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Naming and physical properties of alcohols .

Naming and physical properties of alcohols . Naming alcohols. Alcohols are an homologous series with the general formula; C n H 2n+1 OH. A suffix, -ol, is used to indicate the presence of an hydroxyl group. Eg; CH 3 CH(OH)CH 3 propan- 2-ol. Classifying alcohols.

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Naming and physical properties of alcohols .

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  1. Naming and physical properties of alcohols.

  2. Naming alcohols Alcohols are an homologous series with the general formula; CnH2n+1OH A suffix, -ol, is used to indicate the presence of an hydroxyl group. Eg; CH3CH(OH)CH3 propan- 2-ol

  3. Classifying alcohols Look at the number of alkyl groups attatched to the carbon which bears the hydroxyl group.

  4. Primary alcohols Have ONE alkyl group on the carbon that bears the hydroxyl group. R Eg; CH3CH2OH

  5. Secondary alcohols R Have TWO alkyl groups on the carbon with the hydroxyl group. (CH3)2CHOH R

  6. Tertiary alcohols R R (CH3)3COH Have THREE alkyl groups on the carbon with the hydroxyl group. R

  7. CH3OH CH3CH2CH(OH)CH3 (CH3)2(C2H5)COH CH3C(CH3)2CH2OH Methanol (1o) Butan 2 ol (2O) 2 methyl butan 2 ol (3O) 2,2 dimethyl propan 1 ol (1o) Name the following alcohols, stating whether they are primary, secondary or tertiary;

  8. Heptan 1 ol 2,2 dimethyl hexan 3 ol 4 methyl octan 4 ol CH3(CH2)5CH2OH (1o) (CH3)3 CH(OH)(CH2)2CH3 (2O) CH3(CH2)2CH(OH)(CH2)2 CH3 (3O) Draw out the structures of the following alcohols, stating whether they are primary, secondary or tertiary;

  9. Boiling points Plot BP against Mr and comment on the trends.

  10. BPs of alcohols compared with those of alkanes. Alcohols have much higher BPs than those of the corresponding alkane. But in alcohols there are much stronger hydrogen bonds. The intermolecular bonds in alkanes are only weak van der Waals.

  11. Solubility of alcohols Alcohols are miscible in water.

  12. The hydroxyl group can hydrogen bond with water. δ+ δ+ δ- δ+ δ- δ+ δ- δ+

  13. Solubility decreases with chain length. The hydroxyl group can hydrogen bond… But hydrocarbon chains can only make van der Waals interactions.

  14. Naming carbonyl compounds. Carbonyl compounds are a homologous series with the functional group C=O and a general formula CnH2nO • There are two types; • Aldehydes • Ketones.

  15. Aldehydes vs Ketones Aldehydes have the carbonyl group, C=O, at one end. But in ketones it is in the interior of the molecule.

  16. Naming Carbonyl compounds Aldehydes and ketones are named using the usual IUPAC rules with the addition of an appropriate suffix to the number of carbons. For aldehydes -al For ketones -one Eg; CH3(CH2)3CHO is pentanal Eg; CH3(CH2)3COCH3 is hexanone

  17. Eg; 3C molecule with the carbonyl group at one end. So this is propanal. 3C molecule with the carbonyl group in the interior. So this is propanone.

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