Functional Groups Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings 1.

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  • Functional Groups

    Copyright 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings*

  • Functional groups area characteristic feature of organic molecules that behave in a predictable, similar way. composed of an atom or group of atoms. groups that replace a hydrogen atom in the corresponding alkane.a way to classify families of organic compounds.Functional Groups*

  • Alkenes and AlkynesAlkenes contain a double bond between adjacent carbon atoms.(Double bond: 4 electrons)

    Alkynes contain a triple bond.(Triple bond: 6 electrons)

    Copyright 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings*

  • OH- vs -OHOH- : hydroxide anion found in bases (e.g NaOH)

    -OH: hydroxyl group colvalently bound to carbon atom in an organic compound(e.g. ethanol CH3-CH2OH)*

  • 2. Ethers

    In an ether, an oxygen atom is bonded to two carbon atoms. COC . has a common name that gives the alkyl names of the attached groups followed by ether.

    Copyright 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings*Diethyl ether

  • 3. AldehydesAn aldehyde contains a carbonyl group (C=O), which is a carbon atom with a double bond to an oxygen atom.

    Copyright 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings*acetaldehydeformaldehyde

  • 4. Ketones

    In a ketone, the carbon of the carbonyl group is attached to two other carbon atoms.Copyright 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings*Acetone

  • 5. Carboxylic Acids and EstersCarboxylic acids contain the carboxyl group, which is a carbonyl group attached to a hydroxyl group. O COHCopyright 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings*Acetic acid

  • 5. EstersAn ester contains the carboxyl group between carbon atoms.Copyright 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings*Methyl acetate

  • Organic compounds with Carbon-Nitrogen bonds1. AminesIn amines, the functional group is a nitrogen atom. H HC N H or C N C

    Copyright 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings*Methyl amineDimethyl amine

  • Naming simple aminesSimple 1 amines are named as alkylamineExamples:methylamine CH3NH2ethylamine CH3CH2NH2butylamine CH3CH2CH2CH2NH2

    Symmetrical 2 or 3 amines are named as dialkylamine or trialkyamineExamples:diethylamine (CH3CH2)2NH; trimethylamine (CH3)3N

  • Examples:Amines are much more polar, than hydrocarbons, especially in acidic conditions

  • Heterocyclic aminesSome amines have a nitrogen as part of a ring. These generally have common (non-systematic) names:anilinepyridinepyrimidinepyrrolequinolineindoleimidazolebenzimidazole

  • Properties of aminesAmines are moderately polar and are capable of hydrogen bonding.

    Low MW amines (up to about C5) are soluble in water; higher MW amines will dissolve in acidic solution (as their conjugate acid).

    Many amines have foul odors.

    Amines are weak bases.

  • Example of biologically active amines

  • More biologically active amines

  • More biologically active amines

  • Learning CheckClassify each of the following as: alcohol, ether, aldehyde, ketone, carboxylic acid, ester, amine or amide.1)CH3CH2CH2OH2) CH3OCH2CH33) CH3CH2NH2

    O O 4) CH3COH 5) CH3COCH3

    alcoholetheraminecarboxylic acidester*

  • Organic compounds with Carbon-Oxygen bonds1. AlcoholsAn alcohol contains the hydroxyl (-OH) functional group.(instead of an H in that place)Copyright 2005 by Pearson Education, Inc.Publishing as Benjamin CummingsEthanol

  • AlcoholsAn alcohol contains a hydroxyl group (OH) attached to a carbon chain.

    A phenol contains a hydroxyl group (OH) attached to a benzene ring.

    water alcohol phenolCopyright 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings*

  • Naming AlcoholsThe names of alcoholsin IUPAC replace the -e with -ol.with common names use the name of the alkyl group followed by alcohol.

    FormulaIUPACCommon Name CH4 methaneCH3OH methanol methyl alcoholCH3CH3ethaneCH3CH2OH ethanol ethyl alcohol*

  • Classification of alcohols isdetermined by the number of alkyl groups attached to the carbon bonded to the hydroxyl.primary (1), secondary (2), or tertiary(3).

    Primary (1) Secondary (2) Tertiary (3) 1 group 2 groups 3 groups H CH3 CH3 | | | CH3COH CH3COH CH3COH | | | H H CH3Classification of Alcohols*

  • Properties of Alcohols and Ethers

    Copyright 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings*

  • Boiling Points of AlcoholsAlcoholscontain polar OH groups. form hydrogen bonds with other alcohol molecules.have higher boiling points than alkanes and ethers of similar mass.Copyright 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings*

  • Boiling Points of EthersEthersdo not have a polar group.have an O atom, but there is no H attached. cannot form hydrogen bonds between ether molecules.Copyright 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings*

  • Solubility of Alcohols and Ethers in WaterAlcohols and ethers are more soluble in water than alkanes because the oxygen atom can hydrogen bond with water. *

  • Comparing Solubility and Boiling Points Molar Boiling Soluble Compound Mass Point (C) in Water?Alkane CH3CH2CH3 44-42 No

    Ether CH3OCH3 46-23 Yes

    Alcohol CH3CH2OH 4678 Yes

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