Preparation of Haloalkanes and Chemical Kinetics

A comprehensive set of flashcards covering key concepts, definitions, and mechanisms related to the preparation of haloalkanes and chemical kinetics in nucleophilic substitution reactions.

Nucleophilic Aliphatic Substitution

A reaction where one functional group in a substrate is replaced by another functional group.

Nucleophile (Nu:)

A molecule or ion with a pair of electrons available for bonding to an electron-deficient center.

Leaving Group (L)

A group that can depart with a pair of electrons when a covalent bond is broken.

SN1 Mechanism

A unimolecular nucleophilic substitution mechanism involving two steps, including formation of a carbocation.

SN2 Mechanism

A bimolecular nucleophilic substitution mechanism involving a single concerted step with both substrate and nucleophile participating.

Carbocation

A positively charged carbon atom that is typically unstable and susceptible to rearrangement.

Rate-Determining Step

The slowest step in a reaction mechanism that determines the overall reaction rate.

Polar Solvent

A solvent with a significant electric dipole moment that can stabilize ions and polar intermediates.

Equilibrium Position

The state at which the concentrations of reactants and products remain constant over time.

Hydrobromic Acid (HBr)

A strong acid used in the preparation of haloalkanes from alcohols.

Protonation

The addition of a proton (H+) to a molecule, often increasing its reactivity.

Oxonium Ion

A positively charged ion formed by the protonation of an alcohol.

Alkyl Halide

Organic compounds derived from alkanes that contain a halogen atom (X) as a substituent.

Thionyl Halide (SOX2)

A reagent used in the preparation of haloalkanes which prevents carbocation rearrangements.

E1 Mechanism

A unimolecular elimination mechanism involving the formation of a carbocation intermediate.

E2 Mechanism

A bimolecular elimination mechanism that occurs in a single concerted step.

Competition Between Substitution and Elimination

The phenomenon where substitution and elimination reactions may compete, particularly under basic conditions.

Hydrogen Bromide Gas

A gaseous compound that can be used to convert alcohols to haloalkanes when added to alcohol at elevated temperatures.

Phosphorus Tribromide (PBr3)

Reagent used for the conversion of alcohols to haloalkanes, especially effective for secondary alcohols.

Side Reactions

Unwanted reactions that can produce by-products, affecting the yield of the main desired product.

Alkyl Hydrogen Sulfate

An intermediate formed when alcohol reacts with sulfuric acid, sometimes leading to side reactions.

Molecular Rearrangement

A process where the structure of a molecular ion changes, leading to different products during a reaction.

Bimolecular Reaction

A reaction involving two reacting species in the rate-determining step.

Equilibrium Shifting

The process by which the position of the equilibrium is altered by changes in concentration, temperature, or pressure.

Sodium Bromide (NaBr)

A salt that can generate hydrobromic acid when reacted with sulfuric acid in situ for halogenation reactions.

Boiling Point Determination

A method to identify the temperature at which a liquid turns to gas, relevant in verifying the purity of products.

Gas Chromatography

A technique used to separate and analyze compounds that can be vaporized in a gas phase.

Nucleophile Concentration

The amount of nucleophile present in a reaction, influencing the reaction mechanism and rate.

Primary Alcohol

An alcohol where the hydroxyl group is attached to a carbon atom that is only connected to one other carbon.

Secondary Alcohol

An alcohol where the hydroxyl group is attached to a carbon atom connected to two other carbons.

Tertiary Alcohol

An alcohol where the hydroxyl group is attached to a carbon atom connected to three other carbons.

Self-Made HBr

A procedure to generate hydrogen bromide from sodium bromide and sulfuric acid during organic reactions.

Yield Calculation

The process of determining the efficiency of a reaction by measuring the amount of product obtained compared to the theoretical maximum.

Reflux

The process of heating a reaction mixture while continuously cooling the vapor to return it to the liquid phase.

Aqueous Layer

The layer containing water and soluble substances, separating from organic layers during extraction.

Separation Funnel

Laboratory glassware used to separate immiscible liquids based on density differences.

Purification Process

The series of steps undertaken to remove impurities from a product to achieve the desired chemical purity.

Concentration of Oxonium Ion

The amount of oxonium ions present in the reaction mixture, affecting the rate and equilibrium of the reaction.

Dehydration Reaction

A reaction that involves the removal of a water molecule, often leading to the formation of alkenes from alcohols.

Vinyl Product

An alkene product formed when HBr adds across a carbon-carbon double bond.

Dilute Sodium Bicarbonate Solution

A mild base used to neutralize excess acid in product purification.

Distillation

A separation process that relies on differences in boiling points to purify liquids.

Requirements for a drying agent

A drying agent must be

Efficient in its action so that most or all of the water will be removed by the desiccant in a short period of time

How does a desiccant function

A drying agent that forms a hydrate

Needs to be completely removed by gravity filtration or decantation before the dried liquid is distilled

At what temp do most hydrates decompose with a loss of water?

30-40 degrees Celsius