Chemistry- JIB Organic Chemistry

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<ul><li> Unit 6: Organic Chemistry <ul><li>Cover introduction, alkanes, &amp; cycloalkanes </li></ul><ul><li>There will be two quizzes </li></ul></li> <li> Standards Covered Today: <ul><li>1. Describe the features of a homologous series. </li></ul><ul><li>2. State names and draw structural formulas for organic compounds using the IUPAC Naming System. </li></ul><ul><li>3. Draw structural formulas and state names of non-cyclic (straight chain) alkanes up to C 10 , including isomers. </li></ul><ul><li>4. Draw structural formulas and state names of cyclic structures up to C 10 </li></ul></li> <li> Introduction <ul><li>In all organic compounds, </li></ul><ul><li><ul><li>all carbon atoms must make four bonds, </li></ul></li></ul><ul><li><ul><li>all oxygen atoms must make two bonds, </li></ul></li></ul><ul><li><ul><li>all nitrogen atoms must make three bonds, </li></ul></li></ul><ul><li><ul><li>all hydrogen atoms must make one bond, </li></ul></li></ul><ul><li><ul><li>and all halogens must make one bond. </li></ul></li></ul></li> <li> Names of Structures <ul><li>Lewis Structures </li></ul><ul><li>Structural Formulas </li></ul><ul><li>Condensed Formulas &amp; Structures </li></ul><ul><li>Line Structures </li></ul>C 6 H 14 or CH 3 (CH 2 ) 4 CH 3 </li> <li> Notes on Structures <ul><li>Structural Formula: shows all bonds including hydrogen </li></ul><ul><li>Condensed Formula: These are generally written without lines indicating bonds, or showing lone pairs, and parentheses are used for identical groups. </li></ul><ul><li>Line Formula: Bonds are represented by lines, carbon atoms are assumed to be present at the start and finish of a line. </li></ul><ul><li><ul><li>Nitrogen, oxygen and halogens are labeled, but hydrogens are only shown when bonded to a drawn atom. </li></ul></li></ul><ul><li><ul><li>Each atom is assumed to have sufficient hydrogen atoms around it to make it neutral. </li></ul></li></ul></li> <li> Isomers <ul><li>Draw a structural formula for C 4 H 10 </li></ul><ul><li>An isomer is a compound that has the same molecular formula as another. </li></ul><ul><li>Structural Isomers : these are isomers that differ in their bonding sequence. They have different bond connectivity. </li></ul></li> <li> Introduction to Nomenclature of Organic Molecules <ul><li>Four Categories: </li></ul><ul><li><ul><li>Alkanes </li></ul></li></ul><ul><li><ul><li>Alkenes </li></ul></li></ul><ul><li><ul><li>Alkynes </li></ul></li></ul><ul><li><ul><li>Cyclic Structures </li></ul></li></ul></li> <li> Alkanes <ul><li>Alkanes are the simplest organic molecules, they only contain C and hydrogen, and only contain single bonds. </li></ul><ul><li><ul><li>Considered to be hydrocarbons </li></ul></li></ul><ul><li>Compounds that have the maximum number of bonded hydrogens, are said to be saturated. </li></ul><ul><li><ul><li>Therefore, alkanes are the most saturated compounds </li></ul></li></ul><ul><li>General Formula: C n H 2n + 2 </li></ul></li> <li> Nomenclature for compounds <ul><li>The root name of the compound is based upon the number of carbon atoms in the longest continuous chain . </li></ul>Number of C atoms Root 1 Meth- 2 Eth- 3 Prop- 4 But- 5 Pent- 6 Hex- 7 Hept- 8 Oct- 9 Non- 10 Dec- </li> <li> <ul><li>Any series that differs only by an increasing number of CH 2 - groups is known as a homologous series . The individual members are said to be homologs of each other. </li></ul><ul><li><ul><li>The series must contain the same functional group. </li></ul></li></ul></li> <li> IUPAC Naming System: Alkanes <ul><li>1) Find the longest continuous chain of carbon atoms. This is the base name of the compound. </li></ul><ul><li>2) Number the longest chain beginning with the end nearest a substituent. </li></ul><ul><li>3) Name the substituent groups attached to the longest chain as alkyl groups. Also state the location of each alkyl group according to its numbered carbon on the main chain. </li></ul><ul><li>4) When two or more substituents are present, list them in alphabetical order. If two or more of the same alkyl groups are present, use the prefixes di-, tri- etc. to avoid repetition. </li></ul></li> <li> Alkane Nomenclature Examples <ul><li>1) </li></ul>3-methyl hexane <ul><li>If there are two chains of equal length, choose the chain that has the highest number of substituents. </li></ul></li> <li> <ul><li>Numbering starts at the end nearest a substituent so that the alkyl substituents have as low numbers as possible. </li></ul>Alkyl groups are named by replacing the ane suffix of the alkane name with yl. E.g. CH 3 CH 3 Ethane CH 3 CH 2 - Ethyl group CH 3 CH 2 CH 3 PropaneCH 3 CH 2 CH 2 - Propyl group </li> <li> <ul><li>Prefixes are used when there are more than one type of alkyl substituent. </li></ul><ul><li><ul><li>Di = 2 </li></ul></li></ul><ul><li><ul><li>Tri = 3 </li></ul></li></ul><ul><li><ul><li>Tetra = 4 </li></ul></li></ul><ul><li><ul><li>Penta = 5 </li></ul></li></ul><ul><li>The prefixes do not count when alphabetizing. </li></ul></li> <li> 3-ethyl-2,4,5-trimethylheptane </li> <li> Recognizing Types of Substitution </li> <li> Cycloalkanes <ul><li>Cycloalkanes are simply alkanes that are cyclic. </li></ul><ul><li><ul><li>Just add cyclo-before their name. </li></ul></li></ul><ul><li><ul><li>Notice the general formula for cycloalkanes is C n H 2n </li></ul></li></ul></li> <li> Two simple rules of cycloalkanes <ul><li>Rule A: Decide whether the cyclic or acyclic (non-cyclic) portion contains more carbons. This determines the base name. (Alkyl substituted cycloalkane or cycloalkane substituted alkane). </li></ul><ul><li>Rule B: Carbons are numbered to give the lowest numbers for substituted carbons. </li></ul></li> <li> <ul><li>Numbering starts at the most substituted carbon, and goes around in order to give the lowest numbers. </li></ul>1,1,3-trimethylcyclopentane <ul><li>When there are more acyclic than cyclic carbons, the cyclic part becomes a cycloalkyl substituent. </li></ul>4-cyclopropyl-3-methyloctane </li> <li> Complex Substituents <ul><li>These are named as follows: </li></ul><ul><li>(a) The base alkyl group is numbered staring with the carbon bonded to the main chain. </li></ul><ul><li>(b)The substituents are listed with the appropriate numbers, and parentheses are used to separate the substituent name. </li></ul></li> <li> Examples <ul><li>Draw structures for the following compounds: </li></ul><ul><li><ul><li>1.) 3-ethyl-3-methylpentane </li></ul></li></ul><ul><li><ul><li>2.) 3-methyl-5-propylnonane </li></ul></li></ul><ul><li><ul><li>3.) 2,2,4,4-tetramethylhexane </li></ul></li></ul><ul><li><ul><li>4.) pentylcyclohexane </li></ul></li></ul><ul><li><ul><li>5.) 2,3-dimethyl-4-propylnonane </li></ul></li></ul><ul><li>Give the IUPAC names of the following alkanes: </li></ul><ul><li><ul><li>1.) (CH 3 ) 2 CHCH 2 CH(C 2 H 5 )C(CH 3 ) 3 </li></ul></li></ul><ul><li><ul><li>2.) </li></ul></li></ul>3.) (CH 3 CH 2 ) 3 CH 4.) (CH 3 ) 2 CH(CH 2 ) 3 CH 3 </li> <li> Physical Properties of Alkanes <ul><li>Nonpolar </li></ul><ul><li>What type of intermolecular forces? </li></ul><ul><li>Since weak interactions.so low boiling point and melting point </li></ul><ul><li>As molecular weight increases, interactions increase </li></ul><ul><li>As interactions b/w molecules increase, so does the strength of the interactions. </li></ul><ul><li>So what conclusions can we make? </li></ul>Dispersion Forces </li> <li> <ul><li>The higher molecular weights.. </li></ul><ul><li>The more branches </li></ul>Leads to liquids, then solids More compact structure, surface area decreases Less contact between molecules, dispersion forces decrease, so lower boiling point </li> <li> Try these: <ul><li>Arrange in increasing boiling point: </li></ul><ul><li>CH 3 CH 2 CH 2 CH 3 , CH 3 CH 2 CH 2 CH 2 CH 2 CH 3 , CH 3 (CH 2 ) 8 CH 3 </li></ul><ul><li>CH 3 (CH 2 ) 6 CH 3 , CH 3 C(CH 3 ) 2 CH 2 CH(CH 3 ) 2 , </li></ul><ul><li>CH3CHCH3(CH 2 ) 4 CH 3 </li></ul><ul><li>c. 2-methyl butane, 2,2-dimethylpropane, pentane </li></ul></li> <li> <ul><li>Alkene and Alkyne Nomenclature </li></ul><ul><li>Make sure you study the different functional groups over the break (sheet of paper with table on it) </li></ul><ul><li>This will need to be memorized for the quiz and test. </li></ul><ul><li>Quiz when we get back! </li></ul></li> <li> Elements of Unsaturation <ul><li>A saturated hydrocarbon: C n H 2n+2 </li></ul><ul><li>Each multiple bond (and each ring) decreases the number of Hs by two. </li></ul><ul><li>Each of these is an element of unsaturation. </li></ul><ul><li>To calculate: find number of Hs if it were saturated, subtract the actual number of Hs, then divide by 2. </li></ul></li> <li> Propose a Structure for C 5 H 8 <ul><li>First calculate the number of elements of unsaturation. </li></ul><ul><li>Remember: </li></ul><ul><li><ul><li>A double bond is one element of unsaturation. </li></ul></li></ul><ul><li><ul><li>A ring is one element of unsaturation. </li></ul></li></ul><ul><li><ul><li>A triple bond is two elements of unsaturation. </li></ul></li></ul></li> <li> Alkene Nomenclature <ul><li>Parent is longest chain containing the double bond. </li></ul><ul><li>-ane changes to -ene. (or -diene, -triene) </li></ul><ul><li>Number the chain so that the double bond has the lowest possible number. </li></ul><ul><li>In a ring, the double bond is assumed to be between carbon 1 and carbon 2. </li></ul></li> <li> Try these: 1-butene 2-methyl-2-butene 3-methylcyclopentene 2-(1-methyl propyl)-1,3-cyclohexadiene 3-propyl-1-heptene </li> <li> Geometric Isomerism <ul><li>Similar groups on same side of double bond, alkene is cis. </li></ul><ul><li>Similar groups on opposite sides of double bond, alkene is trans. </li></ul>trans -2-pentene cis -1,2-dibromoethene </li> <li> Alkynes <ul><li>Alkynes contain a triple bond. </li></ul><ul><li>General formula is C n H 2n-2 </li></ul><ul><li>Two elements of unsaturation for each triple bond. </li></ul></li> <li> Alkyne Nomenclature <ul><li>Find the longest chain containing the triple bond. </li></ul><ul><li>Change -ane ending to -yne . </li></ul><ul><li>Number the chain, starting at the end closest to the triple bond. </li></ul><ul><li>Give branches or other substituents a number to locate their position. </li></ul></li> <li> Try these propyne 5-bromo-2-pentyne 3-methyl-1-hexyn-5-ene </li> <li> Practice Problems <ul><li>Two worksheets </li></ul></li> <li> Agenda <ul><li>Review of alkanes, alkenes, alkynes, &amp; cyclic structures </li></ul><ul><li>Nomenclature of Functional Groups </li></ul></li> <li> Alcohols <ul><li>Simple alcohols are named as derivatives of the parent alkane, using the suffix -ol , using the following simple rules: </li></ul><ul><li>Select the longest continuous carbon chain, containing the hydroxyl group, and derive the parent name by replacing the -e ending with -ol. </li></ul><ul><li>Number the carbon chain, beginning at the end nearest to the hydroxyl group. </li></ul><ul><li>Number the substituents and write the name, listing substituents alphabetically. </li></ul></li> <li> Alcohol Examples </li> <li> Ether Nomenclature <ul><li>Simple ethers are named either by identifying the two organic residues and adding the word ether . </li></ul>CH 3 OCH 3 Dimethyl ether CH 3 CH 2 OCH 2 CH 3 Diethyl ether </li> <li> Aldehydes Nomenclature <ul><li>Aldehydes are named by replacing the terminal -e of the parent alkane with the suffix -al </li></ul><ul><li>The parent chain selected must contain the carbonyl group. </li></ul><ul><li>Number the carbon chain, beginning at the end nearest to the carbonyl group. </li></ul></li> <li> Aldehyde Example methanal butanal 2-methyl butanal </li> <li> Ketone Nomenclature <ul><li>The suffix for ketones is -one. </li></ul><ul><li>The parent chain selected must contain the carbonyl group. </li></ul><ul><li>Number the carbon chain, beginning at the end nearest to the carbonyl group. </li></ul></li> <li> Ketone Examples 3-pentanone propanone 3-methyl-2-butanone </li> <li> Carboxylic Acid Nomenclature <ul><li>Simple carboxylic acids are named as derivatives of the parent alkane, using the suffix -oic acid </li></ul><ul><li>Select the longest continuous carbon chain, containing the carboxylic acid group, and derive the parent name by replacing the -e ending with -oic acid. </li></ul><ul><li>Number the carbon chain, beginning at the end nearest to the carboxylic acid group. </li></ul><ul><li>Number the substituents and write the name, listing substituents alphabetically. </li></ul><ul><li>Carboxylic acid substituents attached to rings are named using the suffix -carboxylic acid. </li></ul></li> <li> Carboxylic Acid Examples </li> <li> Ester Nomenclature <ul><li>Esters are named by replacing the terminal of end with the suffix -oate </li></ul><ul><li>The parent chain selected must contain the </li></ul><ul><li>Number the end of the carbon chain (after the second O), and give it an yl ending. </li></ul><ul><li>Practice Problems </li></ul></li> <li> Amine Nomenclature <ul><li>RNH 2 , R 2 NH, R 3 N </li></ul><ul><li>In amines, a nitrogen is bonded to one, two or three carbon atoms. </li></ul><ul><li>Practice Problems </li></ul></li> <li> Functional Groups as Isomers <ul><li>Some functional groups can exist as isomers of each other. </li></ul><ul><li>Example: C 4 H 8 O 2 </li></ul></li> <li> Try the following: </li> </ul>

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