A compound that is partly soluble and insoluble in water
Give an example of a cationic surfactant?
quaternary ammonium salt with a long hydrocarbon chain
How do cationic surfactants work?
-long chain insoluble in water to attaches to non polar grease -polar head group will dissolve in water
What are cationic surfactants used for?
detergents, hair product etcs
What do amines act as and why?
Bases because the accept protons (BLB)
What does the strength of the amine base depend on?
how available the nitrogen's lone pair of electrons is
more available= more likely to accept proton
Why are primary aromatic amines weak bases?
benzene ring draws electrons towards itself electron density on nitrogen decreases lone pair less available
Why are primary aliphatic amines strong bases?
alkyl groups push electrons away from itself lone pair more available
What is the functional group of an amide?
What is a N-substituted amide?
one of the hydrogens has been substituted with an alkyl group N- ethylethanamide
Other than nucleophilic substitution, how else can an amine be formed?
Reduce Nitriles using LiAlH4 in dry ether and dilute acid
What is used instead in industry?
Nickel Catalyst/ H2 high temp and pressure
How to make an aromatic amine?
Nitrobenzene Sn conc HCl reflux Add NaOH phenylamine
Overall equation to produce phenylamine
nitrobenzene + 6[H] ---> phenylamine + 2H2O
Name the two types of condensation polymers
Polyesters Polyamides /peptide bonds
How to make polyamides?
Condensation reaction dicarboxylic acid diamine water is eliminated
Structure of Nylon 66
1,6 diaminohexane hexanedioic acid
The uses of Nylon 66
strong and resistant to abrasion-clothing,carpet,rope,airbags, parachutes
Structure of Kevlar
benzene-1,4-dicarboxylic acid 1,4- diaminobenzene
The uses of Kevlar
light and strong- bulletproof vests, car tyres, sports equipment
How is a peptide formed?
When two amino acids react in condensation reactions.
How is a polyester formed?
dicarboxylic acid diol
Structure of Terylene
benzene-1,4 dicarboxylic acid ethane-1,2-diol
Uses of Terylene
stable at hot and cold temps good containers for food
How to reverse a condensation polymer reaction?
Hydrolysis but too slow with water so acid/ alkali is used
Polyamides are hydrolysed more easily
in acidic conditions
Polyesters are hydrolysed more easily
in alkaline conditions
Why are condensation polymers stronger than addition polymers?
strong hydrogen bonding between chains
Why are polyalkenes chemically inert unlike condensation polymers?
bonds between repeating units are non polar non susceptible to attack by nucleophiles
Structure of an amino acid
How to amino acids act as acids?
COOH ---> COO- + H+ donate a proton
How do amino acids act as bases
NH2 + H+ ---> NH3
How to name amino acids?
-longest carbon chain COOH -NH2 have 'amino'
What is the isoelectric point?
pH where the overall charge is 0
What does the isoelectric point depend on?
The R group
Amino acids in acidic conditions
Amino acid is fully protonated i.e. (-NH3+) and (-COOH)
Amino acids in basic conditions
Amino acid is fully deprotonated i.e. (-COO(-)) and (-NH2)
What are proteins?
Sequences of amino acids joined by peptide links
What is the primary structure of an amino acid?
sequence of amino acids that make up the polypeptide chain covalent bonds
What is the secondary structure of amino acids?
What is the tertiary structure of amino acids?
-coiled and folded -extra bonds form -3d shape result of hydrogen bonds and disulfide bonds
Where and how does disulfide bonding occur?
in cytesine S-S
What can affect the shape of proteins
temp and pH
How do inhibitors work?
Similar shape to substrate block the active site
What are the three nucleotides that make up DNA?
Phosphate group pentose sugar (2-deoxyribose) Base
Structure of a nucleotide
What is a phosphodiester bond?
H2O is lost condensation polymerisation
How is the structure of DNA formed?
2 hydrogen bonds adenine and thymine 3 hydrogen bonds guanine and cytosine
How does cisplatin work in a ligand replacement reaction?
Nitrogen on guanine replaces one of the chlorine ligands Second guanine can replace other chlorine too
How to lessen the risks of cisplatin?
lower doses target tumour specifically
What does NMR spectroscopy measure the difference in?
energy absorbed by nuclei in different environments relative to a standard substance
What is the standard for NMR? Why?
Tetramethylsilane -single peak far to right -inert -non toxic -volatile so easily removed
Carbons next to what type of atoms will have a higher chemical shift
In H NMR what type of deuterated solvent is used?
What is the mobile phase?
Where the molecules can move. Liquid or gas.
What is the stationary phase?
Where the molecules cant move. Must be a solid or a liquid on a solid support.
What does the separation depend on?
solubility in the mobile phase retention by the stationary phase
What is the mobile phase in TLC?
liquid solvent- ethanol
What is the stationary phase in TLC?
thin layer of silica fixed onto a glass/metal plate
How to carry out TLC?
-draw baseline in pencil -add drops of mixture to baseline -allow spots to dry on the plate -place plate in solvent and cover with watch glass -solvent moves up plate and chemicals separate out -remove plate and mark the solvent front -place plate in fume cupboard to dry
Why is a watch glass used?
stops solvent from evaporating
Why must the solvent level be below the baseline?
so it doesn't dissolve samples away
What are the two ways to perform TLC if the chemicals are colourless?
-shine under uv lamp to view -leave plate in a jar of iodine crystals, iodine will stick to chemicals and spots will appear purple
How to small Rf values arise?
not very soluble in mobile phase strongly adsorbed in stationary phase
How to large Rf values arise?
Substance very soluble in mobile phase weakly adsorbed in stationary phase
What is column chromatography used for?
purifying an organic product
How does column chromatography work?
Stationary phase- glass column packed with aluminium oxide coated with water Mobile phase- solvent runs slowly and continuously through column
How can components of the mixture be identified using column chromatography?
Using the retention time.
What is Gas chromatography used for?
a mixture of volatile liquids
What is the stationary phase in gas chromatography?
solid or solid coated with oil (viscous liquid) packed into a long column
What is the mobile phase in gas chromatography?
Unreactive carrier gas such as nitrogen which is passed through at high temp and pressure
How to ensure accuracy of gas chromatography?
run a known sample through under same conditions for comparison
In a chromatogram what do the area under the peaks represent?
amount of each component present in the mixture
What is GC-MS?
sample separated using gas chromatography fed into a mass spectrometer mass spectrum produced
Why is GC-MS more useful?
components can be positively identified impossible to do this just using GC as similar compounds have similar retention times
What method of purification should be used if product is insoluble in water?
How does separation of organic product work?
-organic layer and aqueous layer containing soluble impurities separate out -open tap and run off each layer into separate beakers
What is solvent extraction?
-used if your product and impurities are dissolved in a solution together -shake impure product with immiscible solvent
What drying agent can be used to remove traces of water?
anhydrous MgSO4 or CaCl2
What method of purification should be used if there's liquids with different boiling points?
How to perform distillation?
Heat impure product and when the liquid you want boils collect in a beaker
What method of purification should be used if product is a solid?
What are the steps for recrystallisation?
dissolve in minimum amount of hot solvent leave to cool and crystals form filter under reduced pressure using a buchner filter
Diagram of buchner filter
Steps to test purity of organic compound?
-pack small sample into capillary tube -increase temperature until solid turns to a liquid -measure melting point and compare with data tables
How to produce cyclohexene?
1. -add H2SO4 and H3PO4 to a round bottom flask with cyclohexanol -add anti bumping granules -heat mixture to 83'c -collect the liquid product
2. -transfer to separating funnel and add water -settle in layers and filter off
3. -drain off impure cyclohexene -add anhydrous CaCl2 and allow mixture to dry for 20 mins -distill again