TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Process: Alcohol is added in stoichiometric excess. The molar ratio alcohol/fatty acid is preferably 2-10. The temperature is preferably 120-170degreesC. The process is operated in batch or continuous system. It is operated in a batch system with two reactors working intermittently with reaction and flash vase. Spatial time in relation to outflow of fatty acid and volume of solid catalyzer is 30-160 minutes. The concentration of catalyzer is 0.05-3%.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Catalyst: The acid catalyst is sulfated zirconia with sulfur content of 3-6%, with superficial area of 30-200 m2/g, pre-calcined at 300-800degreesC; tungsten-doped zirconia with tungsten content of 5-15%, with superficial area of 70-200 m2/g, pre-calcined at 300-800degreesC; hydrogen form zeolite having silicon/aluminum molar ratio of 4-160, superficial area of 200-800 m2/g; aluminum chloride, anhydride or chemically supported; concentrated chloridric acid, or concentrated phosphoric acid.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Catalyst: It is concentrated methane-sulfonic acid or para-toluene-sulfonic acid,Preferred Components: Alcohol is methanol, ethanol, iso- or n- propanol or iso-, sec-, or n-butanol. The free fatty acids are carboxylic acids having a 6-24C chain, such as caproic acids, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, vaccenic acid, linoleic acid, linolenic acid, arachidic acid, gadoleic acid, arachidonic acid, behenic acid, erucic acid, lignoceric acid, ricinoleic acid and/or mixtures of these containing glycerol and glycerides or not. The fatty acid is a mixture of carboxylic acids with chains containing preferably 12-20C.    TECHNOLOGY FOCUS - POLYMERS - Preferred Catalyst: It is polynaphthalene-sulfonic acid, prepared by calcination at 200-350degreesC, with atmosphere containing oxygen at 0.01-1% from a mixture of naphthalene/concentrated sulfuric acid at a mass ratio of 0.5-10, respectively, the time of calcination varying from 1-8 hours. EXAMPLE - Esterification was carried out using beta-zeolite catalyst having a molar ratio of silicon dioxide/alumina of 40, at catalyst mass of 0.2 g with a pellet diameter of 1.5 mm and superficial area of 600 m2/g. Temperature was 130degreesC and pressure was 175 psi. The mass of palm acid sediment was 15 g, and mass of methanol was 10 g. The methylic ester produced by the process contained sulfur (0.012%), ashes (0.007%), total glycerol of 0.10% and free glycerol of 0.01%. It had cinematic viscosity of 6 mm2/second, brightness point of 147degreesC, and acidity of 0.04 mg potassium hydroxide/g.