Generic formula. Suffix or prefix. Family Name. alkene -ene C n H 2n. alkyne -yne C n H 2n-2 -OH R-OH. propan-2-ol. F- Cl- Br- I- 2-bromobutane

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1 Chemistry 30 Notes Hydrocarbon Derivatives these notes cover textbook pages A functional group is a special arrangement of atoms that is mainly responsible for the chemical and physical behaviour of the molecule. The table below shows the common functional groups used in this course: Family Name Suffix or prefix Functional group Example Generic formula alkene -ene C n H 2n alkyne -yne C n H 2n-2 alcohol -ol - R- called a hydroxyl group propan-2-ol alkyl halide fluoro chloro bromo iodo F- Cl- Br- I- 2-bromobutane R-X where X is a halogen. O carboxylic acid -oic acid R C R-CO propanoic acid ester -oate R-COOC-R methylpropanoate In the table above R and R denote carbon groups. Chemistry 30 Lesson 4-04 Page 1

2 Alcohols Contain the hydroxyl functional group: - Since the hydroxyl group is very polar, small alcohol molecules like methanol and ethanol are completely miscible with water. As the carbon parent increases in length the overall polarity decreases and the alcohols become less water soluble. The boiling points of alcohols are much higher than their alkane counterparts, since the hydroxyl group allows hydrogen bonding to occur between alcohol molecules. Nomenclature: 1. parent chain is the longest continuous chain of carbons that contains the hydroxyl group. 2. parent chain name ends in -ol (drop the e ending) 3. the carbon number for the hydroxyl group must also be listed (method the same as for multiple bonds). The hydroxyl group must have the lowest carbon number even before multiple bonds. For 2 or more groups, don t drop the -e suffix, just add the appropriate amount prefix (di, tri etc.) and -ol Examples: If there is a multiple bond present, the parent chain must contain both the hydroxyl group(s) and the multiple bond. When this occurs, put the carbon number(s) for the hydroxyl group(s) just before the -ol suffix. Examples: benzene with only one group is given the special name phenol: Chemistry 30 Lesson 4-04 Page 2

3 groups can also be named as side groups with the name hydroxy. Examples: Cl Some large biologically important molecules containing alcohol (hydroxyl) groups: Cholesterol: Estradiol (a female hormone): Testosterone (a male hormone): Chemistry 30 Lesson 4-04 Page 3

4 Alkyl Halides Hydrocarbons that contain at least one halogen (group 17) atom as the functional group. alkyl halides are named using the same rules as for branched alkanes, using the following prefixes to indicate the halogen atoms attached to the parent chain: o fluoro for fluorine o chloro for chlorine o bromo for bromine o iodo for iodine Note: the element symbol must be used in line diagrams. Example 1: Example 2: Complete the following practice problems in your textbook: p. 567 #28-30; p.569 #31 & 32 Chemistry 30 Lesson 4-04 Page 4

5 Chemistry 30 Organic Halides Hydantoin parent chain of the active ingredients: O HN NH 4 O Chemistry 30 Lesson 4-04 Page 5

6 Chemistry 30 Formative problems Organic Halides Name or draw structures for the following compounds. 1. 2,3-dibromo-1,1-dichloropropane (soil fumigant) 6. 1,4-dichlorobenzene (component of moth balls) 2. (an antiseptic) H 7. 1,2,3,4,5,6-hexachlorocyclohexane (agricultural insecticide) I C I I 3. 1,2-dichloropropane (used as a dry cleaning fluid) 8. 1-bromo-3-iodocyclobutene 4. (a dry cleaning solvent) F Cl 9. Br F Cl Br 5. 2-bromo-2-chloro-1,1,1-trifluoroethane (used as an inhalation anaesthetic for surgery) Chemistry 30 Lesson 4-04 Page 6

7 10. Consider the following information. Chlorine derivative of methane Boiling point ( C) chloromethane -24 dichloromethane 40 trichloromethane 61 tetrachloromethane 77 Account for the general trend in boiling points for the above alkyl halide derivatives of methane. 11. Which of the following compounds, bromomethane, chloromethane, iodomethane and fluoromethane, would be expected to be most soluble in water? Which would be least soluble? Show support for your conclusion. Chemistry 30 Lesson 4-04 Page 7

8 Chemistry 30 Formative Problem Set Alcohols Name the following compounds or draw their structures. 1. methanol (gas line and windshield washer antifreeze) 7. 2,2,2-trichloroethane-1,1-diol (a sedative) 8. pentachlorophenol (wood preservative) 2. propan-2-ol (rubbing alcohol) 3. (hydraulic brake fluid) hydroxy-2-propylbenzene 4. Cl Cl 5. ethane-1,2-diol (automotive coolant) 6. (used for paint, cosmetics and explosives) Chemistry 30 Lesson 4-04 Page 8

9 Use the following information to answer the next three questions. Alcohol Melting point ºC Boiling point ºC Solubility in H 2 O (g/100 ml) methanol Completely ethanol Completely propan-1ol Completely pentan-1-ol hexan-1-ol heptan-1-ol octan-1-ol Account for the general trend in melting and boiling points of alcohols from methanol to hexan-1-ol. 2. Account for the general trend in solubility of alcohols from methanol to hexan-1-ol. 3. Estimate the melting point, boiling point and solubility of heptan-1-ol. m.p. ºC b.p. ºC solubility g/100 ml Chemistry 30 Lesson 4-04 Page 9

10 Reactions Reacting an alcohol with acid removes the group, replacing it with a double bond. Isomers are possible. Water is a by-product. Example: acid + H+ H Reacting alkenes and alkynes with water in an addition reaction can make alcohols. Isomers are possible. Example: HO-H H- Chemistry 30 Lesson 4-04 Page 10