Organic Compounds

Organic Halides A hydrocarbon in which one or more hydrogen atoms have been replaced by halogen atoms Freons (chlorofluorocarbons) in refrigeration and air conditioning Teflon (polytetrafluoroethane) DDT, PCBs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 Halides Recall: Substitution reaction produce halides in alkanes and aromatic hydrocarbons

Preparing Organic Halides Recall: 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 nonpolar compounds

Hydration Reactions Alkene + water --> alcohol Follows Markovnikov’s rule Combustion of Alcohols

Elimination Reactions Dehydration (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 H 2 O

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. CH 3 -O-C 2 H 5 is methoxyethane

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

Aldehydes and Ketones Ketone: 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 a terminal carbon. Alkane name with -al suffix

Properties of Aldehydes and Ketones Lower boiling point and less soluble in water than alcohols (no -OH) More polar than hydrocarbons (higher boiling points and more soluble) Good solvents (both polar and nonpolar)

Oxidation Reactions Alcohol + an oxidizing agent (removes electrons) to form an aldehyde or ketone and water The oxidizing agent removes two H-atoms (one from the -OH group and one from the adjacent carbon) resulting in C=O and H 2 O

No available H-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, larger members are insoluble) pH < 7 (H-atom in -OH group)

Oxidation Reactions Recall: 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

Esterfication Recall: 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 boiling points (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