Alcohols and Haloalkanes Overview

A chemical reaction where a water molecule is removed from an alcohol molecule, resulting in the formation of an alkene. This reaction often involves heating the alcohol with concentrated phosphoric acid.

Alcohols that have the -OH group attached to a carbon atom bonded to three other carbon atoms. They are not easily oxidized.

The oxidation of primary alcohols with acidified potassium dichromate(VI) produces this.

The process used to separate the desired aldehyde product from the reaction mixture during the oxidation of a primary alcohol.

The oxidation of an aldehyde with acidified potassium dichromate(VI) under reflux conditions yields this.

Alcohols with the -OH group attached to a carbon atom bonded to two other carbon atoms.

The oxidizing agent used in the oxidation of alcohols with a colour change from orange to green indicating the reaction is taking place.

These compounds contain a polar carbon-halogen bond, where the halogen is more electronegative and draws electron density towards itself, creating a partial positive charge on the carbon and a partial negative charge on the halogen.

A functional group containing a carbon atom bonded to a hydroxyl (-OH) group. They follow the general formula CnH2n+1OH.

Alcohols are named using the IUPAC system and have the suffix '-ol'.

A primary alcohol has the hydroxyl group bonded to a primary carbon atom (a carbon atom attached to one other carbon atom). A secondary alcohol has the hydroxyl group bonded to a secondary carbon atom (a carbon atom attached to two other carbon atoms). A tertiary alcohol has the hydroxyl group bonded to a tertiary carbon atom (a carbon atom attached to three other carbon atoms).

Alcohols are polar molecules due to the large difference in electronegativity between oxygen and carbon. This allows them to form hydrogen bonds with water molecules.

Hydrogen bonds are stronger intermolecular forces than van der Waals forces, so more energy is required to overcome them. This makes alcohols less volatile than alkanes which only have van der Waals forces.

Alcohols react with oxygen to produce carbon dioxide and water, releasing energy. This makes them good fuels.

Alcohols react with halogenating agents like PCl5 and a mixture of concentrated sulfuric acid and potassium bromide to form haloalkanes where the -OH group is replaced by a halogen. This is a nucleophilic substitution reaction.

The reaction of an alcohol with PCl5 produces white steamy fumes that turn damp blue litmus paper red. This can be used as a test to identify alcohols.

A technique used to heat a reaction mixture continuously, preventing loss of volatile reactants or products.

A specialized glassware used in reflux to condense vapors back to liquid, allowing them to return to the reaction mixture.

A glassware used in distillation to collect the condensed vapors as a liquid.

A technique used to separate two immiscible liquids with different densities.

A method to assess the purity of a substance by comparing its measured boiling point to the known value.

A specialized glass tube used to determine the boiling point of a substance.

A nucleophile is a chemical species that donates an electron pair to form a new covalent bond. They are attracted to positively charged regions of molecules.

Nucleophilic substitution is a reaction where a nucleophile replaces an atom or group in a molecule.

In nucleophilic substitution, a nucleophile attacks the electrophilic carbon, displacing the leaving group.

Primary (1°) and secondary (2°) haloalkanes undergo nucleophilic substitution reactions more readily than tertiary (3°) haloalkanes.

The rate of nucleophilic substitution increases with increasing size of the halogen atom in the haloalkane.

Chlorofluorocarbons (CFCs) are haloalkanes containing only carbon, chlorine, and fluorine atoms.

CFCs contribute to ozone depletion by catalyzing the breakdown of ozone molecules in the stratosphere.

The depletion of the ozone layer can lead to increased levels of harmful UV radiation reaching the Earth's surface.

The region of an IR spectrum between 500-1500 cm⁻¹, which is unique for each molecule and serves as a fingerprint for identification.

A method that analyzes the time it takes for ions to reach a detector, revealing the presence and relative abundance of isotopes.

The process of converting a neutral atom into a charged ion by removing an electron.

The process of accelerating charged ions towards a detection plate using an electric field.

The deflection of ions in a curved path by a magnetic field, where the path's radius depends on ion charge and mass.

The process of detecting ions as they hit the detection plate, producing a flow of charge that's proportional to ion abundance.

The process of analyzing the current values and flight times to generate a spectrum that displays the relative abundance of each isotope.

The highest peak on the mass spectrum, representing the molecular ion with the highest mass-to-charge ratio (m/z).

Haloalkanes are classified based on the position of the halogen atom attached to the carbon chain. A primary haloalkane has the halogen attached to a primary carbon (a carbon attached to only one other carbon atom). A secondary haloalkane has the halogen attached to a secondary carbon (a carbon attached to two other carbon atoms). A tertiary haloalkane has the halogen attached to a tertiary carbon (a carbon attached to three other carbon atoms).

The reactivity of haloalkanes in substitution and elimination reactions depends on the strength of the carbon-halogen bond. The strength of this bond is inversely proportional to the size of the halogen atom. Larger halogen atoms have weaker bonds, leading to faster reaction rates.

The electronegativity of halogens decreases down the group. This means that the carbon-fluorine bond is more polar than the carbon-iodine bond. The increased polarity and shorter bond length make the carbon-fluorine bond stronger than the carbon-iodine bond.

The reaction of a haloalkane with an aqueous alkali, such as aqueous sodium or potassium hydroxide, results in the formation of an alcohol through a nucleophilic substitution reaction. The hydroxide ion acts as a nucleophile attacking the carbon atom bearing the halogen, replacing it with a hydroxyl group.

The reaction of a haloalkane with ethanolic potassium hydroxide (KOH) leads to the formation of an alkene through an elimination reaction. The hydroxide ion acts as a base, abstracting a proton from a carbon adjacent to the carbon bearing the halogen, leading to the formation of a double bond and the removal of the halogen.

The hydrolysis of a haloalkane with aqueous silver nitrate in ethanol involves the reaction of the haloalkane with water, where water acts as a nucleophile. This leads to the formation of an alcohol and the release of halide ions into the solution. The halide ions then react with silver ions from silver nitrate to form silver precipitates.

The color of the silver precipitate formed in the hydrolysis of haloalkanes with silver nitrate can be used to identify the halide ion present. A white precipitate indicates chloride ions, a cream precipitate indicates bromide ions, and a yellow precipitate indicates iodide ions.

The rate of precipitate formation in the hydrolysis of haloalkanes with silver nitrate indicates the relative stability of the haloalkanes. A faster rate of precipitate formation corresponds to a less stable haloalkane and a faster rate of hydrolysis. This is due to the weaker carbon-halogen bond in less stable haloalkanes.