Alkanes
● Alkanes are a type of hydrocarbon with single bonds and saturated.
○ They all have a general molecular formula of C n H 2 n+2
○ In the structural formula keep in mind they have single bonds
○ Empirical formula is not the simplest ratio.
○ A list of the different Alkanes
○ Alkanes can often take different shapes while having the same mass. This is known as isomers.
■ Isomers have different properties
● There are multiple different features of Alkanes
○ Branched alkanes normally exhibit lower boiling points than unbranched alkanes of the same carbon content.
○ Solid alkanes are normally soft, with low melting points
○ Insoluble in water
● As the amount of carbon atoms present increases so does the boiling and melting point.
Alkene
● Alkenes are unsaturated hydrocarbon chain with a double bond.
● They often end in the suffix – ene
● There are multiple different isomers of Alkenes when they are linear. There are two kinds of isomers which can be seen when looking at Alkenes: location of the double bond and structural.
○ Location of the double bond:
○ Structural
■ Double bonds have both sigma and PI bonds, unlike single bonds. The PI bonds restrict the movement around the double bond. This results in something known as CIS-trans- isomers.
● Forms of alkenes that have the same structure except of orientation of components around the PI bond.
● An example of this can be seen in Butene
- The general formula for alkene is \(\mathrm{C}_n \mathrm{H}_{2 n}\)
- Generally in commercial industries Alkenes are converted to Alkanes. This is carried out to make food healthier or stay longer.
○ For example vegetable oil of polyunsaturated fat – means multiple double bonds. This is healthier although harder to spread as they are liquid at room temp. So food scientists use hydrogenation to make them saturated hence easy to spread.
Alcohols, Carboxylic Acids & Esters
● Alcohols – Are a type of functional group.
○ The general formula included :\(\mathrm{C}_n \mathrm{H}_{2 \mathrm{n}+1} \mathrm{OH}\)
○ They can be created through the hydration of an alkene
○ Single bonded carbon and hydroxide atoms
○ They are a bunch of compounds with one OH group
● Carboxylic
○ Organic compounds which contain the functional group – COOH
○ Often has an ending in “oic” acid. For example Ethanoic acid.
● Esters
○ They are a group of organic compounds which all contain the functional group – COO-.
■ Typical characteristics they include; volatile and have fruity smells.
Crude Oil
Crude Oil can be seen as a mixture of different hydrocarbons which are mixed together.
An important step is often separating the different components. After the sand and water are removed fractional distillation is used to separate the remaining components.
• Fractional Distillation with crude oil can be broken down into three steps – Distillation, Cracking and Reforming
Distillation
▪ Crude oil is heated in a furnace at extremely high temps. But the temperature along the vessel varies with the top being the coolest compared to the bottom.
▪ As the mixture is heated different hydrocarbons evaporate and condense at different levels.
▪ The boiling point is directly proportional to amount of carbon in Hydrocarbon.
▪ The ones with the highest boiling point condense towards the bottom, and vice versa.
▪ They are piped out of the distillation depending where they
condense.
Cracking –
▪ Large saturated hydrocarbon molecules are broken down into smaller, more useful hydrocarbons.
▪ This can be done through the use of a catalyst; for example EOLITE.
▪ Or can be done with high temperature and pressure.
Reforming
▪ In the presence of hydrogen and a heated catalyst, hydrocarbons, with small carbon chain become more stable Benzene rings.
● Some products of this often include
Reactions
● Substitution
○ A reaction in which one functional group in a chemical compound is replaced by another functional group.
● Esterification
○ A reactions of acid with alcohol to make an ester (a condensation reaction even takes place). The acid often acts as a catalyst.
○ This will result in an ester and water
An acid must be present as a catalyst. Often Alcohol is used
● Addition Reaction
○ Addition Polymerization and Hydrogenation (two or more molecules combine to form one longer molecule)
● Hydrogenation
○ The breaking of double bonds into more stable saturated molecules, often through the use of hydrogen.
○ Alkenes + Hydrogen —> Alkanes
○ Alkynes + Hydrogen —> Alkenes or Alkanes ( depends on the amount of hydrogen)
○ An example is
■ Ethene + Hydrogen → Ethane
○ In industry this is often used on unsaturated oil to make then more spreadable.
● Polymerization
○ Addition Reactions: Are reactions in which monomers are joined to create one long chain of monomers.
○ Condensation Reactions The joining of two different monomers to form 2 products. A polymer and water.
IUPAC
● Non- Cyclic hydrocarbons
○ Identity the functional groups present.
■ Look for stuff such as number of bonds (single/double/triple). Then select appropriate suffix.
○ Find the longest continuous carbon chain that contain the functional group, and count the number of carbon atoms in that chain. Use this information for the prefix.
○ Number the carbons in the longest carbon chain (Important: If the molecule is not an alkane (i.e. has a functional group) you need to start numbering so that the functional group is on the carbon with the lowest possible number). Start with the carbon at the end closest to the functional
group.
○ Look for any branched groups
■ Name them by counting amount of carbon atoms
■ Name the position of the main carbon using the numbers. If two are present, then list both numbers
■ The branched groups must be listed before the name of the main chain in alphabetical order
○ For alkyl halides and halogen atoms it is treated much the same way as branched groups
■ To name them take the name of the halogen atom (e.g. iodine) and replace the “ine” with “o” (e.g. iodo).
■ If more than one is present when listing the prefix should be used and position shown(e.g. 3,4-diodo- or 1,2,2-trichloro-)
○ Combine all info in the order
■ branched groups/halogen atoms in alphabetical order (ignoring prefixes)
■ prefix of main chain
■ Name ending according to the functional group and its position on the longest carbon chain.
● For naming alcohols, ester and acids please refer to the following link: