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Section 2.1 - Organic Compounds

· Where do you find organic compounds?

FertilizersHerbicidesPesticides

· Simplest type of organic compound is a hydrocarbon.

Compounds composed of carbon

Contain carbon & hydrogen

Which of the above are saturated? Unstaurated?

Single bonds = saturated (i.e. butane)

Double bonds & triple bonds = unsaturatedEthene = double bondEthyne = triple bond

Alkane - "ane" = single bondsAlkene - "ene" = double bondsAlkyne - "yne" = triple bonds

File Attached Steps:

1. Determine suffix2. Name longest

chain.3. Locate position

of multiple bond.

4. Locate & Name branches

5. Combine all parts

Hydrocarbons with aromatic or phenyl or benzene rings = cyclicalEx. Benzene C6H6 = Hexagonal

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BenzeneComponent to gasoline - restricted in %age because it is:· Carcinogenic· Concerns with leaching if spilt in water or soil.· Cleaned up with remediation; although benzene is difficult to

break down.Why?

Ring structure is stable/Resonance

· Persistent organic pollutant (POP)

PAHs - polycyclic aromatic hydrocarbons· Produced by incomplete combustion of oils from foods and from

diesel emissions.· Can interact with DNA and potentially cause mutations.· Use low-temp grill to reduce flare-ups and the PAHs present in

food.

Synthetic Organic Molecules - Human made organic compound

Functional Group - An arrangement of single atoms or groups of atoms, other than carbon or hydrogen, attached to an organic molecule. THE DATABOOK IS YOUR FRIEND HERE!!

Halogenated HydrocarbonsWhat are the halogens?

Group 17- A hydrocarbon that has one or more hydrogen atoms

replaced by atoms of chlorine, fluorine, bromine or iodine.

Ex. CFC = Chlorofluorocarbon

Naming Halogenated Hydrocarbons

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Steps:1. Name parent chain.2. Locate halogen substituents.3. Determine position, number

and name of substituents.4. Name it

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Attached File

Work through as a class!

CFCs & OZONE (O3(g))· Invented in the 1920s.· Nonflammable, nontoxic· Used in air-conditioners & refridgerators· Destroy the ozone layer

Website Link

The ozone layer is a portion of the stratosphere, (the portion of the atmosphere between 10 km and 50 km above Earth’s surface.)www.theozonehole.co

m

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Ozone, O3(g), is produced and decomposed in a natural process involving UV radiation and O2(g) in a cycle, as follows:

Production of O3(g)

O2(g) + UV energy greater than 8.25 x 10-19 J yields 2 O(g).

O(g) + O2(g) in the presence of a catalyst yields O3(g).

Decomposition of O3(g)

O3(g) + UV energy (between of 6.22 x 10-19 J - 7.10 x 10 -19 J)

yields O2(g) + O(g).

This cycle maintains a steady level of O3(g), which protects the Earth from exposure of excessive levels of ultraviolet radiation from the Sun.

The Sun emits energy in the form of radiation, including visible light, infrared radiation and ultraviolet radiation, etc.

UV radiation is harmful because it can cause damage to living tissue. It possesses more energy than visible light or other forms of radiation and can excite molecules and initiate chemical reactions.

It was discovered that freed Cl, or a free radical, from CFCs in the atmosphere, caused the depletion of the ozone layer, as follows:

Animation

Free radicals can also have a damaging effect on your body.

-chemicals that have an unpaired electron in the valence shell. - react easily with other substances to fill the valence shell. - exposure to radiation or substances in food, may result in the

production of oxygen-containing free radicals, which can react with lipids, proteins, and DNA affecting the function of body cells.

These oxygen-containing free radicals can be reduced by including antioxidants in your diet

-vitamin E-vitamin C- beta-carotene - lycopene

These antioxidants prevent the oxidation reaction that produces free radicals of oxygen.

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Ozone Depletion and Environmental Concerns

The Montreal Protocol is an international agreement to cease the production of CFC’s and to replace it with less harmful HCFC’s which contain fewer Cl atoms or HFC’s which do not contain any chlorine atoms.

Also, the thickness of the ozone layer is monitored throughout the year to assess damage.

Although other halogenated hydrocarbons are also destructive to the ozone layer, they are not restricted in the Montreal Protocal because there is no viable alternative for this chemical.

Ex. methylbromide, a pesticideEx. Halon 1211, a fire retardant used in airplanes.

Ex. tetrachloromethane (carbon tetrachloride) used as a cleaning solvent until it was found to be carcinogenic

Ex. polyvinyl chloride,(PVC) used to make garden hoses and floor tile.

Others and their structures are on page 259 in your textbook.

Biomagnification and Halogenated Hydrocarbons

Many herbicides and pesticides contain halogen atoms and are a health concern because of their effect on your body, (the central nervous system, heart, liver, and kidneys) and accumulate through biomagnification

Ex. PCBsEx. DDT

Section 2.2 Alcohols, Carboxylic Acids, and Esters

1. Alcohols - organic molecules that contain a hydroxyl functional group (R-OH)

- soluble in water

- polar molecules

Example: Methanol (wood alcohol)

- found in solvents, fuels, pharmaceutical production & disinfectants.

- ingesting methanol will cause blindness or be fatal because enzymes in your liver will break it down into very toxic compounds.

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Example: Glycol

- found in solvents

Example: isopropanol

- found in disinfectants

Example: Ethanol

- found in solvents, fuels, alcoholic beverages, production of pharmaceuticals, disinfectants

- made for at least 6000 years by adding yeast to solutions that are rich in either sugars or starches. The yeast cells obtain energy from enzyme-catalyzed reactions that convert sugar or starch to ethanol and CO2(g).

C6H12O6(aq) ---->2 CH3CH2OH(aq) + 2 CO2(g) [Fermentation]

Naming Alcohols

Steps:1. Find hydroxyl group2. Determine parent chain starting at nearest to hydroxyl group3. Determine parent name.4. Communicate location of hydroxyl group5. Use sufiix "ol"

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2. Carboxylic Acids

- a carbonyl functional group is formed by the joining of an oxygen atom to a hydrocarbon by a double bond R=O.

- a carboxylic acid is a functional group formed by the joining of a single C atom to a single O atom with a double bond and a hydroxyl group OH (or alcohol) with a single bond R-COOH

- Carboxyl groups have the carbonyl group and the hydroxyl group

Examples:

- Vinegar

- Citrus Fruit

- Vitamin C

Example:

PABA - para-aminobenzoic acid

Benzene and carboxylic acid together

- Found in sunscreen - Benzene can absorb the UV rays - some people are allergic to PABA LINK to UNIT A -- Immunity & Anaphylactic shock

Naming Carboxylic Acids:

Steps:1. Locate parent chain2. suffix is "oic acid"

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3. Esters

Alcohols and carboxylic acids react to form esters

Esterification is the process of creating an ester by removing the H from the alcohol and the OH from the hydroxyl group in the carboxylic acid. The product of this reaction is an ester.

Esters usually have a pleasant odor and are the flavor for many foods.

PolyestersThere are many different types of plastics. One type is a polymer called polyester, which is a polymer of many ester functional groups. It is created from the reaction of many alcohols and carboxylic acids forming long chains or filaments.

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a disadvantage of plastics is that they are non-degradable. Modern technology is using bioplastics which are degradable.

Made of naturally occurring compounds - can be broken down by bacteria

Made from polyester of corn, soy, hemp or bacteria

Polymer - a large molecule made up of many small and identical submolecules.

- put together like a string of beads

Ex. Silk

Ex. Sap

Synthetic Polymers - manmade- characteristics we want

Ex. plastics

Section 2.3 Understanding Exposure

Many organic products have been produced to benefit mankind, however some organic compounds or their by-products have turned out to have harmful side effects.

1. VOC’s or volatile organic compoundsOff-gassing is an important environmental concern and is

the release of volatile organic compounds (VOCs) from building materials such as paints, treated lumber and flooring, wall coverings, etc.

To reduce exposure:*use materials that do not contain VOCs*avoid direct contact by using gloves, etc.*work in well ventilated areas

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2. Pesticides

A pesticide is a substance that is used to kill fungi, insects, animals or plants considered as pests.

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Considerations when using a pesticide:

1. Specificity

Target specificity is the range of organisms affected by the pesticide. It is important to chose the pesticide that is targeted for a specific pest.

Broad Spectrum pesticide is a chemical substance that can control the population of a large variety of organisms.

Toxicity is the ability to cause damage to living tissue, impair the function of a body system or cause death when injested, inhaled, or absorbed.

Toxicity is rated according to LD50 and LC50.

LD50 is the dosage of a chemical substance, given all at once, that kills half (50%) the population tested within a specified time.

LC50 is the concentration of a chemical substance in air or water that kills half (50%) the population tested within a specified time.

The values are expressed in mg/kg.

Regardless of toxicity, pesticides should not affect non-target organisms.

Ex. 2,4 D (2,4-dichlorophenoxyethanoic acid)

2. Combined Effects

There is a concern regarding the effects that combinations of organic compounds used in pesticides may have on the environment and on humans.

For example, absorption of some pesticides through the skin is higher when sunscreens are worn.

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3. Drift, Grasshopper Effect and Resistance

Drift is the transfer of the pesticide by wind or air currents from the location where it was sprayed.

Grasshopper effect is the transport of pesticides that result from the evaporation in warmer climates and condensation in colder climates. Ex. pesticides are being detected in the Arctic.

Persistence is the resistance of a chemical substance being broken down by biological or chemical means. Soil micro-organisms can act on pesticide molecules---using them as a source of carbon for their own growth. However, pesticides containing halogenated hydrocarbons or benzene rings cannot be easily broken down. As a result, these pesticides remain in the water, air and soil and through biomagnification result in toxic effects for organisms higher up in the food chain.

4. Water QualityWater quality can be affected by acid deposition, persistent organic compounds, and the leaching of metal ions, and fertilizers or organic matter.

-- Can result in Algal Blooms

Ex. Algal bloom - leaching of fertilizers and organic matter, rich in nitrogen and

phosphorous, from fields into surface water adds additional nutrients which encourage the rapid growth of algae. -toxins produced by the algae may be harmful to humans and animals. - decomposition of the algae on the surface affects the oxygen content in the water which can result in a winterkill of fish species in the water. - Biochemical or Biological Oxygen Demand (BOD) is a measure of the amount of oxygen required for the decomposition of organic matter. The test consists of comparing the dissolved oxygen concentration of a sealed water sample. A decrease in the concentration of dissolved oxygen occurs when micro-organisms decompose organic matter. Water samples containing high levels of organic matter (high BOD) demonstrate a large reduction in dissolved oxygen concentration.

Thus water contaminated with organic matter from human or animal waste may have a high BOD or may serve as a source of nitrogen and phosphorous that promotes the growth of algal bloom.

5. Resistance

A resistant population is a group of organisms not affected by a pesticide.

Genetic principles, including mutations, create variations in a population and this variation can result in some members of a population possessing resistance to a pesticide.

As a result, only members resistant to a pesticide will survive.

Breeding between resistant and non-resistant populations tend to result in offspring that are resistant.

Thus pest control practices designed to kill higher percentages of pest population results in a faster development of resistant pest populations.

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So what can be done?1. Governments are involved in the management of chemical

substances.

2. Rather than using pesticides, there are alternative methods to control pests: