Zusammenfassung der Ressource
What's in a Medicine?
- Functional Groups
- Carboxylic acid
- Acid anhydride
- Can be attached to a
benzene ring
- Has a high enough H+ conc to react
with carbonates to produce CO2
- Ester
- Alcohol + Carboxylic acid
- Ethanol + ethanoic acid = ethyl ethanoate + wayer
- Catalyst: conc sulfuric
or conc hydrochloric
- Heated under reflux
- Reversible - forms equilibrium
- Alcohol - yl
- Carboxylic acid - oate
- Alcohol +Acid anhydride
- More reactive than carboxylic acids
- React completely - higher yield of ester
- Produce carboxylic acid + ester
- Ethanoic anhydride
- Ether
- Same molecular formular as
alcohols (structural isomer)
- General formula: R-O-R
- Longer chain is chosen as
parent alkane (second name)
- e.g. methoxyethane
- Carbonyl group C=O
- Aldehyde
- Carbonyl group on
the end of the chain
- Suffix -al
- Ketone
- Carbonyl group within an alkane chain
- Suffix -one
- Alcohol
- Primary
- -OH bonded to a carbon bonded to ONE other carbon atom
- Butan-1-ol
- RCH2OH
- Secondary
- -OH bonded to a carbon bonded to TWO other carbon atoms
- Butan-2-ol
- RCH(OH)R
- Tertiary
- -OH bonded to a carbon bonded to THREE other carbon atoms
- 2-methylpropan-2-ol
- R2C(OH)R
- Formation of esters
- Oxidation
- Conditions
- Heating under reflux
- Under the presence
of an oxidising agent
- Acidified potassium
dichromate (VI) solution
- Products
- Primary alcohol
- Alcohol in excess - distilation
- Aldehyde
- Oxidising agent in excess - reflux
- Carboxylic acid
- Secondary alcohol
- Ketones
- Final colour
- Primary
- Secondary
- Tertirary
- Dehydration
- Forms alkenes
- Heated Al2O3 at 300ºC or
refluxing with conc H2SO4
- Elimination reaction
- Molecule of water is removed
- Substitution
- Nucleophilic substitution
with halide ions
- Presence of a strong acid
- Produces haloalkanes
- Hydrogen bonds raise the boiling point
and make them soluble, but solubility
decreases as chain length increases
- Don't react with strong
bases or carbonates
- Phenol
- Reactivity
- Ethanol < water < phenol < carboxylic acids
- Ethanol and water are only slightly acidic
- Phenols and carboxylic acids can react with strong bases to form salts
- e.g. NaOH
- Remain in solution after the reaction
- Phenols won't make carbonates fizz
- Test with neutral iron (III)
chloride to give a purple colour
- -C=C--OH group forms a complex with Fe3+
- Reacts with acid anhydride
- Alkaline conditions
- Phenol + ethanoic anhydride -> phenyl ethanoate + ethanoic acid
- DOES NOT react with carboxylic
acids to produce an ester
- Making a solid organic product
- Purification
- Reduced pressure filtration
- 1. Connect a conical flask to a vacuum pump via the side arm
- 2. Dampen a piece of filter paper and
place it flat in the Buchner funnel
- 3. Switch the vacuum pump on and then
carefully pour in the mixture to be filtered
- 4. Disconnect the flask from the vacuum pump
before turning the pump off to avoid 'suck back'
- Used to separate a solid
from a filtrate rapidly
- Recrystalisation
- Used to purify solid crude organic productss with small amounts of impurities
- 1. Chose the correct solvent
- Desired product must be very soluble in solvent when
it is hot, but be insoluble when solvent in cold
- 2. Dissolve the mixture in the
minimum quantity of hot solvent
- The smaller the amount of solvent used,
the better the yeild of purified product
- 3. Filter to remove any insoluble
impurities and retain the filtrate
- It is best to preheat the filter funnel and conical
flask to prevent any solid crystallising out
- 4. Leave the filtrate to cool
until crystals form
- 5. Collect the crystals by vaccum filtration
- Remove soluble impurities
- 6. Dry the crystals in an oven or in the
open, covered by an inverted filter funnel
- Melting point determination
- Used as evidence of a solid
products purity and identity
- 1. Seal the end of a glass melting point (capillary)
tube by heating it to melting in a bunsen flame
- 2. Put a small amount of the solid into the
open end of the tube, and tap the tube so that
the solid falls to the bottom of the sealed end
- 3. Fix the tube in the melting point apparatus and heat the
surrounding liquid gently, stirring to ensure even heating
throughout. The temperature should rise very slowly
- 4. Note the temperature that the solid starts and finishes
melting. The difference between the highest and lowest
temperatures recorded is known as the melting range
- 5. Compare experimental value to published value.
The wider the range, the more impure the substance
- A pure compound should melt within
0.5ºC of its true published melting point
- Thin layer chromatography
- Used to separate small quantities of organic products
- To check purity or to purify
- To follow the progress of a
reaction over time
- Requires a suitable solvent as different
organic compounds have a different
affinity with each solvent
- Chromatography paper is paper chromatography
- Using a silica plate is thin layer chromatography
- 1. Spot test mixture and reference
samples on a pencil line 1cm from
the base of the plate or paper
- 2. Suspend the plate in a beaker containing the solvent,
ensuring the solvent does not touch the samples. Cover
beaker with a watch glass to prevent evaporation
- 3. Remove plate when the solvent front is near the top.
Mark how far the solvent has reached and allow to dry
- 4. Locate the spots of samples using iodine, ninhydrin, or under an ultraviolet lamp
- 5. Match heights reached (Rf values) of sample with those of known compounds
- Rf = distance travelled by spot divided
by distance moved by solvent
- Making a liquid organic product
- Heating under reflux
- Used for volatile and
flammable liquids
- 1. Put reactants into a pear-shaped
flask and add anti-bumping granules
- These burst the bubbles in the
boiling mixture and reduce the
chance of boiling over
- 2. Do not stopper the flask
- This would cause the
pressure to build up and
glassware could crack
- 3. Atttach a condenser vertically to the flask so that water flows into the
condenser at the bottom and out the condenser at the top
- This ensures the condenser is
always full of cold water
- 4. Heat so that the reaction mixture boils gently,
using a Bunsen flame or heating mantle. The liquid
should drip back into the reaction flask steadily
- Vapours should reach no more than
half way up the condenser before
being condensed back into liquid
- Purifying
- When the organic produce is mixed with another immiscible
liquid, the layers can be separated using a separating funnel.
- 1. Allow the layers to settle, leaving the denser layer on the bottom
- 2. Run off and dispose of the aqueous layer
- 3. Run the organic layer into a clean conical flask
- If acidic purities are present, add soduim hydrogen
carbonate solution and shake well to remove them.
- If the crude product is alkaline and needs neutralising,
add dilute acid until the mixture is neutral
- Dry the crude product by adding anhydrous
sodium sulfate and swirling the mixture
- Other anhydrous salts, such as
calcium chloride, can also be used
- The pure product can then
be separated by distilation
- Preparing liquid product
- Green chemistry
- Developing chemical products and
processes that are as sustainable and
as environmentally friendly as possible
- Better atom economy
- More of the feedstock is
incorporated into the product and
fewer waste products are produced
- Prevention of waste products
- This is better than treating and disposing waste
- Less hazardous chemical synthesis
- Using less hazardous chemicals in the reaction
- Safer chemical products
- Use safer solvents
- Minimise the use of organic solvents
- Lower energy usage
- Lower temperature and pressure processes mean it is more sustainable
- Use renewable feedstocks instead of
depleting natural resources
- Reduce reagents used and the number of
steps, as these can generate watse
- Use catalysts and more selective catalysts
- These reduce energy usage and waste products
- Design chemical products for degredation
- When released into the environment, they
should break down into harmless substances
instead of degrading the environment
- Use real time process monitoring to
reduce waste products
- Use safer chemical processes
- Reduce the potential of gas release, fires, and explosions
- Analytical techniques
- Mass spectrometry
- M+ Peak is the mass of
the heaviest element.
- This is the molecular ion and helps
to determine the molecular mass
of the compound being analysed
- Used to find atomic mass
and relative abundances
of isotopes in an element.
- Other peaks are due to
positive ions from fragments
- The fragmentation pattern
- M+1 peak caused by 13C isotope
- Infrared
- Specific frequencies make
specific bonds in organic
molecules vibrate more
- Energy of molecules is quantised - they must
take a small number of definite energy values
- Determines functional groups but not the number of
them or where they are in a molecule
- Exposes substances to 10[14]-10[13] Hz
frequency, which makes vibrational energy
changes occur in the molecules
- Frequency and wavelength are related
- Speed of light c = wavelength λ x frequency v
- Speed of light is constant
- frequency = 1/ λ
- Wavenumber of radiation measured in cm
- SImple molecules have less complex spectra
- Weaker bonds require
less energy to vibrate
- Below 1500 is the fingerprint region, which is not
used to determine functional groups