Topic 3: Organic Chemistry

Organic Chemistry Organic chemistry is the study of carbon and carbon containing molecular compounds Organic compounds often also contain contain hydrogen and oxygen. Carbon containing compounds are sometimes called hydrocarbons Examples include Methane, Propane, Ethanol, Methanol, Ethanoic acid (acetic acid) vinegar

Petrochemical Industry Crude oil is an example of an organic fuel Petrochemical Industry Crude oil is an example of an organic fuel. Thus it is also called hydrocarbon fuels

Crude Oil petroleum gases(l) gasoline jet fuel kerosene diesel oil lubricating oils wax fuel oil asphalt Fractionating tower separates crude oil into different materials

Page 9 of your data booklet has everything organic you need to know Alkanes Hydrocarbons/carbon chains with only single bonds between them Said to be saturated General Formula is CnH2n+2 Examples include methane (CH4) ethane (C2H6) propane (C3H8) Page 9 of your data booklet has everything organic you need to know

Diagrams like this maybe seen on the diploma as well… Ethane C2H6 Methane CH4 Hexane C6H14

Naming Alkenes and Alkynes Alkenes are hydrocarbons that contain a double bond (unsaturated) Alkynes are hydrocarbons that contain a triple bond (unsaturated) Unsaturated fatty acids are more reactive than saturated fatty acids To name these, you use same prefixes as alkanes Suffix changed: Alkenes – ene suffix Alkynes – yne suffix

Alkenes & Alkynes CnH2n-2 CnH2n

Example 1 and 2 : Name these molecules 2,4 dimethylhexane C 4-methylpent-2-ene

Example 3 and 4 : Name these molecules hex-2-ene C 3,5-dimethylhex-2-ene

Example 5 and 6 : Name these molecules hex-3-yne C hexyne

Example 7 : Name this molecule 4,5-dimethylhex-2-yne

Benzene Rings Hydrocarbons are often seen in a linear shape (in a line). But sometimes, they are in a ring shape

Benzene Shapes Benzene are compounds that have a hexagonal shape and have the general formula C6H6 A benzene ring can also be called a phenyl ring or aromatic ring

Benzene Uses Benzene is a stable component of: Gasoline and plastic rubber cement bug repellant, fungicides. Because benzene is stable and not easily broken down by chemical or biological means, it is classified as a persistent organic pollutant (POP’s)

Dangers of Benzene Burning steak on bar-b-que forms Benzopyrene, a multiple benzene ring “polycyclic aromatic hydrocarbon (PAH)”. Bezopyrene is found in the blackened parts on the meat and can causes DNA mutations. What are some of the dangers of benzene containing compounds? Carcinogenic when leaked into soil and water (also present in tobacco smoke and vehicle exhaust) Carcinogenic substances interfere with DNA base pairing Very stable Found in the incomplete combustion of oils, gas, diesel, wood, Cool Trivia

Benzene and DNA Mutations PAH mimics compounds naturally found in DNA PAH is not only found on charred food but in tobacco smoke and engine exhaust

1. Halogenated Hydrocarbons also called alkyl halides Halogenated hydrocarbons are hydrocarbon molecules that has one or more hydrogen atoms replaced by a halogen (chlorine, flourine, bromine, iodine) Examples: CFC (Freons) (Chlorofluorocarbons) Used in refrigerators and air conditioners Linked to stratospheric ozone depletion PVC (polyvinyl chloride) Carbon tetrachloride, used as cleaning solvent, now known to be carcinogenic!

Naming Halogenated Hydrocarbons Naming halogenated hydrocarbons is similar to naming regular hydrocarbons Step 1: Name the parent chain Step 2: Find all the halogen atoms Step 3: Determine the prefix if necessary (di-, tri-) Step 4: Communicate where each halogen atom appears F Cl C Example 1: CH Cl Example 2: Trichloromethane Trichlorofluoromethane

Naming Halogenated Hydrocarbons Example 3: Example 4: C Cl F Cl C 1,1,2- trichloro-1,2,2-trifluoroethane Tetrachloromethane

Ozone and Concerns Regarding CFC’s There are 2 types of ozone that exists in our atmosphere: 1. tropospheric (low level) ozone …the bad stuff 2. high altitude ...in the stratosphere…good stuff!! Absorbs and protects us from excess UV radiation Chlorofluorocarbons (CFC’s) cause stratospheric ozone to become thin = extra UV radiation

Harmful Halogenated Compounds Many compounds contain halogenated compounds Examples: DDT (dichlorodiphenyltrichloroethane) – used in pesticides Dioxins and furans (contains Cl2)- by product of pulp & paper industry PCB’s (Polychlorinated biphenyls) – used in older electric transformers agent orange (herbicide) burning garbage that contains chlorine DDT, dioxins and furans and PCB’s can bioaccumulate in the food chain Many alkyl halides and benzene compounds cause birth defects and are known as teratogens

Abnormal bill: cannot eat!! DDT Synthetic organic pesticide Initially mixed with talcum powder Put into soldiers clothing Helped prevent spread of typhus, malaria, yellow fever Eventually used as pesticide to kill insects Affects calcium metabolism in organisms hence joint problems occurred in soldiers deformities seen in fish abnormally thin egg shells in birds Double crested Cormorant From Great Lakes Crossed bill caused by DDT Abnormal bill: cannot eat!!

Agent Orange Herbicide used during Vietnam war Defoliated jungles Caused birth defects Contains 2 main ingredients: 2,4,5-T and 2,4-D 2,4,5-trichlorophenoxyacetic acid 2,4-dichlorophenoxyacetic acid Dioxins are a by-product of the manufacture of these

2. Alcohols All alcohols contain a hydroxyl functional group Examples: --OH (not hydroxide) Examples: CH3CH2OH (ethanol) CH3OH (methanol)

Naming Alcohols Name is the same as with alkanes, EXCEPT: Step 1: Drop the e from ane Step 2: Add -ol CH3OH (methanol) C2H5OH (ethanol) C3H7OH (propanol) C4H9OH (butanol) Step 3: Position of the OH group should be indicated if necessary (2-ol means the hydroxyl is on carbon 2)

Name these molecules C OH Pentan-3-ol C OH Pentan-2-ol

Name this molecule C C C C C C OH Hexan-3-ol

Carboxylic Acids All carboxylic acids contain the carboxyl functional group – COOH Common carboxylic acids include: Vinegar Citric acid Lactic acid (build up in muscles causes cramping) Asprin (acetylsalicylic acid) Organic acids have similar properties as acids studies earlier. Carbonyl group hydroxyl group

Propanoic acid prevents mold growth in bread Carboxylic Acids Naming carboxylic acids Step 1: alkane base, drop “e” Step 2: add “-oic acid” C H OH O C H OH O Methanoic acid found in bee stings Propanoic acid prevents mold growth in bread

Esters Esters are formed from a carboxylic acid and alcohol joined together All esters contain the –COO- functional group This is found in the middle joining the carboxylic acid and alcohol Esters are commonly found in fats, polyester, plastic (bioplastics), soap and used as flavour and aroma

A Membrane Lipids B Storage Fats C True Waxes Esters

Synthesis of Polyesters Identify the functional groups!! It’s important to know that polyesters are made of an acid and an alcohol joined together.

Naming Esters C O H Methyl methanoate Naming esters: (Esters always end in …oate) Step 1: Find the ester functional group and circle it. Step 2: Name the alcohol chain (single bonded oxygen) attached to the carbon (ex. Methyl-) Step 3: Name the carboxylic acid (double bonded oxygen) attached to the carbon (ex. Methan-) Step 4: Combine the 2 names followed by the suffix -oate C O H Example 1 Methyl methanoate

Naming Esters C O H C O H Ethyl ethanoate Ethyl methanoate Example 2

Pesticides and persistent organic pollutant (POP’s) Identify the functional groups A pesticide is a substance used to kill unwanted fungi, insects, animals and plants Recall: Many pesticides contain halogenated hydrocarbons, especially Cl and benzene !!!!

Identify the functional groups in the following POP’s Carboxylic acid, benzene, halogenated hydrocarbon 2,4-D Carboxylic acid, benzene, halogenated hydrocarbon dioxin benzene, halogenated hydrocarbon

Effects of Insecticides Most affect the nervous system Some inactivate cholinesterase (an enzyme in the synapse) Without cholinesterase, acetylcholine continuously stimulates post synaptic fiber causing convulsions & death! Can mix with water and affect soil and aquatic organisms Can drift to areas where insecticides are not used Can lead to pesticide resistant organisms Target Specific: so that it minimizes effects on other organisms and the environment

Fertilizer and Organic Matter Excess use of fertilizers rich in nitrogen and phosphorous can leach from fields into our water system. This results in what is known as an algal bloom (increase in algae) Is this bad? Yes, it uses up all the oxygen available in the water.

Biological Oxygen Demand (BOD) BOD is the measure of the amount of oxygen used by microorganisms (such as algae) as they decompose waste High BOD indicates that there is a high amount of organic waste or sewage in our water systems Things that increase BOD: Large amounts of organic waste Nitrates and phosphates from run off and fertilizers (= high algae growth) Warm temperatures Answer to the table is ACB and BAC Is high BOD a good thing?

Biomagnification Biomagnification, aka bioamplification, or biological magnification the increase in concentration of pesticides, dioxins and furans and heavy metals as we move up the food chain or very slow breakdown of the substance (accumulate in water). Toxins accumulate in fatty tissues and are not released in wastes

Alternatives to Chemical Insecticides Genetically engineering plants to produce own pesticides, or are resistant to pests Biological control / Natural Predators …ladybugs in Muttart Sterilizing males …by radiation or chemicals Juvenile hormone …prevent adulthood & breeding Pheromones …baits males into traps & disorients males so they can’t find a mate