Chapter 8Introduction to Alkyl Halides, Alcohols, Ethers,

Thiols, and Sulfides

Alkyl Halides

• Organic compounds containing at least one carbon-halogen bond (C-X)– X = F, Cl, Br, or I– X replaces an H

• Properties and some uses– Fire-resistant solvents– Refrigerants– Pharmaceuticals and precursors

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Nomenclature

• Two systems:1) Common2) IUPAC

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Common Naming Rules

• Generally used only for simple compounds1) Identify the alkyl group and name it as a substituent

• change the ending from “-ane” to “-yl,” if applicable

2) Identify the halide and name it3) Leave a space between the two names from steps 1

and 2.

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Alkyl Halides

• Other common names to learn:

58.1 Nomenclature

IUPAC Naming Rules

1) Identify the longest carbon chain and name it as the parent• Contains double or triple bond if present

2) Number the parent chain beginning at the end nearest any substituent (alkyl or halogen)

3) If more than one of the same kind of substituent is present, number each and use the Greek prefixes to indicate how many

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4) If different substituents are equidistant from the ends of the parent chain, begin at the end nearer the substituent whose name comes first in the alphabet.

Problems

• Name the following alkyl halides using common nomenclature

• Name the following alkyl halides using IUPAC nomenclature:

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Problems

1) CHCl3 is commonly known as chloroform. What is its IUPAC name?

2) Based on what you know from question #1, what are the common and IUPAC names for CHBr3, CHI3, and CHF3?

General Classifications

• Alkyl halides can be classifed as methyl, primary, secondary, or tertiary based on the number of organic groups bonded to the halogen bearing carbon

108.1 Nomenclature

Problem

• Draw 4-chloro-3,4-dimethyl-1-octene. Classify this alkyl halide based on degree of substitution.

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Alcohols

• Contain an OH group connected to a saturated (sp3-hybridized) Carbon– Important solvents and synthesis

intermediates– Methanol (Methyl Alcohol)

• Common solvent• Fuel additive

– Ethanol (Ethyl Alcohol)• Solvent• Fuel• Beverage

– Isopropanol (Isopropyl Alcohol)• Rubbing alcohol• Solvent• Disinfectant

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Phenols

• Compounds containing an OH group bonded to a carbon in a benzene ring

• Building polycarbonates, epoxies, Bakelite, nylon, detergents and a large collection of drugs, herbicides and pharmaceuticals.

13BPA Eugenol

Glycols

• Compounds containing two or more hyrodoxyl (-OH) groups– Diol: contains two –OH groups

• Geminal: OH’s are on the same carbon• Vicinal: OH’s are on adjacent carbons• General: OH’s located in non-geminal/non-

vicinal positions

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Ethylene Glycol Resorcinol

General Classification

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Nomenclature

• Two types:– Common– IUPAC

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Common Naming Rules

• Used for simple and common alcohols1) Identify the alkyl group to which the hydroxyl group

is attached and name this as a substituent• Ethane Ethyl

2) Add the word “Alcohol”

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IUPAC Naming Rules

1) Select the longest carbon chain containing the hydroxyl group, and derive the parent name by replacing the “-e” ending of the corresponding alkane with “-ol “

2) Number the chain from the end nearest to the hydroxyl group

3) Number substituents according to position on chain and then list them in alphabetical order as usual

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2-chloro-5-methyl-1-hexanol

Or 2-chloro-5-methylhexan-1-ol

4) If there are more than one hydroxyl groups, use Greek prefixes to indicate how many

• Do not drop the final e of the alkane

5) If stereochemistry is known, indicate it

Naming Phenols

1) Use “phenol” (the French name for benzene) as the parent hydrocarbon name, not benzene

2) Name substituents on aromatic ring by their position from OH

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Problems

1) Name the following molecules:

2) Classify the first two molecules above based on level of substitution (1°, 2°, 3° alcohol)

3) Draw the following molecules– 1,2,3-propanetriol– 2-ethyl-3-methylphenol

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Thiols• Compounds that contain a carbon bonded to a

sulfhydryl group (-SH)• Sulfur analogs of alcohols

• R-SH vs. R-OH

• Stinky molecules • Also known as “Mercaptans”

• The –SH group is also called a “mercapto” group

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Ethanethiol vs. Ethanol

Nomenclature of Thiols• Common:

– Named in the same fashion as alcohols• The word mercaptan replaces alcohol in the

name of the equivalent alcohol compound– Example: CH3SH would be methyl

mercaptan, just as CH3OH is called methyl alcohol.

Methyl mercaptan Methyl Alcohol

• IUPAC1) Identify the longest carbon chain containing the

sulfhydryl group. Name this chain and add “thiol” to the end (no space).

2) Number the chain so that the carbon connected to the –SH group has the lowest number possible

3) Name and number all of the substituents and place them, in alphabetical order, in front of the parent chain name.

2-hexanethiol 2-ethyl-1-hexanethiol

Problems

• Name the following compounds:

• Draw:– 3,3-dimethyl-1-butanethiol– 2-ethylcyclohexanethiol– Trans-3-heptene-2-thiol

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Hmmmmm….

Principle Group and Principle Chain

• Principle Group: the functional group upon which the name of a molecule is based• Cited as the suffix in the name

• Example: Pentanol• Have priorities in a molecule• All other substituents are cited as prefixes (except

multiple bonds)• Carboxylic acid > anhydride > ester > acid halide >

amide > nitrile > aldehyde > ketone > alcohol/phenol > thiol > amine

278.1 Nomenclature

1) Identify the principle group (e.g., -OH > -SH)2) Identify the principle chain

• The carbon chain on which is the name is based• Priorities for picking the principle chain:

a) The carbon chain with the greatest number of principle groups

b) The carbon chain with the greatest number of double and triple bonds

c) Of greatest lengthd) With the greatest number of other substituents

Principle Group and Principle Chain

3) Number the carbons of the principle chain giving the lowest numbers:

a) For the principle groupsb) For multiple bonds (C=C > CC)c) For other substituentsd) For the substituent cited first in the name

298.1 Nomenclature

Principle Group and Principle Chain

4) Begin construction of the name with the name of the hydrocarbon corresponding to the principle chain

a) Cite principle group by suffix and number• Will be last number in molecular name

b) If there is no principle group, name the compound as a substituted hydrocarbon

c) Cite the names and numbers of other substituents in alphabetical order

308.1 Nomenclature

Problems

• Name the following compounds: