Chem 110, Chapters 24, 25 UDL(2) edited.pptx

General Chemistry Chem110 Chapter 24,25 Organic Chemistry Synthetic and Natural Organic Polymer Objectives  Classify the organic compounds  Differentiate between Aliphatic and Aromatic Hydrocarbons  Naming different organic compounds  Identify the functional...

General Chemistry Chem110 Chapter 24,25 Organic Chemistry Synthetic and Natural Organic Polymer Objectives  Classify the organic compounds  Differentiate between Aliphatic and Aromatic Hydrocarbons  Naming different organic compounds  Identify the functional groups  Define the Proteins 2 Outline 24.1 Classes of Organic Compounds 24.2 Aliphatic Hydrocarbons 24.3 Aromatic Hydrocarbon 24.4 Chemistry of Functional Groups 25.3 Proteins 3 24.1 Classes of Organic Compounds Organic Chemistry: is the chemistry of carbon compounds. Carbon has the ability to form long chains and ring structure. Hydrocarbons: compounds made of carbon and hydrogen only. Aliphatic Hydrocarbons: do not contain benzene group. Aromatic Hydrocarbons: contain one or more benzene rings 4 24.2 Aliphatic Hydrocarbons Aliphatic hydrocarbons divided into: 1. Alkanes: Only single covalent bonds are present, general formula CnH2n+2, n = 1, 2, …. 2. Cycloalkanes: alkanes whose carbon atoms are joined in rings, general formula CnH2n, n = 3, 4, …. 3. Alkenes: contain at least one carbon-carbon double bond, general formula CnH2n, n = 2, 3 …. 4. Alkynes: contain at least one carbon-carbon triple bond, general formula CnH2n-2, n = 2, 3 …. 5 24.2 Aliphatic Hydrocarbons  Aliphatic hydrocarbons divided into: Name Definition General Formula Alkane Only single covalent CnH2n+2 bonds are present n = 1, 2, …. Cycloalkanes The carbon atoms are CnH2n joined in rings n = 3, 4, …. Alkenes contain at least one C-C CnH2n double bond n = 2, 3, …. Alkynes contain at least one C-C CnH2n-2 triple bond n = 2, 3 …. 6 Alkanes: The general formula CnH2n+2 where n = 1,2,3,… only single covalent bonds Saturated hydrocarbons CH4 C2H6 C3H8 methane ethane propane 7 Alkane 8 Examples Classify a compound has a formula of C10H22. a. alkane. b. alkene. c. alkyne. d. aromatic hydrocarbon. What is the name of C3H8 ? e. hexane f. propane g. decane h. butane 9 Alkanes Nomenclature IUPAC: International Union of Pure and Applied Chemistry 1. Choose the longest chain in alkane (parent alkane) 2. Start numbering from the nearest branching side 3. Indicate the location and the name of the branch 4. If there is more thane one group of same substituent give the prefix di-, tri-, tetra- 5. If there are two different substituent or more, start numbering from the nearest side to the branch with consideration to the alphabetical order Note: the substituent groups are listed alphabetically in the name. 10 Alkanes Nomenclature 11 Alkanes Nomenclature Examples 4-methylheptane 2-methylpentane 4- methylpentane 12 Alkanes Nomenclature Examples 2,3-dimethylhexane 3,3-dimethylhexane 2-bromo-5-methylhexane 13 Alkanes Nomenclature Examples 2-bromo-3-nitrobutane 3-bromo-1-nitrobutane 14 Alkanes Nomenclature Examples Which of the following is the correct systematic name for a) 1-ethyl-2-methylbutane b) 3,3-dimethylpentane 15 Example 24.2 Give the IUPAC name of the following compound: 2,2,4-trimethylhexane 16 Example 24.3 Write the structural formula of 3-ethyl-2,2-dimethylpentane 17 Examples What is the IUPAC name of the following compound? 5-ethyl-2-methyloctane Homework What is the structure of 3,5-dimethyloctane? 18 Cycloalkanes Alkanes whose carbon atoms are joined in rings are called cycloalkanes. The general formula: is CnH2n where n = 3,4,… 19 Alkenes Alkenes: at lease one C-C double bond is present. The general formula: is CnH2n where n = 2,3,4,… ethene or ethylene H2C = CH2 1-butene 2-butene 20 Alkene Nomenclature 1. Start numbering from nearest side to the double bond 2. Indicate the position of the double bond in the parent compound 3. Complete the naming as usual 4. Specify the molecule as cis or trans if applicable 3-methyl-2-heptene 4-bromo-2-pentene 21 Alkene Nomenclature Example Name the following compound: 1,4-pentadiene 22 Alkynes Alkynes: contain at least one C-C triple bond. The general formula: is CnH2n-2 where n = 2,3,4,… 1-butyne 2-butyne 23 24.3 Aromatic Hydrocarbons Aromatic compounds: contain one or more benzene ring 24 Nomenclature of Aromatic Compounds If one H atom has been replaced by another atom or a group of atom → write the name of the atom or group, then benzene 25 Nomenclature of Aromatic Compounds If more than one substituent is present → we must indicate the location of the second group relative to first, then benzene 1,2 ortho o- 1,2-dibromobenzene 1,3 meta m- (o-dibromobenzene) 1,4 para p- 1,4-dibromobenzene 1,3-dibromobenzene (p-dibromobenzene) (m-dibromobenzene) 26 Nomenclature of Aromatic Compounds Compounds in which the tow substituted groups are different are named accordingly. 3-bromonitrobenzene (m-bromonitrobenzene) 27 Examples Which one of these formulas is that of an unsaturated hydrocarbon? a) CH3 – CH2 – CH3 b) CH3 – CH = CH2 c) CH3 – CH2 – OH Which of the following is the general formula for alkynes? d) CnH2n+2 e) CnH2n f) CnH2n-2 28 Example Which of these is the systematic name for the compound represented below? a) 2-ethylbutane b) 3-methyl-1-hexene c) 3-methyl-1-pentene 29 24.4 Chemistry of Functional Groups Functional Groups Groups that are responsible for most of the reactions of the parent compounds. Different Functional Groups forms: Alcohol Ethers Aldehyde Ketones Carboxylic acid Esters Amino acid Amines 30 Alcohols Alcohols: contain the hydroxyl functional group and have the general formula R-OH. 31 Ethers Ethers: have the general formula R-O-R’. Dimethyl ether Diethyl ether 32 Aldehydes and Ketones Aldehydes and Ketones: Contain the Carbonyl functional group Aldehyde: has the general formula, Ketone: has the general formula, Examples: formaldehyde acetaldehyde acetone 33 Carboxylic acids Carboxylic acids: contain the carboxyl ( -COOH ) functional group. 34 Esters Esters: have the general formula R’COOR, where R is a hydrocarbon group, and R’ can be H or a hydrocarbon ethyl acetate The smell and flavor of fruits is due to the ester compounds they contain. 35 Amines Amines: are organic bases with the general formula R3N, where R may be H or hydrocarbon group. Methyl amine Ethyl amine 36 25.3 Proteins  Polymers: are large molecules made up of repeating units called Monomers.  Proteins: are polymers of amino acids. Termed polypeptides  Play a key role in nearly all biological processes Enzymes, the catalysts of biochemical reactions Transport of materials Storage of vital substances Coordinated motion Mechanical support Protection against diseases. 37 25.3 Proteins Proteins have high molar mass; ranging from about 5000 g to 1x107 g Elements in proteins are: C (50-55 %), H (7%), O (23%) , N (16% ), and S (1%). The Basic structural units of proteins are amino acid 38 Amino Acids  Amino acids: are the basic structural units of proteins.  Contain at least one amino group (-NH2)  And at least one carboxyl group (-COOH) Amino acid 39 Amino acids  Amino acids at neutral pH exist as dipolar ions. 40 Amino Acids Amino acids are joined in a protein by the formation of a peptide bond Peptide (amide) bond 41 Example A protein is: a) a polymer of amino acids b) a fatty acid ester of glycerol c) a polysaccharide d) an addition polymer e) a polymer of fatty acids 42 Example Classify each of the following molecules as: alcohol, aldehyde, ketone, carboxylic acid, ether, or amino acid 43  Examples Classify this compound Which of the following is a CH3CH2CH2CH2CH2CH2CH2OH ketone? a) an alcohol a) CH3CH2COCH3 b) an alkene b) CH3CH2CHO c) an alkyne c) CH3OCH3 d) an unsaturated hydrocarbon d) CH3CH2COOH e) H2C=C=CH2 44  Examples Which type of functional group Vanillin is used as a flavoring does not include a carbonyl group agent. Identify the functional in its structure? group circled. a) Carboxylic acid a) Aldehyde b) Ether b) Ketone c) Ketone c) Carboxylic acid d) Aldehyde d) Alcohol e) Ester 45