Organic Chemistry Essentials Chemistry of carbon compounds Carbon can form 4 covalent bonds with other atoms. This allows it to make millions of different compounds. Carbon can form single, double, and triple bonds.

Hydrocarbon compound containing only hydrogen and carbon Ex. CH4 C2H6

Hydrocarbon derivative compound with some hydrogen atoms replaced by other elements (O, N, F, Cl, Br, I) ex. CH3Br

Straight chained hydrocarbon Ex. CH3CH2CH2CH2CH2CH3 or C6H14

Branched hydrocarbon CH3 CH3CH2CHCH2CH3 or C6H14

Saturated hydrocarbon no double or triple bonds

Unsaturated hydrocarbon contains double and/or triple bonds not “saturated” with hydrogen

Structural formulas Condensed Structural formulas CH3-CH3

Alkanes hydrocarbons with only single bonds General formula: CnH2n+2 names end in -ane boiling pt. increases with # of carbons

IUPAC Names Methane 1 CH4 Ethane 2 CH3CH3 Propane 3 CH3CH2CH3 Name # carbons Structural Formula Methane 1 CH4 Ethane 2 CH3CH3 Propane 3 CH3CH2CH3 Butane 4 CH3CH2CH2CH3 Pentane 5 CH3CH2CH2CH2CH3

Name # carbons Structural Formula Hexane 6 CH3CH2CH2CH2CH2CH3 Heptane 7 CH3CH2CH2CH2CH2CH2CH3 Octane 8 CH3CH2CH2CH2CH2CH2CH2CH3 Nonane 9 CH3 CH2 CH2CH2CH2CH2CH2CH2CH3 Decane 10 CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3

Alkenes contain at least one double bond name ends in -ene general formula: CnH2n

Alkynes contain at least one triple bond name ends in -yne general formula: CnH2n-2

Nomenclature naming system IUPAC (International Union of Pure and Applied Chemistry)

Rules for naming alkanes 1. Name the longest carbon chain in the structure. If the chain is cyclic, include the prefix cyclo. 2. Name, in alphabetical order, the kinds of groups which are attached to the chain you named in step 1. Use the appropriate prefix, such as di-, tri-, tetra-, etc., to indicate how many of each group are present.

3. Number the carbon atoms in the longest chain consecutively from the end of the chain which allows the attached groups to have the lowest numbers possible. Assign to each group you named in step 2 the number(s) indicating its position(s) on the main chain.

Rules for naming alkenes and alkynes Name the longest carbon chain containing the carbon-carbon double or triple bond. The name of the longest chain ends in –ene for an alkene; in –yne for an alkyne. The position of the double or triple bond in the carbon chain is indicated by a number before the name of the chain. Name the groups attached as in alkanes.

3. When assigning numbers to atoms in the chain, start numbering from the end of the chain closest to the double or triple bond.

Naming branched chain alkanes substituent- atom or group of atoms that takes the place of hydrogen on a hydrocarbon molecule ex. C, O, N, S, P, Cl, F, I, Br

Alkyl Group hydrocarbon substituent alkane with one H removed drop the -ane ending and add -yl H H C CH3 methyl H H H C C CH3CH2 ethyl

Name the following: 3,3-diethylhexane

4-ethyl-4,6-dimethyl-5-propylnonane

6-ethyl-4,5-dipropylnonane

Draw the following: 2,2,4-trimethylpentane

Draw the following: 3-ethyl-2-hexene

Draw the following: 4-bromo-2,2-dichloro-3,5-diethyl-6-fluorooctane

Properties of Hydrocarbons nonpolar not attracted to water

Structural Isomers compounds that have the same molecular formula but different molecular structures. physical and chemical properties differ Butane 2-methylpropane or isobutane CH3-CH2-CH2-CH3 CH3 CH3-CH-CH3

Geometric Isomers Each of the carbons of the double bond must have at least one substituent. Ex. CH3CH=CHCH3 has 2 geometric isomers because the double bond is not free to rotate. Bond angle (sp2) is 120o.

cis-2-butene trans-2-butene

Stereoisomers Stereoisomerism is the arrangement of atoms in molecules whose connectivity remains the same but their arrangement in space is different in each isomer. The two main types of stereoisomerism are: cis-trans isomerism optical isomerism

Optical isomerism is a form of isomerism where the two different isomers are the same in every way except being non-superimposable mirror images of each other. Optical isomers are known as chiral molecules. A compound is chiral when it cannot be superimposed on its mirror image. The pair of mirror imaged non-superimposable compounds are known as enantiomers. Even though very similar still, different enantiomers of the same chiral drug can have very different pharmological effects, mainly because the proteins they bind to are also chiral. 4 different groups attached to the carbon The two enantiomers of bromochlorofluoromethane

Cyclic hydrocarbons compounds that contain a hydrocarbon ring general formula is: CnH2n Cyclopropane Cyclobutane

Aliphatic compounds hydrocarbon compounds which do not contain rings

Arenes unsaturated cyclic hydrocarbons Benzene, C6H6, is an arene. Benzene is a flat molecule with resonance.

Shorthand ways to draw benzene:

Aromatic compound any substance in which the bonding is like benzene A benzene ring used as a substituent on a hydrocarbon chain is called a phenyl group. Ex. methylbenzene (toluene)

Nomenclature:

Natural gas- 80% methane, 10% ethane, 4% propane, 2 % butane Petroleum = complex mixture of hydrocarbons Cracking= a controlled process by which hydrocarbons are broken down or rearranged into smaller, more useful molecules

Functional Group Chemically reactive part of an organic molecule Learn these functional groups R means the rest of the molecule (usually hydrocarbon

The Common Functional Groups Class General Formula Halohydrocarbons RX Alcohols ROH Ethers ROR Aldehydes

The Common Functional Groups Class General Formula Ketones Carboxylic Acids Esters Amines RNH2

Halocarbons Organic compounds containing F,Cl, Br, or I Halogen groups are named as substituents just as alkyl groups are. Cl I I Cl-C-Cl CH3-CH-CH-CH3 H Cl-CH2-CH3CH3 bromobenzene 2,3-diiodobutane Trichloromethane (chloroform) chloromethane 1-chloropropane

Alcohols Organic compounds with a hydroxyl group (-OH) Naming: drop “e”, add “-ol” Methanol Methyl alcohol “wood alcohol” Ethanol Ethyl alcohol “drinking alcohol”

propanol propyl alcohol n-propanol 1-propanol 2-propanol isopropanol isopropyl alcohol “rubbing alcohol”

Alcohols can be classified as primary, secondary or tertiary.

antifreeze

Glycerine 1,2,3-propantriol

Phenol

Properties of Alcohols Hydrogen bonding Short-chained alcohols are soluble in water Fermentation- production of ethanol from sugars by the action of yeast or bacteria C6H12O6  2CH3CH2OH + 2CO2 Denatured Alcohol- ethanol with an added substance to make it toxic

Ethers Compounds in which oxygen is bonded to two carbon groups R-O-R’ Name the R groups in alphabetical order and add the word ether. dimethyl ether ethyl methyl ether ethyl phenyl ether

diethyl ether 1st reliable general anesthetic, 1842

Aldehydes Organic compounds in which the carbon of the carbonyl group ( C=O ) is always joined to at least one H. Naming: drop “e”, add “-al”, carbonyl carbon is #1

methanal (formaldehyde)

ethanal CH3 H CH3CH2CHCH2C=O 3-methylpentanal

Ketones Organic compounds in which the carbon of the carbonyl group is joined to 2 other carbons. The carbonyl group is in the middle of the chain instead of the end of a chain as in an aldehyde. Naming: drop “e”, and “one”. If carbonyl can be in more than one position, give it a # 3-hexanone Propanone (acetone)

Naming: drop “e”, add “oic acid” The carboxyl carbon is always #1.

butanoic acid methanoic acid “formic acid” propanoic Acid “propionic acid”

Esters Derivatives of carboxylic acids in which the –OH of the carboxyl group has been replaced by an –OR from an alcohol Formed by combination of a carboxylic acid with an alcohol in a dehydration reaction Often common flavors and odors Naming: Name alkyl group, then acid with –ate ending

ethyl ethanoate or ethyl acetate (apple scent) methyl ethanoate or methyl acetate methyl methanoate or methyl formate

Amines -NH2 the suffix amine is added to the alkyl substituent can also be named as an amino group 3-aminopropanoic acid ethylamine cyclohexylamine

POLYMERS made of repeating units called monomers