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Organic Chemistry
Organic Chemistry
• Organ = Greek word for life• Chemistry of living things- both animals and
plants.• Based on the element carbon, also
Hydrogen ,oxygen , phosphorus and sulphur.
Carbon : special properties
• Carbon is the element that by itself, forms more compounds than all the other elements
• put together.• Carbon forms four stable covalent bonds• Carbon can form bonds to itself,producing
long stable chains of carbon atoms.• Carbon can form single ,double and even
triple bonds.
Organic chemistry
• Organic chemistry is a discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation of chemical compounds consisting primarily of carbon and hydrogen, which may contain any number of other elements, including nitrogen, oxygen, the halogens as well as phosphorus, silicon and sulfur
Organic compounds
• Because of their unique properties, multi-carbon compounds exhibit extremely large variety and the range of application of organic compounds is enormous. They form the basis of, or are important constituents of many products (paints, plastics, food, explosives, drugs, petrochemicals, to name but a few) and (apart from a very few exceptions) they form the basis of all earthly life processes.
Description and nomenclature
• Classification is not possible without having a full description of the individual compounds.
• In contrast with inorganic chemistry, in which describing a chemical compound can be achieved by simply enumerating the chemical symbols of the elements present in the compound together with the number of these elements in the molecule,
• in organic chemistry the relative arrangement of the atoms within a molecule must be added for a full description.
• One way of describing the molecule is by drawing its structural formula.
IUPAC• It was realized that as the family of organic
compounds grew, the system would have to be expanded and modified. This task was ultimately taken on by the International Union on Pure and Applied Chemistry (IUPAC). Recognizing the fact that in the branch of biochemistry the complexity of organic structures increases, the IUPAC organization joined forces with the International Union of Biochemistry and Molecular Biology, IUBMB, to produce a list of joint recommendations on nomenclature
Molecular models of caffeine
HYDROCARBON
• In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon.
• Hydrocarbons can be gases (e.g. methane and propane),
• liquids (e.g. hexane and benzene), waxes or low melting point
• solids (e.g. paraffin wax and naphthalene) or polymers (e.g. polyethylene, polypropylene and polystyrene).
Types of organic compounds
• Aliphatic = straight chain with C atom forming long backbone.
• Aromatic = C forms a ring• Saturated = all the bonds between carbon
atoms are single covalent bonds, ie C-C-C-C.• Unsaturated = Carbon skeleton has at least
one double or one triple bond. i.e.• C-C-C-C-C=C-C-C-
Saturated hydrocarbons
• Saturated hydrocarbons (alkanes) are the most simple of the hydrocarbon species and are composed entirely of single bonds and are saturated with hydrogen.
• The general formula for saturated hydrocarbons is CnH2n+2 .
• Saturated hydrocarbons are the basis of petroleum fuels and are either found as linear or branched species.
Unsaturated hydrocarbons
• Unsaturated hydrocarbons have one or more double or triple bonds between carbon atoms. Those with one double bond are called alkenes, with the formula CnH2n (assuming non-cyclic structures). Those containing triple bonds are called alkynes, with general formula CnH2n-2.
Functional groups
• Organic compounds are classified according to functional groups.
• Functional groups form homologous series, i.e. compounds with very similar chemical properties.
• The simplest homologous series is the ALKANES. They are saturated hydrocarbons.
• They have a general formula CnH2n+2
Functional groups
• Alkanes• Alkenes• Alkynes• Alcohols• Aldehydes
Homologous series
Number ofcarbon atoms Alkane Alkene Alkyne
1 Methane CH4 — —
2 Ethane C2H8 Ethene Ethyne
3 Propane C3H12 Propene Propyne
4 ButaneIsobutane Butene Butyne
5Pentane
IsopentaneNeopentane
Pentene Pentyne
6 Hexane Hexene Hexyne
7 Heptane Heptene Heptyne
8 Octane Octene Octyne
9 Nonane Nonene Nonyne
10 Decane C10H22 Decene Decyne
Isomers
• Definition: Isomers are organic compounds which have the same chemical formula but a different structural formula.
• Hydrocarbons with the same molecular formula but different structural formulae are called isomers.
• The knowledge of the chemical formula for an organic compound is not sufficient information because many isomers can exist.
• Example : pentane C5H10
Isomers of pentane
Naming
• Identify longest straight chain of C-C-C• Remember that in 3D, rotation takes place
around a single C – C covalent atom.• Name straight chain based on number of C
atoms.• Check if there is a side chain, branch• Identify functional group
Crude oil
• The most important use of hydrocarbons is in the supply of energy.
• Combustion = hydrocarbons burn in oxygen. • Crude oil cannot be used as it is. It has to be
separated into fractions by fractional distillation.
• This takes place in a refinery.
Crude oil• Raw or unprocessed crude oil is not useful in the
form it comes in out of the ground. • Although oil has been used directly as a burner
fuel for steam vessel propulsion, the lighter elements form explosive vapors in the fuel tanks and so it is quite dangerous, especially so in warships.
• For this and many other uses, the oil needs to be separated into parts and refined before use in fuels and lubricants, and before some of the byproducts could be used.
Petrochemicals
• petrochemical processes to form materials such as plastics, detergents, solvents, elastomers, and fibers such as nylon and polyesters.
• Petroleum fossil fuels are used in ship, automobile and aircraft engines. These different hydrocarbons have different boiling points, which means they can be separated by distillation. Since the lighter liquid elements are in great demand for use in internal combustion engines, a modern refinery will convert heavy hydrocarbons and lighter gaseous elements into these higher value products.
Fractional distillation
• Crude oil is separated into fractions by fractional distillation.
• The fractions at the top of the fractionating column have lower boiling points than the fractions at the bottom.
• The heavy bottom fractions are often cracked into lighter, more useful products. All of the fractions are processed further in other refining units
Cracking• In petroleum geology and chemistry, cracking is the
process whereby complex organic molecules such as heavy hydrocarbons are broken down into simpler molecules (e.g. light hydrocarbons) by the breaking of carbon-carbon bonds.
• The rate of cracking and the end products are strongly dependent on the temperature and presence of any catalysts.
• Cracking, also referred to as pyrolysis, is the breakdown of a large alkane into smaller, more useful alkenes and an alkane.
• Simply put, cracking hydrocarbons is when you break long chain hydrocarbons up into short ones
Products of crude oil
• Natural gas --Refinery gas. C1– C4 -2%• Gasoline - petrol. 15-30% C5 – C10 • Kerosene - jet aircraft fuels. 10-15% , C11-C12 • Diesel fuel – 15-20% Industrial heating, large
ships • Fuel oil - Lubricating oils - Paraffin wax • Asphalt and Tar • Petroleum coke
Refinery gas
• burns cleanly with no soot and very few sulfur emissions, posing no ground or water pollution hazards.
• Large amounts of LPG can be stored in bulk tanks and can be buried underground if required. Alternatively, gas cylinders can be used.
Gasoline
• Gasoline or petrol is a liquid mixture primarily used as fuel in internal combustion engines. It is petroleum-derived, and consists mostly of aliphatic hydrocarbons, enhanced with iso-octane or the aromatic hydrocarbons toluene and benzene to increase its octane rating.
Definition of octane rating
• The octane rating of a spark ignition engine fuel is the detonation resistance (anti-knock rating) compared to a mixture of iso-octane (2,2,4-trimethylpentane, an isomer of octane) and n-heptane.
• By definition, iso-octane is assigned an octane rating of 100 and heptane is assigned an octane rating of zero. An 87-octane gasoline, for example, possesses the same anti-knock rating of a mixture of 87% (by volume) iso-octane and 13% (by volume) n-heptane.
• This does not mean, however, that the gasoline actually contains these hydrocarbons in these proportions. It simply means that it has the same detonation resistance as the described mixture.
Kerosene
• Kerosene is a thin, clear liquid formed from hydrocarbons, with density of 0.78-0.81g/cm3. Kerosene is obtained from the fractional distillation of petroleum between 150 °C and 275 °C, resulting in a mixture of carbon chains containing 12 to 15 carbon atoms.
• The name is derived from Greek keros (κηρός wax).
Diesel
• Petroleum diesel, also called petrodiesel,[3] or fossil diesel is produced from petroleum and is a hydrocarbon mixture, obtained in the fractional distillation of crude oil between 200 °C and 350 °C at atmospheric pressure.
Fuel oil
• Fuel oil is a fraction obtained from petroleum distillation, either as a distillate or a residue.
• Broadly speaking, fuel oil is any liquid petroleum product that is burned in a furnace or boiler for the generation of heat or used in an engine for the generation of power.
• Fuel oil is made of long hydrocarbon chains, particularly alkanes, cycloalkanes and aromatics.
Lubricant
• A lubricant (sometimes referred to as a "Lube") is a substance (often a liquid) introduced between two moving surfaces to reduce the friction between them, improving efficiency and reducing wear.
• They also have the function of dissolving foreign particles. Petroleum-based lubricants like Vaseline tend to dissolve petroleum products such as rubber and plastic, while water-based lubricants will dissolve polar chemicals.
Wax
• Paraffin wax (or simply "paraffin", but see alternative name for kerosene, above) is mostly found as a white, odorless, tasteless, waxy solid, with a typical melting point between about 47 °C to 64 °C .
• Paraffin wax (C25H52)
asphalt
• The word asphalt is derived from the Greek ásphalton, ásphaltos (άσφαλτος), "flawless".
Polymer• A polymer is a large molecule (macromolecule) composed of
repeating structural units typically connected by covalent chemical bonds. The simple building blocks are called monomers. While polymer in popular usage suggests plastic, the term actually refers to a large class of natural and synthetic materials with a variety of properties and purposes.
• Polypropylene IUPAC name poly(propene) Except where noted otherwise, data are given formaterials in their standard state(at 25 °C, 100 kPa)Infobox references Well-known examples of polymers include plastics and proteins. A simple example is polypropylene, whose repeating unit structure is shown at the right.
Monomers
Polymer
Polymers
• Two types: • Natural polymers are made by living organisms,
such as starch.• Biopolymers such as proteins and nucleic acids
play crucial roles in biological processes. A variety of other natural polymers exist, such as cellulose, which is the main constituent of wood and paper.
• Synthetic polymers + Man made.includes Bakelite, neoprene, nylon, PVC, polystyrene, polyacrylonitrile, PVB, silicone, and many more.
Polypropylene
Polypropylene
IUPAC name poly(propene)
Except where noted otherwise, data are given for
materials in their standard state(at 25 °C, 100 kPa)
Infobox references
Polymers
PET Polyethylene terephthalate - Fizzy drink bottles and oven-ready meal trays.
HDPE High-density polyethylene - Bottles for milk and washing-up liquids.
PVC Polyvinyl chloride - Food trays, cling film, bottles for squash, mineral water and shampoo.
LDPE Low density polyethylene - Carrier bags and bin liners.
PP Polypropylene - Margarine tubs, microwaveable meal trays.
PS Polystyrene - Yoghurt pots, foam meat or fish trays, hamburger boxes and egg cartons, vending cups, plastic cutlery, protective packaging for electronic goods and toys.
OTHER Any other plastics that do not fall into any of the above categories. - An example is melamine, which is often used in plastic plates and cups
Benefits of plastics
• The considerable growth in plastic use is due to the beneficial properties of plastics. These include:
• Extreme versatility and ability to be tailored to meet very specific technical needs.
• Lighter weight than competing materials, reducing fuel consumption during transportation.
• Extreme durability. • Resistance to chemicals, water and impact. • Good safety and hygiene properties for food packaging. • Excellent thermal and electrical insulation properties. • Relatively inexpensive to produce.
Use of pastics
Plastics : advantages
• Recyclable – Plastics can be melted and used to make other products.
• Can be incinerated – Plastics can be melted down and may be able to generate electricity.
• Durable – Plastics can take the wear and tear of everyday life without falling apart.
• Resistant to the environment – Plastics are able to endure a variety of weather conditions without disintegrating.
Plastics : disadvantages
• Flammable – This is definitely an advantage in that they can be melted down, however smoldering plastics can release toxic fumes into the environment.
• Cost of Recycling – While recycling is a plus, recycling is a very costly endeavor.
• Volume – In the United States 20% of our landfill is made up of plastics. As more products are being made of plastics, where will this lead us in the future?
• Durability – This is an advantage as well as a disadvantage. Plastics are extremely durable, which means that they last a long time. Those plastics in the landfill will be there for years.
Natural polymers
Monomer Polymer
Fatty acid *Diglyceride, triglyceride
Monosaccharide Polysaccharide
Amino acid Polypeptide (protein)
Nucleotide Nucleic acid (DNA, RNA)
Glucose
Sugars ; Carbohydrates
Proteins
DNA
DNA
Base
Recycle
Renewable energy
Renewable energy
• Definition: energy generated from natural resources—such as sunlight, wind, rain, tides and geothermal heat—which are renewable (naturally replenished).
• In 2006, about 18% of world energy consumption came from renewables, with 13% coming from traditional biomass, such as wood-burning.
• Hydroelectricity was the next largest renewable source, providing 3%, followed by solar hot water/heating, which contributed 1.3%.
• Modern technologies, such as geothermal energy, wind power, solar power, and ocean energy together provided some 0.8% of final energy consumption.
Renewable energy and climate change
• Climate change concerns coupled with high oil prices, peak oil and increasing government support are driving increasing renewable energy legislation, incentives and commercialization.
• European Union leaders reached an agreement in principle in March 2007 that 20 percent of their nations' energy should be produced from renewable fuels by 2020.
• This will to cut emissions of carbon dioxide, blamed in part for global warming. Investment capital flowing into renewable energy climbed from $80 billion in 2005 to a record $100 billion in 2006.
Solar energy• solar energy" refers to energy that is collected from sunlight. Solar energy can
be applied in many ways, including to:• Generate electricity by heating trapped air which rotates turbines in a
Solar updraft tower. • Generate electricity in geosynchronous orbit using solar power satellites. • Generate electricity using photovoltaic solar cells. • Generate electricity using concentrated solar power. • Generate hydrogen using photoelectrochemical cells . • Heat and cool air through use of solar chimneys. • Heat buildings, directly, through passive solar building design. • Heat foodstuffs, through solar ovens. • Heat water or air for domestic hot water and space heating needs using
solar-thermal panels. • Solar air conditioning
Solar cell: how it works
• Photons in sunlight hit the solar panel and are absorbed by semiconducting materials, such as silicon.
• Electrons (negatively charged) are knocked loose from their atoms, allowing them to flow through the material to produce electricity. Due to the special composition of solar cells, the electrons are only allowed to move in a single direction. The complementary positive charges that are also created (like bubbles) are called holes and flow in the direction opposite of the electrons in a silicon solar panel.
• An array of solar panels converts solar energy into a usable amount of direct current (DC) electricity.
Low Cost Solar Cell
• Dye-sensitized solar cell is considered the low cost solar cell.• This cell is because it is made of low-cost materials and does
not need elaborate apparatus to manufacture, so it can be made in a DIY way allowing more players to produce it than any other type of solar cell. In bulk it should be significantly less expensive than older solid-state cell designs.
• It can be engineered into flexible sheets. Although its conversion efficiency is less than the best thin film cells, its price/performance ratio should be high enough to allow them to compete with fossil fuel electrical generation.
Wind power
• Airflows can be used to run wind turbines. Modern wind turbines range from around 600 kW to 5 MW of rated power, although turbines with rated output of 1.5–3 MW have become the most common for commercial use; the power output of a turbine is a function of the cube of the wind speed, so as wind speed increases, power output increases dramatically. Areas where winds are stronger and more constant, such as offshore and high altitude sites, are preferred locations for wind farms.
Biofuel
• Plants use photosynthesis to grow and produce biomass. Also known as biomatter, biomass can be used directly as fuel or to produce liquid biofuel.
• Agriculturally produced biomass fuels, such as biodiesel, ethanol and bagasse (often a by-product of sugar cane cultivation) can be burned in internal combustion engines or boilers.
• Typically biofuel is burned to release its stored chemical energy. Research into more efficient methods of converting biofuels and other fuels into electricity utilizing fuel cells is an area of very active work.
World wind energy
Solar tower
The 11 megawatt PS10 solar power tower in Spain produces electricity from the sun using 624 large movable mirrors called heliostats.
Photovoltaics
• Waldpolenz Solar Park, which will be the world’s largest thin-film photovoltaic (PV) power system, is being built by Juwi at a former military air base to the east of Leipzig in Germany. The power plant will be a 40-megawatt solar power system using state-of-the-art thin film technology, and should be finished by the end of 2009.
• 550,000 First Solar thin-film modules will be used, which will supply 40,000 MWh of electricity per year.
• The installation will be in eastern Germany, to be built on half of the location’s 220 hectares in the townships of Brandis and Bennewitz. The investment cost for the Waldpolenz solar park amounts to some Euro 130 million.
Photovoltaics
• 1 hectare = 10.000 m2
• 220 = 440 plots of land.
• 1 MW = 1.000 KW• How much electricity do we need in
Cyprus???
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