piridina ( molecular Formula C5H5N, Molecular mass : 79,10) is Liquid Colorless of scent disagreeable, similar to the fish. belongs to the family of heterocyclic aromatic compounds, and structurally is related to Benzene, being the unique difference among them the replacement of a group CH of the benzene ring by atom of Nitrogen .
The scent can get to be nauseous and to cause estornudos.
piridina has Fusion point of -42°C and Boiling point of 115°C. This does of piridina a colorless, evil-smelling and injurious liquid to Miscible room temperature, in alcohol and the water, of slightly basic reaction, and forms a crystalline hydrochlorate of p.145°C when reacting with hydrogen chloride. Electronegativity of the atom of Nitrogen impoverishes the electronic densidad of the ring, doing it less susceptible to the electrofílica substitution and fomenting the metalación by means of strong bases.
The equatorial electron pair of nitrogen does not participate in the aromatic system pi in piridina . This does, of this compound, a base with chemical properties similar to tertiary Amines, being pKa of its conjugated acid 5,30. The reaction of piridina with acids protona and forms positively Ion aromatic loaded poliatómico to which the cation name piridinio occurs him. The angles and lengths of union between her and in the cation piridinio do not vary considerably, because the protonación does not involve to the aromatic system pi.
piridina appears in the nature in sinfín of compounds related to the life, among them NAD, Nicotine, niacina B3 Vitamin either (whose lack causes pelagra), and piridoxina B6 Vitamin or, and pirimidínicas Bases Timina, Cytosine and Uracilo, among others.
Nevertheless, piridina pure is an injurious substance if is inhaled it, ingests or if it is absorbed by the skin. It reduces the masculine fertility and it is considered Carcinogen . The more common symptoms of exhibition are: headache, cough, respiratory difficulty, Laryngitis, Nauseas and Vomits
Industrially is obtained it from petroleum and to a lesser extent, of the coal tar (in which its concentration is of approximately 0.1%), or by means of synthesis from Acetaldehyde and Ammoniac . Also of the obtained oil of the destructive distillation of bones can be prepared by Distillation.
Derivatives of piridina can be synthesized making react 1,5-dicetonas with acetic acid ammonium acetate, followed of Oxidation .
piridina and the compounds related to her finds great utility like dissolvent, in chemical analyzes, and like reagents for synthesis of drugs, insecticide, weed killers, coloring saborizantes,, explosive adhesives, paintings,, disinfectants and chemicals for Rubber . Also it is used along with the picolinas as desnaturalizante in antifreeze mixtures and the ethylic alcohol, fungicides, and the tinción of textiles.
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