Ciencias de la tierra II Alkanes (Session 30) Ciencias de la tierra II

Ciencias de la tierra II Alkanes Known by the name of parafin hydrocarbons, they are characterized for being formed by carbon and hydrogen united by simple covalent bonds. They are the primary components of petroleum. General Formula CnH 2n + 2 Nomenclature Basic IUPAC rules are applied. The ending (suffix) for Alkanes is “ane”. Ciencias de la tierra II

Ciencias de la tierra II Alkanes Nomenclature (continuation). The longest chain of carbon atoms is selected to get the base name. If there are substitutes the chain is number in the extreme where the branch is closest. The position and name of the branches are put before the base name. There is a need to memorize for at least the first 10 Alkanes. Ciencias de la tierra II

Systematic name of Alkanes with 1 to 10 carbon atoms Carbon Number Methane 1 Hexane 6 Ethane 2 Heptane 7 Propane 3 Octane 8 Butane 4 Nonane 9 Pentane 5 Decane 10 Ciencias de la tierra II

Ciencias de la tierra II Physical Properties The first 4 Alkanes are gases at room temperature, 5 to 17 (pentane to heptadecane) are liquids, and Alkanes with 18 or more C atoms are solid at room temperature. The boiling points increase when the molecular weight of the alkane increases, Linear Alkanes have greater boiling points than the others that are branched with similar molecular weight. Alkanes are non polar compounds, because of this they are soluble in non polar solvents and insoluble in water. Alkanes are less dense then water, because of this they float in it. Ciencias de la tierra II

Ciencias de la tierra II Chemical properties Oxidation CH3 – CH3 + 3½ O2  2CO2 + 3H2O + Heat Halogenated (Substitute Reaction) R – CH3 + X2  R – CH2-X + HX Catalyst: light, heat or peroxides where X2 = F2, Cl2, Br2 y I2 Ciencias de la tierra II

Applications and Importance of Alkanes Sources of energy: Propane gas (gas LP), gasoline, tyrosine, Kerosene, etc. Solvents: hexane, ether of petroleum, etc. Asphalt used in resurfacing of highways. Wight gasoline (to dry clean). Lubricant oils. Source for primary matter for the petrochemical industry. Ciencias de la tierra II

Ciencias de la tierra II Bibliography Remote Education Operated by Software. (2003). Basic organic reactions [Image]. Remote Education Operated by Software. Obtained on May 27 2003 from World Wide Web: http://eros.pquim.unam.mx/olimpiada/material/organica/reacciones.htm Accelrys, Inc. (2003). Material Studio Gallery [Image]. Accelrys, Inc. Obtained May 27 2003 from World Wide Web: http://www.accelrys.com/gallery/mstudio/methane.jpg Ciencias de la tierra II

Ciencias de la tierra II Bibliography Bloomfield, M. (1997). Chemistry of Living Organisms. 1st ed. Mexico: LIMUSA Editorial Rakoff, H. et al. (1992). Fundamental Organic Chemistry. 1st ed. Mexico: LIMUSA Editorial Solomons, G. (1996). Fundaments of Organic Chemistry. 2nd. ed. Mexico: LIMUSA Editorial Ciencias de la tierra II