R C OH - Mr. de Bruin's...

Chemistry 30 Lesson 4-04 © 2012 T. de Bruin

Chemistry 30 Notes – Hydrocarbon DerivativesØ these notes cover textbook pages 565-568

· A functional group is a special arrangement of atoms that is mainly responsible for the chemicaland physical behaviour of the molecule.

· The table below shows the common functional groups used in this course:

Family Name Suffix orprefix Functional group Example Generic

formula

alkene -ene CnH2n

alkyne -yne CnH2n-2

alcohol -ol-OH

called a hydroxyl group

propan-2-ol

R-OH

alkyl halide

fluorochlorobromoiodo

F-Cl-Br-I- 2-bromobutane

R-X

where X is ahalogen.

carboxylicacid -oic acid R C

O

OH propanoic acid

R-COOH

ester -oate

methylpropanoate

R-COOC-R’

· In the table above R and R’ denote carbon groups.


Alcohols

· Contain the hydroxyl functional group: -OH· 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 polaritydecreases and the alcohols become less water soluble.

· The boiling points of alcohols are much higher than their alkane counterparts, since the hydroxylgroup 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 beforemultiple bonds. For 2 or more OH groups, don’t drop the “-e” suffix, just add the appropriateamount prefix (di, tri etc.) and “-ol”Examples:

OH

OH

OH

· If there is a multiple bond present, the parent chain must contain both the hydroxyl group(s) andthe multiple bond. When this occurs, put the carbon number(s) for the hydroxyl group(s) justbefore the “-ol” suffix.Examples:

OH OH

OH

· benzene with only one OH group is given the special name phenol:


· OH groups can also be named as side groups with the name hydroxy.Examples:

OH

Cl

OH

OH

Some large biologically important molecules containing alcohol (hydroxyl) groups:

Cholesterol:

Estradiol (a female hormone): Testosterone (a male hormone):


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 fluorineo chloro for chlorineo bromo for bromineo 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:Ø p. 567 #28-30; p.569 #31 & 32


Chemistry 30 – Organic Halides

Hydantoin parent chain of the active ingredients:

NHHN

O

O

12

3

45


Chemistry 30 Formative problems – Organic Halides

Name or draw structures for the following compounds.

1. 2,3-dibromo-1,1-dichloropropane (soil fumigant)

2. (an antiseptic)

I C I

H

I

3. 1,2-dichloropropane (used as a dry cleaning fluid)

4. (a dry cleaning solvent)

F

F

Cl

Cl

5. 2-bromo-2-chloro-1,1,1-trifluoroethane (used as an inhalation anaesthetic for surgery)

6. 1,4-dichlorobenzene (component of moth balls)

7. 1,2,3,4,5,6-hexachlorocyclohexane (agricultural insecticide)

8. 1-bromo-3-iodocyclobutene

9.Br

Br


10. Consider the following information.

Chlorine derivative of methane Boiling point (˚C)chloromethane -24dichloromethane 40trichloromethane 61tetrachloromethane 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 beexpected to be most soluble in water? Which would be least soluble? Show support for your conclusion.


Chemistry 30 Formative Problem Set – Alcohols

Name the following compounds or draw their structures.

1. methanol(gas line and windshield washer antifreeze)

2. propan-2-ol (rubbing alcohol)

3. (hydraulic brake fluid)

OH

4.

OH

Cl

Cl

5. ethane-1,2-diol (automotive coolant)

6. (used for paint, cosmetics and explosives)

OH

OH

OH

7. 2,2,2-trichloroethane-1,1-diol (a sedative)

8. pentachlorophenol (wood preservative)

9.OH

10. 1-hydroxy-2-propylbenzene


Use the following information to answer the next three questions.

Alcohol Melting point ºC Boiling point ºC Solubility in H2O(g/100 ml)

methanol -97 64 Completelyethanol -115 78 Completelypropan-1ol -126 97 Completelypentan-1-ol -90 118 7.9hexan-1-ol -52 156 2.3heptan-1-oloctan-1-ol -15 195 0.05

1. 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. ____ ºCb.p. ____ºCsolubility ______ g/100 mL


Reactions· Reacting an alcohol with acid removes the OH group, replacing it with a double bond. Isomers are

possible. Water is a by-product.Example:

OH

acid

H++

HOH

· Reacting alkenes and alkynes with water in an addition reaction can make alcohols. Isomers are possible.Example:

OH

OH

HO-H

H-OH

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