Small groups of atoms that lend characteristic properties to molecules they are attached to.
Functional Groups: Halides
(= F, Cl, Br, or I)
Functional Groups: Alcohol, phenol
Functional Groups: Ether
Functional Groups: Aldehyde
Functional Groups: Ketone
Functional Groups: Carboxylic Acid
Functional Groups: Ester
Functional Groups: Amine
Functional Groups: Amide
Haloalkanes, aka Alkyl Halides
Alkanes with at least one hydrogen atom replaced with a halogen atom.
Properties of haloalkanes
Many a highly toxic; many pesticides are aromatic compounds with several halogen atoms.
For haloalkanes, a substitution in which a nucleophile replaces the halogen atom.
A reactant that seeks out centers of positive charge in a molecule.
Examples of nucleophiles
-OH and H₂O; the oxygen, in both cases.
ex. water in hydrolysis
19.1 Haloalkanes Summary
Haloalkanes are alkanes in which at least one hydrogen atom has been replaced by a halogen atom; they undergo nucleophilic substitution.
A polar group.
An organic compound containing a hydroxyl group not connected directly to a benzene ring or to a >C=O group.
Ethyl alcohol, grain alcohol.
3 ways of naming alcohols
- Add the suffix -ol to the stem of the parent hydrocarbon; if the location must be specified, the number of the carbon atom to which it is attached is given.
- Name the parent hydrocarbon as a group and attach the name alcohol, ex. ethyl alcohol.
- Name the -OH group as a substituent, in which case the name hydroxy is used, ex. 2-hydroxybutane.
Three classes of alcohol
Divided by the number of organic groups attached to the carbon atom connected to the -OH group:
- Primary; one R group
- Secondary: two R groups
- Tertiary: 3 R groups; often shortened to "tert"
A compound with two hydroxy groups.
ex. ethylene glycol, used as antifreeze.
Volatility of Alcohols
Higher than hydrocarbons of the same mass due to their ability to form H-bonds.
19.2 Alcohols Summary
The formulas of alcohols are derived from that of water by replacing one of the hydrogen atoms with an organic group. Like water, they form intermolecular hydrogen bonds.
An organic compount of the form R-O-R.
Volatility of Ethers
More volatile than alcohols of the same molar mass because they do not form H-bonds to one another; also less soluble in water for the same reason.
Reactivity of Ethers
They are not very reactive and have low molecular polarity, making them useful solvents for other organic compounds. However, they are flammable.
Cyclic ethers with alternating -CH₂CH₂-O- units; named for their crownline structure.
Properties of Crown Ethers
They bind very strongly to some metal cations, ex. encasing a K⁺, with the Os pointing towards the K⁺ and the hydrocarbons wrapped around the outside. This lets you mix polar solutes into nonpolar solvent.
19.3 Ethers Summary
Ethers are not very reactive. They are more volatile than alcohols with similar molar masses because their molecules cannot form hydrogen bonds with one another. Crown ethers adopt shapes that can enclose ions and carry them into nonpolar solvents.
An organic molecule containing a hydroxyl group attached directly to an aromatic ring.
Many occur naturally and are often components of essential oils.
19.4 Phenols Summary
Phenols are weak acids as a result of delocalization and stabilization of the conjugate base.
Occurs in two closely related families of compounds: Aldehydes and Ketones.
How the carbonyl group is written in different situations
In ketones, it is written as -CO-
In aldehydes, it is written as -CHO
Systematic names for aldehydes and ketones
Aldehydes are named by replacing the ending -e with -al, ex methane → methanal.
Ketones are named using the suffix -one.
19.5 Aldehydes and Ketones Summary
Aldehydes and ketones can be prepared by the oxidation of alcohols. Aldehydes can be more easily oxidized than ketones can.
Weak acids of the form R-COOH.
Naming of carboxylic acids
Replace the -e of the parent hydrocarbon with -oic acid.
The production of carboxylic acids
Carboxylic acids can be prepared by oxidizing primary alcohols and aldehydes with a strong oxidizing agent; in some cases an alkyl group can be oxidized directly to a carboxyl group.
19.6 Carboxylic Acids Summary
Carboxylic acids have an -OH group attached to a carbonyl group to form the carboxylic group, -COOH.
The product of a reaction between a carboxylic acid and an alcohol.
The process of creating esters, ex. the heating of acetic acid and ethanol to produce ethyl acetate and water.
Properties of Esters
Many esters are fragrant and contribute to the flavor of fruits. Other esters are oils or fats.
A reaction in which two molecules combine to form a larger one and a small molecule, usually water, is eliminated. The reaction can be catalyzed by a small amount of strong acid.
Change the -anol of he alcohol to -yl and the -oic acid of the parent acid to -oate.
Methanol + Ethanoic Acid → Methyl Ethanoate
19.7 Esters Summary
Alcohols condense with carboxylic acids to form esters.
An organic compound containing NH₃. Amines are classified according to the number of R groups on the nitrogen:
- Primary: RNH₂
- Secondary: R₂NH
- Tertiary: R₃NH
In all cases the N atom is sp³ hybridized.
Quaternary Ammonium Ion
A tetrahedral ion of the form R₄N⁺.
A carboxylic acid that contains an amino acid as well as a carboxyl group.
A form of a molecule in which a basic part has been protonated and an acidic part deprotonated; in an amino acid, the amino group would have been protonated and the carboxyl group deprotonated.
There are four possible forms of an amino acid
They differ in the extend of protonation of the two functional groups, i.e. changed/changed, changed/unchanged, u/c, u/u.
Amino acids in which the -NH₂ group is attached to the carbon atom next to the carboxyl group, ex. glycine, NH₂CH₂COOH.
The product of an amine condensing with a carboxylic acid.
Mechanism of amide formation
The amine could act as a base and simply accept a proton from the carboxylic acid; however, upon heating, a thermodynamically more favorable reaction takes place, the proton transfer is reversed and the amine acts as a nucleophile as it attacks the carbon of the carboxyl group.
Amines are named by specifying the groups attached to the nitrogen atom in alphabetical order followed by the suffix -amine. Amines with two amino groups are called diamines.
The -NH₂ group is called amino- when it is a substituent.
Name the halogen atom as a substituent by changing the -ine to an -o, ex. 2-chlorobutane.
19.8 Amines, Amino Acids, and Amides Summary
Amines are derived from ammonia by the replacement of hydrogen atoms with organic groups. Amides result from the condensation of amines with carboxylic acids. Amines and many amides take part in hydrogen bonding.
Macromolecular compounds in which chains or networks of small repeating units form giant molecules. They are made mainly by addition and condensation reactions.
A process in which alkenes react with themselves to form long chains.
A subunit of a polymer.
The structure that repeats over and over to produce a polymer chain.
Polymerization by a radical chain reaction.
A catalyst containing titanium tetrachloride and triethylaluminum which is used to ensure that polymers are stereoregular.
When each unit or repeating unit has the same relative orientation.
19.9 Addition Polymerization Summary
Alkenes undergo addition polymerization. When a Ziegler-Natta catalyst is used, the polymer is stereoregular and has a high density.
Polymers made via condensation reactions.
Polymers formed by linking together monomers that have carboxylic acid groups with those that have alcohol groups.
Why polyester molecules make good fibers
Growth can only occur at the functional groups, so chain branching is much less likely, keeping the polymers linear.
A polymer formed from the condensation polymerization of amines with carboxylic acids. Commoly known as nylons.
19.10 Condensation Polymerization Summary
Most condensation polymers are formed by the reaction of a carboxylic acid with an alcohol to form a polyester or with an amine to form a polyamide.
Polymers made of more than one type of repeating unit.
A copolymer where the differing subunits alternate.
A copolymer in which a long segment of one monomer is followed by a block of another monomer.
A copolymer in which different monomers are linked in no particular order.
A copolymer consisting of a long chain of one monomer with shorter side chains of another monomer attached as side groups.
19.11 Copolymers Summary
Copolymers combine the advantages of more than one component material.
Because synthetic polymers consist of chains of varying lengths, there can only be averages - average chain lengths, molar masses, etc. Properties are from averages.
Linear vs branched chain packing
Linear chains can pack more tightly than branched ones, so materials with aligned linear chains tend to be dense and tough.
A substance's ability to return to its original shape after being stretched.
Polymeric materials that return to their original shapes after stretching.
A polymer that can be softened again after having been molded.
A polymer that cannot be remolded after taking on a hardened shape.
19.12 Physical Properties of Polymers Summary
Polymers melt over a high range of temperatures, and polymers consisting of long chains tend to have high viscosities. Polymer strength increases with increasing chain length and the extent of crystallization. Thermoplastic polymers are recyclable.
Essential Amino Acids
The amino acids that the human body cannot produce and thus must obtain by via consumption.
A molecule formed by the condensation of two or more amino acids.
The -CO-NH- link found in a peptide.
What each monomer used to form a peptide is called.
A peptide containing only a few amino acids.
A peptide with only two residues.
Primary Structure of a Protein
The sequence of residues in a peptide chain.
Secondary Structure of a Protein
The shape adopted by the polypeptide chain; in particular, how it forms coils or sheets.
The most common secondary structure in animal proteins; a helical conformation of a polypeptide chain held in place by H-bonds between residues.
The second most common secondary structure found in animal proteins; consisting of pleated sheets.
Tertiary Structure of a Protein
The shape into which a protein's secondary structure is folded into as a result of interactions between residues.
An important link found in tertiary structures; -S-S-
Diseases caused by the infectious misfolding of proteins.
A protein structure in which neighboring polypeptide units stack together in a specific arrangement.
When a protein loses its structure; contrary to the MCB definition, the Chem 204 version also includes the cleavage of primary structure sequences.
19.13 Proteins Summary
Proteins are polymers made of amino acid units. The primary structure of a polypeptide is the sequence of amino acid residues; secondary structure is the formation of helices and sheets; tertiary structure is the folding into a compact unit; quaternary structure is the packing of individual protein units together.
Hydrates of carbon.
Polymers of glucose.
Starch is made of two components: 20-25% amylose, and amylopectin.
Amylose consists of chains of several thousand glucose molecules.
Amylopectin consists of chains of glucose molecules with branches. Each molecule contains ~1 million glucose.
The structural material of plants, held together by hydrogen bonds.
19.14 Carbohydrates Summary
Carbohydrates include sugars, starches, and cellulose. Glucose is an alcohol and an aldehyde that polymerizes to form starch and cellulose.
A unit consisting of a nitrogenous base and a ribose sugar.
A unit consisting of a nitrogenous base, ribose sugar, and phosphate group.
Polymeric species built from nucleotide units.
19.15 Nucleic Acids
Nucleic acids are copolymers of four nucleotides joined by phosphate ester links. The nucleotide sequence stores all genetic information.