Transcript Notes
Organic Chemistry Chemistry 2013-2014 Organic chemistry is the chemistry of carbon compounds Carbon can form 4 covalent bonds with other atoms. This allows it to make millions of different compounds. Carbon can form single, double and triple bonds. A hydrocarbon is a compound that only contains hydrogen and carbon atoms. Saturated hydrocarbons contain no double or triple bonds. Unsaturated hydrocarbons contain double and/or triple bonds. Can be straight or branched. Boiling point increases as number of carbon atoms increases. Hydrocarbons: Alkanes Definition/Functional group: single bonds only; saturated; nonpolar Suffix: -ane Examples Methane Ethane Hydrocarbons: Alkenes Definition/Functional group: at least one double bond; unsaturated; nonpolar Suffix: -ene Example: ethene, C2H4 Hydrocarbons: Alkynes Definition/Functional group: at least one triple bond; unsaturated; nonpolar Suffix: -yne Examples Ethyne, C2H2 Butyne, C4H6 Benzene Rings Definition/Functional group: contain at least one benzene ring, often with other groups added (“substituted” for hydrogen). Benzene exists as a resonance structure. It is also a carcinogen. Prefix: Benz Examples Benzene Benzaldehyde Alcohols Note: not all alcohols are safe to drink (ethanol is the “alcohol” in all alcoholic beverages). The “alcohol” family is large and its members have many properties. For example, methanol is highly toxic! Definition/Functional group: contain an –OH group, called a “hydroxyl” group. Suffix: -ol Examples Methanol Ethanol Propanol Aldehydes Definition/Functional group: contain an oxygen atom double-bonded to a carbon atom at the end of a hydrocarbon chain. Suffix: -anal Examples: Methanal, CH2O Ethanal, C2H4O Ketones Definition/Functional group: contain an oxygen atom double-bonded to a carbon atom NOT at the end of a hydrocarbon chain. Suffix: -none Examples Propanone, C3H6O Ethers Definition/Functional group: a hydrocarbon chain in which one of the links is an oxygen atom, bonded to a carbon atom on either side. Suffix: -ether Examples Esters Definition/Functional group: a hydrocarbon where one carbon atom is bonded to another carbon and two oxygen atoms, one through a single bond and one through a double bond. That sounds pretty confusing, but esters are easy to recognize. They all have the same basic shape as the picture above, where the letter “R” means carbon atoms or other “organic” groups. Suffix: -ate Examples Cyclic Alkanes Definition/Functional group: these are alkanes that are cyclic, meaning that the ends are connected to form a regular geometric shape. Ex. triangle, square, pentagon, hexagon, etc. Benzene is not a cyclic alkane due to its double bonds and resonance. Prefix: Cyclo Examples: Cyclopropane, C3H6 Cyclobutane, C4H8 Nomenclature We’re going to focus on naming the simplest kinds of organic molecules—alkanes, alkenes, alkynes, alcohols, and aldehydes. However, you will have to be able to classify the names and structures of each type of organic molecule in these notes, or to pick a name from a list that most closely fits a structure. Prefixes (stand for number of carbon atoms in chain): Number of Carbon Atoms Prefix Number of Carbon Atoms Prefix 1 Meth- 6 Hex- 2 Eth- 7 Hept- 3 Prop- 8 Oct- 4 But- 9 Non- 5 Pent- 10 Dec- What type of organic molecules are these prefixes and suffixes used for? Alcohol Alkene Ester Ketone Benzene ring Alkane What kind of prefix or suffix matches each of these structures? -none -yne Cycl0-ane -ane Benz- To determine the name of an organic molecule, first classify it by type. Then count the number of carbon atoms in the molecule. For example, the following structure has one double bond, so its suffix is –ene. There are six carbon atoms in the chain, so its root is hex-. The name of this structure is hexene. Structure Prefix Cyclo- Root Suffix Name Prop- -ene Propene -hept- -ane Pent- -yne Cycloheptane Pentyne Structure Prefix Root Suffix Name Prop- -anal Propanal Pent- -ol Pentanol Draw the following: Propanol Cyclobutane Pentanal