Chapter 16 Organic Chemistry In this chapter, we will explore basic organic concepts including nomenclature, structure, and functional groups.

What Is an Organic Compound? ● Organic vs Inorganic ● Vital Force ● Synthesis of urea ● Carbon chemistry Most naturally occurring or synthesized compounds.

What Is an Organic Compound? ● Carbon chemistry C-C covalent bonds C bonds with other nonmetals Strong Multiple bonds

The Saturated Hydrocarbons or Alkanes ● C x H y ● If y = 2x+2, compound is a saturated hydrocarbon, also known as an alkane. ● Tetravalent C

The Saturated Hydrocarbons or Alkanes ● Straight Chain ● Branched Chain ● Isomers ConstitutionalOthers….later.

Rotation Around C-C Bonds ● Conformations EclipsedStaggered

The Nomenclature of Alkanes ● Longest chain ● Substituents ● Number the chain. ● Prefixes (di, tri,...) ● Alphabetical substituents

The Unsaturated Hydrocarbons: Alkenes and Alkynes ● Hydrocarbons with C=C or C C are unsaturated. ● Alkene for double bond, alkyne for triple bond. ● Unsaturated because they do not contain the maximum possible H per C.

The Unsaturated Hydrocarbons: Alkenes and Alkynes ● Nomenclature -ane to -ene or -yne. Number C atoms and indicate where multiple bond is located.

Aromatic Hydrocarbons and Their Derivatives ● Benzene, C 6 H 6, prototypical. ● Structure was a mystery for a long time. Kekule’s solution. Resonance structures.

Aromatic Hydrocarbons and Their Derivatives ● Monosubstituted benzenes Toluene, phenol, etc. ● Disubstituted benzenes Ortho, Meta, Para

The Chemistry of Petroleum Products ● Natural gas (mostly methane) Typically distributed by pipeline ● Crude oil Mixture of hydrocarbons – Thermal reforming, cracking – Catalytic reforming, cracking Used to increase octane number.

The Chemistry of Coal ● Complex solid C 137 H 97 O 9 NS C 240 H 90 O 4 NS

The Chemistry of Coal Figure 16.2

The Chemistry of Coal ● Large US supply ● Prefer liquid fuels over solid fuels Converted to synthetic gas – …on to methanol or other liquid fuels. ● Fischer-Tropsh reaction Liquid hydrocarbons from coal.

Functional Groups ● The presentation of organic reactions is organized around functional groups. ● As an example, the double bond in an alkene is a functional group. ● There are many others.

Functional Groups Table 16.5 and Table 16.6

Oxidation-Reduction Reactions ● Already discussed these in Chapter 12. ● Oxidation numbers discussed in Section 5.16 ● Organic redox can be characterized by Changes in oxidation numbers, or Changes in number of H atoms present, or Changes in number of O atoms present.

Oxidation-Reduction Reactions Table 16.7

Oxidation-Reduction Reactions ● For example, carbon monoxide to carbon dioxide is an oxidation ● …methanol to methane is a reduction.

Alkyl Halides ● Formed from alkane and halogen in the presence of UV light. ● Chain-reaction mechanism

Alkyl Halides ● Chain reaction mechanism InitiationPropagationTermination

Alcohols and Ethers ● Alcohol, ROH, is a functional group. ● Names end in ol. Also common names such as wood alcohol. ● Classified as primary, secondary, or tertiary. ● Are Brønsted acids.

Alcohols and Ethers ● Conjugate base of alcohol is alkoxide. ● Alcohol related to water by replacement of one H. ● Replace both Hs in water and get ether.

Alcohols and Ethers ● Ethers, ROR’. ● Alcohols H bond, ethers do not. Affects bp. Affects solubility in water. ● Ethers are an example of aprotic solvents.

Aldehydes and Ketones ● Primary Alcohol that has be dehydrogenated CH 3 CH 2 OH → CH 3 COH ● If alcohol is secondary, ketone results. RC(OH)HR’ → RCOR’

Aldehydes and Ketones ● Nomenclature Aldehydes named from corresponding carboxylic acid Ending with al.

Aldehydes and Ketones ● Nomenclature Ketones named with two alkyl groups plus ketone. ethyl methyl ketone

Reactions at the Carbonyl Group ● RR’C=O has negative end (O) and positive end (C). Electrophiles are attracted to O. – For example, H +. Nucleophiles are attracted to C. – For example, alkoxide.

Carboxylic Acids and Carboxylate Ions ● OH attached to carbonyl C makes a carboxylic acid, -COOH. ● Carboxylate ion, -COO -. Resonance structures ● Names end in -oic acid. ● Common names

Carboxylic Acids and Carboxylate Ions Table 16.8

Esters ● Carboxylic acid plus alcohol produces ester plus water. ● Other more efficient methods to prepare esters. ● Name also includes product of strong acid and alcohol Carboxylic acid esters are RCO 2 R’.

Amines, Alkaloids, and Amides ● Ammonia with one or more H replaced with alkyl. ● Like alcohols, have primary, secondary, and tertiary. ● Name has -amine at end. ● Amines are bases, just like ammonia.

Amines, Alkaloids, and Amides ● To improve water solubility, ammonium salts prepared. ● Amides are a combination of carboxylic acids and amines. Produced via acyl chloride and amine – RCOCl + 2R’NH 2 → RCONHR’+ R’NH 3 Cl - ● Alkaloids isolated from plants…

Amines, Alkaloids, and Amides Figure 16.6

Alkene Stereoisomers ● Already discussed constitutional isomers in section 16.2 ● Another type of isomer is called stereoisomer. cis and trans are stereoisomers. ● Not all alkenes have cis and trans isomers.

Alkene Stereoisomers ● cis and trans not always enough to describe alkene stereoisomer. E and Z methods more versatile. – Substituent atoms prioritized by atomic number: E and Z used to describe position of the two highest priority atoms.

Stereogenic Atoms ● The two C atoms in C=C when cis and trans isomers are possible are stereogenic atoms. ● Other possibilities for stereogenic atoms. The C in CHFClBr is stereogenic.

Stereogenic Atoms ● Any tetrahedral C with 4 different atoms attached will be stereogenic.

Stereogenic Atoms ● Stereoisomers may be mirror images of each other: enantiomers. If the mirror images are not superposable, the stereoisomers are chiral. Figure 16.12

Stereogenic Atoms …or they may not be mirror images of each other: diastereomers. cis and trans isomers are diastereomers.

Optical Activity ● Optically active compounds Rotate the plane of polarized light. ● Specific rotation is a measure of the ability of a compound to do this.

Optical Activity ● Need a method for distinguishing the left handed and right handed version of a chiral center in a molecule or ion. As before, substituents are prioritized. R and S used to designate the two possible orientations of substituents.