Chpt. 22: Some Families of Organic Compounds (Organic Chemistry)

Previously studied organic families: Alkanes Alkenes Alkynes Aromatic Compounds This section involves the study of further organic families: Chloroalkanes Alcohols Aldehydes Ketones Carboxylic Acids Esters

All ten of these families can be split into two groups: Group 1 – Tetrahedral *Do Not Take Diagram

Group 2 – Planar *Do Not Take Diagram

Group 1: Tetrahedral Group 2: Planar Chloroalkanes Alcohols Alkynes Alkenes Alkynes Aldehydes Ketones Carboxylic Acids Esters Aromatic Conpounds

Tetrahedral Carbon Compounds In saturated organic compounds, ALL of the carbon atoms are tetrahedral CHLOROALKANES: Chloroalkanes are compounds in which one or more of the hydrogen atoms in an alkane molecule have been replaced by a chlorine atom The part of an alkane remaining after one hydrogen is removed is an alkyl group e.g. Methane CH4 minus a hydrogen group leaves methyl -CH3

Remember: Alkyl Radicals Name Alkyl Radical Methyl CH3 Ethyl C2H5 Propyl C3H7 Butyl C4H9 *Do Not Take This Slide

Chloroalkanes are named after the alkane from which they are derived with the prefix chloro- indicating the presence of chlorine.

Number of Chlorine atoms Chloroalkanes of METHANE Number of Chlorine atoms Name of Compound Chemical Formula Structural Formula 1 Chloromethane CH3Cl 2 Dichloromethane CH2Cl2 3 Trichloromethane (Chloroform) CHCl3 4 Tetrachloromethane CCl4

*Important Note* You must be able to name and draw the structure of all the chloroalkanes for the first four alkanes!!! (methane, ethane, propane, butane)

Naming and Drawing structural formulas of Chloroalkanes: 1. Draw full structural formula of compound 2. Identify longest continous chain of carbon atoms - parent alkane 3. Number carbon atoms from the end that gives lowest number to the carbon atom to which the chlorine atom is attached 4. Indicate position of chlorine atom e.g 2-chloro- 5. Name compound

Example: Name the compounds: a) CH3CH2CHClCH3 b) CH3CCl2CHClCH3 c) CH3CCl(CH3)CH3 Student Questions: Workbook – pg 60 W22.1, W22.2, W22.3 Homework: Book – pg 360 22.1,22.2, 22.3

Physical State and Properties of Chloroalkanes Chloroalkanes are slightly polar Chloroalkanes are insoluble in water but are soluble in non-polar solvents e.g. cyclohexane, methylbenzene Chloroalkanes have low boiling points but because of the polarity of the carbon/chlorine bond chloroalkanes have higher boiling points than corresponding alkanes. *Note: Boiling point depends on the strength of the intermolecular forces, so, because longer carbon chains have stronger van der Waals forces between molecules they will have higher boiling points.

Most chloroalkanes liquid at room temperature, exception – chloromethane* and chloroethane are gaseous Main use is as solvents: - for removing oil and grease machinery, dry cleaning - paint stripper (dichloromethane) - Tippex* *Ozone Layer

Functional Group (Active Group) A functional group is an atom or group of atoms that defines the particular chemistry of a homologous series. Homologous Series Functional Group Alkanes C-C single bond Alkenes C=C double bond Alkynes C=C triple bond

ALCOHOLS

Alcohols form a homologous series of compounds of formula: CnH2n + 1OH Functional group – OH group (V-shaped) called hydroxyl group AlcOHol Alcohols are formed when the hydrogen atom in an alkane is replaced by the hydroxyl group (OH) Carbon atoms including that joined to the OH group are *TETRAHEDRAL* Named by replacing -ane at end of corresponding alkane with -ol

Primary, Secondary Tertiary Alcohols