Fragrances and Skincare
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Define essential oils
concentrated extracts of the volatile non water soluble aroma compounds from plants
2 stages of extraction of essential oils
Steam distillation Solvent extraction
Define steam distillation
Steam travels through mashed plant and is condensed. Separated using a separating funnel
Define solvent extraction
Impure essential oils shaken and stopped with suitable solvent (esters)
Define terpenes
unsaturated compounds based on an isoprene unit
Isoprene unit
C5 H8
Isoprene unit systematic name and molecule
2-methylbuta-1,3-diene CH2=C - CH = CH2 CH3
3 terpene uses
Small ones in fragrances Retinol in antioxidants Natural rubber is a polyterpene
What happens when terpenes oxidise
Forms new compounds some of which are harmful
What does UV light do
Give sunburn Ages skin Causes cancer
Define UV light affect
UV light has enough energy to break chemical bonds and cause reactions in the skin
Heterolytic fission
Polar bonds
Homolytic fission
Non polar bonds
Initiation phase
Stable compound/element becomes a free radical as a result of UV
Propagation
Free radical shares electrons making more free radicals
Termination
2 free radicals join making a stable compound
sunblock
Sunblock contains compounds such as titanium dioxide that reflect all the UV so that it does not reach the skin at all.
sunscreen
Sunscreen contains organic compounds that absorb the UV so that less reaches the skin.
functional groups that absorb UV (3)
C=C C=O CH3O
why do you need to reapply sunscreen
The compounds degrade when they absorb UV light so stabilisers that absorb over a narrow wavelength range are added to prevent the cream becoming ineffective
What do natural free radicals do
reacts with free radicals to make stable compounds
aldehyde strongest IMF
PD-PD
How are free radicals formed
UV light breaks covalent bonds
Name 2 processes for extracting essential oils
Steam distillation and Solvent extraction