carboxylic acids and carboxylic acid derivatives chapter 14

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  • Carboxylic Acids and Carboxylic Acid DerivativesChapter 14

  • 14.1 Carboxylic AcidsStructure and Physical PropertiesThe carboxyl group of the carboxylic acid consists of a carbonyl group and a hydroxyl groupBoth are very polar This means carboxylic acids are polarThey bond to each other through H-bonding as well as to water moleculesBecause of the strong intermolecular bonds of the H-bonds, they boil at higher temps than aldehydes, ketones or alcohols of similar molecular mass

  • 14.1 Carboxylic AcidsStructure and Physical Properties

    Carbonyl Hydroxyl

  • 14.1 Carboxylic AcidsStructure and Physical PropertiesCompare boiling points on page 453

    Much like alcohols, the smaller the carboxylic acid, the more soluble it is in water. As the carbon chain grows on the carboxylic acid, solubility decreases because it becomes more like a hydrocarbon and therefore, less polar.

  • 14.1 Carboxylic AcidsStructure and Physical PropertiesCarboxylic acids with lower molecular masses have a very sour taste and bad smellsFormic acid is what causes the burning when you are bit by an ant!Acetic acid is found in vinegarPropionic acid gives swiss cheese its tangy flavorButyric acid causes the smell associated with rancid butter and gas gangrene

  • 14.1 Carboxylic AcidsNomenclature (IUPAC)Determine the parent compound (the longest continuous carbon chain containing the carboxyl group.)Number the chain so that the carboxyl carbon is carbon-1.Replace the e ending of the parent alkane with the suffix oic acid. If there are 2 carboxyl groups, the suffix dioic acid is used.Name and number the substituents the usual way.

  • 14.1 Carboxylic AcidsNomenclature (IUPAC)A carboxylic acid with 1 carboxyl group

    Butanoic Acid

    A carboxylic acid with 2 carboxyl groups

    Butanedioic Acid

  • 14.1 Carboxylic AcidsNomenclature (IUPAC)Name the following:

  • 14.1 Carboxylic AcidsNomenclature (IUPAC)Carboxylic acid derivatives of cycloalkanes are named by adding the suffix carboxylic acid to the name of the cycloalkane or substituted cycloalkane. The carboxyl group with always be on carbon-1 and the other substituents named and numbered as usual.

  • 14.1 Carboxylic AcidsNomenclature (IUPAC)Name the following:

  • 14.1 Carboxylic AcidsNomenclature (Common)Table 14.1 on page 456 shows sources of common namesCommon names end in ic rather than oic.In this system , substituted carboxylic acids are named as derivatives of the parent compound.Greek letters are used to indicate position of the substituent. The carbon bonded to the carboxyl carbon is the alpha carbon, the next is betaand so on.

  • 14.1 Carboxylic AcidsNomenclature (Common)Alpha ()Beta ()Gamma ()Delta ()Epsilon ()Zeta ()

  • 14.1 Carboxylic AcidsNomenclature (Aromatic Carboxylic acids)Benzoic acid is the simplest aromatic carboxylic acidCan be named using either system as derivatives of benzoic acidThe oic acid or ic acid is attached to the appropriate prefixCommon names are frequently used (See page 458)

  • 14.1 Carboxylic AcidsNomenclature (Aromatic Carboxylic acids)The phenyl group is often treated as the substituent and the name comes from the parent chain attached to the benzene (alkanoic parent chain)

  • 14.1 Carboxylic AcidsSome Important Carboxylic AcidsLarger carboxylic acids have very strong, foul odorsPentanoic (valeric) acid from the valerian plant has an aroma described to be like over-ripe cheese or a wet dogExtracts of it have been used for thousands of years as a sedative Hexanoic (caproic) acid was first isolated from goats and said to smell like goats.Heptanoic (enanthic) acid is said to smell like rancid oil.

  • 14.1 Carboxylic AcidsSome Important Carboxylic AcidsWhen carboxylic acids react with alcohols they produce esters which create the fragrance and flavor of many fruits.More pages 461-462

  • 14.1 Carboxylic AcidsReactions Involving Carboxylic AcidsPreparation of carboxylic acids (oxidation reaction)Carboxylic acids are produced by the oxidation of a primary alcohol or aldehydes.Chromic acid is a common oxidizing agent.

  • 14.1 Carboxylic AcidsPreparation of carboxylic acidWrite the mechanism (equation) for the oxidation of butanol to butanoic acid.

  • 14.1 Carboxylic AcidsAcid-Base ReactionsCarboxylic acids behave as acids because they donate protons.They are weak acids that dissociate to form a carboxylate ion and a hydrogen ionCarboxylic acids do not completely dissociate (only 5% ions created)

  • 14.1 Carboxylic AcidsAcid-Base ReactionsWhen strong bases are added to carboxylic acid, neutralization occurs.The hydrogen ions from the acid and hydroxide ions from the base form water.Carboxylic acid salt is also formed.

    + NaOH + H2O

    Butyric acid Sodium Sodium butyrate Waterhydroxide

  • 14.1 Carboxylic AcidsAcid-Base ReactionsNotice that the carboxylic acid salt changed from ic to ate.Acetic acid would become acetate, benzoic acid would become benzoate.In the front of the name, you place the cation, in this case it was sodium.

  • 14.1 Carboxylic AcidsEsterificationCarboxylic acids react with alcohol to form esters and waterR and R1 represent alkyl groups (can be the same or different) Acid

    Carboxylic AlcoholEsterWater Acid

  • 14.2 EstersStructure and Physical PropertiesMildly polar, pleasant aromasFound in natural foods (banana oil, pineapple, raspberriesetc.)Boils at approx. same temperature as aldehydes and ketones of similar massSomewhat soluble in water

  • 14.2 EstersNomenclatureEsters are carboxylic acid derivatives (organic compounds that come from carboxylic acids)Formed from the reaction of a carboxylic acid and an alcohol1. Use the alkyl or aryl portion of the alcohol name as the first name2. The ic acid ending of the carboxylic acid is replaced with ate and follows the first name

  • 14.2 EstersNomenclatureExamples

    Ethyl Butanoate

  • 14.2 EstersReactions Involving EstersPreparation of Esters (Esterification)Dehydration reaction Requires heat & small amount of acid


    Carboxylic AlcoholEsterWater Acid

  • 14.2 EstersEsterification ExampleWrite an equation showing the esterification of propyl ethanoate.

  • 14.2 EstersReactions Involving EstersHydrolysis of EstersHydration reaction (adding water)

    Ester Water C.A. Alcohol

    Requires heat (a small amount of acid may also be added)Reverse of esterification

  • 14.2 EstersHydrolysis of EstersExample

    Ethyl methanoate Methanoic Ethanolacid

  • 14.2 EstersSaponificationWhen you use a base instead of an acid as a catalyst, you make carboxylic acid salt.

  • 14.2 EstersSaponification ExamplesPropyl ethanoate + water

    Propyl hexanoate + water

  • 14.2 EstersSaponificationFats and oils are triesters of the alcohol, glycerol (they have 3 esters in their structure)AKA triglycerides- solid fats from animals or liquid oils from plants

  • 14.2 EstersSaponificationSaponification is when esters are hydrated (water added)Soap is produced (soaps are the salts of long chain carboxylic acids- fatty acid salts)Roman Legend!- Soap was discovered by washerwomen after a heavy rain on Mons Sapo Mount Soap. The rain mixed with the remains of animal sacrifices, wood ash & animal fat. The ingredients of soap accidently came together (H2O, fat & K2CO3/KOH from the ash). The soap ran into the Tiber River where its value was quickly realized.

  • 14.2 EstersSaponificationWe still make soap the same wayWater, strong base, fats/oils from animals or plantsSolubility of the soap is determined by the C-chain lengthUp to 12 carbons is good (has lower mass) and gives larger bubblesHigher mass carbon chains (14-20 carbons) are less soluble in water and create smaller bubbles and a fine latherSolubility is also affected by the cation used, whether KOH or NaOH. K+ is more soluble than Na+ when formed with the carboxylic acid.

  • 14.2 EstersSaponificationHow does soap remove oil/grease?The long hydrocarbon chain of soaps resembles alkanes & they dissolve other nonpolar compounds (oil/grease- like dissolves like).Large hydrocarbon- hydrophobicCarboxylate end- hydrophilicWhen soap dissolves in water, the carboxylate end dissolves the carbon chain is repelled so a thin layer of soap forms on the surface (chains protrude out).

  • 14.2 EstersSaponificationHow does soap remove oil/grease?When soap comes into contact with oil or grease the C-chaindissolves in the oil/grease but the polar carboxylate groupremains dissolved in water

  • 14.2 EstersSaponificationHow does soap remove oil/grease?When soap molecules form around oil/grease, you get micelles. Micelles repel each other because they are surrounded by the carboxylate ions in the water.Mechanical action is what creates the micelles and removes them.

  • 14.2 EstersCondensation PolymersRecall from chapter 11A polymer is a macromolecule made from the combination of smaller monomersCan be made from a single polymer (same)- homopolymers.OR 2 different monomers- heteropolymers

  • 14.2 EstersCondensation PolymersPolyesters are heteropolymers- also called condensation polymersFormed by polymerization of monomers in a reaction that forms water or alcohol.This reaction is created using a dicarboxylic acid and a dialcohol (diol).DO NOT NEED TO KNOW REACTION

  • 14.2 EstersPolyestersWhen formed as fibers, polyesters are used as fabric for clothing.Trendy in the 70s during the disco era, it lost popularity after

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