Part 2: Functional Groups Organic Chemistry Part 2: Functional Groups

Functional Groups Added to a H-C chain in place of a H at terminal C in between carbons Determine unique chemical & physical properties Examples of functional groups alkyls & halogens hydroxyl group alcohols aldehyde group carboxyl group Organic acids Ketones Ether / Esters Amine / Amide

Alcohols Functional group simply replaces one or more H in the H-C chain R - OH hydroxyl group not bases not hydroxide polyatomic ion Hydroxyl group forms a covalent bond with a carbon atom a.k.a. non-electrolyte In bases the OH- forms an ionic bond with a + cation and will ionize a.k.a. electrolyte

Monohydroxy Alcohols Only one OH group Primary alcohols -OH group is bonded to a C that is bonded to 1 other C. Secondary alcohols -OH group is bonded to a C that is bonded to 2 other Cs Tertiary alcohols -OH group is bonded to a C that is bonded to 3 other Cs

Structural formula, name and molecular formula? CH3OH CH3CH2OH CH3CHOHCH3 COHCH3CH3CH3

Dihydroxy alcohols Alcohols that contain 2 hydroxyl groups CH2OHCH2OH structural formula? molecular formula? name? 1, 2 - ethanediol Common name - ethylene glycol antifreeze

Trihydroxy alcohols 3 hydroxyl groups per molecule CH2OHCHOHCH2OH structural formula? molecular formula? Name? 1, 2, 3 - propanetriol common name = glycerol / glycerine Alcohols with 3 OH groups end in triol

Structural formula, name and molecular formula? CH2OHCHOHCH3 CH2OHCH2CH2COHOHCH3 Structural formula & name? CHBrOHCHCH3CHBrOH

Aldehydes Aldehyde group is found at end of H-C chain H C O no number is needed to designate the aldehyde it is ALWAYS the #1 Carbon R - CHO aldehyde name ends in -al Ex. Formaldehyde Methanal H C O

You can add alkyl groups and halogens to an aldehyde, but remember the C=O is always the number one carbon. CH3CHCH3CH2CH2CHO Always #1

Structural Formulas & Names HCHO CH3CH2CHO CH3CH3CH3CCHO CHBrBrCHO

Molecular Formula of Aldehydes When writing the molecular formula count all C’s & H’s together and keep the functional group separate They will all end in CHO Ex. c.s.f. = CH3CH2CH2CHO molec. f. = C3H7CHO

Ketones O C Functional group found in middle of H-C chain R - CO - R’ ketone names end in - one Ex. Acetone Propanone Used as solvents O C

Ketones Methanone Ethanone Propanone 2- Butanone 2- Pentanone Don’t exist Ethanone Propanone 2- Butanone 2- Pentanone

Naming ketones O C Designate where the functional group and side chains are located with lowest possible number given to the functional group O C

Practice 2-methyl-3-pentanone 3,3-dimethyl-2-butanone 4-methyl-3-hexanone 5,5-dibromo-4-methyl-3-hexanone

Ethers O naming ethers name R groups in alphabetical order ALKYL groups Ethers Functional group found inside H-C chain R - O - R’ O naming ethers name R groups in alphabetical order put spaces between alkyl groups and add “ether” as your ending

Structural formula & name? diethyl ether a.k.a. Ether CH3OCH3 CH3CH2OCH2CH3 Molecular formula? C2H5OC2H5 CH3OCH2CH3 Molecular formula? CH3OC2H5 CH3CH2CH2OCH2CH2CH2CH3 Molecular formula? C3H7OC4H9

Carboxylic Acids O C O H naming Functional group found at end of H-C chain R - COOH carboxyl group O C O H naming drop “e” of alkane name and add - oic acid

Structural formula & name CHOOH methanoic acid A.k.a. formic acid CH3COOH ethanoic acid A.k.a. acetic acid CH3CH2COOH

6,6,7-trichloro-4-methylheptanoic acid More complex naming If the H-C chain contains halogen substitutions and methyl side chains number your carbons from the functional group H - C - C - C - C - C - C - C Cl Cl H C H H O H Cl H H H H OH | | | | | | H H H 1

Properties of Carboxylic Acids Weak ionization in water H C H O C H OH H C H O C H O- water + H2O + H3O+ hydronium ion ethanoic acid acetic acid acetate ion Organic acids are weak electrolytes

Properties . . . . #2 Solubility of R-COOH if R = C1 - C3 As carboxylic acid H-C chains increase solubility decreases. #2 Properties . . . . Solubility of R-COOH if R = C1 - C3 completely miscible (soluble) if R = C4 - C5 somewhat miscible (3.7g in 100g H2O) if R > C5 completely immiscible (insoluble) fatty acids

Properties . . . . #3 H C H O C H OH + + NaOH HOH NaCH3COO water Organic acids react with bases to produce salts neutralization H C H O C H OH water + NaOH HOH + NaCH3COO sodium hydroxide sodium acetate (salt) ethanoic acid acetic acid

Esters & Esterification Slow, reversible dehydration process organic acid reacts with an alcohol Products are an ester and water ester water alcohol acid

Esters have sweet fruity odors Functional Group R - COO - R’ R groups are alkyl groups Esters have sweet fruity odors

ACID Naming Esters Alcohol 1. Name the R group bonded to the -O 2. Name the R group bonded to the = O drop the e (of the alkane name) add -oate ACID

Organic Reactions X + O2  CO2 + H2O Combustion Burning H-Cs in the presence of O2 (g) will burn to produce CO2 and H2O X + O2  CO2 + H2O

Law of Conservation of Matter Substitution When one or more hydrogen atoms of a H-C chain is replaced by a halogen. C2H6 + Cl2  C2H5Cl + HCl C2H6 + Cl2  C2H4Cl2 + H2

Addition Involves breaking a multiple bond Unsaturated compounds become more saturated Alkyne becomes an alkene Alkene becomes an alkane C2H2 + Br2  C2H2Br2 C2H4 + Br2  C2H4Br2

Polymerization The process of bonding many small molecules (monomers) together to make a very long chain (polymer) Water must be a product Examples of polymers starches Proteins nylon

Esterification Reaction ethyl ethanoate Ethanoic acid ethanol water

Structural formula & Naming CHOOCH3 What were the alcohol and the acid? CH3COOCH3 What were the alcohol and the acid? CH3COOCH2CH3 alcohol and acid? CH3CH2COOCH2CH2CH2CH3

Esterification must be done in the presence of a catalyst to make the reaction go faster Because Esterification deals with organic MOLECULES the reaction is slow

Esterification resembles Neutralization Double Replacement Reactions Esterification resembles Neutralization Reactants Alcohol Carboxylic acid Products Ester Water Ions not involved Slow reaction needs a catalyst Reactants Acid (Org or inOrg) Base Products Salt Water Ions Fast reaction No catalyst

Amines First functional group to contain Nitrogen N can only make 3 bonds It has a total of 5 valence electrons 3 are unpaired

Naming Amines Drop the e from the parent chain name and add amine You must number your carbons to show where the amine group is located methanamine

Amides Functional group containing a Nitrogen AND a carbonyl group (C=O) at the end of the chain Carbonyl is always the #1 carbon Drop the e from the parent chain name and add - amide butanamide

Looooong carboxylic acid Soap Metallic salt of a higher carboxylic acid Contains Na+ or K+ Looooong carboxylic acid ~ C12 - C 18 Most common soap sodium salt of stearic acid CH3(CH)16COONa

Saponification soap Reactants fat or oil Products trihydroxy alcohol ester strong base NaOH KOH Products trihydroxy alcohol 1,2,3-propanetriol a.k.a. glycerol soap sodium stearate

Saponification Reaction (C17H35COO)3C3H5 + 3NaOH  C3H5(OH)3 + 3C17H35COONa Sodium soap = bar soap Potassium soap = liquid

Hard water ex. Ca2+ Mg2+ Fe2+ Hard water contains metallic ions When soap is used in hard water the stearate ion combines with these ions and forms a greasy precipitate soap scum

How do soaps clean? Soaps are ionic compounds and will ionize Na+ and CH3(CH2)16COO- Charged end is hydrophillic “water loving” Non-polar end is hydrophobic “water hating”

Greece Grease H2O H2O H2O H2O H2O H2O H2O H2O H2O H2O H2O H2O H2O H2O

Animated Soap micelle

Advanced Isomers Isomers Same molecular composition Same number of C, H, and/or O Different structural formula Different chemical properties reactivity Different physical properties Melting point, boiling point, vapor pressure, evaporation rate, solubility

The End