The study of carbon-based compounds and their properties.

Historically the distinction between inorganic and organic substances was based on whether or not they were produced by living systems. It was believed that some sort of “life force” was needed to synthesize them.

In 1828, the German chemist Freidrich Wohler ( ) prepared urea from the inorganic salt ammonium cyanate by simple heating. NH 4 OCN  H 2 N—C—NH 2 O urea

Hydrocarbons: contain only hydrogen and carbon Hydrocarbons AliphaticAromatic AlkanesAlkenesAlkynesCyclic Hydrocarbons can be divided into different types, depending on their bonding.

Naming Organic Molecules Alkanes - - Carbon chain, no double or triple bonds. All single bonds (saturated) Alkenes - - Carbon chain, contains double bond(s) (unsaturated) Alkynes - - Carbon chain, contains triple bond(s) (unsaturated)

Naming Organic Molecules There are two parts to the main name of each molecule… prefix: tells the # of carbons in main chain or ring suffix: tells the type of bonding in the chain or ring

Prefix: indicates number of carbon atoms in the main chain or ring 1meth- 2eth- 3prop- 4but- 5pent- 6hex- 7hept- 8oct- 9non- 10dec-

Suffix Explained….  The chemical suffix or end part of a chemical name needs careful attention.  There is a big difference between the "ide", "ate" and "ite" suffixes.  1. As a general rule an "ide" suffix indicates an element. eg. sulfide S 2-, nitride N 3- and phosphide P 3-  The exceptions are hydroxide OH - and cyanide CN -  2. "ates" and "ites" always contain oxygen. eg. nitrate NO 3 - and nitrite NO 2 -  3. "ates" always have a higher number of oxygen atoms the corresponding "ites". eg. sulfate SO 4 2- and sulfite SO 3 2-

Suffix: indicates types of bonds present Alkanes: (all single bonds) ___ -ane Alkenes: (double bond) ___ -ene Alkyne: (triple bond) ___ -yne

Saturated Hydrocarbons:  the ALKANES: chains of carbon connected by single bonds: contain only single C-C bonds

Saturated v. Unsaturated fats Saturated with H Single bonds are free to rotate, so these fats can pack tightly room temp)

Which one is saturated?

For a bit of a demonstration…  Good Eats fat train analogyfat train analogy Watch episode from 1:30 to 5:00

ALKANES

ALKANES propane, C 3 H 8

ALKANES butane, C 4 H 10

ALKANES pentane, C 5 H 12

ALKANES hexane, C 6 H 14

ALKANES octane, C 8 H 18

Don’t write this example down, but watch to see where we’re going with this…

“Normal” v. Branched  “normal” hydrocarbons are straight chains; no branching  Branched-chain hydrocarbons – isomers of “normal” hydrocarbons; have same formula, but different structures

Timberlake LecturePLUS29 Alkanes Contain C and H only Contain single bonds C-C Have 4 bonds to every carbon (C) atom Are nonpolar

Timberlake LecturePLUS30 Complete Structural Formulas Show the bonds between each of the atoms H H  H  C  HH C H  H H CH 4, methane

Timberlake LecturePLUS31 More Alkanes H HCondensed Structural Formulas H C C HCH 3 CH 3 H HEthane H H H H C C C HCH 3 CH 2 CH 3 H H H Propane

Timberlake LecturePLUS32 IUPAC Names Name# carbons Structural Formula Methane1CH 4 Ethane2CH 3 CH 3 Propane3CH 3 CH 2 CH 3 Butane4CH 3 CH 2 CH 2 CH 3 Pentane5CH 3 CH 2 CH 2 CH 2 CH 3

Timberlake LecturePLUS33 IUPAC NAMES Name # carbons Structural Formula Hexane 6 CH 3 CH 2 CH 2 CH 2 CH 2 CH 3 Heptane 7 CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 Octane 8 CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 Nonane 9 CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 Decane 10 CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3

Timberlake LecturePLUS34 Learning Check Alk1 A. What is the condensed formula for H H H H H C C C C H H H H H B. What is its molecular formula? C. What is its name?

Timberlake LecturePLUS35 Solution Alk1 A.CH 3 CH 2 CH 2 CH 3 B. C 4 H 10 C.butane

n-butane

Naming side chains Root is the longest possible HC chain Must contain multiple bonds if present Add -yl to get name of side chain Common side chains include: CH 3 - methyl CH 3 CH 2 - ethyl CH 3 CH 2 CH 2 - propyl (CH 3 ) 2 CH- isopropyl Br- (bromo) Cl- (chloro) F- (fluoro) I- (iodo)  Give 1 st bond (1 st point of difference) lowest #  include di, tri, tetra, penta, etc. before ene/yne  Comma between #s, hyphen between #-letter

2-methylpropane

n-pentane

2-methylbutane

Another branched alkane: 2,2-dimethylpentane

Naming side chains Example: name the following structure Step 1 - choose the correct ending

Naming side chains Step 2 - find the longest chain

Naming side chains Step 3 - add the prefix naming the longest chain

Naming side chains Step 4 - number the longest chain with the lowest number closest to the double bond

Naming side chains Step 5 - add that number to the name

Naming side chains ethyl methyl Step 6 - Name the side chains

Naming side chains ethyl methyl Step 7 - Place the side chains in alphabetical order & name the compound

Name

Draw the structures below 3-ethyl-2-methylpentane 3-ethyl-1,5,5-trimethylcyclohexene

More practice

2,2-dimethyl-3-hexene 2,5-dimethyloctane octane 1,3-diethylcyclopentane

cyclopentane Cycloalkanes

 cyclobutane

Cycloalkanes  ________________________ methyl- ethyl green or red? -ethyl- -methylcyclopentane13

Unsaturated Hydrocarbons: ALKENES – contain C-C double bonds 2-pentene

Unsaturated Hydrocarbons: ALKENES – contain C-C double bonds 2,4-hexadiene

Unsaturated Hydrocarbons: ALKYNES – contain C-C triple bonds 1-butyne

Unsaturated Hydrocarbons: ALKYNES – contain C-C triple bonds 3-ethyl-1-pentyne

Numbering carbons Draw 1-pentene Name these C2H4C2H4

Aromatic Hydrocarbons: benzene – the simplest aromatic hydrocarbon; has a symmetrical ring structure

Aromatic Hydrocarbons: benzene – can be drawn like this…

Derivatives of benzene: 1-ethyl-2-methylbenzene

Derivatives of benzene: 1-propyl,3,4-dimethylbenzene

For your homework: If a halogen is attached, use the following prefixes: fluoro- chloro- bromo- iodo- (instead of methyl-, ethyl-, propyl-, etc.)

Multiple multiple bonds – Practice CH 3 CH 2 CH 2 CH=C=CH 2

3,3-dimethyl,1-cyclopentene cyclopropane 4-nonene 6-ethyl-2-octyne

cyclobutene 1,2-dimethyl-6-propylcyclodecane benzene 3,4-diethyl-2-hexene

4-ethyl-1,2-dimethylcycloheptane 2-hexene 2,7,8-trimethyldecane 3,3-diethylpentane

3-ethyl-2-methylpentane 3-ethyl-1,5,5-trimethylcyclohexene 20 21