Some Applications of Alkanes

The small alkanes, CH4 to C4H1Q, are called together natural gas, and they are found in deposits collected in porous rocks and deep in the oceans. Methane (CH4), the main component of natural gas, is produced in marshes and wetlands by 

The solid alkanes from C20H42 onward are wax, tar, and asphaltic bitumen. Bitumen is used for the construction of asphalt roads. One of the uses of waxes, such as C23H48, C25H52, and C27H56, in nature is ecological. These waxes are produced by the female bees and used as pheromones (sex attractants) to attract male bees. The orchid (called the spider orchid) also produces this mixture of waxes, attracts the male bees, and makes the bees its agent of pollination. All these materials have immense importance to our well-being and, of course, to the female bees and the orchid  

As we discussed in previous lectures, the release of energy in a chemical reaction arises whenever the bonds in the product molecules are stronger than those in the reactant molecules. In our case, the bonds of the CO2 and H2O molecules are stronger than the C—C/C—H bonds in the alkane and the 0—0 bond in O2, and hence the excess energy is released. And if we can harness it, we can use it to work for us, in an engine, or in an electricity wire, or simply in a heater. It is customary to feel that these 

SCHEME 4.6 Alkanes as sources of energy (a) in the reaction of CH4 with O2 and (b) in the reaction of a general alkane with O2. The vertical arrows mean that energy is released during these reactions. 

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