Presentation on theme: "Unit A: Organic Chemistry"— Presentation transcript:
1 Unit A: Organic Chemistry Innisfail High SchoolChemistry 30Ms. LittkeSpring 2014
2 AssessmentFormativeStudents must participate in lessons- complete daily notes and examples.Students are expected to self assess and seek help if necessaryComplete daily activities and review new concepts regularlyF/S - Quizzes will be given periodically throughout the unitYou should use these to your advantage as they test smaller sections of the curriculum and help prepare you for the Unit ExamLabs – 2 labs per unitSummative Unit Exam – test format will be given to you later
3 Organic Chemistry Unit A: Chapters 9 and 10 Today’s Objectives: Define organic compounds as compounds containing carbon, recognizing inorganic exceptions such as carbonates, cyanides and carbidesIdentify and describe significant organic compounds in daily life, demonstrating generalized knowledge of their origins and applicationsSTS: Demonstrate an understanding that science and technology are developed to meet societal needs and expand human capabilityUnit A: Chapters 9 and 10
4 Organic Introduction Today’s Agenda: Introduce organic chemistry and review the origins and applications of some major organic compounds“Carbon – The element of life” videoAre You Ready pg. 354 #1-6 – due tomorrowSection 9.1 (pg )
5 What is Organic Chemistry? The early definition related to compounds obtained only from living things.Today, it is a major branch of chemistry that deals with compounds of carbon, called ORGANIC compounds*.*Carbon compounds that are exceptions and considered INORGANIC are compounds like:Oxides carbon monoxide (CO(g) ) and carbon dioxide (CO2(g) ), andIonic compounds of carbon-based ions, such as carbonate CO32-, cyanide CN-, and carbide ions, SiC (silicon carbide)The major source of carbon compounds is still living or previously living things, such as plants, animals and all types of fossil fuels.
6 Organic or Inorganic?? Formula Organic or Inorganic? CaCO3(s) Inorganic (carbonate ion)C25H52(s)OrganicCa2C(s)Inorganic (carbide ion)CCl4(l)CH3COOH(l)CO2(g)Inorganic (oxide)KCN(s)Inorganic (cyanide)C12H22O11(s)
7 Why is carbon special?There are millions or organic compounds and only a thousand inorganic compounds. WHY?Carbon has a bonding capacity of 4Remember Lewis Dot Diagrams from Chem 20??This means carbon can bond extensively and can bond together to form chains effectively = called PolymerismCarbon covalently bonds by sharing 4 pairs of electrons. These bonds may be single, double or triple, all producing stable compoundsCompounds can form with same number of each type of atom but different structures = Isomerism
8 Determining Lewis Formulas So why do we care about bonding capacity?If we know how many bonding e-’s an atom has, we can predict what structure a molecular compound will haveAtomNumber ofvalence electronsbonding electronsBonding capacitycarbon4nitrogen53oxygen62halogens71hydrogenHI.e. Carbon can form 4 single bonds, 2 double bonds, 1 triple and 1 single, or 1 double and 2 singles
10 IsomersCompounds with the same number of each type of atom but different structures (C4H10)We will talk about this in more detail later
11 Importance of Organic Chemistry Building units of all living matter: carbohydrates, proteins, fatsAll foods are organic compoundsPhotosynthesis is a reaction that makes carbon a part of our food. Carbon is passed along through food chains and sugar from photosynthesis is modified and combined with other materials.Dead organisms are food for other organisms, or are buried in the earth and converted to fossil fuels like peat, coal and petroleumPetroleum is the source of fuel and starting material for plastics, fabrics and industrial chemicals
12 The carbon cycle is an illustration of the interrelationship of all living things with the environment and with technologies that refine and use fossil fuelsWe will continually outline the importance of organic compounds in our daily lives
13 Carbon: The Element of Life Complete the worksheet provided as you watch the following video (20 min)
15 Today’s homeworkEnsure video worksheet is complete and in your notes to review laterWork on Are you Ready pg # 1- 6 – due tomorrowWhat is coming up tomorrow?Naming alkanes, branched alkanes and cycloalkanes
16 Naming Organic Compounds Today’s Objectives:Name and draw structural, condensed structural, and line diagrams and formulas for saturated and unsaturated aliphatic (including cyclic)Containing up to 10 carbon atoms in the parent chain/cyclic structureContaining only one type of a functional group or multiple bondUsing the IUPAC nomenclature guidelinesIdentify types of compounds from the functional groups, given the structural formulaDefine structural isomerism and relate to variations in propertiesSection 9.2 (pg )
17 Four Types of FormulasMolecular Formulas C5H10(g) Not very useful for organic compounds because so many isomers can existStructural FormulasCondensed Structural FormulasLine Diagrams– end of line segment represents carbon– it is assumed to satisfy each carbon’s octet
18 Naming Organic Compounds Aliphatic Hydrocarbons – contains only hydrogen and carbon atomsStraight line chains of carbon atomsAlicyclic hydrocarbons have carbon atoms forming a closed ring. Still considered aliphaticAlkanesAlkenesAlkynesOnly single C-C bondsDouble C-C Bond presentTriple C-C bond presentGeneral formula CnH2n+2General formula:CnH2nCnH2n-2SaturatedUnsaturated
19 Naming Organic Compounds In organic chemistry, names have a root and a suffix.The root describes the number of carbons present in the chain or ring.The suffix describes the type of compound it is.
21 Naming ALKANESFind the parent chain (the longest continuous chain of carbon atoms). Use the appropriate root and the suffix-ane.
22 Naming ALKANESFind the parent chain. Use the appropriate root and suffix.Number the carbon atoms, starting from the end closest to the branch(es) so that the numbers are the lowest possibleIdentify any branches and their location number on the parent chain (us the suffix –yl for branches)Write the complete IUPAC name, following the format: (number of location, if necessary) – (branch name) (parent chain)2-methylheptane
23 Naming ALKANESIf more than one of the same branch exist, use a multiplier to show this (di, tri). Remember to include all numbersDraw 2,4,6-trimethylheptane
24 ethyl before methyl (e before m in the alphabet) Naming ALKANESIf different branches exist, name them in alphabetical orderethyl before methyl (e before m in the alphabet)
25 Naming ALKANESIf there is more than one branch of the same type, a locating number is given to each branch and a prefix indicating the number of that type of branch is attached to the name.This numbering prefix does not affect the alphabetical order of the branchesDraw the structural formula for 3,4-dimethylhexane
26 Summary of Naming Alkanes Find the parent chain. Use the appropriate root and suffix.Number the parent chain carbon atoms, starting from the end closest to the branch(es) so that the numbers are the lowest possibleIdentify any branches and their location number on the parent chain (us the suffix –yl for branches)If more than one of the same branch exist, use a multiplier (di, tri) to show this. Remember to include all numbersIf different branches exist, name them in alphabetical orderSeparate numbers from numbers using commas, and numbers from words using dashes (no extra spaces)
27 Don’t forgetQuestions will specifically ask about structural, condensed structural or line structural formulas.You must be comfortable drawing any of the three
28 Practice Write the IUPAC name for the following 2,5-dimethyl-4-propyloctane
29 Correct the following names: 4-ethyl-2-methylpentaneACTUALLY 2,4-dimethylhexaneALWAYS LOOK FOR LONGEST CHAIN!!
30 Correct the following name: 4,5-dimethylhexaneActually 2,3-dimethylhexane**Want branch numbers to be as low as possible
31 CYCLOALKANESBased on evidence, chemists believe that organic carbon compounds sometimes take the form of cyclic hydrocarbons:Cycloalkanes: Alkanes that form a closed ringGeneral Formula CnH2nTwo less hydrogens are present than in straight chain alkanes because the two ends of the molecule are joinedAre these considered saturated?? Yes, because they have only single bonds and the max amount of hydrogen's bonded to the carbonsCyclo-compounds will have a higher boiling point than their straight chain partners (because there is an additional bond present)
32 Naming CYCLOALKANESCycloalkanes are named by placing the prefix cyclo in front of the alkane name, as in cyclopropane and cyclobutaneIf branches are present, treat the cycloalkane as the parent chain and identify the branches.Since there is no end at which to start the numbering, use the lowest numbers possible
33 Name the following: 1. 2. 1,2-dimethylcyclopentane ethylcyclohexane 1,2-dimethylcyclopentane ethylcyclohexane**Why don’t we need a number?
34 Today’s homework Pg. 370 – 71 #7 – 11 Pg. 372 #5-6 What is coming up tomorrow?Naming Alkenes, Alkynes, Cycloalkenes and CycloalkynesComparing properties of Isomers
35 Naming Organic Compounds: Alkenes and Alkynes Today’s Objectives:Name and draw structural, condensed structural, and line diagrams and formulas for saturated and unsaturated aliphatic (including cyclicContaining up to 10 carbon atoms in the parent chain/cyclic structureContaining only one type of a functional group or multiple bondUsing the IUPAC nomenclature guidelinesIdentify types of compounds from the functional groups, given the structural formulaDefine structural isomerism and relate to variations in propertiesSection 9.3 (pg )
36 Review:Find and name all of the isomers of pentane (C5H12(l))
37 Structural IsomerismCompound with the same molecular formula but different structuresThey will have different chemical and physical properties – based on their different structures
38 Alkenes and AlkynesAlkenes – hydrocarbons containing a double C-C bondGeneral formula (CnH2n) - (like cycloalkanes)Alkynes – hydrocarbons containing a triple C-C bondGeneral formula (CnH2n-2) – (like cycloalkenes)Alkenes and Alkynes are considered unsaturated compounds. They do not have the maximum number of hydrogen atoms surrounding each carbon.Reactivity: Alkynes (highest), Alkenes, Alkanes (lowest)
39 Naming Alkenes and Alkynes Find the parent chain. It MUST contain the multiple bond.If the bond is a double, the suffix for the parent chain will be -eneIf the bond is a triple, the suffix for the parent chain will be –yneCount carbon atoms so that the multiple bond will be on the lowest possible number. Indicate the number that the multiple bond falls on directly before the suffixName branches as before
40 Naming Alkenes and Alkynes Draw the following as condensed structural formulas:4-methylpent-2-ynemethylpropene(why don’t we need a number?)
41 Naming Alkenes and Alkynes Name the following:3-methylbut-1-ene5-methylhex-2-ene
42 Naming Alkenes and Alkynes It is possible for a molecule to have more than one double bond. These are called alkadienes and have the same general formula as alkynes (CnH2n-2)If this is the case, indicate both numbers where the double bond is formed, and change the suffix to –diene.a) Draw buta-1,3-diene:b) What is the IUPAC name for the following:buta-1,2-diene
43 Cycloalkenes and -ynes The rules for naming cycloalkenes and cycloalkynes are the same as naming cycloalkanesThe numbering for the carbon atoms begins with the double bond; the carbons of the double bond are carbons 1 and 2; lowest numbers possibleDraw 3-methylcyclohexene as a condensed structural formula
44 Today’s homework Pg. 377 #1-5 Pg. 380 #6, 7, 11 What is coming up tomorrow?Hydrocarbon Quiz #1Naming AromaticsBoiling point and Chemical Properties Analysis
45 Naming Organic Compounds: Aromatics Today’s Objectives:Name and draw structural, condensed structural, and line diagrams and formulas for aromatic carbon compoundsUsing the IUPAC nomenclature guidelinesIdentify types of compounds from the functional groups, given the structural formulaDefine structural isomerism and relate to variations in propertiesSection 9.4 (pg )
47 AromaticsOriginally, organic compounds with an aroma or odour were called aromatic compoundsNow, aromatics refer to compounds containing a benzene-ring structureBenzene’s formula is C6H6, which would suggest a highly unsaturated and reactive compoundBenzene is actually quite unreactive and is considered more stable than alkenes and alkynesDid You Know?? Benzene is a carcinogen and is found naturally in petroleum – why would this be a problem?
48 What do we know about benzene? Formula is C6H6 (3D link)Unreactive – so no true double or triple bondsCarbon-carbon bonds are the same length and strengthEach carbon is bonded to a hydrogenSo what does benzene look like??We will use this line structural formula to represent benzene in compoundsThe three double bonds resonate resulting in an overall bond length somewhere in between a single and a double bond, explaining benzene’s stability
49 Common Aromatic Compounds Include Aspirin and Vanillin (one of the flavour molecules in vanilla)You will notice many aromatic molecules are often depicted using a condensed structural formula except for the benzene ring, which is shown as a line structural formula.This combination is commonly used by chemists, and we will use this method when drawing aromatics.
50 Contains a phenyl branch Naming AromaticsIf an alkyl branch is attached to a benzene ring, the compound is named as an alkylbenzene.Alternatively, the benzene ring may be considered as a branch of a large molecule: in this case, the benzene ring is called a phenyl branch. Which has a phenyl branch?An alkylbenzeneContains a phenyl branch
51 Naming AromaticsIf more than one alkyl branch is attached to a benzene ring, the branches are numbered using the lowest numbers possible, starting with one of the branches.Given the choice between two sets of lowest numbers, choose the set that is in both numerical and alphabetical order1-ethyl-2,4-dimethylbenzene3-phenyl-4-propyloctane
52 Practice Naming Aromatics Draw 1,2-dimethylbenzeneAre there any isomers of this compound?There is also classical way of naming these isomers. The arrangements are denoted by the prefixe:s ortho (o), meta (m) and para (p). These names are still used in industry so you may encounter them in other references.1,2-dimethylbenzene1,3-dimethylbenzene1,4-dimethylbenzeneo-dimethylbenzenem-dimethylbenzenep-dimethylbenzene
53 Practice Naming Aromatics Draw the line structural formula for 1-ethyl-3-methylbenzeneDraw the line structural formula for 2-phenylpentane
54 Practice Naming Aromatics Draw 3-phenylpent-2-eneName the followingpropylbenzeneWhy is no number needed?Are the hydrogen’s wrong??
55 SummaryWe have now learned about both aliphatic and aromatic hydrocarbons. You will need to be comfortable naming all of the following:
56 Teacher Note: End if not enough time for two dry labs Can use during the Station Lab Periods
57 Review of Intermolecular Forces London Forces – temporary dipoles resulting from an uneven distribution of e- in all moleculesTemporary (-) end will repel e- in neighbouring molecules and so onDepends on size of molecule (number of e-’s)Weakest of the intermolecular forcesDipole-Dipole – only exists in polar moleculesAttraction between + and – ends of moleculeHydrogen Bonding – super strong forceOnly exists when H-N, H-F, H-O bonds are present
58 Applications Read pg. 384 Lab Exercise 9.A – complete the parts in red Purpose: To test the generalization that aromatic hydrocarbons react like saturated rather than unsaturated hydrocarbonsDesign: cyclohexane, cyclohexene and benzene are all mixed with potassium permanganate (purple). Evidence for a reaction is a change in the initial purple colour of the solution.Prediction: Based on your current knowledge, predict the order in which the compounds will react, from least reactive to most reactive. Explain your reasoning.Analysis: On the basis of the evidence, determine the order of the reaction rate for the three compounds.Evaluation: Determine if your prediction was verified or falsified. Was the generalization about aromatic hydrocarbons acceptable based on the evidence? Was the purpose of the investigation accomplished?
60 Applications Read pg. 384 Lab Exercise 9.B – complete the parts in red Purpose: To test the ability of the concept of London forces to predict the relative boiling points of aliphatic and aromatic compounds(Remember: the more electrons in a compound = the stronger the intermolecular forces = the higher the boiling point needed to pull the molecules apart)Problem: What is the relative order of the boiling points of hexane, hex-1-ene, cyclohexane, cyclohexene, and benzene?Prediction: Determine the number of electrons in each molecule and use these numbers to determine the order of boiling pointsAnalysis: On the basis of the evidence given, determine the order of the boiling points. (from lowest to highest)Evaluation: Determine if your prediction was verified or falsified. Was the predictive power of the concept of London forces judged to be acceptable based on the evidence? Was the purpose of the investigation accomplished?
62 Extra Practice for Lab Reports Complete pg. 355 #6Complete the prediction, analysis and evaluationRemember lab report guidelines in textbook starting on pg. 790
63 Today’s homework What is coming up tomorrow? Pg. 385 #3-8 – due tomorrowWhat is coming up tomorrow?Review Aromatic and Aliphatic CompoundsRefining
64 Properties of Organic Compounds & Crude Oil Refining Today’s Objectives:Compare boiling points and solubility of organic compoundsDescribe fractional distillation and solvent extractionDescribe major reactions for producing energy and economically important compounds from fossil fuelsSection 9.5 and 9.6 (pg )
65 Physical Properties of Simple Hydrocarbons AlkanesNon-polar moleculesOnly intermolecular forces are London ForceBoiling point and melting point increase with number of carbonsAll insoluble in water (like dissolves like) – nonpolar and polar don’t mix1-4Cs = gas, 5-16Cs = liquid 17 and up = solid at SATPAlkenesNon-polar molecules, therefore insoluble in waterBoiling points slightly lower than alkanes with the same number of carbons due to less electrons (unsaturated), resulting in lower London ForcesAlkynesIn theory boiling points slightly lower than alkenes with the same number of carbons due to less electrons (unsaturated), resulting in lower London ForcesBranchingThe more branching, the less significant the London Force (~lower b.p.)- more surface area in straight chain hydrocarbons allows moreseparation of charge, resulting in greater London Force- see Table #3 pg (i.e. pentane (with 5Cs) has a b.p. of 36oCwhich is much higher than dimethylpropane (5Cs) -12oC) = becausebranching decreased the strength of the London force
66 Sample QuestionPredict the relative order of boiling points of the following compounds (lowest to highest). Explain your reasoning.butanol but-1-ene cyclobutane butanoic acid butaneLowest > Highestbut-1-ene cyclobutane butane butanol butanoic acidReasoning: but-1-ene has lower LF’s for than butane because it is unsaturated, cyclobutane has lover LF’s than butane, butanol has H- bonding, butanoic acid has stronger polar forces)Which would be soluble in water?Butanol and butanoic acid – because they are the only polar molecules and like dissolves like!
67 Crude Oil RefiningCrude oil is a complex mixture of hundreds of thousands of compounds, all of which have different boiling pointsWe can take advantage of these different b.p.’s and physically separate the different components using heatThis process is called fractional distillation or fractionation
68 Electronic VisualA fractional distillation tower contains trays positioned at various levels.Heated crude oil enters near the bottom of the tower.The bottom is kept hot, and the temperature gradually decreases toward the top of the tower.As compounds cool to their boiling point, they condense in the cooler trays. The streams of liquid (called fractions) are withdrawn from the tower at various heights along the tower.
70 A more detailed look…The vaporized components of the crude oil rise and gradually cool.To get from one level to the next, the vapours are forced to bubble through the liquid condensed in each tray.The figure shows the bubble caps used to allow this to happen.If a gas cools to its boiling point, it will condense and be piped out through the draining tubeCrude oil is heated in the fractionation tower without air being present to reduce the risk of mixtures starting to burn or explodeQ: How does the number of carbon atoms in a hydrocarbon chain affect its boiling point?Smaller molecules have fewer electrons, so weaker London forces compared with larger molecules. The fractions with higher boiling points are found to contain much larger molecules (see Table 1 pg. 387)
71 CrackingCracking: large hydrocarbons are broken into smaller fragmentsHistorically, thermal cracking used extremely high temperatures but created large quantities of solid coke.Now, catalytic cracking uses a catalyst to speed up the reaction and produce less residual products like tar, asphalt and cokeExample: C17H36(l) C9H20(l) + C8H16(l) + C(s)larger molecules smaller molecules + carbonIn 1960, hydrocracking was developed, which combines catalytic cracking and hydrogenation and produces no coke.Example: C17H36(l) + H2(g) C9H20(l) + C8H16(l)larger molecule + hydrogen smaller molecules
72 Oil Refining Physical Processes Chemical Processes The refining of crude oil can be divided into two main categories:Physical ProcessesFractional Distillation: see previous slidesSolvent Extraction: solvent is added to selectively dissolve and remove an impurity or to separate a useful product from a mixtureChemical ProcessesCracking – larger molecules are broken down into smaller onesReforming – large molecules are formed from smaller onesThese chemical processes are needed because fractional distillation does not produce enough of the hydrocarbons that are in demand (i.e. gasoline) and produces too much of the heavier fractions
74 Catalytic Reforming and Alkylation Catalytic Reforming: improves the quality of the gasolinealiphatic molecule aromatic molecule + hydrogenAlkylation: increases the branching; improves the quality of the fuelaliphatic molecule more branched molecule(AKA: isomerization because it converts molecules into a branched isomer)FYI pg. 392 on Octane Numbers
76 Combustion Reactions Burning of hydrocarbons in the presence of oxygen Complete Combustion: abundant supply of oxygen; products are carbon dioxide, water vapour and heatEx. C3H8(l) + 5O2(g) 3CO2(g) + 4H2O(g)Incomplete Combustion: limited supply of oxygen; products are carbon monoxide, soot (pure carbon) or any combination of carbon dioxide, carbon monoxide and soot in addition to water vapour and heatEx. 2C8H18(l) + 17O2(g) 16CO(g) + 18H2O(g)OR 2C8H18(l) + 9O2(g) 16C(s) + 18H2O(g)** Assume complete combustion unless specified otherwise
77 Balancing FYI C8H18(l) + 9/2 O2(g) 8C(s) + 9H2O(g) Ex. 2C8H18(l) + 17O2(g) 16CO(g) + 18H2O(g)Can also be balanced using a fraction (you need to becomfortable using this method) – divide each number by 2C8H18(l) + 17/2 O2(g) 8CO(g) + 9H2O(g)Ex. 2C8H18(l) + 9O2(g) 16C(s) + 18H2O(g)can also be balanced as …C8H18(l) + 9/2 O2(g) 8C(s) + 9H2O(g)
79 Today’s homework What is coming up tomorrow? Read pagesPg. 391 #9,Pg. 397 #1, 4, 5, 8, 12, 13What is coming up tomorrow?Chapter 9 Exam Review (Unit A Part 1)Exam on FridayFunctional Groups and Hydrocarbon ReactionsHalides, alcohols, carboxylic acids, esters and polymersAddition, Substitution and Elimination, esterfication and polymerization
80 Hydrocarbon Quiz #2Aliphatic and Aromatic Compounds
81 Organic Halides and Alcohols Organic Chemistry:Organic Halides and AlcoholsToday’s Objectives:Name and draw structural, condensed structural and line diagrams and formulas for organic halides and alcoholsIdentify types of compounds from their functional groups, given the structural formula and name of the functional groupsSection 10.2 and 10.3 (pg )
82 Today’s Agenda: Review You will have another Hydrocarbon Quiz next class covering all aliphatic and aromatic compoundsToday’s agenda:Review Quiz – go over common mistakesPg. 385 #6-8**7d) 4-methyl (not 3-methyl)Make the change in your book if not done already
83 Review of Intermolecular Forces London Forces – temporary dipoles resulting from an uneven distribution of e- in all moleculesTemporary (-) end will repel e- in neighbouring molecules and so onDepends on size of molecule (number of e-’s)Weakest of the intermolecular forcesDipole-Dipole – only exists in polar moleculesAttraction between + and – ends of moleculeHydrogen Bonding – super strong forceOnly exists when H-N, H-F, H-O bonds are present
84 Organic HalidesOrganic compounds where one or more hydrogen has been replaced with halogens (F, Cl, Br, I)Common example: CFC (chlorofluorocarbons)Nomenclature is similar to naming branch chains of hydrocarbons, but the branch name used is based on the halogen usedchloro-, fluoro-, bromo-, iodo-
85 Organic Halides What do you need to know about organic halides? May by polar or nonpolar molecules or may have a relatively nonpolar (hydrocarbon) end and a polar (halide) end (**Remember Electronegativity differences)Have higher boiling points than similar hydrocarbonsHave very low solubility in water but higher solubility than similar hydrocarbonsAre typically good solvents for organic materials such as fats, oils, waxes, gums, resins or rubberUsually toxic or ecologically damaging (DDTs and PCBs)
86 Practice Naming Organic Halides Draw 1,2-dichloroethaneDraw 2,2,5-tribromo-5-methylhexane
87 Practice Naming Organic Halides Name the following:CH2Cl21,2-dibromoetheneBonus: Try 1,2-dibromo-1,2-dichloroethenechlorobenzenedichloromethane
88 Did You Know?There is always a new concept to learn that extends what you have already learned.In addition to the structural isomers that you know about, there are cis and trans isomers
89 AlcoholsAn alcohol is an organic compound that contains the –OH functional group (hydroxyl)General formula is R-OH (R = rest of molecule)Alcohols are classified as primary, secondary or tertiary depending on the number of carbons bonded to the carbon that contains the hydroxyl group
90 Common AlcoholsMethanol (also called wood alcohol) is extremely toxic, causing death and blindnessEthanol (also known as grain alcohol) is the alcohol found in alcoholic beverages and is used in the production of vinegarGas line antifreeze,windshield de-icer,windshield washerfluid – all containmethanol
91 Naming Alcohols propan-1-ol Locate the longest chain that contains an –OH group attached to one of the carbon atoms. Name the parent alkaneReplace the –e at the end of the name of the parent alkane with –ol (i.e. butane becomes butanol)Add a position number before the suffix –ol to indicate the location of the –OH groupREMEMBER to number the main chain of the hydrocarbon so that the hydroxyl group has the lowest possible position numberpropan-1-ol
92 Naming AlcoholsIf there is more than one –OH group (called polyalcohols), leave the –e in the name of the parent alkane and put the appropriate prefix before the suffix –ol (i.e. diol, triol, tetraol)Name and number any branches on the main chain. Add the names of these branches to the prefix.Draw 2,3-dimethylbutan-2-ol
93 Practice Naming Alcohols Draw line structural formulas for:cyclohexanolphenolThe three isomers of C5H11OH that are pentanolsThese are the only two cyclic or aromatic alcohols you will need to know as they get very complicated
94 Alcohols What do you need to know about alcohols? Question: Why is the propane used in a barbecue a gas at room temperature, but propan-2-ol (also known as rubbing alcohol) a liquid at room temperature?Answer: Propane is a non-polar hydrocarbon with weak intermolecular forces, thus it has a low boiling point and is a gas at room temperature.Propan-2-ol is an alcohol, with a polar hydroxyl group and strong intermolecular forces, thus it has a higher boiling point than propane and is a liquid at room temperature
95 Alcohols What do you need to know about alcohols? Question: Glycerol (propane-1,2,3-triol) is more viscous than water, and can lower the freezing point of water. When added to biological samples, it helps to keep the tissues from freezing, thereby reducing damage. From your knowledge of the molecular structure of glycerol, suggest reasons to account for these properties of glycerol.Answer: Each molecule of glycerol contains three hydroxyl groups which can hydrogen-bond with water, interfering with the attractions between water molecules and thus interfering with the freezing of water. When water in tissues does not freeze, there is less damage to the tissues.
96 Application QuestionPredict the order of increasing boiling points for the following compounds, and give reasons for your answer.butan-1-ol pentane chlorobutaneAnswer: (Lowest b.p.): pentane, 1-chlorobutane, butan-1-olWhy? All molecules have a similar number of electrons. Pentane has the lowest boiling point, because it is non-polar so will only have London forces between the molecules. 1- chlorobutane is polar so will have dipole-dipole forces as well as London forces. Butan-1-ol has the highest boiling point because its molecules will have all three intermolecular forces, most importantly, hydrogen bonding
97 Today’s homework What is coming up tomorrow? Pg. 418 #1-5Pg 424 #2-3Pg. 430 #5,6,7,8Due tomorrowWhat is coming up tomorrow?Carboxylic Acids and Esters
98 Carboxylic Acids and Esters Organic Chemistry:Carboxylic Acids and EstersToday’s Objectives:Name and draw structural, condensed structural and line diagrams and formulas for carboxylic acids and estersIdentify types of compounds from their functional groups, given the structural formula and name of the functional groupsSection 10.4 (pg )
99 Carboxylic acids are weak organic acids A carboxyl group is composed of a carbon atom double bonded to an oxygen atom and bonded to a hydroxyl group (-COOH)Note: Because the carboxyl group involves three of the carbon atom’s four bonds, the carboxyl is always at the end of a carbon chain or branchExamples:Carboxylic acids are weak organic acidsmethanoic acidethanoic acid
100 Naming Carboxylic Acids Name the parent alkaneReplace the –e at the end of the name of than parent alkane with –oic acidThe carbon atoms of the carboxyl group is always given position number 1. Name and number the branches that are attached to the compound.Draw 3-methylbutanoic acidRemember COOH or HOOC can also represent the carboxyl groupHOOC
101 Naming Carboxylic Acids Draw trichloroethanoic acid (key ingredient in chemical peels)CCl3COOHDraw 3-propyloctanoic acidDo you need the CH3 here? No – but sometimes you will see it written this way. Don’t be confused because it doesn’t change the meaning
102 EstersThe reaction between a carboxylic acid and an alcohol produces an ester molecule and a molecule of waterThis reaction is known as a condensation or esterification reactionThe ester functional group –COO– is similar to that of a carboxylic acid, except that the H atom of the carboxyl group has been replaced by a hydrocarbon branch.Esters are responsible for natural and artificial fragrance and flavourings in plants and fruits.
103 EstersIn naming an ester you have to recognize that an ester has 2 distinct parts. The main part contains the C=O group which comes from the parent acid. The second part is the alkyl group.
104 Naming EstersIdentify the main part of the ester, which contains the C=O group. This part comes from the parent acid.Begin by naming the parent acid but replace the –oic acid ending of the name with –oate. (propanoic acid becomes propanoate)The second part is the alkyl group that is attached to the single oxygen atom. Name this as you would any other alkyl group (in this case = methyl)Put the names together. Note that esters are named as two words.
105 Naming EstersName the following ester and the acid and alcohol from which it can be prepared.A strong acid catalyst, such as H2SO4(aq) is used along with some heating to increase the rate of the organic reactionbutanoic acidethanolethyl butanoatewaterTip: The branch attached to the oxygen (of the –COO) comes first in the name, the chain attached to the carbon (of the –COO) comes second
106 Naming EstersName the following ester and the acid and alcohol from which it can be prepared.benzoic acidethanolethyl benzoatewater
107 Today’s homework What is coming up tomorrow? Organic Reactions Pg. 438 #1,2Pg. 441 #3-4Due tomorrowWhat is coming up tomorrow?Organic ReactionsSummary and Review of all organic moleculesFull Naming Quiz (in two days)
108 Physical Properties of Hydrocarbon Derivatives AlcoholsMuch higher boiling points than hydrocarbons (1-12Cs are liquids at SATP) due to hydrogen bonding between hydroxyl groups of adjacent moleculesSmall alcohols are totally miscible in water, but the larger the hydrocarbon part of the alcohol (nonpolar part), the more nonpolar the alcohol isCarboxylic AcidsLike alcohols they have hydrogen bonding, but is more significant due to the C=O. This means greater bps and solubility than alcohols with same number of Cs.Carboxylic acids with 1-4Cs arecompletely miscible in waterEstersFruity odour in some casesPolar but they lack the –OH bond therefore do not have hydrogen bonding, so lower bps than both alcohols and carboxylic acidsEsters with few carbons are polar enough to be soluble in waterCompoundBoiling Point (oC)butane-0.5butan-1-ol117.2butanoic acid165.5
109 Summary Table - Organic Complete the summary table of all of the organic compounds we have studied. This will be a good page to reference when studying
110 Hydrocarbon Reactions: Addition, Substitution and Elimination Today’s Objectives:Define, illustrate and provide examples of simple addition, substituion, elimination and esterification (condensation)Predict products and write and interpret balanced equations for the above reationsSection 10.2,10.3 and 10.4 (pg )
112 Hydrocarbon Reactions Additionalkenes and alkynes + H2(g) alkanes (hydrogenation)alkenes and alkynes + HX (or X2) organic halidesSubstitutionalkanes and aromatics + X2 organic halidesEliminationalcohols alkenes + water (dehydration)organic halides + OH- alkenes + halide ion + waterEsterification (already covered, just review)carboxylic acid + alcohol ester + waterPolymerization – monomer + monomer = polymeraddition and condensation
113 Addition with H2(g) (also called hydrogenation) Addition Reactions: reaction of alkenes and alkynes with hydrogen gas, a halogen compound, a hydrogen halide compound or water.Addition reactions usually occur in the presence of a catalystAddition with H2(g) (also called hydrogenation)
114 Excess bromine promotes this second step. Addition Reactions: reaction of alkenes and alkynes with hydrogen gas, a halogen compound, a hydrogen halide compound or waterAddition of a halogen1,2-dichloroethane is a useful solvent and is used to produce chloroethene, the monomer used to make PVC.See Pg. 417 equationSince addition reactions involving multiple bonds are very rapid, the alkene product 1,2-dibromoethene can easily undergo a second addition step to produce 1,1,2,2-tetrabromomethane.Excess bromine promotes this second step.
115 Addition of an HX (hydrogen halide) molecule Addition Reactions: reaction of alkenes and alkynes with hydrogen gas, a halogen compound, a hydrogen halide compound or waterAddition of an HX (hydrogen halide) moleculeShow both possible isomers when predicting the productsThe addition of hydrogen halides (HF, HCl, HBr or HI) to unsaturated compounds can produce structural isomers, since the hydrogen halide molecules can add in different orientations. However, the type of isomers produced are not always equal.For example only a tiny amount of 1-chloropropane is produced compared to 2-chloropropane in the above reaction.
116 Practice Addition Reactions For each of the following questions, draw condensed structural diagrams and name all productsethene bromine hydrogen chloride + ethene 3-methylbut-1-yne + excess hydrogen 1,2-dibromoethanechloroethane2-methylbutane__
117 Substitution Reactions – breaking of a C-H bond in an alkane or an aromatic ring and replacing it with another atom or group of atomsUsually occur slowly at room temperature, so light may be necessary as a catalystOften substitutes a halogen for a hydrogenNo change in saturationPropane contains hydrogen atoms bonded to end carbons and the middle carbon atom, so two different products (isomers) are formed, in unequal proportions
118 Substitution Reactions – breaking of a C-H bond in an alkane or an aromatic ring and replacing it with another atom or group of atomsBenzene rings are stable, like alkanes, so they react slowly with halogens, even in the presence of light.As with alkanes, further substitution can occur in benzene rings, until all hydrogen atoms are replaced by halogen atoms (in the presence of excess halogens)
119 Practice Substitution Reactions For each of the following questions, draw condensed structural diagrams and name all productspropane fluorine ethane chlorine 1-fluoropropane + 2-fluoropropane + hydrogen fluorideF - FH - Fchloroethane + hydrogen chloride
120 Elimination Reactions – involves eliminating atoms or groups of atoms from adjacent carbon atoms; decreases the level of saturationAlkane cracked into an alkene (uses high temperatures)Alcohol is reacted with a catalyst to produce an alkene and water (dehydration – removes a water molecule from the alcohol)Alkyl halide reacts with a hydroxide ion (OH-) to produce an alkene (dehydrohalogenation – removes a hydrogen and halogen atom)
121 Practice Elimination Reactions Write a structural formula equation for the preparation of but- 2-ene from chlorobutane, in the presence of a strong baseWrite a structural formula equation for the preparation of but- 2-ene from butan-2-ol
122 Reaction typeComplete CombustionAdditionEliminationSubstitutionEsteri-ficationReactantsHydrocarbon* + O2ene or yne + HOH, X2, HX, or H2alcohol or alkyl halidealkane or aromatic + X2alcohol + carboxylic acidProductsCO2(g) + H2O(g) or (l)alcohol, alkyl halide*, alkanealkene + HOH or HXalkyl halideester + waterOthertriple or double to singlesingle to doubleslow; needs uv lightacid catalyst neededmore bonds*fewer bonds*
123 Today’s homework What is coming up tomorrow? Polymerization Pg. 422 #7,8 (Addition and Substitution)Pg. 433 #18-19 (Elimination)Pg. 443 #1, 5-8 (Esterfication)What is coming up tomorrow?PolymerizationSTS Connections
124 Polymerization Reactions Organic Chemistry:Polymerization ReactionsToday’s Objectives:Define, illustrate, and give examples of monomers, polymers, and polymerization in living and non-living systemsSTS: 2) Illustrate how science and technology are developed to meet societal needs and expand human capabilitiesSTS: 3) Illustrate how science and technology have both intended and unintended consequencesSection 10.5 (pg )
125 PolymerizationPolymers are large molecules made of chains of monomers, small molecules that link together.Polymerization is the formation of polymers from these small unitsPolymers can occur naturally (proteins, carbohydrates) and can be synthesized (nylon, Teflon, polyethylene)They play an integral part in the function of life systems and have revolutionized the way society functions
127 Addition Polymerization Many plastics (synthetic polymers) are made by this processThe polymerization process is initiated with a free radical (a species with an unpaired electron). The free radical attacks and breaks the double bond forming a new free radical that attacks another monomer
128 Addition Polymerization always results in one product, the polymer Requires unsaturated hydrocarbon monomers and bond saturation occurs when the polymer is madeCommon polymers produced by addition polymerization:
129 Things to know about addition polymers… The polymer names end in –ene (i.e. polystyrene, polypropene). Does this mean they have double bonds?No, the double bonds are saturated by adjacent monomers, as the polymer is made. The name refers to the starting monomer (i.e. polyethene is started by the monomer ethene)What properties make Teflon a good product for non-stick materials?Teflon is made up of C-F bonds which are very strong (not C-H bonds). These very strong bonds make the Teflon highly unreactive (non-sticking), it has a high melting point and it has a slippery surface
130 Condensation Polymerization Monomers combine to form a polymer and a bi-product. Each time a bond forms between monomers, small molecules, such as water, ammonia, or HCl are “condensed” out.The polymerization of nylon:For condensation polymerization to occur, monomers must be bifunctional, meaning they have at least two functional groups.If they only had one functional group, then only one bond would form.
131 Condensation Polymerization Condensation polymerization also produces natural polymers, called proteins.Amino acids (monomers) polymerize to make peptides (short chains of amino acids) or proteins (long chains of amino acids)
132 Comparison of Addition and Condensation Polymerization Needs a double or triple bond in the monomerProduces only one product, the polymerNeeds bifunctional monomers (have two functional groups)Produces two products: the polymer and the biproduct (water, ammonia or HCl)
133 PolyesterWhen a carboxylic acid reacts with an alcohol in an esterification reaction, a water molecule is eliminated and a single ester molecule is formed.This esterification reaction can be repeated so many esters are joined in a long chain… a polyesterThis is created using a dicarboxylic acid (an acid with a carboxyl group at each end) and a diol (an alcohol with a hydroxyl group at each end)The ester linkages are formed end to end between alternating acid and alcohol molecules
134 Polyester: Dacron Another example of a polyester: Note the two carboxyl groups in the dicarboxylic acid and the two hydroxyl groups in the polyalcohol that start the chain reaction
135 Natural Polymer Examples Starch, wood, silk, DNA