Organic - Chapter 5: Carboxylic Acid & Esters

Carboxyl Group

The COOH functional group.

Carboxylic Acid

Group of molecules containing the carboxyl functional group.

abundantly

Carboxyl-containing compounds are found _______ in nature. Ex.) Lactic acid

tart

The ____ flavor of foods that taste sour is usually caused by the presence of one or more carboxylic acids.

-oxo

Ending of ketone branches.

priority

Carboxylic acids are the top _______ when naming organic molecules.

True

T or F: Carboxylic acids were among the first organic compounds to be studied due to their abundance in nature.

familiar source

Carboxylic acids were usually named after some _____________.
Ex.) Acetic acid was named after Latin word for vinegar, acetum.

Formic Acid

(IUPAC = Methanoic Acid) Stinging agent of certain ants and beetles, used in food preservation.

Acetic Acid

(IUPAC = Ethanoic Acid) Active ingredient in vinegar, used in food preservation.

Propionic Acid

(IUPAC = Propanoic Acid) Salts used as mold inhibitors.

Butyric Acid

(IUPAC = Butanoic Acid) Odor-causing agent in rancid butter.

Caproic Acid

(IUPAC = Hexanoic Acid) Characteristic odor of Limburger cheese.

Oxalic Acid

(IUPAC = Ethanedioic Acid) Present in leaves of some plants such as rhubarb and spinach, used as a cleaning agent for rust stains on fabric and porcelain.

Citric Acid

(IUPAC = 2-Hydroxy-1,2,3-PropaneTriCarboxylic Acid) Present in citrus fruits, used as a flavoring agent in foods, present in cells.

Lactic Acid

(IUPAC = 2-HydroxyPropanoic Acid) Found in sour milk and sauerkraut, formed in muscles during exercise.

liquid

Low molecular weight carboxylic acids are ______ at room temperature.

unpleasant

Carboxylic acids have characteristically sharp or ______ odors.

increases

The boiling point of carboxylic acids ________ as the molecular weight increases.

waxlike

Heavier carboxylic acids (greater than ten carbons) are ________ solids.

highest

Carboxylic acids have the ________ boiling points when compared to compounds with similar molecular weights.

polar

The -COOH group is very ______ and has the ability to hydrogen bond with other -COOH groups.

alcohols

Carboxylic acids have stronger intermolecular forces (higher boiling points) than ______, because they can form dimers.

Dimer

Two identical molecules bonded together by two hydrogen bonds.

soluble

Low molecular weight carboxylic acids are very _______ in water due to the hydrophilic carboxyl group. The
-COOH groups can hydrogen bond with water.

hydrophobic

As the length of the ________ hydrocarbon portion increases, the water solubility decreases.

True

T or F: Carboxylic acids containing eight or more carbon atoms are considered to be insoluble in water.

False

T or F: The same trend found in BP is found in solubility.
hydrocarbons < ethers < aldehydes & ketones < carboxylic acids < alcohols

acidic behavior

The most important chemical property of carboxylic acids is their ___________.

hydrogen

The acidic character of carboxylic acid is caused by the ________ attached to the oxygen of the carboxyl group.

Carboxylate Ion

Formed when the H+ leaves the carboxylic acid in water.

weak acids

Carboxylic acids behave as ________ having a low dissociation.

reversible

The acidic reactions are _________.

Le Chatelier's Principle

The addition of H3O+ (low pH) favors the formation of the carboxylic acid where the removal of H3O+ (high pH) favors the formation of the carboxylate ion.

7.4

At pH ____ (the pH of blood/body fluids), the carboxylate form predominates.

salts

Even though carboxylic acids are weak, they can still readily react with strong bases (NaOH & KOH) to form _______.

Pyruvic Acid

(Pyruvate) An important intermediate in the energy conversion reactions in living organisms.

metal

Both common names and IUPAC names are assigned to carboxylic acid salts by naming the _____ first and changing the ending the -ic ending of the acid name to -ate.

solid

Carboxylic acid salts are _______ at room temperature.

ionic

Carboxylic acid salts are usually soluble in water because they are _______.

Fatty Acids

Carboxylic acids with long hydrocarbon chains (12-20 carbon atoms), first isolated from natural fats.

True

T or F: Even long chain acids with an extensive nonpolar hydrocarbon portion can be solubilized by converting them into salts.

soaps

Na+ and K+ salts of long-chain acids are used as ______.

preservatives

Calcium and sodium propanoate are used commercially as ____________ in bread and cheese (prevent mold growth).

Sodium Benzoate

Another preservative that occurs naturally in foods such as cranberries and prunes, it is also used in products such as ketchup and carbonated beverages.

Zinc 10-undecylenate

Used to treat athlete's foot.

buffer

A mixture of sodium citrate and citric acid is widely used as a _______ to control pH.

anticoagulant

In blood, the buffer (citrate/citric acid) functions as an __________.

maintain

Products sold as foams or gels (jelly, ice cream, whipped cream) ________ their desirable characteristics at certain pHs which can be controlled by the citrate/citric acid buffer.

Ester

Group of molecules containing the -COOR functional group (a carbonyl next to an alkoxy group).

acid catalyst

When carboxylic acids are heated with alcohols in the presence of an ___________, carboxylic esters are formed.

Esterification

The process of forming an ester linkage between a carboxylic acid and an alcohol.

ester linkage

The ester functional group has an ___________ between the carbonyl carbon and the oxygen atom.

structural

The ester functional group is a key _________ feature in fats, oils, and other lipids.

fragrances

Esters are found in many fruits and flowers, giving them their __________.

flavoring agents

Because of esters being found in fruits and flowers, they are commonly used as ___________ in foods and as scents in personal products.

Polyesters

Polymers made by esterification reaction.

Condensation Polymerization

When monomers combine to form polymers and a small molecule (usually water).

contrast

Condensation polymerization is in _______ to addition polymerization where all atoms of the alkene monomer are incorporated into the polymer.

False

T or F: In many polymerization reactions each monomer has only one functional group so the chain only grows at one end.

True

T or F: You must have the same number of monomers and alcohols for a polyester to form.

monomers

Molecules of product from these reactions continue to react with available __________ until the polyester is formed.

three

Over ______ billion pounds of polyester (PET) are produced annually.

spinnerettes

Polyester fibers are formed by melting the polymer and forcing the liquid through tiny holes in devices called _____________. The resulting fibers are spun into thread or yarn.

PET Uses

Automobile tire cords, permanent-press clothing, sutures for blood vessels & the esophagus, and sheets/films for manufacturing magnetic tapes for tape recorders.

good yields

The reversible nature of the esterification reaction does not always allow for ____________ of product.

Carboxylic Acid Chlorides

More reactive than carboxylic acids thus they are used instead to obtain higher product (ester) yields.

Carboxylic Acid Anhydrides

More reactive than carboxylic acids thus they are used instead to obtain higher product (ester) yields.

breaking

The most important reaction of esters (commercially and biologically) involve the ________ of the ester linkage. Ex.) Hydrolysis & Saponification

Ester Hydrolysis

Reaction of an ester with water to break the ester linkage and produce an alcohol and a carboxylic acid (reverse of esterification).

Strong acids

___________ are used as the catalyst of Ester hydrolysis and the reaction is reversible.

digested

Ester formation and hydrolysis are very important in biological processes (esters such as animal fats and vegetable oil are hydrolyzed when ________).

Saponification

Reaction of an ester with a strong base (KOH or NaOH) to break the ester linkage and produce an alcohol and a carboxylate salt.

fats, oils

Saponification of _____ and _____ is important in the production of soaps.

inorganic acids

Alcohols can form esters by reacting with ____________ such as sulfuric, nitric, and phosphoric acids.

biochemistry

The most important inorganic acid in ___________ are the esters of phosphoric acids (H3PO4).
Ex.) phospholipids and nucleic acids (diesters)

Phosphoric acid

Because _____________ has three -OH groups, it can form monoesters, diesters, and triesters.

life

Monoesters and diesters are essential to _____ and represent some of the most important biological molecules.

body pH

At _________, the two -OH groups of phosphoric acid are ionized and the phosphate group has a charge of -2.

chemical energy

Phosphate esters are key compounds in the storage and transfer of ___________ in living systems.

Phosphoric Anhydrides

Compounds that contain multiple phosphate groups linked together. The most important are diphosphate esters and triphosphate esters.

Adenosine Diphosphate

(ADP) Phosphoric anhydride of great biological importance.

Adenosine Triphosphate

(ATP) Phosphoric anhydride of great biological importance.

Aspirin

An ester prepared from salicylic acid used as a pain reliever, anti-inflammatory agent, and anticoagulant.

Nitroglycerin

A nitrate ester resulting from the reaction of nitric acid and glycerol used as an explosive.