A Short On Preparation Of Alkanes

Alkanes are organic compounds with no extra functional groups that are solely made up of single-bonded carbon and hydrogen atoms. Linear straight-chain alkanes, branched alkanes, and cycloalkanes are the three types of alkanes. CnH2n+2 is the general formula for them. The hydrogenation process can be used to create alkane from alkene and alkyne. In this reaction, the current catalyst introduces dihydrogen gas to alkynes and alkenes. Finely divided catalysts such as nickel, palladium, or platinum are utilised to make alkanes.

What Are Alkanes?

Alkanes, commonly known as hydrocarbons, are chemical compounds made up of carbon (C) and hydrogen (H) atoms. Alkanes have only one bond in their chemical structure. The chemical structures of two alkanes are ethane and pentane.

Types of Alkanes

Linear straight-chain alkanes, branched alkanes, and cycloalkanes are the three types of alkanes.

Linear Alkanes

The carbons in linear alkanes are bound together in a snake-like chain structure.

Branched Alkanes

Branched alkanes are produced from linear alkanes, but their chemical structure is branched with one or more alkyl groups instead of merely a straight chain. A group of carbon and hydrogen atoms connected to an alkane molecule is known as an alkyl group.

Cyclic Alkanes

Cyclic alkanes, also known as cycloalkanes, are made up of hydrogen and carbon atoms bound together by single bonds, with the carbon atoms forming a ring or loop.

Alcohols

An alcohol is an organic molecule with at least one hydroxyl functional group (OH) linked to a saturated carbon atom in chemistry. The principal alcohol ethanol (ethyl alcohol), which is used as a drug and is the major alcohol contained in alcoholic drinks, was initially referred to by the name alcohol.

Aldehydes

Any organic compound in which a carbon atom has a double bond with an oxygen atom, a single bond with a hydrogen atom, and An aldehyde is a chemical compound that has a single bond with another atom or group of atoms (designated R in general chemical formulas and structure diagram).

Ketones

Ketones are organic compounds that have an oxygen atom attached to a carbon atom that is connected to two or more carbon atoms. Ketones, like aldehydes, can be termed using either the common or IUPAC systems.

Fatty acid

Carboxylic acids with lengthy hydrocarbon chains are referred to as fatty acids. The length of the hydrocarbon chain might range from 10 to 30 carbons (most usual is 12-18). The polar acid functional group is counterbalanced by the non-polar hydrocarbon alkane chain.

Preparation of Alkanes By Reduction Of Alcohol

Alcohols are notoriously difficult to convert directly to alkanes. Conversion of alcohols into leaving groups (such as halides and sulfonate esters) is frequently followed by reduction with metal hydrides (such as LiAlH₄, LiHBEt₃ , Bu₃  SnH⁺ radical initiator) in a two-step process. Other traditional procedures for halide reductive elimination include heterogeneous hydrogenation and the Birch reduction. PX₃ , PX₅ , SOCl₂ , and (COCl₂) are reagents that make the halogenation step simple. When halogenation under neutral circumstances is required, the Appel conditions are ideal. The mechanism can be described as hydride nucleophilic displacement (for the reactions using metal hydrides).

R^___OH   Red P + 2HI→   R^___H  + H₂O + I₂ 

                          200^oC

Preparation of Alkanes By Reduction Of Aldehyde

The hydrazone is formed by condensation of the carbonyl molecule with hydrazine, and treatment with base causes the carbon to be reduced while the hydrazine is oxidised to gaseous nitrogen, yielding the equivalent alkane.

R^___CHO  Red P + 4HI→  R^___CH₃ + H₂O + 2I₂

                   200^oC     

Preparation of Alkanes By Reduction Of Ketones

Ketone is reduced to corresponding alkane when it is treated with phosphorus and heated concentrated hydriodic acid (hydrogen iodide) at 150^oC. 

RCOR’ + 4HI         P       →   RCH₂R’ + 2I₂ + H₂O 

                         150^oC

Preparation of Alkanes By Reduction Of Fatty Acids

Fatty acid is reduced to corresponding alkanes when it is treated with red phosphorus and heated concentrated hydroiodic acid at 200 degrees Celsius.  

R^___COOH   Red P + 6HI→  RCH₃ + 2H₂O + 3I₂

                       200^oc

Conclusion

Alkanes are significant chemical raw materials as well as the main component of gasoline and lubricating oils. Methane and ethane make up the majority of natural gas, which is utilised for heating, cooking, and power generation (gas turbines). Non-polar solvents are alkanes. Because they only include C and H atoms, alkanes are nonpolar. Alkanes are immiscible in water, although they are miscible in a variety of non-polar solvents. Because alkanes with weak dipole dipole bonds are unable to break the strong hydrogen connection between water molecules, they are not miscible in water.