Carboxylic Acids (alkanoic acids) Carboxylic acids contain a carbonyl group with an -OH attached. The carboxyl functional group is -COOH: Carboxylic acids are weak acids. Named like alkanes with “-oic acid” at the end. Typical carboxylic acids are found in spinach, vinegar, cleaners, vitamin C, aspirin, and citrus fruits. Carboxylic acids are also used to make polymers for fibers, paints, and films.

Reactions of Carboxylic Acids Donate proton to a base (form alkanoate ion) Esterification (squeeze play) – react with alcohol to form an ester. Also referred to as condensation. 3. Amide formation (also condensation) – react with amine to form an amide. + H2O + H2O

Esters Some common esters are: benzocaine (in sun burn lotions), ethyl acetate (nail polish remover), vegetable oils, polyester thread, and aspirin. Esters contain -COOR groups: Esters can be prepared by reacting a carboxylic acid with an alcohol and eliminating water:

Esters are named first using the alcohol part and then the acid part (in the above example: ethyl from ethanol and ethanoate from ethanoic acid). Esters tend to have characteristic odors and are used as food flavorings and scents.

Amines Amines are organic bases. Just as alcohols can be thought of organic forms of water, amines can be thought of organic forms of ammonia. Treat NH2 groups as substituents called “amino” Examples 1. 1-aminobutane 2. 1,6-diaminohexane

Amides Amides are composites of carbonyl and amine functionalities: Named by longest chain followed by “anamide” Example: propanamide

Nitriles Contain a cyanide group (CN) Named as alkane (full name) followed by “nitrile” Example: butanenitrile

Halogenoalkanes (chloroalkanes, bromoalkanes) – contain a halogen atom in place of a hydrogen. Halides are treated as substituents Examples 1. 2. 3. Reactions of halogenoalkanes – nucleophilic substitution the “X” atom is replaced by a “nucleophile.” 3-chlorohexane 2,3-dibromohexane 2-bromo-2-chloropropane

Nucleophile – something with an unshared pair of electrons (attracted to a partially-positive carbon atom) Examples: OH-, NH3, CN-, R’-O, R’-NH2, H2O, etc. Hydroxide (OH-) is a better nucleophile than water (H2O), since it is more attracted to the partially-positive carbon atom.

Primary halogenoalkanes (contain only 1 carbon attached to the carbon with the halogen atom) – react by a mechanism called SN2 (heterolytic fission of the bond): S = N = 2 = Substitution Nucleophilic bimolecular Curvy (curly) arrows indicate the movement of electrons.

strength of nucleophile (CN- > OH- > NH3 > H2O) Rate of SN2 depends on: concentrations of both reactants strength of nucleophile (CN- > OH- > NH3 > H2O) identity of halogen (bond strength) I is fastest and F is slowest Tertiary halogenoalkane – SN1 reaction (heterolytic fission) – faster than SN1 1 = unimolecular (RDS) – rate depends only on the concentration of the halogenoalkane 1. 2.

Examples – Write reactions for these nucleophilic substitutions, using “curly arrows.” Potassium cyanide + 2. Ammonia +

Elimination Reactions of Bromoalkanes Elimination of HBr molecule to form an alkene. Occurs in NaOH in hot ethanol, heated under reflux. The H and Br are removed from neighboring carbon atoms. E1 – unimolecular elimination reaction – a carbocation is formed (similar to SN1), then the OH- removes the H: OH-