Organic Chemistry

Organic compounds Compounds must contain carbon will also contain hydrogen may contain oxygen, nitrogen, sulfur and/or phosphorus There are only ~ 60,000 inorganic compounds BUT millions of organic compounds

HOW? Carbon has 4 unpaired valence electrons and needs 4 more e- to complete its outer shell. Carbon makes a total of 4 bonds Simplest: CH4 Carbon can bond with itself to form chains of many lengths

Counting in the language of organic 1 meth 2 eth 3 prop 4 but 5 pent 6 hex 7 hept 8 oct 9 non 10 dec Organic names directly related to # of carbons

Characteristics of Organics . . . Forces of attraction molecules contain covalent bonds molecules tend to be non-polar intermolecular attractions tend to be weak van Der Waals The longer the molecule is the stronger the forces are

So . . . High vapor pressure evaporate quickly & have strong odors low boiling points & melting points when compared to ionic compounds

Conductivity Solubility organic molecules do not ionize do not conduct electricity Solubility because organic molecules are non-polar they are soluble in non-polar substances miscible insoluble in polar substances immiscible Few organic substances are miscible in water sugar, acetic acid, alcohols

Reactivity Rate of reaction flammable / highly combustible because of the covalent bonding, reactivity rates tend to be slow Strong covalent bonding doesn’t allow activated complexes to form easily random collisions don’t provide enough KE to overcome activation energy. Many collisions aren’t effective

Different types of formulas molecular formula tells you how many of each element are in the molecule ex. C6H12O6 empirical formula gives you lowest possible ratio of atoms in the molecule ex. CH2O

structural formula condensed structural shows the “blueprint” of the molecule condensed structural gives a sense of the structure without all the lines CH2OH(CHOH)4COH

Hydrocarbons Type of organic molecule that contains only hydrogen and carbon Shapes straight chain branched cyclic closed not necessarily circular

H-C characteristics Vary greatly in size smallest tend to be gases largest tend to be solids As H-C chains become longer the b.p. and m.p. increase due to increased van der Waals forces Larger molecules are attracted to each other (more than smaller molecules) because they contain more p+ and e-

Sources of fuel: Lowest b.p. gasoline, wax, butane, propane C1 - C4 methane ethane propane butane Sources of fuel: gasoline, wax, butane, propane C4 - C12 octane C12 - C16 Jet fuel C16 - C18 Diesel fuel C18 - C20 C20 - C40 Wax candles Wax paper Highest b.p. C40 + tar

Naming Simple Hydrocarbons Count the longest continuous chain of Carbons this is your “parent chain” use organic “language” as your prefix meth, eth, prop, but . . . Determine suffix according to which homologous series it belongs to alkane or alkene or alkyne

Series of Hydrocarbons Alkanes contain only single bonds BETWEEN Cs ane suffix to hydrocarbons Cn H(2n + 2) a.k.a. Saturated every carbon is bonded to 4 other atoms

Series of Hydrocarbons Alkenes contain a double bond BETWEEN Cs ene suffix Cn H2n Alkynes contain a triple bond BETWEEN Cs yne suffix Cn H(2n-2) H C C H

Alkenes & Alkynes a.k.a. Unsaturated LAST RULE FOR NAMING multiple bonds between Cs tend to be more reactive than saturated H-Cs because double and triple bonds easily broken LAST RULE FOR NAMING 3. Where is the double or triple bond? Always use the lowest possible number!

Practice Draw the structural formula and/or condensed structural formula & name it C2H6 C2H4 C3H4 CHCCH2CH2CH3 CH3CH2CHCH2

How do you name more complex Organic Molecules? IUPAC naming system

Halogenated H-Cs A halide has been substituted for a H Group 17 Prefix Fluorine Fluoro- Chlorine Chloro- Bromine Bromo- Iodine Iodo-

If a particular halogen appears more than once use prefixes di - tri - A number must also be used to indicate the position of each halogen Number your parent chain low BUT a multiple bond gets preference

If more than one halogen, name them alphabetically The complete name # , # - group name(s) parent name Dashes between numbers and name Comma between numbers

Practice CH2BrCH2CH3 CH2FCHFCH2F CHI2CHBrCH3 CH3CF2CHBrCH2CHCH2

Alkyl groups Alkane with one H removed CH4 methane becomes -CH3 methyl C2H6 ethane becomes -C2H5 ethyl -C3H7 propyl -C4H9 butyl Alkyls form side chains: must be included in the name with the number of the carbon it is attached to.

If a particular alkyl group appears more than once use prefixes di - tri - Which carbon is it on? Lowest number C

# , # - alkyl name(s) parent name If more than one . . . ABC’s The complete name # , # - alkyl name(s) parent name Comma between numbers Dashes between numbers and name

Practice CH3CHCH3CH3 CH3CH2CHCH3CH3 CH3(CH2)3CC2H5 CH3CH2CH3 CH3(CH2)3CCH3CH3CHC2H5CH3 3, 4 - diethyl - 2- methylnonane

What if you have halogens and alkyl groups????

1,1,1-trichloro-3-methylbutane WHAT?!!! H - C - C - C - C - Cl H H H Cl | | | | | | | H H Cl H - C - H | H

Use the IUPAC naming system Name the parent chain Longest continuous chain NOT NECESSARILY STRAIGHT H - C - C - C - C - Cl H H H Cl | | | | | | | H H Cl H - C - H | H

Number the carbons of the parent chain so lowest possible numbers are given to side chains and substitutions H - C - C - C - C - Cl H H H Cl | | | | | | | H H Cl H - C - H | H 4 3 2 1

H H H Cl | | | | H - C - C - C - C - Cl | | | H H Cl H - C - H | 1, 1, 1 - trichloro- 1 H - C - C - C - C - Cl H H H Cl | | | | | | | H H Cl H - C - H | H methyl group 3

1,1,1-trichloro-3-methylbutane Halogen If more than one….ABC’s Alkyl If more than one . . .ABC’s

Practice CH3CClClCHC2H5CHCH3CH2CH3 CH3CHCH3CClCH3CH2Br 1,2-dibromo-3-ethyl-2-methylpentane

Isomers C4H10 n - butane 2-methylpropane CAN’T just bend the end same molecular formula Same # of C, H, O, N . . . 2 or more different structures C4H10 n - butane 2-methylpropane CAN’T just bend the end

different molecular STRUCTURES they have Because Isomers have different molecular STRUCTURES they have different chemical & physical properties m.p., b.p., odor, appearance reactivity, flammability . . .

Practice CH4 CH3CH3 CH3CH2CH3 CH3CH2CH2CH3 CH3(CH2)3CH3 n-octane If your new structural formula has a different name . . . YOU’VE GOT AN ISOMER CH4 CH3CH3 CH3CH2CH3 CH3CH2CH2CH3 CH3(CH2)3CH3 n-octane 1-butene

Organic Reactions X + O2  CO2 + H2O Combustion Burning H-Cs in the presence of O2 (g) will burn to produce CO2 and H2O X + O2  CO2 + H2O

Law of Conservation of Matter Substitution When one or more hydrogen atoms of a H-C chain is replaced by a halogen. C2H6 + Cl2  C2H5Cl + HCl C2H6 + Cl2  C2H4Cl2 + H2

Addition Involves breaking a multiple bond Unsaturated compounds become more saturated Alkyne becomes an alkene Alkene becomes an alkane C2H2 + Br2  C2H2Br2 C2H4 + Br2  C2H4Br2

Polymerization The process of bonding many small molecules (monomers) together to make a very long chain (polymer) Water must be a product Examples of polymers starches Proteins nylon

To be continued . . .