Organic Chemistry Chem 2014

Organic Chemistry Organic Chemistry: - the chemistry of carbon and carbon-based compounds - (C – C or C – H or C – R) - (can be a few to hundreds of carbons covalently bonded to one another) Characteristics of Organic Compounds: *Usually have strong odors and low boiling points * Most do not conduct electricity * Most will ignite and burn * Slower rates of reactions

Organic Chemistry in everyday life: Smells & tastes: fruits, chocolate, fish, mint Medications: Aspirin, Tylenol, Decongestants, Sedatives Addictive substances: Caffeine, Nicotine, Alcohol, Narcotics Hormones/Neurotransmitters: Adrenaline, Epinephrine Food/Nutrients: Carbohydrates, Protein, Fat, Vitamins Genetics: DNA, RNA Consumer products: Plastics, Nylon, Rayon, Polyester

Animals, plants, and other forms of life consist of organic compounds. Nucleic acids, proteins, fats, carbohydrates, enzymes, vitamins, and hormones are all organic compounds Besides carbon, the most common elements in organic compounds are hydrogen, oxygen, nitrogen, sulfur, and the halogens. All of the preceding elements are non-metals, therefore organic compounds have covalent bonding.

Numbers and Types of Bonds for Common Elements in Organic Compounds Application of the octet rule indicates that these elements should bond as shown below: Copyright © Houghton Mifflin Company. All rights reserved. Section 14.1

Review: Octet Rule Rule of Eight – elements want either 8 or 0 electrons in its outermost level (except for H and He which want 2 or 0) Each energy level can only hold a certain number of electrons. 1st level 2 electrons 2nd level 8 electrons 3rd level 8 electrons 4th level 18 electrons

Periodic Table and Valence electrons Group Number Number of Valence Electrons 1 2 13 3 14 4 15 5 16 6 17 7 18 8 *Helium only has 2 valence electrons

Let’s Practice Bohr Diagrams Energy Levels Diagram HW wkst http://phet.colorado.edu/sims/html/build-an-atom/latest/build-an-atom_en.html

Lewis Structure Placing valence electrons around element symbol to decipher bonding patterns

Lets practice Lewis dot structures

Practice Lewis Dot Structures 1. Oxygen (e = _________) 2. Potassium (e = _______) 3. Bromine (e = ________) 4. Germanium (e= ______) 5. Aluminum (e = ______) 6. Phosphorus (e = ______)

Big Idea in Organic Chemistry Structure controls Function Each functional group has predictable reactivity = atom or group of atoms that gives characteristic chemical properties to a class of organic compounds

Drawing Organic Structures Shortcuts make structures easier & faster to draw Butane: C4H10 Lewis Structure Structural formula Carbon Atoms Line Structure Carbon Skeleton Only shows bonds C atoms assumed at each end and intersection of bonds H atoms not shown Assume 4 bonds to each C Fulfill C’s 4 bonds by adding H’s Condensed Structures molecular formula CH3CH2CH2CH3 CH3(CH2)2CH3

Types of Organic Compounds Classified according to functional group Alkane Alkene Alkyne Halocarbon Alcohol Ether Ketone Aldehyde Carboxylic acid Amine Amino acid Amide Hydrocarbons (H & C only) What about esters? What are halolkane? Ester

Characteristics and Examples Hydrocarbons Alkane Alkene Alkyne Contain C – C single bond C = C double bond C ≡ C triple bond Formula n is # of carbons CnH2n+2 CnH2n CnH2n-2 Naming Prefix (# of C’s)-ane # (count from smallest direction of =) – Prefix (# C’s) - ene # (count from smallest direction of ≡) – Prefix (# C’s) - yne Examples See following Slides for examples Linear/ skeletal structure \/ \

Organic Prefixes Meth- 1 carbon Hept- 7 carbon Eth- 2 carbon Oct- 8 carbon Prop- 3 carbon Non- 9 carbon But- 4 carbon Dec- 10 carbon Pent- 5 carbon Hex- 6 carbon

Lewis/ Structural Formula Condensed Structural Formula Examples Name Molecular Formula Lewis/ Structural Formula Condensed Structural Formula Linear propane C3H8 CH3CH2CH3 \/ ethane C2H6 CH3CH3 \ 2-pentene C5H10 CH3CHCHCH2CH3 2-butene C4H8 CH3CHCHCH3

Condensed Structural Formula Name Molecular Formula Structural Formula Condensed Structural Formula 3-heptyne C7H12 CH3CH2CCCH2CH2CH3 1-propyne C3H5   CHCCH3

Alkanes – Energy Related Products Methane = primary component of natural gas Propane & Butane = primary component of bottled gas Gasoline = pentane to decane Kerosene = alkanes with n = 10 to 16 Alkanes with n > 16  diesel fuel, fuel oil, petroleum jelly, paraffin wax, lubricating oil, and asphalt Copyright © Houghton Mifflin Company. All rights reserved. Section 14.3

Organic Compound Nomenclature Due to the large number, variety, and complexity of organic compounds, a consistent method of nomenclature has been developed. Copyright © Houghton Mifflin Company. All rights reserved. Section 14.3

IUPAC System of Nomenclature For Alkanes Compound is named as a derivative of the longest continuous chain of C atoms. Positions & names of the substituents added If necessary, substituents named alphabetically More than one of same type substituent – di, tri, tetra The C atoms on the main chain are numbered by counting from the end of the chain nearest the substituents. Each substituent must have a number. Copyright © Houghton Mifflin Company. All rights reserved. Section 14.3

Hydrocarbons wkst

Names of Linear Alkanes and Alkyl Substituents C atoms Alkane Alkyl substituents 1 2 3 4 5 6 7 8 9 10 CH4 CH3CH3 CH3CH2CH3 CH3CH2CH2CH3 Methane Ethane Propane Butane Pentane Hexane Heptane Octane Nonane Decane -CH3 -CH2CH3 -CH2CH2CH3 Methyl Ethyl Propyl etc. Root: number of C atoms Suffix: functional group (-ane for alkanes) (-yl for alkyl groups)

An Example to Consider The longest continuous chain of C atoms is five Therefore this compound is a pentane derivative with an attached methyl group Start numbering from end nearest the substituent The methyl group is in the #2 position The compound’s name is 2-methylpentane. Copyright © Houghton Mifflin Company. All rights reserved. Section 14.3

Drawing a Structure from a Name An Example Draw the structural formula for 2,3-dimethylhexane. Note that the end name is hexane . Draw a continuous chain of six carbon (C) atoms, with four bonds around each. Copyright © Houghton Mifflin Company. All rights reserved. Section 14.3

Drawing a Structure from a Name An Example (cont.) Number the C atoms from right to left. Attach a methyl group (CH3--) to carbon number 2 and number 3. Add necessary H atoms. 2,3-dimethylhexane Copyright © Houghton Mifflin Company. All rights reserved. Section 14.3

Drawing a Structure from a Name Confidence Exercise Draw the structural formula for 2,2,4-trimethylpentane. Note that the end name is pentane . Draw a continuous chain of five carbon (C) atoms, with four bonds around each. Copyright © Houghton Mifflin Company. All rights reserved. Section 14.3

Drawing a Structure from a Name Confidence Exercise (cont.) Number the C atoms from right to left. Attach two methyl groups (CH3--) to carbon number 2 and one to number 4. Copyright © Houghton Mifflin Company. All rights reserved. Section 14.3

Drawing a Structure from a Name Confidence Exercise (cont.) Add necessary H atoms. 2,2,4-trimethylpentane Copyright © Houghton Mifflin Company. All rights reserved. Section 14.3

H C C H Methane CH4 Butane C4H10 H C ? C H ? R R Methyl -CH3 Butyl -C4H9 Where R = any other C atom or arrangement of C atoms

Example of R group C H 2 - methylbutane Expanded Structure Line Structure 2 - methylbutane

First Ten Hydrocarbons: Properties Number of Carbon Atoms Molecular Formula Melting Point, oC Boiling Point, oC # of Isomers Name Methane Ethane Propane Butane Pentane Hexane Heptane Octane Nonane Decane 1 2 3 4 5 6 7 8 9 10 CH4 C2H6 C3H8 C4H10 C5H12 C6H14 C7H16 C8H18 C9H20 C10H22 -182.5 -183.2 -187.7 -138.3 -129.7 95.3 90.6 56.8 53.6 29.7 -161.5 -88.6 -42.1 -0.5 36.1 68.7 98.4 125.7 150.8 174.0 1 2 3 5 9 18 35 75

Properties of Alkanes Nonpolar → only London Dispersion Forces IMF Larger molecular weight → Stronger London dispersion forces Compound Methane Ethane Propane Butane Pentane Formula CH4 C2H6 C3H8 C4H10 C5H12 MW 16 30 44 58 72 Boiling point (°C) -164 -88.6 -42.1 -0.5 +36.0 Linear Alkanes: 1 - 4 C atoms: gas at room temp 5 - 15 C atoms: liquid at room temp >15 C atoms: solid at room temp

Naming Branched Alkanes (IUPAC) Octane 4-ethyl 6 2 8 4-ethyl-3,5-dimethyloctane 5 4 7 3 1 3-methyl and 5-methyl = 3,5-dimethyl Root name: name of longest continuous C chain (parent chain) 2 equally long? Choose the one with more branches Number C atoms in chain, starting at end with first branch Identify substituents, give each a number (C it is connected to) Two or more identical substituents: use prefixes (di-, tri-, tetra-, etc.) List substituents alphabetically before root name Do not alphabetize prefixes Punctuation: commas separate numbers from each other hyphens separate numbers from names no space between last substituent & root name

Alkenes are very Reactive and are termed “unsaturated hydrocarbons” Alkenes will characteristically react with hydrogen to form the corresponding alkane. Copyright © Houghton Mifflin Company. All rights reserved. Section 14.3

Alkynes are Unsaturated Hydrocarbons Due to the triple carbon bond, each alkyne molecule can react with two molecules of hydrogen. Copyright © Houghton Mifflin Company. All rights reserved. Section 14.3

Chapter 26 Hydrocarbon Derivatives

Hydrocarbon Derivatives Derivatives = molecules that contain C and H, as as hydrocarbons, but also contain other elements derivatives depend on their functional groups which are atoms or group of atoms that give the derivative its characteristic chemical behavior

Derivatives Alkane Alkene Alkyne Halocarbon Alcohol Ether Ketone Aldehyde Carboxylic acid Amine Amino acid Amide Esters

Halocarbon Definition One or more of hydrogen atoms replaced with a member of halogen family General Formula R – X R symbolizes the hydrocarbon portion X symbolizes the halogen atom X can be F, Cl, Br, or I Naming (IUPAC) 1. Name hydrocarbon portion 2. Add prefix to indicate halogen, add -o 3. # of halogen placement Properties Primarily non polar Low boiling points Insoluble in water Soluble in hydrocarbon solvent Structure Examples CFC’s –chlorofluorocarbons Methanol (aerosol cans, refrigerate gases) Pesticides Dry cleaning chemicals

Alcohols Definition One or more of hydrogen atoms replaced with a member of hydroxyl group (-OH) General Formula R – OH R symbolizes the hydrocarbon portion OH – hydroxyl group Naming (IUPAC) Suffix –ol added to hydrocarbon root Properties *Similar to water (OH) *Up to 4 C are soluble in water *Higher boiling points *Can be –diol (2 –OH) or –triol (3 -OH) Structure Examples Butanol Methanol Ethanol – grain alcohol

Ethers Definition Oxygen atom that is bonded to two carbon atoms General Formula R – O – R’ R and R’ → hydrocarbon chains -O- → functional group Naming (IUPAC) 1. Suffix –oxy added to smaller chain bonded to central oxygen atom, remainder is named as before 2. Or use similar name: add suffix –yl to each hydrocarbon and add ether Properties Oxygen creates slightly polar region Some smaller molecules are soluble in water No H bonds so lower boiling points than alcohol but higher than hydrocarbons Structure Examples Ethers

Worksheet Review

Definition -oxygen atom bonded to single carbon atom by a double bond -called a carbonyl group (C=O)   Aldeyde has carbonyl group attached to end of hydrocarbon chain General Formula R – CHO Naming (IUPAC) Add suffix –al to the root name Properties More polar than hydrocarbons Higher melting and boiling points than hydrocarbons Lower melting and boiling points than alcohol Structure Examples -Methanol (HCOH) = formaldehyde – used to make polymers and used to be used for biological preservation – found to be carcinogenic -Used as flavorings in food and candy and as fragrances in inhalants and perfumes -Vanilla flavor in ice cream and cinnamon in hot chocolate Aldehydes

Definition Ketone has a carbonyl group on the interior of a hydrocarbon General Formula R-COR’ Naming (IUPAC) Add suffix –one to the root name Name must include which C it is attached to b/c always on interior C when a Ketone Properties More polar than hydrocarbons Higher melting and boiling points than hydrocarbons Lower melting and boiling points than alcohol Structure Examples -Propanone (CH3COCH3) = acetone - volatile liquid and vapor is flammable -Cortisone= hormonal response to fight or flight, treatment of severe allergic reactions; too much bad b/c breaks down connective tissue, increases production of stomach acid and decreasing protective mucus membranes resulting in gastric ulcer Ketones

Worksheet Review

Carboxylic Acids Definition Characterized by presence of a carboxyl group General Formula R – COOH Naming (IUPAC) Prefix + -anoic acid Properties -carboxyl end is very polar making it soluble in water -higher boiling points than hydrocarbons Structure Examples (see also book pg 852) -Fatty acids Formic acids (simplest form HCOOH) – from ants Acetic acid – (CH3COOH) – responsible for sour taste of vinegar -lactic acid – responsible for sour cow’s milk Carboxylic Acids

Definition Similar to carboxylic acid, but has hydrocarbon group in place of H atom of carboxy group General Formula R-COOR’ Naming (IUPAC) -named for the alcohol and acid from which they are produced -alcohol name (suffix changed to –yl) + acid name (suffix changed to –oate) Example : ethanol + propanoic acid = ethyl propanoate OR -alcohol name (-yl) + acid (-ate) = propyl alcohol + formic acid = propyl formate Properties -polar but do not form H bonds with each other -boiling points are lower than BP of similar alcohols or acids -distinctive odors based on alcohol and acid reaction (typically fruity odors) Structure Examples (see also book pg 856) Ester

Worksheet Review

Definition Contains an amino group (-NH2) attached to hydrocarbon chain General Formula R-NH2 2◦ = R-NHR’ 3◦ = R-NR’R” Naming (IUPAC) -add suffix –amine to root name of hydrocarbon Properties -amino group is polar -higher boiling points than HC but lower than alcohols -weak bases Structure Examples -amino groups found in DNA, vitamins, anesthetic drug -basis of nicotine, cocaine, amphetamines -unpleasant odors = cadaverine produced by bacteria on decaying organisms – can cause food poisoning -found in suntan lotion Amines

Amides Definition Amino group attached to carbon of carboxyl group General Formula R-CONH2 Naming (IUPAC) -add suffix –amide to root of hydrocarbon Properties Structure Examples Amides nylon and urea, which exist in chains, and caffeine, which exists in a ring

Worksheet Review