Organic Compounds

Organic Halides• A hydrocarbon in which one or more

hydrogen atoms have been replaced byhalogen atoms

• Freons (chlorofluorocarbons) in refrigerationand air conditioning

• Teflon (polytetrafluoroethane)• DDT, PCBs

Naming Organic Halides• Consider halogen as a branch.

Properties of Organic Halides• Halogen makes the molecule more polar, increasing

strength of the intermolecular forces– Higher boiling points than their corresponding hydrocarbons– More soluble in polar solvents

• Molecules with more halogens are more polar

Preparing Organic HalidesRecall: Substitution reaction produce halides in alkanes and

aromatic hydrocarbons

Preparing Organic HalidesRecall: alkyl halides are produced in halogenation reactions

with hydrocarbons

Elimination Reactions• Preparing alkenes from alkyl halides• Most common method of preparing alkenes• Alkyl halides can eliminate a hydrogen and a halide ion

from adjacent carbon atoms forming a double bond.• Presence of a hydroxide ion is required

Alcohols• Organic compounds containing a hydroxyl group -OH• E.g. ethanol, cholesterol, retinol (vitamin A)Naming:• -ol suffix e.g. methane + OH = methanol

Polyalcohols• Alcohols containing more than one -OH

group• -diol, -triol suffix• Or hydroxy prefix

1,2-dihydroxyethane 1,2,3-trihydroxypropane

Properties of Alcohols• More polar and can hydrogen bond

– Higher boiling points– More soluble in polar solvents

• Long-chain alcohols are nonpolar(hydrocarbon portion) and polar (-OH)– Ideal solvents in organic reactions because

they will dissolve both polar and nonpolarcompounds

Hydration Reactions• Alkene + water --> alcohol• Follows Markovnikov’s rule

Combustion of Alcohols

Elimination ReactionsDehydration (Condensation) Reactions:• Under certain conditions alcohols can decompose to

produce alkenes and water• A catalyst (sulfuric acid) removes a hydrogen atom and a

hydroxyl group from neighbouring carbons• Resulting in C=C and H2O

Ethers• Molecules with C-O-C group• More polar than hydrocarbons• But, unlike alcohols, ethers cannot hydrogen bond

Naming:• Add oxy to the prefix of the smaller hydrocarbon group and

join it to the alkane name of the larger hydrocarbon group• E.g. CH3-O-C2H5 is methoxyethane

Condensation Reactions• When two alcohols combine, an ether and water are formed

Aldehydes and KetonesKetone: Molecule with a carbonyl group (C=O) between two

carbon atoms. Alkane name with -one suffix

Aldehyde: Molecule with a carbonyl group (C=O) on aterminal carbon. Alkane name with -al suffix

Properties of Aldehydes andKetones

• Lower boiling point and less soluble in water than alcohols(no -OH)

• More polar than hydrocarbons (higher boiling points andmore soluble)

• Good solvents (both polar and nonpolar)

Oxidation Reactions• Alcohol + an oxidizing agent (removes

electrons) to form an aldehyde or ketoneand water

• The oxidizing agent removes two H-atoms(one from the -OH group and one from theadjacent carbon) resulting in C=O and H2O

NoavailableH-atom

Oxidizing agent

Hydrogenation Reactions• The C=O double bond can undergo an addition reaction with

hydrogen to form an -OH group.• Aldehydes always produce 1˚ alcohols

• Ketones always produce 2˚ alcohols

Carboxylic Acids• Molecules with a carboxyl group -COOH• E.g. lactic acid, citric acid

• Alkane name with -oic acid• E.g. methanoic acid

Properties of Carboxylic Acids

• Polar and can hydrogen bond• Similar properties to alcohols (smaller

members are soluble in water, largermembers are insoluble)

• pH < 7 (H-atom in -OH group)

Oxidation ReactionsRecall: A 1˚ alcohol can be oxidized to form an aldehyde.

An aldehyde can be further oxidized to form a carboxylic acid

A ketone cannot be oxidized because there is mo free H-atom

Oxidation Reaction

EsterficationRecall: acid + base --> salt + water (neutralization reaction)

Carboxylic acid + alcohol --> ester + water

Properties of Esters• Similar to carboxylic acids, but lacking -OH group

• Esters are less polar (less soluble in water), lower boilingpoints (no H-bonds)

• Not acidic

Naming Esters• 1st part is the name of the alkyl group in the alcohol• 2nd part is the ending of the acid name changed from -oic

to -oate

Amines• An ammonia molecule in which one or more H-atoms are

substituted by alkyl or aromatic groups

Naming:• Amino + alkane name OR• Alkyl group + amine

Naming 2˚ and 3˚ Amines• N- prefix used for the substituted groups on the nitrogen

atom• Alkyl groups are listed alphabetically

N,N-dimethyl-2-aminopropane

Properties of Amines• N-C, and N-H polar bonds• H-bonding occurs but N-H is less polar than

O-H

Synthesizing Amines from Alkyl Halides• Alkyl halide + ammonia --> 1˚ amine + HX

• Alkyl halide + 1˚ amine --> 2˚ amine + HX

• Alkyl halide + 2˚ amine --> 3˚ amine + HX

Synthesizing Amines from Alkyl Halides

Amides• Similar to esters, except N instead of O

Recall: Carboxylic acids + alcohols --> esters + water

Carboxylic acids + ammonia/1˚/2˚ amines--> amides + water

Naming Amides• 1st part is the name is from the amine• 2nd part is the ending of the acid name changed from -oic

to -amide• Alphabetical order with N- groups

N-ethyl propanamide

Summary