Chapter 1 – Reactions of Organic Compounds

Reactions Involving Hydrocarbons Reactions of Alkanes

Single bonds (C-C) are strong and very hard to break, therefore these compounds are relatively unreactive

Participate in _______________________________ (the reaction of a substance with oxygen, producing oxides and energy)

Complete combustion o Produces _______ and_________ only o Dependent upon availability of oxygen (must be in ____________)

C2H8(g) + 5 O2(g) 3 CO2(g) + 4 H2O(g)

Incomplete combustion o Produces ________, ________, ________ and ________ because the hydrocarbon is

not fully oxidized o ______________________________________________________________________

2 C3H8(g) + 7 O2(g) 2 C(s) + 2 CO(g) + 2 CO2(g) + 8 H2O

Alkanes more commonly participate in _____________________________________ o A hydrogen atom is substituted with a halogen atom (F2, Cl2, Br2) o Require heat or UV light to dissociate the halogen molecule before the substitution can

proceed o The product is a halogenated alkane (the halogen atom is a functional group) which is in

the family of alkyl halides

Substitution Reaction of Alkanes

As the reaction above proceeds, the concentration of bromoethane increases causing it to react with Br2 again to produce 1,2-dibromoethane.

NOTE –

Reactions of Alkene and Alkynes

More reactive than alkanes due to __________________________________________________

Undergo ________________________________________ where atoms are added to the molecule with no loss of H atoms

Addition reactions can involve halogens (____________________), H (____________________), hydrogen halides, or water (____________________)

Addition Reactions of Alkenes and Alkynes

Markovnikov’s Rule o When molecules of non-identical atoms are added to an alkene (ie. HBr, H2O), 2

possible products may form

o However, the hydrogen is added to the carbon with the greater number of hydrogens

already bonded to it (___________________________________)

NOTE –

+ HCl

+ 2 HCl Sample Problem What compound will be produced when water reacts with 2-methyl-1-pentene?

1. Write the structural formula for 2-methyl-1-pentene

2. Identify the C atom within the double bond that has more H atoms attached to it – this carbon

will accept the H atom, while the other will accept OH

3. Predict and name the products

Reactions of Aromatic Hydrocarbons

Undergo __________________________________

Reactivity is between that of alkanes and alkenes

As reaction (b) proceeds, bromobenzene reacts with Br2 to substitute another Br and create 3 possible isomers

In practice, the 1,3 isomer is favoured

A reaction with benzene and nitric acid

A reaction with benzene and an alkyl halide (R – X)

The halide (Cl) joins the H from the benzene ring to produce HCl, while the alkyl group is substituted onto the benzene ring

Sample Problem Predict the product or products formed when benzene is reacted with chloromethane, in the presence of a catalyst (AlCl3). Draw structural diagrams of the reactants and products. The methyl group of chloromethane substitutes for one of the H atoms on the benzene ring, forming methyl benzene and releasing the chloride to react with the displaced H.

Reactions Involving Organic Halides (R – X)

Preparing Organic Halides

Can be produced by ____________________________________ (See previous section in notes) o Substitution to alkanes and aromatic compounds o Addition to alkene and alkynes

Preparing Alkenes from Alkyl Halides

This is the opposite process of producing alkyl halides

Undergo _________________________________________________ o Atoms or ions are removed from a molecule and a double bond is put in their place o OH- ion is needed

NOTE – A metal hydroxide may also be used to assist an elimination reaction (ex. NaOH). In this case, the halide will form a compound with the metal ion (ex. NaCl), and hydrogen with form a compound with the OH- ion (water).

Reactions Involving Alcohols Hydration Reactions (Making Alcohols)

Alcohols are made by addition reactions of water to unsaturated hydrocarbons

Elimination Reactions (Making Alkenes from Alcohols)

The above reaction can also proceed in reverse

Catalyzed by _____________________________

Removes an H atom and OH group from neighbouring atoms to leave a double bond

May also be called _________________________ because it creates water

Combustion of Alcohols

Alcohols combust in the presence of oxygen to produce carbon dioxide and water

o ___________________________________________

Sample Problems

1. Draw the structural diagrams to represent the addition reaction of propene to form an alcohol. Draw your reactant: What must be added to produce an alcohol? Draw your reaction:

Remember Markovnikov’s Rule

to determine which C the H

and OH will bond to

2. Draw the structural diagrams to represent the dehydration reaction of ethanol. Draw the reactant. Eliminate water (H and OH) from neighbouring atoms to leave a double bond between them.

Be aware... When a reaction may yield two or more products, you must include all possibilities in the reaction equation. Ex. The dehydration of 2-butanol produces 1-butene, 2-butene and water

+ + H2O 2-butanol 1-butene 2-butene This also applies for previous reactions discussed (another good example is addition to a benzene ring that already has a branch).

Reactions Involving Ethers

Preparing Ethers

Ethers are formed when two alcohols react to eliminate a molecule of water

This is known as a ___________________________________ because water is released

+ + H2O methanol methanol methoxymethane water

Sample Problem Write a balanced equation to show the formation of an ether from 1-propanol. Begin by drawing your reactants. Circle the components that will be eliminated to form water (H from one alcohol, OH from another). Join the alcohols to form an ether.

Reactions Involving Aldehydes and Ketones

Preparing Aldehydes and Ketones

Done by the controlled ___________________of ___________________

Oxidation – a gain of oxygen, or a loss of hydrogen

In this case, oxygen atoms are supplied by ________________________________

Ex. hydrogen peroxide (H2O2), potassium dichromate (K2Cr2O7), and potassium permanganate (KMnO4)

The symbol (O) will be used to indicated the presence of an oxidizing agent Example:

The reactive (O) _______________________________ (one from OH and the other from the “R” group) resulting in a C=O group and H2O. When a _________________________________ is oxidized...

When a _________________________________ is oxidized...

A tertiary alcohol cannot be oxidized!

Hydrogenation of Aldehydes and Ketones

The carbonyl group (C=O) undergoes an _____________________ reaction with _______ (only)

to create an alcohol (_____________________________________)

Requires high heat, pressure, and a catalyst Aldehyde Primary Alcohol

Ketone Secondary Alcohol

Sample Problem 1 Draw the structural formula and write the IUPAC names to represent the controlled oxidation of an alcohol to form butanone. First, draw the structural formula for butanone. What C atom is the carbonyl group attached? ______________________________ What alcohol must be oxidized? __________________________________ Draw the complete reaction. Sample Problem 2 Draw structural diagrams and write IUPAC names to show the hydrogenation of methanal. Draw your reactant. What must be added to hydrogenate the C=O bond? ________ Write the reaction and name all products.

Reactions Involving Carboxylic Acids

Preparing Carboxylic Acids

When an alcohol is oxidized to an aldehyde, a further oxidation can occur to result in a carboxylic acid

______________________________________________________________________________ Example Step 1: Step 2:

Sample Problem 1 Write an equation to show the controlled oxidation of an aldehyde to form butanoic acid. Write the structural formula of the product. The aldehyde required must have the same number of carbons, so it must be ____________________. Write the reaction.

Sample Problem 2 Write a series of equations to show the reactions needed to produce methanoic acid from methanol. Write IUPAC names for all reactants and products. Remember – alcohol aldehyde carboxylic acid Step 1: Step 2:

Reactions Involving Esters

Preparing Esters

________________________________________________________________

This condensation reaction is known as ________________________________

Identify acid and alcohol used from the name of the ester (alcohol is the first part of the name, acid is the second part of the name with the suffix “-oate”)

General Reaction

Example

Sample Problem 1 Draw a structural diagram and write the IUPAC name for the ester formed in a reaction between 1-propanol and benzoic acid. Write the reactants, and complete the condensation reaction. Name all compounds. Sample Problem 2 Write a condensed structural diagram equation for the esterification reaction to produce the ester CH3CH2CH2COOCH2CH3. Write the IUPAC names for all reactants and products. Identify the acid. _________________________ Identify the alcohol. _________________________ Draw the reaction:

Hydrolysis of Esters When an ester is treated with an acid or base, the reverse of esterification occurs

The ester splits into its acid and alcohol components

Also known as ____________________________ General Example (in a basic solution, the products are the sodium salt of the acid and the alcohol)

Reactions Involving Amines and Amides

Preparing Amines

________________________________________________

Substitution reaction Examples _______________________________________________________ primary amine

_______________________________________________________ secondary amine

_______________________________________________________ tertiary amine

The primary amine produced

can also react with an alkyl

halide to produce a secondary

amine

Preparing Amides

Similar to the preparation of esters

Condensation reaction – _______________________________________

______________________________

carboxylic acid + ______________________________ amide

______________________________

Remember – the amide functional group is a carbonyl group (C=O) attached to a N atom (which can only make 2 other bonds to either H or C atoms)

o This is why a tertiary amine cannot react with a carboxylic acid Examples ____________________________________________________ amide

____________________________________________________ amide

___________________________ of Amides Like esters, amides can be hydrolyzed in acidic or basic conditions to ____________________________ _____________________________________. This is essentially the reverse of the formation of amides. Remember – Carboxylic acids can produce amides and esters

Sample Problem Draw a structural diagram of the amide formed from the reaction between 3-methylbutanoic acid and ethylmethyl amine. Name the amide formed. Draw the structural diagram for the reactants. An OH group is eliminated from the carboxyl group of the acid and an H atom from the amine group of the alcohol. A water molecule is eliminated. A bond forms between the C atom of the carboxyl group and the N atom of the amine group. Draw your reaction equation and name the amide formed.