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Download 3. Ethers
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Ethers, Aldehydes and ketones •Ether = R-O-R where R can be: •They are chemically: •They are slightly ________________ due to the lone pairs on the oxygen, but hydrogen bonds between ether molecules ( can cannot) form as there is no polarised O-H bond. •Because of the lack of_____________________________________ they have ______ boiling points: diethyl ether BP = _______°C dimethyl ether BP = _______°C –However the lone pairs on the oxygen allow hydrogen bonding with water and hence they are ___________ soluble than alkanes and approach alcohols of equivalent weights. •Ethers are important as: •Diethyl ether was first used in this regard over 150 years ago. But it had the disadvantage that patients: Ethers – Nomenclature for simple ethers: •Draw Chloromethyl cyclohexyl ether. •If both groups are the same: •Lastly - for more complicated ethers the term______________may be used as a prefix. •Draw Methoxy butane •Draw Diethoxy benzene •Draw Phenoxy phenol •___________________________________ ether is used as a octane enhancer in petrol. •It is also used in a: • Aldehydes and Ketones: Contain a: –The C=O group is the: •The C=O group is called a: •However the differing electronegativity of O compared to C means the bond is ______________________________ Aldehydes and Ketones – Properties Draw the formulas Name Formula MW BP Solubility (°C) in Water Butane 58 0 Insol. Ethyl methyl ether 60 11 Sol. Propanal 58 49 Sol. Acetone 58 56 Sol. 1-Propanol 60 97 Sol. Ketones - ________________________ is used in nail polish remover ___________________________________________ is used in fake tans •Identify the three functional groups in the flavour vanilla: •A carbonyl. • An ether. • A phenol. Aldehydes and Ketones - Nomenclature •Essentially the same naming system is used as __________________________, except the C=O group has priority. –Aldehydes Suffix:________________ Ketones Suffix:______________________ •Hence you must number the chain so that the C=O group is given the lowest number. •Aldehydes: (1) (2) –Ketones (1) (2) •Examples: Draw propanal 3-hexanone 1-bromo-5-hexen-3-one •Cyclic systems also follow the same rules as_____________________. Draw 4-ethyl-3-methoxycyclohexanone •This was used in 1893 by BAYER to change:
