UNIT 5: ORGANIC CHEMISTRY

Transcription

1 onour hemistry Unit 5: rganic hemistry hapter 5: ydrocarbon ompounds 5.: ydrocarbons UNIT 5: RGANI EMISTRY ydrocarbons: - compounds that contains hydrogen and carbon atoms. - it may contain oxygen, nitrogen and other halogen atoms. In complex organic compound, it may even contain transition metals. Examples: 4 (Methane), 8 (Propane), 6 6 (Glucose), (Methanol) are hydrocarbons. (arbon dioxide) and (arbon monoxide) are not hydrocarbons (no hydrogen atoms). Lewis Structure of ydrocarbons: - each carbon has 4 valence electrons; therefore it has a maximum of 4 bonding sites. - all lone pairs must be drawn in. Example: 5 (Propanoic Acid) Note that there are 4 bonds around each carbon atom. Structural Formulas: - a Lewis structure without any lone pairs notations. - there are many forms to write the structural formulas Example: Molecular Formula: 5 (-Pentanol) omplete Structural Formula Skeletal Forms (Each endpoint of the zigzag represents a carbon atom) or or or ( ) 4 (ondensed Structural Formulas) (Notice the two lone pairs around the oxygen atom are not drawn) opyrighted by Gabriel Tang B.Ed., B.Sc. Page 97.

2 Unit 5: rganic hemistry onour hemistry Prefixes of rganic ompounds Nomenclature (You are responsible for the first 0 prefixes.) carbon Meth~ 6 carbons ex~ carbons Undec~ 0 carbons Icos~ carbons Eth~ 7 carbons ept~ carbons Dodec~ carbons enicos~ carbons Prop~ 8 carbons ct~ carbons Tridec~ carbons Docos~ 4 carbons But~ 9 carbons Non~ 4 carbons tetradec~ 0 carbons Triacont~ 5 carbons Pent~ 0 carbons Dec~ 5 carbons pentadec~ 40 carbons Tetracont~ Alkane: - a group of hydrocarbons that has a molecular formula n n +. - nomenclature of alkane involves the use of the suffix ~ane (like in Alk ~ane). Straight hained ydrocarbons: - also called Unbranched ydrocarbons. - hydrocarbons that do NT branched out. Example : Name the following organic compounds or give the molecular formula. Provide a structural formula for these compounds. a. 6 b. 5 Alkane: () + Ethane Alkane: 5 (5) + Pentane c. ctane d. Decane Alkane: 8 (8) Alkane: 0 (0) + 0 or ( ) 6 Branched ydrocarbons: - hydrocarbons that consist of a main chain along with substituent groups Example: Substituent Straight hain Branched (the branched group is called a substituent) Page 98. opyrighted by Gabriel Tang B.Ed., B.Sc.

3 onour hemistry Unit 5: rganic hemistry Alkyl Group: - the substituent component of a branched hydrocarbon. - nomenclature of alkyl group involves the use of the suffix ~yl (like in Alk ~yl). This is followed by the longest main chain of the hydrocarbons. Nomenclature of Alkanes. Identify the number of carbons in the longest chain. (It is not always the straight one. It can be bent). Example: 7 arbons: root name is heptane nly 6 arbons: Not the Longest hain. Number the carbons of the longest chain with the first alkyl group at the lowest carbon position possible. Example: Alkyl Group: arbon (methyl) at Position methyl at Position 5 (Not the Lowest arbon Position) Start with the position of the alkyl group, then the name of the alkyl group. Finally the name of the main chain (root name). Example: -methylheptane yphen should be added between number and alphabet. There is no space between the alkyl group and the root name. 4. If there are more than one alkyl groups, and they are at the different carbon positions, the alkyl groups shall be name by their positions but their appearance in the final name has to follow alphabetical order. Example: methyl at Position 5-ethyl--methylheptane (orrect Name) methyl at Position 6 4 -ethyl-6-methylheptane (Incorrect Name position combination is larger) -methyl-5-ethylheptane Alkyl Group: (Incorrect Name substituent groups arbon (ethyl) are not in alphabetical order) at Position 5 ethyl at Position opyrighted by Gabriel Tang B.Ed., B.Sc. Page 99.

4 Unit 5: rganic hemistry onour hemistry 5. If there are more than one alkyl groups, and they are at the same carbon position, then we can name the position as a repeated number separated by a comma. In any case, we have to name all positions. If the alkyl groups have the same name, then we can use prefixes with the alkyl groups. (These prefixed are the same as the ones for molecular formulas.) Example: 4 5,5-diethyl-,-dimethyl heptane (orrect Name) 6 7 Two methyl groups and both at position (,-dimethyl) Two ethyl groups at positions and 5 (,5-diethyl) Properties of Alkanes. All Alkanes are Non-Polar. The only intermolecular bonds they have are London Dispersion Forces.. The more carbon the alkane has, the higher the boiling point.. The smaller alkanes tend to have low melting and boiling points. They tend to be gas and liquid at room temperature (methane to butane are gases; pentane to decane are liquids). 4. Alkanes do NT Dissolve in Water. Assignment 5. pg. 747 #, ; pg. 749 #; pg. 750 #4, 5; pg. 75 #6 to 8, 0 Page 00. opyrighted by Gabriel Tang B.Ed., B.Sc.

5 onour hemistry Unit 5: rganic hemistry 5.: Unsaturated ydrocarbons Saturated ydrocarbons: - hydrocarbons that consist of all single bonds only. Unsaturated Bonds: - hydrocarbons that contain double or triple bond(s). Alkenes: - hydrocarbons that contain a = (double bond) - nomenclature of alkane involves the use of the suffix ~ene (like in Alk ~ene). - hydrocarbons with two double bonds are named with the suffix ~diene (~di ene as in two double bonds). - hydrocarbons with three double bonds are named with the suffix ~triene (~tri ene as in three double bonds). - unless it is understood, all double bond locations along the longest carbon chain must be identified. - prefixes to indicate the number of carbon atoms in the longest chain along with the naming of any alkyl group remains the same as alkane compounds with the lowest numerical combination given to the double bonds. Note: The alkene group takes precedent in the root naming over any substituents. - for one double bond alkenes, the molecular formula n n. Example : Name the following alkenes or give the molecular formula or vice-versa. Provide a structural formula for these compounds. a. 4 b. -octene Alkene: () c. -decene Ethene Alkene: 0 (0) Alkene: 8 (8) The double bond starts at carbon = or ( ) The double bond starts at carbon-. = or ( ) 5 opyrighted by Gabriel Tang B.Ed., B.Sc. Page 0.

6 Unit 5: rganic hemistry onour hemistry d. =( 5 )= ( ) First, we draw the structural formula. methyl at Position Root Name:,-hexadiene ethyl at Position Positions of the two double bonds -ethyl-5-methyl-,-hexadiene (orrect Name) This is a longer chain. But, it does NT include all the Double Bonds. Therefore, it is wrong! (Double Bonds take precedent over substituents) Alkynes: - hydrocarbons that contain a (triple bond) - nomenclature of alkane involves the use of the suffix ~yne (like in Alk ~yne). - hydrocarbons with two triple bonds are named with the suffix ~diyne (~di yne as in two triple bonds). - hydrocarbons with three triple bonds are named with the suffix ~triyne (~tri yne as in three triple bonds). - unless it is understood, all triple bond locations along the longest carbon chain must be identified. - prefixes to indicate the number of carbon atoms in the longest chain along with the naming of any alkyl group remains the same as alkane compounds with the lowest numerical combination given to the triple bonds. Note: The alkyne group takes precedent in the root naming over any substituents. - for one triple bond alkenes, the molecular formula n n. Example : Name the following alkynes or give the molecular formula or vice-versa. Provide a structural formula for these compounds. a. 4 b. -heptyne Alkyne: () Propyne Alkene: 7 (7) 7 The triple bond starts at carbon-. or ( ) Page 0. opyrighted by Gabriel Tang B.Ed., B.Sc.

7 onour hemistry Unit 5: rganic hemistry c. ( 5 ) ( ) First, we draw the structural formula. ethyl at Position methyl at Position 7 6 Root Name:,5-nonadiyne 7 8 Positions of the two triple bonds 9 4-ethyl-7-methyl-,5-nonadiyne (orrect Name) Properties of Alkenes and Alkynes. Most Alkenes and Alkynes are Non-Polar. They only have London Dispersion Forces.. Their boiling points are comparable to alkanes. The double bonds and triple bonds do NT have any effect on their physical properties.. They do give off more heat (more exothermic) when burned (combusted) compare to alkanes. This is because there are more energy stored in the double and triple bonds. When this energy is released during a chemical reaction, more heat is given off. ombustion is a chemical property. 4. Because of the non-polar nature of alkenes and alkynes, they do NT Dissolve in Water. 5.: Isomerism Structural Isomers: - hydrocarbons with the same molecular formula that can have other structural formulas. - all have very different chemical and physical properties. Example: 4 0 has two structural formulas. butane (bp 0.5 ) -methylpropane or methylpropane (bp 0. ) Example : Provide the names and structural formulas for all the isomers of heptane. (int: there are 9 isomers) heptane ( ) 5 opyrighted by Gabriel Tang B.Ed., B.Sc. Page 0.

8 Unit 5: rganic hemistry onour hemistry or -methylhexane ( ) or -methylhexane ( ) or,-dimethylpentane ( ) ( ),-dimethylpentane ( ) or,-dimethylpentane,4-dimethylpentane -ethylpentane ( 5 ) or,,-trimethylbutane ( ) Page 04. opyrighted by Gabriel Tang B.Ed., B.Sc.

9 onour hemistry Unit 5: rganic hemistry Geometrical isomers: - hydrocarbons or which differ in the positions of atoms (or groups) relative to a reference plane. Also refer to as cis-trans isomers. - in the cis-isomer the atoms are on the same side. - in the trans-isomer they are on opposite sides. - all have different chemical and physical properties. Examples: 4 cis--butene (bp.7 ) trans--butene (bp 0.9 ) 4 Example : Draw the structural formula and state the name for the following organic compounds. a. cis--pentene b. 4 5 () 4 5 trans-,4-dimethyl--pentene (trans are on the main chain) Assignment 5. pg. 75 # to 5. pg. 757 #6, 8 opyrighted by Gabriel Tang B.Ed., B.Sc. Page 05.

10 Unit 5: rganic hemistry onour hemistry 5.4: ydrocarbon Rings yclic ydrocarbons: - hydrocarbons where carbons form a ring of some geometrical shape. yclic Alkane: - where the ends of an alkane chain are connected to each other in a cyclical shape. - the molecular formula has a form of n n. - naming contains the prefix cyclo~ before the root name. - substituents are named the same way as branched alkanes (pick any corner as carbon ). yclopropane ( 6 ) (bond angle 60 ) (Too tight unstable) yclobutane ( 4 8 ) (bond angle 90 ) (still tight unstable) yclopentane ( 5 0 ) (bond angle 08 - close to tetrahedral - stable) -D (use molecular model to demonstrate) hair onformation yclohexane ( 6 ) (bond angle same as tetrahedral) (very stable) Boat onformation Example : Provide a structural formula for these organic compounds below. The hair formation is slightly more stable a. methylcyclopentane b.,-dimethylcyclohexane Whenever the position of the substituent is not stated, it is always assume as position. ( ) 4 ( ) 4 Page 06. opyrighted by Gabriel Tang B.Ed., B.Sc.

11 onour hemistry Unit 5: rganic hemistry Example : Provide the names and structural formulas for all the isomers (non-cyclic and cyclic) of 5 0. There are 9 isomers to pentene -pentene -methyl--butene ( ) -methyl--butene ( ) or -methyl--butene ( ) cyclopentane ( ) 5 methylcyclobutane ( ) dimethylcycloproane ( )( ) ethylcycloproane ( 5 ) Aliphatic ydrocarbons: - alkanes, alkenes, alkynes, and cyclic alkanes. Aromatic ydrocarbons: - cyclic hydrocarbons characterize by alternating double bonds in a ring. Example: 6 6 (Benzene): a very stable compound due to the delocalized double bonds to form a ring. Resonance structures for benzene opyrighted by Gabriel Tang B.Ed., B.Sc. Page 07.

12 Unit 5: rganic hemistry onour hemistry Naming Aromatic ompounds:. If benzene is used as the main group then the word benzene becomes the root name.. If benzene is used as a substituent as 6 5 (like methyl from 4 ), then the substituent name becomes phenyl.. The positions of substituents on the benzene ring is like those on the cyclo-aliphatic hydrocarbons. We pick a substituent corner and call it carbon position. Then, we go around the benzene ring such that the final combinations of the positions are the lowest. Example 6: Name the following aromatic compounds a. b. c. methylbenzene ommon name: Toluene d. e.,-dimethylbenzene (ortho-dimethylbenzene) ommon name: (o-xylene),-dimethylbenzene (meta-dimethylbenzene) ommon name: (m-xylene),4-dimethylbenzene (para-dimethylbenzene) ommon name: (p-xylene) trans--phenylpropene Page 08. opyrighted by Gabriel Tang B.Ed., B.Sc.

13 onour hemistry Unit 5: rganic hemistry 5.5: ydrocarbons from Earth Fossil Fuel: - hydrocarbon fuels that came from fossils of decayed organisms.. Natural Gas: - fossil fuel that consists of mainly small alkanes (80% methane, 0% ethane, 4% propane, % butane, 4% nitrogen). - usually burns efficiently (complete combustion). omplete ombustion: - where the products of combustion are carbon dioxide and water vapour only. -characterized by a blue flame. Example: Propane burns completely. 8 (g) + 5 (g) (g) + 4 (g) Incomplete ombustion: - where the main product of combustion is carbon monoxide, along with carbon dioxide and water vapour. - happens when carbon particles started to form during combustion and deposited as soot as they cooled, or when there is insufficient oxygen. - characterized by a yellow flame. Example: Incomplete combustion of Propane. 8 (g) + 4 (g) (g) + (g) + 4 (g). Petroleum (rude il): - fossil fuels that consist mainly of heavier alkanes along with small amounts of aromatic hydrocarbons, and organic compounds that contain sulfur, oxygen and nitrogen. - gasoline is composed of 40% of crude oil, whereas natural gas is composed of only 0%. Fractional Distillation: - a method of heating crude oil in a tall column to separate its different components by their different boiling points. - lighter alkanes in the natural gas will rise up to the top of the column because of their low boiling points. - the heavier, fuel and lubricating oils will boil off at the bottom of the column due to their high boiling points. opyrighted by Gabriel Tang B.Ed., B.Sc. Page 09.

14 Unit 5: rganic hemistry onour hemistry Petroleum Refining: - a process to isolate different types of fuel from crude oil using fractional distillation or cracking. racking: - a chemical process whereby bigger alkanes are broken up into smaller ones using a catalyst and heat. - since gasoline and natural gas only consists of 50% of crude oil, cracking is necessary to convert heavier fuel to more common fuel used in today s world. Example: The racking of exadecane catalyst and heat Reforming: - a chemical process where smaller alkanes are combined together and hydrogen is removed to form heavier alkanes or changed unbranched alkanes into branched alkanes. - branched alkanes are easier to burn and has a higher octane value in gasoline. (isooctane or,,4-trimethylpentane has the best octane rating assigned as 00). oal: - a carbon-based mineral consists of very dense hydrocarbon ring compounds with high molar masses. - leaves a lot of soot and burns incompletely. - usually contains 7% sulfur and when combusted with oxygen gives off S and S, which is the main source of air pollution and acid rain. Assignment 5.4 pg. 76 #0 to 5.5 pg. 765 #4 to 7 hapter 5 Review: pg #8 to 45, 49 to 50, 5, 55; pg. 77 #68, 69 Page 0. opyrighted by Gabriel Tang B.Ed., B.Sc.

15 onour hemistry Unit 5: rganic hemistry hapter 6: Functional Groups and rganic Reactions 6.: Introduction to Functional Groups Functional Group: - a reactive portion of a molecule that gives the resulting hydrocarbon derivatives their special chemical and physical properties. alocarbons (RX): - hydrocarbons that contain halogen substituent(s) (also known as alkyl halides). - R symbolizes the rest of the carbon chain. - uses the same rules as naming branched alkanes. - F (fluoro), l (chloro), Br (bromo), I (iodo). Example : Name the following halogen derivates or give the molecular formula. Provide a structural formula for these compounds. a. l b. F Br l F Br Br,-dibromo--fluoropropane (Incorrect Naming number sequence could be better) chloroethane,-dibromo--fluoropropane c. dichlorofluoromethane d.,,-trichloro-,-diiodo--methylbutane l l l l F l l F I I l I li Properties of alocarbons:. Depending on the number of alkyl halides, some halocarbons can be polar; some are non-polar.. The Polar alocarbons are soluble in water while the Non-polar ones do not.. In general, the more alkyl halides groups a halocarbon have, the higher its boiling point. This is because halogens are heavier atoms that are governed by van der Waals Forces (London Dispersion and sometimes Dipole-Dipole Interactions). opyrighted by Gabriel Tang B.Ed., B.Sc. Page.

16 Unit 5: rganic hemistry _ onour hemistry alogen Substitution Reaction: - a reaction where a halogen element (X ) is reacting with alkane (R ) to form halocarbon (RX) and a hydrogen halide (X) under the presence of light energy or a catalyst. Alkane (R ) + alogen (X ) hν alogen Derivate (RX) + X hν = light energy (heck out animation at Example: Propane + hlorine -chloropropane + ydrogen hloride 8 (g) + l (g) l (g) + l (g) + l l ν l h + l alogenation Addition: - when a halogen element (X ) or hydrogen halide (X) is added across a double bond or triple bond to form halocarbons. Alkene ( n n ) + alogen (X ) Alkane alogen Derivative ( n n X ) Alkene ( n n ) + ydrogen alide (X) Alkane alogen Derivatives ( n n+ X) (heck out the animation at Example: Propene + hlorine,-dichloropropane 6 (g) + l (g) l l (l) = + l l (heck out the animation at Example: Propene + ydrogen hloride -chloropropane + -chloropropane 6 (g) + l (g) l (l) + l (l) l l = + l l l Assignment 6. pg. 777 # to 4, 6; pg. 784 #a, b. Page. opyrighted by Gabriel Tang B.Ed., B.Sc.

17 onour hemistry Unit 5: rganic hemistry 6.: Alcohols and Ethers Alcohols: - organic compounds containing a hydroxyl functional group, (R-), substituted for a hydrogen atom. (R represent the rest of the carbon main chain.) - naming of alcohols starts with the prefix of the number of carbon in the longest chain including the group but end with the suffix ~ol (like in Alcoh ~ol). - hydrocarbons with two groups are named with the suffix ~diol (~di ol as in two groups). - hydrocarbons with three groups are named with the suffix ~triol (~tri ol as in groups). - unless it is understood, all locations along the longest carbon chain must be identified. - prefixes to indicate the number of carbon atoms in the longest chain along with the naming of any alkyl group remains the same as alkane compounds with the lowest numerical combination given to the group. Note: The alcohol group takes precedent in the root naming over any substituents (alkyl and halogen substituents). a. Primary Alcohol: - group attaches to a carbon with one alkyl group. - can react to form functional group like aldehydes (will be explain later). b. Secondary Alcohol: - group attaches to a carbon with two alkyl groups. - can react to form functional group like ketones (will be explain later). c. Tertiary Alcohol: - group attaches to a carbon with three alkyl groups. - do not usually react to form other functional groups (chemically stable). R Primary Alcohol (one alkyl group R attached to which attached to group) R R' Secondary Alcohol (two alkyl groups R and R attached to which attached to group) R R' R" Tertiary Alcohol (three alkyl groups R, R, and R attached to which attached to group) Example : Name the following alcohols or give the molecular formula or vice-versa. Provide a structural formula for these compounds. Indicate whether the alcohol is primary, secondary or tertiary. a. 5 b. -propanol Alcohol: 5 Ethanol Primary Alcohol Product of Fermentation () opyrighted by Gabriel Tang B.Ed., B.Sc. Page. The group is at carbon-. Rubbing Alcohol Secondary Alcohol

18 Unit 5: rganic hemistry _ onour hemistry c. 6 5 d. ethandiol Alcohol with Benzene Benzenol (or Phenol) Secondary Alcohol Primary Alcohol The groups are at both carbons. ommonly known as ethylene glycol (Automobile Antifreeze) () () e. ( ) First, we draw the structural formula. methyl at Position ydroxyl group takes 4 5 -methyl--penten--ol Tertiary Alcohol hydroxyl at Position Root Name: -penten--ol Positions of the double bond precedent over alkene double bond when numbering carbon chain Properties of Alcohol:. All Alcohols are Polar. Because of the group, they all have hydrogen bonding.. Alcohols that have four carbons or less are very soluble in water (R- compares to ).. Alcohols that have more than four carbons are not as soluble in water due to the long carbon chain, which is non-polar. 4. Most alcohols have high boiling points due to the hydrogen bonds. This is especially true for alcohol molecules that have more than one group. 5. Primary Alcohols has the ighest Boiling Point, whereas Tertiary Alcohol has the Lowest Boiling Point. This is because primary alcohols have the group at the carbon atom that is the least crowded Thus, hydrogen bonds are stronger and boiling points are higher. Alcohol Substitution Reaction: - a reaction where a base (A) is reacting with a halocarbon (R X) to form alcohol (R) and an alkali halide (AX) under the aqueous condition of water at high temperature. alocarbon (R X) + Alkali alide (A) at 00 o Alcohol (R) + Alkali alide AX Page 4. opyrighted by Gabriel Tang B.Ed., B.Sc.

19 onour hemistry Example: -chloropropane + Sodium ydroxide at 00 l (l) + Na at 00 (aq) o o Unit 5: rganic hemistry -propanol + Sodium hloride (l) + Nal (aq) l + Na + (aq) + (aq) o at 00 + Na + (aq) + l (aq) ydration Addition: - when water ( ) is added across a double bond to form an alcohol under acidic condition. Alkene ( n n ) + Water ( ) acid Alcohol ( n n+ ) Example: Propene + Water acid -propanol + -propanol 6 (g) + (l) acid (l) + () (l) = + acid + ydrogenation Addition: - when hydrogen is added across a double bond or triple bond alkanes with the aid of a catalyst. Alkyne + ydrogen catalyst Alkene Alkene + ydrogen catalyst (heck out the animation at Example: Propyne + ydrogen catalyst Propene 4 (g) + (g) catalyst 6 (g) + catalyst = Example: Propene + ydrogen catalyst Propane 6 (g) + (g) catalyst 8 (g) = + catalyst (Note: From Propyne to Propane ydrogenation, it is stepwise.) Alkane opyrighted by Gabriel Tang B.Ed., B.Sc. Page 5.

20 Unit 5: rganic hemistry _ onour hemistry Ethers: - organic compounds containing a hydroxyl functional group, (R R ), substituted for a hydrogen atom. (R and R represent the two alkyl groups.) - naming of ethers starts with the two alkyl groups (in alphabetical order) ending with ether. - hydrocarbons with two similar alkyl groups can use the prefix di~. Example : Name the following ethers or give the molecular formula or vice-versa. Provide a structural formula for these compounds. a. diethyl ether b. 4 9 Ether with two ethyl groups: 5 5 c Used as anaesthetic in the past. Now it is an industrial solvent. butyl substituent butylmethyl ether methyl substituent propyl substituent phenylpropyl ether phenyl substituent Properties of Ethers:. Ethers are Polar. This is due to the bent shape and the two lone pairs around the oxygen atom.. Ethers have igher Boiling Points than Alkanes with the same molar mass. owever, they have Lower Boiling Points than comparable Alcohols. This is because even though ethers are polar, they do not have hydrogen bonds like alcohols do.. Ethers are very Soluble in Water. Assignment 6. pg. 784 #7 to, c; pg. 777 #5 Page 6. opyrighted by Gabriel Tang B.Ed., B.Sc.

21 onour hemistry Unit 5: rganic hemistry 6.: arbonyl ompounds arbonyl Group: - a group.. Aldehydes: - compound containing a carbonyl group with at least one hydrogen atom (R-) attached to it. Note that it is as aldehyde not as alcohol. R - polar molecules (due to oxygen s two lone pairs); very soluble in water (hydrogen bonding between water and carbonyl group). - Aromatic aldehydes are commonly used as artificial flavours. - naming of aldehydes starts with the prefix of the number of carbon in the longest chain including the = group but end with the suffix ~al (like in al -dehyde). Example : Name the following aldehydes or give the molecular formula or vice-versa. Provide a structural formula for these compounds. a. methanal b. 7 Aldehyde: Methanal (-arbon) ommonly known as formaldehyde. Used as embalming fluid in mortuary. Aldehyde: 4-arbons Butanal c. 6 5 d. trans--phenyl--propenal (cinnamaldehyde) ( 6 5 ) Used as cinnamon flavour.. Ketones: - compound containing a carbonyl group with no hydrogen atom (R-=R ) attached to it. Note that it is R =R as ketone not R R as ether. - polar molecules (due to oxygen s two lone pairs); very soluble in water (hydrogen bonding between water and carbonyl group). - Aromatic ketones are commonly used as artificial flavours. - naming of ketones starts with the prefix of the number of carbon in the longest chain R' including the = group but end with the suffix ~one (like in ket~one). The carbonyl position along the longest carbon chain must be indicated. R Aldehyde: Benzene ( 6 5 ) Benzenal Used in peaches, cherries and almond flavours. Note: The aldehyde and ketone carbonyl groups take precedent in the root naming over any substituents (alcohol, ether, alkyl, and halogen substituents). 7 opyrighted by Gabriel Tang B.Ed., B.Sc. Page 7.

22 Unit 5: rganic hemistry _ onour hemistry Example : Name the following ketones or give the molecular formula or vice-versa. Provide a structural formula for these compounds. a. b. -pentanone Ketone: (-arbons) c. -phenyl--hexanone Propanone Ketone: (6-arbons Main hain) 6 5 ( ) phenyl substituent at Position No need to label -propanone because the ketone carboxyl group can only exist in this case at carbon. therwise it would be an aldehyde. 4 5 Ketone: (5-arbons) ( ) The carboxyl group is at carbon-. 6 The carboxyl group is at carbon arboxylic Acids: - compound containing a carbonyl group (R-). - polar molecules (due to oxygens four lone pairs); very soluble in water (hydrogen bonding between water and carbonyl group). - naming of carboxylic acid starts with the prefix of the number of carbon in the R longest chain including the group but end with the suffix ~oic acid (like in carb~o~xyl~ic acid). Note: The carboxylic acid group takes precedent in the root naming over any substituents (alcohol, ether, alkyl, and halogen substituents). Example : Name the following carboxylic acid or give the molecular formula or vice-versa. Provide a structural formula for these compounds. a. methanoic acid b. arboxylic Acid: (Methanoic Acid) carbon arboxylic Acid: ( carbons) Ethanoic Acid ommonly known as Acetic Acid (Vinegar) Page 8. opyrighted by Gabriel Tang B.Ed., B.Sc.

23 onour hemistry Unit 5: rganic hemistry c. 6 5 d.,4-dibromo-butanoic acid arboxylic Acid with Benzene Benzenoic Acid 4 Br Br BrBr 4. Ester: - compound containing a carbonyl group (RR ). - polar molecules (due to oxygens four lone pairs); very soluble in water (hydrogen bonding between water and carbonyl group). R - commonly use as artifical flavorings. - form when alcohol is reacted with carboxylic acid. R' - naming of ester starts with the alkyl group R, then the prefix of the number of carbon in the longest chain including and connected to the R group and ends with the suffix ~oate. Note: The ester group takes precedent in the root naming over any substituents (hydroxy, oxy, alkyl and halogen substituents). Esterification (Ester ondensation): - when alcohol reacts with carboxylic acid to form ester and water (condensation because water is produced). - the alcohol chain becomes the alkyl group of the ester (R ). - the carboxylic acid chain becomes main carbon chain for the ester functional group. arboxylic Acid (R) + Alcohol (R ) Ester (RR ) + R R' R R' Example: Methanoic Acid + Ethanol ethyl methanoate + water (l) + 5 (l) 5 (l) + (l) Used as Rum flavouring opyrighted by Gabriel Tang B.Ed., B.Sc. Page 9.

24 Unit 5: rganic hemistry _ onour hemistry Example 4: Name the following esters or give the molecular formula or vice-versa. Provide a structural formula for these compounds. Suggest an esterification reaction to produce each ester below. a. methyl butanoate 7 butanoate main chain including carboxyl group methyl substituent at single bond Butanoic Acid + Methanol methyl butanoate + water 7 (l) + (l) 7 (l) + (l) Used as Apple flavouring b. ( ) ( ) ethanoate main chain including carboxyl group methyl substituent at Position 4 of the pentyl substitutent 5 4-methylpentyl substituent 4 at single bond Ethanoic Acid + 4-methyl--pentanol 4-methylpentylethanoate + water (l) + ( )( ) (l) ( ) ( ) (l) + (l) + + Used as Banana flavouring Example 5: Name the following organic compound given the structural formula below. ethanoate main chain including carboxyl group -methylbutylethanoate 4 -methylbutyl substituent at single bond Used as Pear flavouring Page 0. opyrighted by Gabriel Tang B.Ed., B.Sc.

25 onour hemistry Unit 5: rganic hemistry Elimination Reactions: - reactions that turn saturated hydrocarbons into unsaturated ones using oxidizing agent like KMn 4 or K r 7 in an acidic environment. Dehydrogenation: - an elimination reaction where alkanes is turned into alkenes or alkynes by removing hydrogen. Alkane Alkene KMn 4 or Kr7 and S4 KMn 4 or Kr7 and S4 Alkene + ydrogen Alkyne + ydrogen Example: Propane KMn 4 or Kr7 and S4 8 KMn 4 or Kr7 and S4 KMn 4 or Kr7 and S4 Propene + ydrogen 6 + (g) = + Example: Propene KMn 4 or Kr7 and S4 6 KMn 4 or Kr7 and S4 = KMn 4 or Kr7 and S 4 Propyne + ydrogen 4 + (g) + (Note: From Propane to Propyne Dehydrogenation, it is stepwise.) Dehydrations: - elimination reactions where primary alcohols are turned into aldehydes or secondary alcohols are converted to ketones by removing hydrogen. Primary Alcohol Secondary Alcohol KMn 4 or Kr7 and S4 KMn 4 or Kr7 and S4 Example: -Propanol KMn 4 or Kr7 and S KMn 4 or Kr7 and S 4 4 Aldehyde + ydrogen Ketone + ydrogen Assignment 6. pg. 794 # to 6 opyrighted by Gabriel Tang B.Ed., B.Sc. Page. KMn 4 or Kr7 and S4 Example: -Propanol KMn 4 or Kr7 and S () KMn 4 or Kr7 and S 4 4 KMn 4 or Kr7 and S4 Propanal + ydrogen + (g) + Propanone + ydrogen + (g) +

26 Unit 5: rganic hemistry _ onour hemistry 6.4: Polymerization Polymers: - are large organic molecules that are often chainlike. - include plastics (Polyethylene, Polyvinyl chloride [PV]), synthetic fibres (polyesters, nylon), and a wide variety of modern day materials (Teflon, synthetic rubber, polypropylene, polyurethane). Monomers: - small units that are the building blocks of the chainlike polymers. (Mono means one unit) - usually contain a set of double bond or active functional groups on either end of the monomer molecule. Polymerization: - molecules react with one another much like train carts hooking up to form a long train. Dimers: - the resulting molecule when two monomer molecules combined (Di means two units) which can undergo further polymerization with other monomers. - dimer is usually a free radical (a molecule with unpaired electron(s)), which allows it to hook up more monomer for further polymerization. Addition Polymerization: - polymerization process involving the addition of monomers across their double bonds. ondensation Polymerization: - polymerization process involving the esterification of monomers across their carboxylic acid functional group with the alcohol function group. Example: The Polymerization of Ethene into Polyethylene. (Addition Polymerization) monomers start the polymerization Double bonds open up Dimer results (with two free radical sites) +... Additional polymerizations (heck out animation at ondensed Notation for Polymerization of Ethene into Polyethylene: n represents many monomer molecules n = n n represents many units of chained monomers Page. opyrighted by Gabriel Tang B.Ed., B.Sc.

27 onour hemistry Unit 5: rganic hemistry Example: The Polymerization of Ethylene glycol and p-terephthalic acid into Polyester. (ondensation Polymerization) Dimer results (with two sites for additional polymerizations) + Ethylene glycol and p-terephthalic acid are the monomers of the polymerization + ondensation of Water n () + n p- 6 4 () n + n Example : Describe the polymerization of hloroethene (Vinyl hloride) into Polyvinyl chloride (PV). l monomers start the polymerization l + l l l Double bonds open up Dimer results (with two free radical sites) l... Additional polymerizations n = l l n Assignment 6.4 pg. 800 #7 to 9 hapter 6 Review: pg #0 to 6, 4 to 4, 48 to 50 opyrighted by Gabriel Tang B.Ed., B.Sc. Page.