materi kimia alcohol and ether kelas XII

materi sma alkohol dan eter, pengertian, rumus, dan contoh soal

1. Chemistry XII US “Alcohol and Ether” Miss Uly Yayasan Pendidikan Shaffiyatul Amaliyah July 21, 2022

2. Functional Group The functional group of a carbon compound is a group of atoms that determines the characteristics of the compound General Formula Example C n H 2n+2 O CH 3 OH (methanol) C n H 2n+2 O CH 3 -O-CH 3 (dimethyl ether) C n H 2n O ( ethanal ) C n H 2n O (acetone) C n H 2n O 2 (ethanoic acid) C n H 2n O 2 (methyl ethanoic)

3. Functional Group Alcohol and Ether Alcohol and Ether has the same molecular formula ( C n H 2n+2 O) , but has different functional group. They called Functional isomerism. Alcohol binds to the –OH group, while ether binds to the –OR functional group.

4. General Rules Name for Alcohol Find the length of the stem by counting the longest continuous chain of carbon Number the longest chain to the lowest possible number to the carbon bearing the hydroxyl group (-OH). Locate the position of the hydroxyl group by the number of the C to which it is attached Locate and name any other substituents or branch Combine the name and location for other groups, the hydroxyl group location, and the longest chain into the final name. Example of alcohol : IUPAC CH 3 OH = CH 3 CH 2 OH = CH 3 CH 2 CH 2 OH = CH 3 CH(OH)CH 3 = =

5. Draw structural formulas for the following molecules: 3-methyl-2-pentanol 2,4,4,5-tetramethyl-2-heptanol

6. Types of Alcohol Types of alcohol Primary alcohol :  the carbon atom that carries the -OH group is only attached to one alkyl group . S econdary alcohol : the carbon atom with the -OH group attached is joined directly to two alkyl group T ertiary alcohol : the carbon atom holding the -OH group is attached directly to three alkyl groups

7. 1. Primary alcohol 2. Secondary alcohol 3. Tertiary alcohol

8. 1. Hydrogen bonding The oxygen-hydrogen bond is an especially polar bond because oxygen is much more electronegative than hydrogen is. Physical Properties of Alcohol • The O—H bond is therefore a polar bond, and any molecule which contains an O—H bond (like an alcohol) is a polar molecule .

9. 2. Polarity Physical Properties of Alcohol The OH bond is very polar. Polar molecules with a large non-polar hydrocarbon part are less polar than polar molecules with a smaller non-polar hydrocarbon part. For example, octanol , CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 OH is less polar than ethanol, CH 3 CH 2 OH

10. Physical Properties of Alcohol 3. Solubility of Alcohols The general rule in solubility is “like dissolves like .” Since the OH group makes alcohols polar, they will mix with polar solvents like water , as long as the carbon chain is fairly short. The longer the carbon chain, the less soluble the alcohol is. Molecules that can form hydrogen bond s with water, or can accept hydrogen bonds from water, are usually soluble in water. For example, many alcohols are soluble in water because they can form hydrogen bonds with water.

11. Physical Properties of Alcohol 4. Boiling Points of Alcohols Molecules that can form hydrogen bonds with themselves have a higher boiling point than similar molecules that cannot form hydrogen bonds with themselves. For example, alcohols can form hydrogen bonds , but alkanes cannot . Therefore, alcohols have higher boiling points than alkanes. The boiling point of alcohols increases as the molecules become larger . Name Structure Molecular Weight Boiling Point propane CH 3 CH 2 CH 3 44.09 g/ mol -42.1°C dimethyl ether CH 3 OCH 3 46.07 g/ mol -24°C ethanol CH 3 CH 2 OH 46.07 g/ mol 78.3°C

12. Reaction with alcohols The reaction of alcohol with reactive metals , example sodium, will produce hydrogen gas. R eacting with is one of the differentiating reactions with ether . A lcohol can react, while ether can not. R-OH + Na R-Ona +   The reaction of alcohol with HCl using ZnCl 2 catalyst will produce alkyl chloride . R-OH + HCl ZnCl2 R-Cl + H 2 O The reaction of an alcohol with PCl 5 will produce an alkyl chloride. R-OH + PCl 5 R-Cl + POCl 3 + HCl Chemical Properties of Alcohol

13. Primary alcohol oxidation produces aldehydes which will be oxidized again to carboxylate , secondary alcohols produce ketones , tertiary alcohols cannot be oxidized Primary alcohol aldehyde carboxylate Secondary alcohol ketone Primary Secondary

14. Tertiary alcohols, because there is by definition no hydrogen on the alcoholic carbon, cannot be oxidized Tertiary

15. alcohols react with carboxylic acids to form esters + 3H 2 O Glycerol stearic acid triglycerides(lipid) water If alcohol is heated with concentrated sulfuric acid it will dehydrate . At 140 o C ether will be produced, while at 180 o C an alkene will be produced 2CH 3 -CH 2 -OH CH 3 -CH 2 -O-CH 2 -CH 3 + H 2 O CH 3 -CH 2 -OH CH 2 =CH 2 + H 2 O

16. Use of ethanol as a fuel Ethanol burns to produce carbon dioxide and water, as shown in the equation below, and can be used as a fuel in its own right or in mixtures with petrol (gasoline). CH 3 CH 2 OH+3O 2 → 2CO 2 +3H 2 O Methanol as a fuel Methanol also burns to form carbon dioxide and water: 2CH 3 OH+3O 2 → 2CO 2 +4H 2 O Ethanol as a solvent Ethanol is widely used as a solvent. It is relatively safe and can be used to dissolve many organic compounds that are insoluble in water. It is used, for example, in many perfumes and cosmetics . Alcoholic Drinks The word "alcohol" in alcoholic drinks refers to ethanol (CH 3 CH 2 OH ). Uses of Alcohol

17. Functional Group Ether In the ether functional group, two carbon groups are connected to a single oxygen

18. Ether Nomenclature IUPAC Name Step 1 Choose the longest alkyl group as the parent alkane. Give it an alkane name. Step 2 Treat the second alkyl group , along with the oxygen atom , as an alkoxy group attached to the parent alkane. Name it by replacing the - yl ending of the corresponding alkyl group’s name with - oxy . Give it a position number . Step 3 Put the prefix and suffix together: alkoxy group + parent alkane . —CH 3 methyl — OCH 3 methoxy —CH 2 CH 3 ethyl — OCH 2 CH 3 ethoxy Common Name (Trivial) Step 1 for ethers are obtained by first naming the two carbon groups attached to the oxygen (in alphabetical order) and then adding the word “ether” to the end. Step 2 If the two groups are the same, the prefix “di-” is used, although sometimes this is simply dropped (“ethyl ether ”).

19. Give the IUPAC name and the common name of the following ether. CH 3 - CH 2 - O - CH 2 - CH 2 - CH 3 IUPAC Name Step 1 The longest alkyl group is based on propane . Step 2 The alkoxy group is based on ethane (the ethyl group). It is located at the first carbon atom of the propane part. Therefore, the prefix is ethoxy - . Step 3 The full name is ethoxypropane . Common Name Step 1 The two alkyl groups are ethyl and propyl . Step 2 The full name is ethyl propyl ether . Naming an Ether

20. Example of ether : IUPAC Trivial CH 3 -O- CH 3 = Metoxy methane Dimethyl ether CH 3 -O-CH 2 CH 3 = Metoxy ethane Etyhl methyl ether CH 3 CH 2 -O-CH 2 CH 3 = Etoxy ethane Diethyl ether = 2-etoxy propane Ethyl Isoprophyl ether = 2-methyl 2-metoxy propane Methyl tertiary- buthyl ether

21. Physical Properties of Ether Hydrogen Bond Alcohols hydrogen-bond to each other because they have highly polar O—H bonds . Ethers do not have O—H bonds, and so do not hydrogen-bond to each other.

22. Physical Properties of Ether Polarity Ethers are slightly polar , and can hydrogen-bond to water, although very weakly , through the oxygen atom : The solubility of an ether decreases as the size of the alkyl groups increases Boiling Points Ethers therefore have low boiling points , and a higher solubility in water than hydrocarbons. Ethers are inert to most reagents, so they make good solvent for chemical reactions . Some ethers make good anesthetics . boiling point : alcohols > ethers > alkanes water solubility : alcohols > ethers > alkanes

23. Chemical Properties of Ethers Cleavage of C-O bond Ethers are generally very unreactive in nature . When an excess of  hydrogen  halide is added to the ether, cleavage of C-O bond takes place leading to the formation of alkyl halides . 2. Halogenation of Ethers Aromatic ethers undergo halogenation, for example, bromination , upon the addition halogen in the presence or absence of a catalyst.

24. Dimethyl ether is used as refrigerant and as solvent at low temperature Diethyl ether is used as an anesthetics in surgery Diethyl ether is also used as a solvent for oils, gums, resins Phenyl ether is used as a heat transfer medium because of its high boiling point. Uses of Ether

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