Chemistry Unit II: Organic Chemistry

Transcription

1 Chemistry 2202 Unit II: Organic Chemistry Name: What is Organic Chemistry? - the study of the compounds that contain the element Carbon - all living organisms contain a wide variety of organic compounds - cells - though composed of seventy to ninety percent water, most of the rest of the cell is composed of carbon based material - DNA, proteins, carbohydrates, etc. Carbon accounts for the endless diversity in biological organisms. - fossil fuels - food / drink - paper - clothes - soap / perfume There is such a large number, and variety, of organic compounds, more than 10 million, there is a special naming system used to organize, classify and name them. Chemical Compounds Ionic Compounds Inorganic Compounds Molecular Compounds - contains only non-metallic elements Any compound that does not contain carbon Inorganic Compounds Organic Compounds The carbon oxides, such as CO 2 and CO, along with polyatomic ions containing carbon, such as CO 3 2- and HCO 3 -, however, are also considered inorganic. 1 Any compound that does not contain carbon Any compound that does contain carbon atoms. Exceptions include carbon oxides, such as CO 2 and CO, and polyatomic (complex) ions containing carbon.

2 Organic Compounds - historically thought to only come from living or once-living sources (vital source) Frederich Wohler produced, by accident, the first organic compound named urea - (a substance found naturally in the urine of animals) from an inorganic compound (ammonium cyanate) - now chemists invent more than 250,000 new organic compounds every year - there are millions of organic compounds and they are organized and categorized based on chemical and physical properties. Naming and classifying these compounds does prove difficult, however, as there is more than one classification and naming system. Inorganic Compounds - historically thought to only come from non-living materials such as minerals - now defined as any molecule that does NOT contain C (some exceptions include the poly-atomic ions that contain carbon atoms; Eg. CO 3, HCO 3 -, SCN, etc.) Examples of Organic Compounds - Natural: - proteins, lipids, carbohydrates, cellulose - fossil fuels (Ex: gas, oil, coal) - natural fibers ( cotton, wool, silk, paper) - Manufactured (Synthetic): - pesticides - CFC s - medicine (ex: painkillers, antibiotics, insulin) - polyesters/plastics - artificial sweeteners/flavouring (sugar twin, vanilla extract) - perfume, cosmetics, soap, detergent - paints, varnish TNT Classifying Organic Compounds - the system for classifying these compounds is based on - Chemical Properties - how these substances react with other substances - Physical Properties - MP/BP - Solubility - Bonding/Structure - Functional Group - key atom arrangement within a molecule - reactions take place at functional group - ex. - ethanol - C 2 H 5 OH or CH 3 -CH 2 -OH - OH is the functional group. It tells us that ethanol is an alcohol Questions pg. 323 # s 1, 5 2

3 Chemistry 2202 Homework Questions pg. 323 # s 1, 5 Name: 1. a. b. c. 5. a. b. c. d. e. f. g. h 3

4 Why Carbon? Why the special consideration for carbon? Considering that carbon makes up only 0.02 % elements in the earth s crust. What makes these molecules so unique? 1. It has high bonding capacity (4 bonding e-). 2. It can form single, double, and triple bonds. It can form chains, branches, rings, spheres, sheets, tubes, etc. 3. C to C bonds are very stable. 4. It can bond with other elements (ex: H, N, O, halogens). 5. There are several times more carbon based compounds that there are compounds of all the other elements combined. 4

5 The following diagram represents the basic classification system for carbon compounds - as studied in Chemistry Organic Compound Pure Hydrocarbons compounds that contain carbon and hydrogen atoms only Hydrocarbon Derivatives compounds that contain carbon, hydrogen and other atoms such as O, N, S, etc. Aliphatic Aromatic Alkyl Halide Aldehyde Alkanes Alcohol Ketone normal branched cyclo Ether Amine Carboxylic Acid (Organic Acid) Ester Alkenes normal branched cyclo Amide Alkynes normal branched cyclo 5

6 Structural Formulas - we use four types of formulas to represent organic compounds. Using the formula C 5 H 12 we consider the four types. Complete Structural Formula - shows all atoms and bonds Skeleton Structural Formula - shows all atoms and bonds Condensed Structural Formula - shows C-C bonds but not C-H bonds Line Structural Formula - shows only C-C bonds as a zigzag - each corner is a C Your Turn! Draw complete, skeletal, condensed and line structural diagrams forc 3 H 8, C 6 H 14 Complete Structural Formula Condensed Structural Formula Line Structural Formula C 3 H 8 C 3 H 8 C 3 H 8 C 6 H 14 C 6 H 14 C 6 H 14 6

7 Organic Compounds Pure Hydrocarbon Hydrocarbon Derivative Aliphatic Aromatic Pure Hydrocarbons - compounds containing only C and H atoms - ex: coal, oil, gas, plastic, polyester - 2 types - aliphatic and aromatic Aliphatic - hydrocarbons in which carbon atoms form: - straight, continuous chain (with or without branches) - cyclic (ring) structure - ex: fats, oils 7

8 Naming Organic Compounds There are special prefixes that indicate the number of C atoms in an organic compound. Note: Only the first four prefixes are new to you. Number of Carbon Atoms Prefix 1 meth 2 eth 3 prop 4 but 5 pent 6 hex 7 hept 8 oct 9 non 10 dec Homologous Series - a series formed when a group of compounds differs by a unit - alkanes are such a series b/c each molecule differs by a CH 2 " unit - propane (C 3 H 8 ) and butane (C 4 H 10) are homologs because they differ in numbers of carbon atoms by only one. 8

9 Aliphatic Hydrocarbons - there are three types of aliphatic type pure hydrocarbons. 1. Alkane - all C-C single bonds - normal (straight chain) - branched - cyclo 2. Alkene - at least one C=C double bond - normal(straight chain) - branched - cyclo 3. Alkyne - at least one C C triple bond - normal(straight chain) - branched 9

10 1. Alkanes - basic formula is C n H 2n+2 - all single C-C bonds - Example - Methane - simplest alkane Note: Alkanes are referred to as saturated hydrocarbons because there are no multiple bonds. Each carbon has the maximum number of hydrogens attached. Try these: C 4 H? What is its formula? # of H = 2(4) + 2 = 10 C 4 H 10 butane C 4 H 10 C? H = 2n = 2n n = 12/2 = 6 C 6 H 14 hexane The formula is C 6 H 14 10

11 Alkane Properties - Boiling and Melting point - increases as # C increases Alkane Boiling Point ( o C) CH C 2 H C 3 H C 4 H State at STP - CH 4 to C 4 H 10 - gas Ex: natural gas, petrochemicals - C 5 H 12 to C 17 H 36 - liquid Ex: C 5 -C 10 is gasoline, C 12 -C 13 is kerosene, jet fuel, diesel - greater than C 17 H 36 solid Ex: C 20 and higher is grease, paraffin wax, tar - Solubility - hydrocarbons generally are tetrahedral shape - hydrocarbons generally non-polar - they DO NOT dissolve in polar water very - Reactivity - Alkanes are sometimes inert b/c H-C bonds and C-C bonds are generally stable. - They do react with halogens (substitution) and oxygen (combustion). 11

12 Naming Alkanes Steps 1. Count # of C in a chain or formula. 2. Select prefix that represents that number of carbons. 3. Finish prefix with ane Structural Formula Name CH 4 CH 3 CH 2 CH 3 CH 3 CH 2 CH 2 CH 2 CH 2 - CH 3 CH 3 CH 2 CH 2 CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 CH 3 CH 3 CH 3 CH 2 CH 2 CH 2 CH 3 12

13 Branched Chain Alkanes - any alkane with one or more branches (alkyl group) coming off the main chain structure - alkyl group never on the end of a chain - Same prefixes for identifying branches (Ex: meth- CH 3 branch) Naming Branched Chain Alkanes 1. Name the parent chain (longest C chain). 2. Number the C atoms in the parent chain, starting with the C closest to branch(es). 3. Identify branch using prefixes and add -yl on the end. 4. Identify location of branch on chain. 5. If there are two or more same type branches use molecular prefixes (di, tri, tetra) to indicate number. 6. Place branch names in alphabetical order. 7. Write name in this format: (#location) - (branch names)(parent chain) NOTE: Dashes separate numbers and words Commas separate numbers Examples Structural Formula Name CH 3 CH 3 CH 2 CH 2 CH 2 CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 CH 3 CH 3 CH 2 CH 2 CH CH - CH 3 CH 2 CH 3 Questions page 336 / 337 # s 5, 6, 7 13

14 Questions page 336 / 337 # s 5, 6, 7 5. a. b. c. d. e. 6. a. b. c. 7. a. b. c. 14

15 Drawing Branched Chain Alkanes 1. Draw chain of C atoms according to the parent name. 2. Attach all branches. 3. Add enough H atoms so each C has 4 bonds. Examples: 2 - methyl propane 2, 2 - dimethyl - 4, 5, 7 tripropyldecane 3,3 - dimethylhexane Q s Page 338 # s 8, 9, 10, 11 15

16 Chemistry 2202 Homework Questions Q s Page 338 # s 8, 9, 10, 11 Name: 8. a. b. c. 9. a. b. c. 10. a. b. c. d. 11. a. b. c. 16

17 Cycloalkanes - basic formula is C n H 2n - carbon chains with a ring type structure - may or may not have branches Naming Cycloalkanes - count the number of carbon atoms and name the same as continuous chain alkanes. - if compound is a ring type structure add prefix cyclo to alkane name. Examples Structural Formula Compound Name cyclopropane cyclopentane cyclohexane cyclooctane 17

18 Chemistry 2202 Organic Chemistry: Aliphatic Hydrocarbons Name: Name the following alkyl groups (branches) CH CH 2 - CH 2 - CH CH 2 - CH 2 - CH 2 -CH CH 2 CH 2 CH 2 CH 2 -CH CH 2 CH 2 CH 2 CH 2 CH 2 -CH CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 -CH 3 Name the following branched chain alkanes. Structural Formula Name 18

19 Draw the condensed and line structural formulas for each of the following. Name Condensed SF Line SF 2-methylpropane 3,3-dimethylhexane 4-ethyl-2-methylpentane 3,4,5-trimethyloctane 3-ethyl-4,4-dimethyloctane 1,2 - diethylcyclopentane 1,2,5 - trimethylcyclooctane 1-ethyl-2,3-dimethylcyclopropane ethylmethylpropylcyclopropane 1-ethyl-3-propylcyclobutane 19

20 Chemistry 2202 Organic Chemistry: Aliphatic Hydrocarbons Aliphatic Hydrocarbons_4 Complete the Following: 1 2 Name: Draw the following: Alkane Skeletal SF Condensed SF Line SF cyclopentane 3,3 - dimethyl octane heptane 20

21 Chemistry 2202 Organic Chemistry: Aliphatic Hydrocarbons (Aliphatic Hydrocarbons_5) Name the following: 1 2 Name: Draw the following: Alkane Skeletal SF Condensed SF Line SF octane 2,3 - dimethyl octane 3 - hexane 21

22 2. Alkenes - basic formula: C n H 2n - hydrocarbons that have at least one C to C double bond - more reactive than alkanes b/c of double bond - these carbon structures are also referred to as unsaturated hydrocarbons - they do not have the maximum number of hydrogens attached to each carbon. - the double bond prevents the compound having the maximum number of hydrogen atoms. - Example: Ethene: C 2 H 6 - simplest alkene - used to treat green fruit to make it ripen faster - in the past used as anesthetic - used as starting material for polymers such as polyethene which is used for plastics, toys, household products, industrial products, etc. Note: When drawing structural formulas for alkenes it is important to remember that each carbon atom must have four bonds. 22

23 Naming Alkenes 1. Count longest chain of C atoms that contains the double bond. 2. Number this chain, counting from the end that is closest to the double bond. 3. Locate double bond and indicate its location in the name with the number of carbon the bond is after. 4. Complete the name using the appropriate prefix plus ene. Examples Structural Formula Compound Name CH 2 CH 2 1-ethene or ethene CH 2 = CH CH 2 CH 3 1-butene or butene CH 3 - CH = CH CH 3 2-butene 3-hexene CH 3 - CH 2 - CH = CH CH 2 CH 3 CH 2 = CH CH 2 CH 2 CH pentene CH 3 - CH = CH CH 2 CH 2 CH hexene CH 3 CH 2 CH 2 CH = CH CH 2 CH 2 CH 2 - CH nonane CH 2 CH 2 CH = CH CH 2 CH 2 CH 2 - CH octane 23

24 Naming Branched Chain Alkenes The method of naming is similar to the alkanes except you count from the end of the carbon molecule that is closest to the double bond, not the end closest to the branch. Examples Structural formula Compound Name 3,4-dimethyl-2-hexene 3-methyl-2-pentene 2-ethyl-4-methyl-1-hexene 2,3-dimethyl-2-butene 4-ethyl-3-octene 24

25 Cycloalkenes - basic formula is C n H 2n Naming Cycloalkenes 1. Count the number of carbon atoms and name the same as continuous chain alkenes. 2. If compound is a ring type structure, add prefix cyclo to alkane name. Examples Structural Formula Compound Name cyclopentene cyclopropene cyclooctene 2-ethyl-1-methyl cyclohexene 1-methyl cyclopropene 1-ethyl-3-methyl cyclobutene 25

26 Chemistry 2202 Organic Chemistry: Aliphatic Hydrocarbons (Aliphatic Hydrocarbons_7) 1. Name the Following: 1 2 Name: 3 4 CH 3 - CH = C CH 2 CH 2 CH 3 CH 2 CH 2 CH 3 5 CH 3 6 CH 3 - CH - CH C CH 2 CH 3 CH 3 CH - CH 2 - CH

27 2. Draw the following: Alkene/Alkyne Skeletal SF Condensed SF Line SF 2-octene 4-ethyl-3-methyl-1- heptene 3-hexene cyclopropene 27

28 Isomers - substances with same molecular formula but different structures - Examples: - C 10 H isomers - C 20 H isomers - C 30 H 62-4,111, 646, 763 isomers Pure Hydrocarbon Isomers Pure Hydrocarbon type Compound Formula Alkanes C n H 2n + 2 Alkenes C n H 2n Alkynes C n H 2n - 2 Cycloalkanes C n H 2n Cycloalkenes C n H 2n - 2 Note: - alkene and cycloalkane compounds can be isomers of each other - alkyne and cycloalkene compounds can be isomers of each other Isomers are actually broken up into three main groups, namely; 1. Structural 2. Geometric 3. Stereo 28

29 1. Structural Isomers - Compounds that have the same molecular formula but different structures. Hydrocarbon C 4 H 10 Isomer examples C 5 H 10 29

30 C 6 H 14 C 4 H 8 30

31 2. Geometric Isomers - Compounds that have the same molecular formula but different geometry (physical arrangement)of bonds. - Rotation in the double bond does not occur, so the groups of atoms attached to the carbon in the double bond remain fixed, resulting in the different geometries - 2 Types of shapes: - Cis - pronounced sis, - groups on same side of double bond - Trans - groups on opposite side of double bond - Cis/Trans written as part of name - e.g. cis-2-butene, trans-2-butene Examples: cis-2-butene trans-2-butene cis-2-pentene trans-2-pentene cis-2-hexene trans-2-hexene cis-3,4-dimethyl-3-hexene trans-3,4-dimethyl-3-hexene 31

32 Chemistry 2202 Organic Chemistry: Aliphatic Hydrocarbons_Isomers (Aliphatic Hydrocarbons_Isomers_1) Name: Fill out the chart below with as many isomers of C 6 H 12 as possible. Structural Formula Name 32

33 Complete Structural Formula Name 33

34 3. Alkynes - basic formula C n H 2n-2 - inert (non-reactive) in many chem rxns - hydrocarbons with at least one triple bond - alkynes are also referred to as un-saturated hydrocarbons because there are multiple C-C bonds since each carbon does not have the maximum number of hydrogens attached. Examples - Ethyne C 2 H 2 - simplest alkyne - common name is acetylene - used in oxyacetylene torches for welding - used as a fuel - Pentyne C 5 H 8 - natural rubber - sticky in hot weather and brittle in cold weather - synthetic rubber - is produced in great quantities today through a process called vulcanization (Vulcan - Roman God of the fire) Naming Alkynes 1. Count longest chain of C atoms. Name using the appropriate prefix plus yne. 2. Locate triple bond and use number to indicate location on chain. Count from the end that is closest to the triple bond. ] 34

35 Examples Structural Formula Name 35

36 Naming Branched Chain Alkynes - The method of naming is similar to the alkenes except you count from the end of the carbon molecule that is closest to the triple bond, not the end closest to the branch. Examples Structural Formula Name 36

37 Summary of Aliphatic Pure Hydrocarbons Aliphatic Hydrocarbon Compound Formula Bond Type Example Alkanes C n H 2n +2 single C 3 H 8 Cycloalkanes C n H 2n single C 3 H 6 Alkenes C n H 2n double C 3 H 6 Cycloalkenes C n H 2n-2 double C 3 H 4 Alkynes C n H 2n-2 triple C 3 H 4 Note that cyclo-alkanes and alkenes are isomers of each other, as are cyclo-alkenes and alkynes. 37

38 Organic Chemistry: Aliphatic Hydrocarbons (Aliphatic Hydrocarbons_1) Chemistry 2202 Name: Compound Skeletal SF Condenced SF Line SF octane propyne 2,3-dimethylpentane 3-hexene 4-ethyl-4-methyl-2-heptyne 3-ethyl-2,2- dimethylhexane cyclohexane cyclohexene 2-ethyl-1- propylcyclopentene 38

39 Chemistry 2202 Organic Chemistry: Aliphatic Hydrocarbons (Aliphatic Hydrocarbons_8) 1. Name the Following: 1 2 Name: Draw the following: Alkene/Alkyne Skeletal SF Condensed SF Line SF 2-octene 3,3-dimethyl-4- octene 3-heptyne cyclopropene 39

40 Chemistry 2202 Organic Chemistry: Aliphatic Hydrocarbons (Aliphatic Hydrocarbons_9) 1. Name the Following: 1 2 Name: Draw the following: Pure Hydrocarbon Skeletal SF Condensed SF Line SF 1-butene cycloheptene 1-butyne cyclopropane 40

41 Oil Refining - crude oil (unprocessed) is formed from marine life buried in ocean sediment millions of years ago - it consists of alkanes, and small amounts of S, O, N - we use physical and chemical processes to treat crude oil and make many marketable products - refined products include gas, crayons, plastics, jet fuel, asphalt, kerosene, fiber, etc. - 95% of all petroleum is used as fuel for vehicles and industry - 5% is used for a variety of household and industrial products such as plastics, detergents, rubber, drugs, etc. Newfoundland and Labrador reserves - Hibernia field has 1,200,000,000 barrels of oil and 64,000,000,000 barrels of gas. - Terra Nova field has 440,000,000 barrels of oil - White Rose field has 232,000,000 barrels of oil - Hebron-Ben Nevis field has 700,000,000 barrels of oil 41

42 Fractional Distillation - oldest and most common method of obtaining a variety of components from crude oil - physical process whereby crude oil is separated into diff components (fractions) using diff in b.p. Process: - crude oil is heated up to a T of 600 o C crude oil becomes a gas(vapour) - vapour enters bottom of column where it rises, cools and condenses in collection trays % of distilled crude oil is produced as gas(c 4 H 10 ) and this amount still does not meet demand (~ 50 % gas needed) - Come By Chance oil refinery processes about 100, 000 barrels of crude per day Oil refineries use both Cracking and Reforming processes to obtain further useful products from the fractional distillation process. Cracking - larger HCs are cracked/broken into smaller, more useful pieces - thermal cracking - heat - catalytic cracking - catalyst - Ex: C 17 H 36(l) -> C 9 H 20(l) + C 8 H 16(l) - propane is sometimes cracked, or broken down to produce methane, ethene, propene and hydrogen, depending on what the hydrocarbon market needs 42

43 Reforming - smaller HCs combined to make larger, more useful ones - platinum used as a catalyst - Ex: C 5 H 12(l) + C 5 H 12(l) -> C 10 H 22(l) + H 2(g) - sometimes straight chain alkanes are reformed to produce branched chain alkanes, or other, depending on what the hydrocarbon market needs. Use as Fuel - the number one use of refined oil is as fuel - the release of energy of HCs is the chemical reaction known as combustion 2 C 8 H 18(l) + 25 O 2(g) -> 16 O 2(g) + 18 H 2 O (g) + energy - internal combustion engines are not 100 % efficient resulting in unwanted byproducts such as carbon monoxide, nitrous oxide, unburned HC - U.S. market consumes 500,000,000,000 barrels per year (131 t. gallons) - 1 gallon is enough enegry to cook 110 McD hamburgers - eq. to 1500 watt heater left on for 24 hours more info: 43

44 Aromatics - historically named because of their odour/aroma - current defined as a compound with at least one benzene ring structure Common Compounds and Uses: - artificial flavouring (ex: vanillin) - ASA (aspirin) - benzocaine (local anesthetic) - adrenaline (natural) - released by the body in response to anxiety, exercise or fear. It is a natural stimulant that the body uses to control heart rate, sweat secretion, saliva production, etc. - amphetamines (synthetic) version of adrenaline - acts as a stimulant creating greater alertness and a feeling of prowess. - First used as a treatment for asthma, later used by military in WW2 and Vietnam as a stimulant. - Today marketed as illicit drugs such as speed, methamphetamine and ecstacy. Adrenaline Amphetamines - styrene (plastic starting material) - added to gas to improve burn quality 44

45 Benzene Structure - basic formula C 6 H 6(l) - the structure remained a mystery for long time because of its similar formula to a cycloalkene - testing, however, proved all the bonds in benzene were the same length and that its behaviour was more like an alkane than an alkene. - in 1865 August Kekule proposed a cyclic structure for the compound benzene. He suggested that benzene has 6 C atoms, each bonded to 1 H atom. He also suggested that the remaining unpaired bonding electrons were delocalized. - delocalized electrons results in a strong hybrid (single/double) bond between C atoms - these bonds make benzene stable - drawn as hexagon with an circle inside. Benzene, however, was traditionally written with a triple bond inside the ring type structure. Complete Line Benzene Properties - liquid at room temperature - boiling point 80.1 o C - planar - non-polar (soluble in non-polar solvents) Branched Benzene Structures (Alkyl Benzene) - any of benzene s six atoms can be substituted by an alkyl group. We consider only two types of substitutions with benzene compounds, namely - mono-substituted - di-substituted 45

46 Mono-substituted Benzene -refers to benzene structures with only one hydrogen atom substituted by an alkyl group. Naming Mono-substituted benzene structures. - Use benzene as the parent name - Determine name of the alkyl group - Add alkyl group name as a prefix (no position needed) Examples Structural Formula Compound Name 46

47 Di-substituted Benzene - refers to benzene structures with two hydrogen atoms substituted by two alkyl groups. - This results in three possible arrangements of the alkyl group around the benzene structure, as follows in the diagram below - As a result, this means there are three possible isomers of each compound. 1 and 2 1 and 3 1 and 4 Naming Di-Substituted Benzene Structures - To name di-substituted benzene structures you simply count clockwise from the first branch, or from the most complex branch, and the position of the alkyl groups is identified using the following system of prefixes. Prefix Position of alkyl groups Ortho (O) 1 and 2 Meta (M) 1 and 3 Para (P) 1 and 4 47

48 Examples Structural Formula Compound Name 48

49 Chemistry 2202 Organic Chemistry: Aromatics(Benzene Structures) (Aromatics_1) Name: Structural Formula Compound Name Name 1 Name 2 Name 1 Name 2 Name 1 Name 2 1-ethyl-3-phenylbenzene o-propylbenzene 49

50 Phenyl Groups - some carbon compounds have a benzene branch that is part of another structure. - In this case the benzene structure is referred to as a phenyl group. Examples Note: Structural Formula these structures will be named using the naming system for branched chain alkanes. Compound Name 50

51 Polymerization Monomers - mono - meaning one - small carbon based molecular units. Polymers - poly - meaning many - long carbon based compounds whose molecules are made up of connected monomers. Polymers can be compared to individual links in a chain. - sometimes form very large(giant) molecules - a polymer may contain one, or more, types of monomers - can be formed naturally - proteins (10 billion on Earth) - examples include glucose and fructose - can be formed synthetically - plastics - there are two methods of producing synthetic polymers - Addition polymerization - Condensation polymerization - good time to discuss the problems associated with synthetic polymers and their long life as pollution in our environment. - long life of materials - wildlife concerns - litter concerns 51

52 Addition Polymerization - this type of reaction occurs when unsaturated monomers react to form longer chain polymers - monomers join in a process that involves breaking double and/or triple bonds between carbon atoms in the monomer. - some products include polyethylene materials such as plastic, wire insulation, plastic freezer dishes, lab grade wash bottles, etc. Examples Condensation Polymerization - formed by a head-to-tail joining of monomers that usually results in the formation of a polymer and some small molecule such as H 2 O, NH 3 and HCl. Eg. glucose + fructose sucrose + water. - some products of this type of reaction include nylon materials, polyesters, tires, and many other household and industrial products. Examples See page of text for example 52

53 Chemical Reactions Involving Pure Hydrocarbons We Will: - Identify Reaction Type - Draw Structural Formulas of organic reactants and products. - Predict products. - Determine name/structure of a missing compound in a reaction. Reaction Types 1. Substitution 2. Addition 3. Cracking 4. Reforming 5. Complete Combustion 6. Incomplete Combustion Halocarbon - alkane or benzene with halogen attached - not found in nature - often used as an anesthetic Chloroethane Trichloromethane Chlorobenzene 53

54 1. Substitution - Alkanes and Benzene structures undergo Substitution Reactions - Reactions often occurs in the presence of light - Light serves as a catalyst - Reactions generally slow strong covalent bonds difficult to break - always involves two reactants and two products General Equation: R-H + X 2 R-X + H-X Where: R - any alkane or benzene structure X 2 - any halogen R-X - halocarbon(organic halide) - alkane or benzene with halogen attached H-X - hydrogen halide - hydrogen with halogen attached Subtype 1: Alkane Single Substitutions - Example 1: Ethane reacts with chlorine - Example 2: Propane reacts with bromine - Example 3: Butane reacts with fluorine 54

55 Subtype 2: Alkane Double Substitutions (Note excess halogen reactant) - Example 1: Ethane reacts with excess chlorine - Example 2: Propane reacts with excess bromine Subtype 3: Benzene Substitutions - benzene behaves chemically like an Alkane - like alkanes, it is very stable and almost unreactive - a catalyst if often needed for benzene reactions Ex: iron - Example 1: Benzene reacts with chlorine - Example 2: Benzene reacts with fluorine - Example 3: Benzene reacts with excess bromine 55

56 Complete the following: 1. Benzene reacts with iodine 2. Pentane reacts with excess chlorine 3. Propane reacts with bromine 4. Butane reacts with excess fluorine 56

57 2. Addition Reactions - Alkenes and Alkynes undergo addition reactions - Alkenes and Alkynes are more chemically reactive - In Alkene double bond is broken into a single bond - In Alkyne triple bond is broken into a double bond or single bond - Results in free bonding electrons around the site of the old multiple bond - Always involved two reactants and one product - Note: Hydrogen atom is not removed from Alkene/Alkyne General Equation -C=C- + X-Y X-C=C-Y Where: - -C=C- - alkene or alkyne - X-Y - H 2 O, halogen or hydrogen halide - X-C=C-Y - single product Subtype 1: Halogen Addition - halogen adds on to double/triple bond site - Example 1: Ethene reacts with chlorine - Example 2: Ethyne reacts with chlorine 57

58 - Example 3: 1-butyne reacts with bromine - Example 4: 1-butyne reacts with excess bromine Note: all multiple bonds are broken Subtype 2: Water Addition - H and OH add on to double/triple bond site - Example 1: 1-butene reacts with water - Example 2: 1-butyne reacts with water - Example 3: propene reacts with excess water - Example 4: 2-butyne reacts with excess water Note: all multiple bonds are broken Subtype 3: Hydrogen Halide Addition - H and halogen add on to double/triple bond site - Example 1: 1-propene reacts with hydrogen bromide - Example 2: cyclohexene reacts with hydrogen chloride 58

59 Chemistry 2202 Organic Chemistry: Organic Reactions Name: Complete the following Addition Reactions. 1 1-butene reacts with chlorine 2 1-proene reacts with water 3 1-butyne reacts with water 4 1-propyne reacts with fluorine 5 Cyclohexene reacts with hydrogen bromide 6 1-propyne reacts with hydrogen iodide 7 2-pentyne reacts with excess chlorine 8 2-pentyne reacts with water 59

60 9 1-propyne reacts with excess bromine 10 2-butene reacts with excess hydrogen chloride 11 cyclobutene reacts with water 12 ethyne reacts with excess bromine 13 3-heptene reacts with iodine 60

61 Chemistry 2202 Organic Chemistry: Organic Reactions Name: Addition Reactions - alkenes and alkynes - one product only Substitution Reactions - alkanes and benzene - two products 1. Complete the reaction and name the type for each of the following; Organic Reaction Type Cyclohexene + water Benzene + bromine Propane reacts with iodine Ethene reacts with iodine 2. Complete the reaction and name the reaction type for each of the following Organic Reaction Type 61

62 Type 3: Cracking - long hydrocarbons, in the presence of heat and/or a catalyst, are broken down into shorter hydrocarbons General Formula: Long Chain Hydrocarbon + H 2 Short Chain Hydrocarbon - Example 1: - Example 2: Type 4 : Reforming - short hydrocarbons, in the presence of heat and/or a catalyst are connected to form longer hydrocarbons General Formula: Short Chain Hydrocarbon Long Chain Hydrocarbon + H 2 - Example 1: - Example 2: 62

63 Type 5: Complete Combustion General Formula: C x H y + O 2 CO 2 + H 2 O - Example 1: - Example 2: Type 6: Incomplete Combustion General Formula: C x H y + O 2 CO + C + CO 2 + H 2 O 63

64 Chemistry 2202 Organic Chemistry: Chemical Reactions (Chemical Reactions_1) Name: There are Six types of Chemical Reactions: 1. Substitution R-H + X 2 R-X + HX 2. Addition C=C + X-Y X-C-C-Y 3. Combustion C x H y + O 2 CO 2 + H 2 O 4. Incomplete Combustion C x H y + O 2 C + CO + CO 2 + H 2 O 5. Cracking long HC chain + H 2 shorter HC chains 6. Reforming short HC chains long HC chain + H 2 1. Name each of the following reaction types. A) + HOH B) C 5 H 12 + C 3 H 8 C 8 H 18 + H 2 C) -C-C-C- + I 2 -C-C-C-I + HI D) CH O 2 CO H 2 O E) + Br 2 + HBr F) C 17 H 36 + H 2 C 9 H 20 + C 8 H 18 G) -C C-C- + 2 HCl -C-C-C- 64

65 2. Predict the products and name each of the following reaction types. A) + I 2 B) -C C- + 2 I 2 C) -C-C-C-C=C- + HOH D) -C-C-C-C-C- + O 2 E) + HBr 3. Write the structural formula of the missing reactant and name the reaction type. A) + H-Cl -C-C-H B) + Cl 2 + HCl C) + HOH C=C D) + Br 2 + HBr E) + 2 HOH -C-C-C-C- F) + Cl 2 65

66 4. Write balanced chemical equations for each of the following hydrocarbon combustion reactions. A) ethane B) butane C) hexane D) 2,2,3-trimethylpentane E) benzene F) cyclobutane 66

67 5. Draw the structural formulas of reactants and products. A) the cracking of heptane into propane and butane B) the cracking of 2-methylpentane with hydrogen to produce two propanes C) the cracking of 1-butene to produce ethyne and ethane D) the cracking of a hydrocarbon and one hydrogen to produce methane and propane E) hexane + ethane octane + hydrogen F) 2-methylbutane + propane 3,3-dimethylhexane + hydrogen G) the forming of decane and hydrogen from two pentanes 67

68 Chemistry 2202 Organic Chemistry: Chemical Reactions MATCH-UP the organic reaction with the reaction TYPE: Name: 1. Addition A. -C-C-C- + F 2 -C-C-C-F + HF 2. Cracking B. CH O 2 CO H 2 O 3. Combustion C. C 8 H 18 + C 9 H 20 C 17 H 36 + H 2 4. Reforming D. -C-C C- + 2 HBr -C-C-C- 5. Substitution E. C 20 H 42 + H 2 C 10 H 22 + C 10 H 22 PREDICT the following reactions: 6. + HOH 7. + Cl C-C-C-C-C- + 2 I C-C C-C- + F WRITE STRUCTURAL formulas for the following reactions: methylpentane and hydrogen cracked to produce propane 11. hexane + ethane 3-ethylhexane + hydrogen BALANCE the following reaction: C 8 H 18 + O 2 CO 2 + H 2 O 68

69 Pure Hydrocarbons Review (Pure Hydrocarbons Review) Chemistry 2202 Terms to Know Organic Chemistry Organic Compound Inorganic Compound Frederick Wohler Pure Hydrocarbon vs. Hydrocarbon Derivative Isomer - Structural, Geometric, Stereoisomer Structural Formula - Complete, Condensed, Skeletal, Line Functional Group Homologous Series Saturated vs. Unsaturated Hydrocarbon Crude Oil Fractional Distillation Cracking/Reforming Complete vs. Incomplete combustion Aliphatic Hydrocarbon - Alkanes, Alkenes, Alkynes Alkanes (C n H 2n+2 ), Cycloalkanes (C n H 2n ) Alkenes (C n H 2n ), Cycloalkenes (C n H 2n-2 ) Alkynes (C n H 2n-2) Aromatic - Benzene (C 6 H 6 ) August Kekule Delocalized Electrons/Hybrid Monosubstituted vs. Disubstituted Benzene Phenyl Groups Addition and Substitution Concepts to Know Properties of carbon Naming and Drawing Alkane, Alkene, Alkyne and Benzene structures Straight Chain, Branched Chain, Cyclic structures Properties of Pure Hydrocarbons Formulas, Boiling Points, Solubility, Reactivity Examples of Pure Hydrocarbons Predicting of Isomers Oil Refining Process Polymerization Naming Reaction Type and Balancing Equation Addition Substitution Cracking Reforming Complete Combustion Incomplete Combustion 69

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