared by the invention has obvious improvement in solubility, stability and bioavailability besides inheriting the characteristics of traditional raw materials for treating hepatitis B disease.
3) To prepare a ethyl 4 aminobenzoate non-destructively modified carbon fiber reinforced paper-based wet friction material, first add carbon fiber, ethyl 4 aminobenzoate and excess hydrochloric acid into a three-necked flask, and then slowly add a certain amount of hypochlorite after the reaction reaches a certain temperature. Sodium nitrate, and short-time diazotization reaction in an oil bath with magnetic stirring to obtain carbon fibers grafted with benzoic acid on the surface. Then, the modified carbon fiber is mixed with aramid fiber, paper fiber, filler and resin to prepare friction material base paper, and then hot-pressed and cured to obtain a paper-based wet friction material modified with ethyl 4 aminobenzoate. The friction material samples were tested for friction and wear performance. The coefficient of kinetic friction reached 0.12-0.15, and the wear rate was 0.9×10-8cm3/J-1.2×10-8cm3/J, showing excellent friction and wear performance. The process is simple and the cost is low. , is an efficient and environmentally friendly graft modification treatment method, which has a wide range of application prospects.
The preparation method of ethyl 4 aminobenzoate is as follows: in the autoclave, add the p-nitrobenzoic acid of 38.0g, the water of 200mL, the tetrahydrofuran of 20mL, the sodium dodecyl sulfonate of 0.4g and the Raney nickel of 1.9g, The nitrogen was replaced three times, filled with hydrogen, the pressure was adjusted to 0.9±0.1MPa, the temperature was adjusted to 100±2°C, and the reaction was kept under pressure for 4h to complete. After the reaction, the catalyst was recovered by filtration, left to stand for stratification, the water layer was directly applied mechanically, the tetrahydrofuran layer was distilled and recovered and applied mechanically, then 1.5 g of activated carbon was added to the ethyl 4 aminobenzoate mother liquor, and under nitrogen protection, heating and refluxing for decolorization for 20min, Filtration, cooling and crystallization of mother liquor, filtration, drying under vacuum at 80-85 °C to obtain 30.3 g of ethyl 4 aminobenzoate with a yield of 97.2%, a melting point of 187.1-187.6 °C, and a content of 100.2% (permanent stop titration method) .