Ch 12 Alcohols, Ether, Thiols Naming

Functional Groups containing Oxygen Functional Groups Molecule Class -OH hydroxyl group Alcohols -O- ether “ Ethers C=O carbonyl “ Aldehydes, Ketones carboxyl “ Carboxylic Acid

Molecules and Functional Groups containing oxygen have a bent shape are polar, soluble in water form H-bonds

I. Alcohols industrial ethanol production

Alcohol Naming -OH H3C -CH2- CH2 –CH- CH2-CH3 1 CH2-OH 5 4 3 2 H3C -CH2- CH2 –CH- CH2-CH3 1 CH2-OH Find longest C-chain containing -OH group. Name: drop the alkane ‘e’ replace with ‘-ol’ pentanol 3. Number: –OH is attached to lowest C number Name: location-alkan-ol: 1-pentanol 4. Locate/list other substituents in front 2-ethyl-1-pentanol

Multiple Hydroxyls Include Carbon number add –di, -tri, -tetra….ol 1,2-propandiol 1,1-propandiol

Warm-up A.) B.) OH A.) 3-methyl-2-pentanol B.) 4-methyl-2,3-pentandiol

Hydroxyls on alkenes/ynes OH group location overides double/triple bond numbering Use the functional group name: Hydroxyl List alpha 2-Hydroxyl-4,4-dimethyl-trans-3-pentene

Phenol Benzene + Alcohol Group, must be called Phenol Hydroxyl is always on C#1

Practice 2-methylphenol

Classification of Alcohols: Primary, secondary, tertiary -OH attached to carbon with two other carbon and one H -OH attached to carbon with one other carbon and two H -OH attached to carbon with three other carbon and no H

Practice Draw the following alcohols in Kekule 1-Hexanol 3-Hexanol 1,2,3-Hexantriol Name and classify as 1st, 2nd, 3rd alcohol A B

Sulfur Instead of Oxygen Same number of valence e- Same number of bonds as oxygen -SH is called a Sulfhydryl/Thiol group

Polarities EN of O: 3.5, S: 2.5, H: 2.1 Evaluate the polarities of the following bonds O-H C-O C-S S-H C-H C-S produces a ____ polar bond than C-O

Thiols -SH Longest carbon chain including thiol: lowest number Name: location-alkanethiol 1-propanethiol multiple: locations- alkanedithiol, -trithiol 1-propanethiol 2-methyl-1-propanethiol 2- propanethiol

-SH on complex Hydrocarbons List alpha as thiol, the highest oxidized group determines numbering (O beats S) SH 2-hydroxyl- 3-methyl- 4-thiol-trans-2-pentene

Ethers -O- Carbon chains on either side of ether are named alkyls according to length followed by ether- location not necessary!!! List alphabetically or use di- if identical diethyl ether ethyl phenyl ether ethyl methyl ether

2. Alcohols, Ethers and Thiols in Nature

Alcohols in Nature Methanol: smallest alcohol in nature, toxic Ethanol: byproduct of alcoholic fermentation (degradation of sugar in the absence of oxygen) C6H12O6 → 2C2H5OH + 2CO2 Glucose Ethanol CO2 causes fizzing, leavening bread… Isopropanol: alcohol for disinfection, rubbing alcohol Many flavors and aromas are alcohols: vanilla, thymol (thyme) eugenol (cloves), menthol

Thiols in Nature Strong, borderline smells in nature are usually Thiols: onion, garlic, aged cheese: break down of amino acid Methionine

Ethers in Nature First anesthesia was done with diethyl ether Inhalation anesthesia Very volatile, and explosive Many side effects Not in use anymore history of ether anesthesia

3. Polarity of Alcohols, Thiols and Ethers

The Role of Oxygen Oxygen has the second highest electronegativity of the PT: 3.5 Complete the table below: (EN: H: 2.1 and C: 2.5) bond C-H O-H C-O ∆EN Polar/ nonpolar?

Polar Bonds = Polar Molecules! In order to be a polar molecule it needs to have both: Polar bonds and b. Polar symmetry Polar Symmetries: Net Dipole Dipole Bent Pyrimidal δ- δ+ δ- δ+

Characteristics of Alcohols, Thiols and Ethers Oxygen containing functional groups makes molecules polar! (Sulfur is not very electronegative (2.5) so does not make hydrocarbons very polar – only structural asymetry) Hydroxyl will change the Melting, Boiling Point and Solubility Example: Methane: gas Methanol: liquid

4. Characteristics of Alcohols, Thiols and Ethers Melting/Boiling Point, Solubility in Water

Characteristics of Hydrocarbons Non-polar Have low Melting/Boiling points Do not dissolve in water Only attractive forces are Van-de-Waals

Characteristics of Alcohols (to some degree Thiols and Ether) Are polar Have a higher Melting/Boiling Point Dissolve in water Attractive forces include: H-bonds, Dipole Interactions and Van-de-Waals

3 Intermolecular Attractions: how they influence MP/BP and solubility in water

1. Hydrogen bonds – strongest intermolecular attraction Intermolecular attraction of adjacent polar points (δ+, δ-) involving a Hydrogen Indicated by a dotted line

2. Dipole Interactions attraction of adjacent polar points δ+, δ- not involving H

3. Van-De-Waals attractions caused by very weak EN differences (0.4 and lower)

Solubility in Water -A Requires Hydrogen Bonds

HC chain length vs # of OH-groups alcohol group polar HC chain length vs # of OH-groups Long HC chains reduce polarity/solubility in water alkane chain: non-polar alcohol group: polar not soluble so forms H-bonds soluble

Solubility of alcohols vs HC

Dissolving Molecules in H2O Draw the molecule in VSEPR Draw in all partial charges (δ+, δ+) Associate 1 (one) H2O molecule per each δ+/- in the correct orientation (+ attracts -) Draw in dotted lines Example: Methanol

Type and number of intermolecular attractions between molecules determines MP/BP Hydrocarbon Ether Alcohols VdW + Dipole - H-Bond

Comparison of Alkanes, Ethers and Alcohols Compound Molar mass g/mole BP Soluble in H2O Butane 58 g/mol 0 Celcius no Ethyl methyl ether 60 g/mol 8 Celcius yes Propanol 97 Celcius

Melting and Boiling Points

Fermentation Fermentation

Warm-up 10 minute summary How and why does alcohol affect the body and how does the body deal with it. You may want to address the following…. which organs/tissues are affected by alcohol? which organs/tissues are responsible for break down? What are the long term affects of chronic alcohol abuse?