Block 4 Flashcards
Aliphatic hydrocarbon:
physical properties of higher members of this class resemble those of the long carbon chain molecules we find in animal fats and plant oils. Greek: aleiphar= fat/oil
Alkyl group:
a substituent group derived from an alkane by removal of a hydrogen atom.
R-C-C-C
|
C
isobutyl
C
|
R-C-C-C
sec-butyl
C
|
R-C-C
|
Ctert-butyl
C-C-C
|
C
isobutane
C-C-C-C
|
C
isopentane
Cyclic hydrocarbon:
a hydrocarbon that contains carbon atoms joined to form a ring.
Cycloalkane:
a cyclic hydrocarbon in which all carbons of the ring are saturated.
C=C
IUPAC name and common name
IUPAC - Ethene
Common - Ethylene
C-C=C
IUPAC name and common name
IUPAC - Propene
Common - Propylene
C
|
C-C=C
IUPAC and common name
IUPAC -2 methlpropene
Common name - Isobutylene
C(triple bond)C
IUPAC name and common name
Ethyne
Acetylene
C-C(triple bond)C
IUPAC name and common name
Propyne
Methylacetylene
C-C(triple bond)C-C
IUPAC name and common name
2-butyne
dimethylacetylene
Saturated hydrocarbon:
Each carbon has the maximum number of hydrogen bonded to it.
Where do we obtain alkanes?
Natural gas and petroleum.
Are alkanes polar or non-polar and why?
Non-polar. Electronegativity difference is too small. The interactions are very weak London dispersion forces.
Are alkanes soluble in water? Why?
No, because they can’t form bonds with the hydrogens in water.
Will alkanes sink or float in water? Why?
Float, because they are less dense than water.
What kind of reaction is an alkane w/ a halogen?
A substitution reaction.
What are chlorofluorocarbons (CFCs)? Why don’t we use them now? What do we use instead?
Aka freon. Used for refrigerators, industrial cleaning agents, and propellants for aerosol sprays.
We don’t use them because they ruin the ozone layer.
Hydrofluoralcarbons, and hydrochlorofluoralcarbons are used now because they dissipate before they reach the ozone.
Thermal Cracking:
an industrial process to produce ethylene
–Ethane is thermally cracked by heating it to 800- 900° C for a fraction of second
Constitutional isomers
Atoms and functional groups are joined together in different ways.
Stereoisomers:
The bond structure is the same, but the geometrical positioning of atoms and functional groups in space differs.
Achiral or Cis- trans isomers:
Orientation of functional groups in molecules without stereocenter.
Chiral isomers:
in molecules having stereocenter.
Explain Cis-Trans Isomerism in Vision
Beta-carotene, a precursor form of Vitamin A, obtained from plants and fruits. Beta-carotene is broken down into 2 molecules of vitamin A, also named as 11-cis-retinol. Hydroxyl group of carbon 15 is converted into aldehyde group, forming 11-cis retinal. The Retina is light detecting layer in the back of eyes. It contains rose colored visual pigments, Rhodopsin. Rhodopsin = 11-cis-retinal + a protein ‘Opsin’. Light changes 11-cis-retinal to 11-trans-retinal
What is terpene?
A large compound whose carbon skeleton can be divided into five-carbon units identical to the carbon skeleton of isoprene. (C5H8)
eg: essential oils, perfumes.
Explain Polymerization
–Show the structure of a polymer by placing parentheses around the repeating monomer unit.
–Place a subscript, n, outside the parentheses to indicate that this unit repeats n times.
–The structure of a polymer chain can be reproduced by repeating the enclosed structure in both directions.
–Attach a prefix poly- to name of monomer
ortho
next carbon
meta
after one carbon
para
opposite carbon
Autoxidation:
a reaction that converts an R-H group to an R-O-O-H (hydroperoxide) group.
Radical:
An atom or molecule with an unpaired electron
Effects of autoxidation.
Hydroperoxides:
●are unstable.
●Under biological conditions, they degrade to short-chain aldehydes and carboxylic acids with unpleasant “rancid” smells.
●Similar reactions in the low-density lipoproteins (LDL) deposited on the walls of arteries leads to cardiovascular disease in humans.
●Cell and tissue damage.
●Many effects of aging are the result of hydroperoxide formation and their subsequent degradation.
What are BHT and BHA and what are they used for?
They are phenols as antioxidants. BHT and BHA are synthetic antioxidants, added to food to ‘retard spoilage’ by autoxidation
Glycols:
compounds containing hydroxyl groups on adjacent carbons
●This term is used only in common name
Nitroglycerin:
An explosive and a drug
Explain Oxidation of Alcohols
- Oxidation of a 1° alcohol gives an aldehyde or a carboxylic acid, depending on the experimental condition:
- oxidation of a 1° alcohol to a carboxylic acid is commonly carried out using potassium dichromate, K2Cr2O7, in aqueous sulfuric acid.
- Potassium dichromate oxidation of ethanol to acetic acid is the basis for the original breath-alcohol screening test
What is Halogenated ethers, enflurane and isoflurane, used for?
inhalation anesthetics
Why do cyclopropals break up?
Because of strain, it breaks apart.
Where do we use ethanol:
- Used in E85, which is a blend of up to 85% ethanol in gasoline
- In alcoholic beverages
- Laboratory and industrial solvent
Where do we use Diethyl ether:
- laboratory and industrial solvent
- general anesthesia
Where do we use Ethylene glycol:
- antifreeze
- paints and plastic surgery
- inks
