Introduction to Organic Chemistry

Introduction to Organic Chemistry

• Organic chemistry studies carbon and carbon-related compounds.
• It's a branch of chemistry focused on the structure, properties, composition, reactions, and synthesis of organic compounds.
• Organic compounds consist primarily of carbon atoms bonded to hydrogen, oxygen, nitrogen, and other elements.

History

• Jons Jacob Berzelius categorized Chemistry into two branches, organic and inorganic.
• In 1828, Friedrich Wohler disproved the "Vitalism" theory.
• The "Vitalism" theory stated exclusively that all organic compounds come exclusively from living things.
• Wohler isolated urea from ammonium cyanate, an inorganic compound..

Organic Compounds Found on Living Things

• Sugar (Carbohydrates) has a ratio of Carbon (C), Hydrogen (H), and Oxygen (O) in a 1:2:1 ratio.
• Sugars can provide immediate energy, such as glucose, and structural components like cellulose in plants.
• Lipids consist of Carbon (C), Hydrogen (H), and Oxygen (O), and might contain phosphorus (P) in phospholipids.
• Lipids function in energy storage like fats and oils, and, structural roles such as phospholipids in cell membranes, also signaling, like steroid hormones.
• Proteins consist of Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), and sometimes sulfur (S).
• Functions of proteins include catalysis, or enzymes, structural support, collagen and keratin, transport hemoglobin, defense or antibodies, and communication like hormones and receptors.
• Nucleic Acids contain Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), and Phosphorus (P).
• Nucleic Acids store and transfer genetic information, and provide energy transfer ATP.

Organic Compounds vs Inorganic Compounds

• Organic compounds usually do not dissolve in water.
• Inorganic compounds generally dissolve in water.
• Organic compounds dissolve in organic solvents like ether, alcohol, benzene, and chloroform.
• Inorganic compounds do not dissolve in organic solvents.
• Organic compounds have low melting and boiling points and usually decompose with heating.
• Inorganic compounds have high melting and boiling points, and usually do not decompose on heating.
• Organic compounds are generally flammable and catch fire easily.
• Inorganic compounds are typically non-flammable and do not burn easily.
• Organic compounds exist as covalent molecules and are non-electrolytes.
• Inorganic compounds are ionic and are electrolytes.
• Organic compounds contain C, H, O.
• By comparison, any compound except ones containing C-H bonds are inorganic.
• Organic compounds form covalent bonds.
• Inorganic compounds form electrovalent, ionic, or covalent bonds.
• Organic compounds have low melting and boiling points.
• Inorganic compounds have high melting and boiling points
• Both organic and inorganic compounds have low solubility in water.
• Organic molecules are poor conductors.
• Inorganic molecules are good conductors.
• Organic compounds are volatile
• Inorganic compounds are non-volatile.
• Organic compounds exhibit catenation.
• Inorganic compounds generally do not exhibit catenation.
• Organic compounds are generally colorless.
• Inorganic compounds are generally colored.
• Organic reactions are slow.
• Inorganic reactions are fast.
• Organic compounds occur in living things.
• Inorganic compounds occur in non-living thing.
• Organic molecules are biodegradable.
• Inorganic molecules non-biodegradable.
• Enzymes, protein, DNA, RNA, fuels, are examples of organic compounds
• Metals, non-metals, salts, are examples of inorganic compounds.

Introduction: Structure and Bonding

• Erwin Schrodinger's model states that electrons do not orbit protons, but exist in a nucleus cloud.
• An atom consists of a nucleus surrounded by electrons equal in number to the protons in the nucleus.
• The Atomic Number (Z) is the number of protons in the nucleus.
• The Mass Number (A) is the number of protons plus neutrons.
• Isotopes are atoms of the same element with different numbers of neutrons and mass number.
• Atoms are electrically neutral because atoms possess positive and negative charges.
• Elements can form isotopes which are from the same element family, all of which share a same number of protons but different number of neutrons.
• The atomic/proton number defines an element's identity, otherwise the element will change if there are irregularities.

Electron Arrangements Within Atoms

• Electrons exist mainly within regions outside the nucleus.
• Electron energies exist at limited values with a specific behavior for each value.
• Electron movement within atoms occurs within shells, subshells, or orbitals.

Electron Shells

• An electron shell is a region surrounding the nucleus where electrons exist.
• A higher shell number has the capacity for more electrons.
• Up to 2 electrons can fill the lowest-energy shell,.
• The second, third, and fourth shells possess a capacity for 8, 18, and 32 electrons, in that respective order.

Electron Subshells

• A subshell refers to a group of orbitals within a shell that share the same principal quantum number and azimuthal quantum number.
• The number of subshells within a shell has equivalency within the shell itself.
  • s = 2 electron
  • p = 6 electron
  • d = 10 electron
  • f = 14 electron

Electron Orbitals

• This refers to where an electron likely exists.. Can hold 2 electrons
• It is also known as wave function.

Electron Configuration

• Electron subshells are filled sequentially from lower to higher energy.
• Quantum mechanics dictates arrangements of electrons within an atom,.
• Electron distribution occurs among various orbitals..

Electron Principles

• Aufbau Principle: electrons fill lower-energy atomic orbitals before filling higher energy ones.
• Pauli's Exclusion Principle: a maximum of 2 electrons can occupy the same orbital only if they have opposite spins.
• Hund's Rule: for degenerate orbitals, electrons fill the orbitals singly before they pair up.
• Heisenberg's Uncertainty Principle: it is impossible to locate and find the velocity electron of an atom.

Electron Configuration Rules

1. The lowest-energy orbitals fill first, meaning: 1s → 2s → 2p → 3s → 3p →4s → 3d, known as the Aufbau "build-up" principle.
2. Electrons spin around an axis with only two orientations, up ↑ and down ↓.

• Only two electrons can occupy an orbital, with an absolute requirement for opposite spin (Pauli exclusion principle) to have unique wave equations.

3. Electrons occupy each with spins parallel until all orbitals have one electron, in orbitals of equal energy, in accordance with Hund's rule.

Classification of Organic Compounds: Hydrocarbons

• These are organic compounds composed entirely of hydrogen and carbon atoms.
• Each carbon forms a four single bonds, or two
  • Alkane
  • Alkene
  • Alkyne
• Carbon atom arrangement determines the skeleton, by which a straight chain and a bent chain are the equivalent skeleton.

Functional Group

• functional group represents a set of specific atoms within a molecule.
• These groups is ultimately responsible for characteristic chemical reactions of that molecule.

Naming Functional Groups

• Alkyl Halide; Rx; none
• Alcohol; ROH; -ol
• Ether; ROR; -ether
• Amine; RNH; -amine
• Sulfide; RSR; -sulfid
• Thiol; RSH; -th

Alkanes

• They are described as “saturated hydrocarbons"
• Alkanes refer to hydrocarbons where the bonds between carbon atoms are single bonds.
• The general formula if CnH2n+2 where n= integer
• Straight-Chain Alkanes are known as “normal(n) alkanes" where carbons are connected in a row.
• Straight-Chain Alkanes are compounds with branched carbon chains.

Numerical Roots for Carbon

• Meth- = 1
• Eth- = 2
• Prop- = 3
• But- = 4
• Pent- = 5
• Hex- = 6
• Hept- = 7
• Oct- = 8
• Non- = 9
• Dec- = 10

Naming of Alkanes

• First, find and name the longest chain (root).
• Second, name the compound type, or suffix.
• For alkanes, add the suffix -ane to the chain root.
• Precede the molecule name with cyclo- if the chain forms a ring.
• Each branch name consists of a subroot, the number of C atoms), and the ending -yl.
• The -yl ending signifies that the the branch is not part of the molecule's main chain.
• In general, branch names precede the chain name.
• Alphabetize the branch names if there are multiple.
• Number the main-chain C atoms consecutively, at the closest branch, to indicate the location of the branch along the chain.
• In terms of numerical position along the chain, make sure to achieve the lowest numbers possible for the branches.
• If the compound has no branches, the molecules name consists solely of the root and suffix.
• The alkane with Cl attached is known as chloro.
• The alkane F attached is known as Fluoro/Floro
• The alkane Br attached is known as Bromo
• The alkane I attached is known as lodo.

Naming Alkanes with Cycloalkane

• These contain rings with carbon atoms.
• They're known as “acyclic (aliphatic cyclic) compounds
• Start counting at the location of the substituents..

Kinds of Organic Reactions

• ADDITION is a chemical reaction where two or more substances combine to form a single product.
• ELIMINATION represents an organic reaction where a molecule loses atoms or groups of atoms.
• SUBSTITUTION.can be described as chemical process where one atom or group of atoms in a molecule is replaced.

Organic Reactions for Alkenes

• Hydrohalogenation is a reaction where a hydrogen halide (HX) is added to an alkene or alkyne.
• Markonikov's rule states that in organic chemistry, it predicts that the addition of hydrogen halides (HX) to asymmetrical alkenes
  • the hydrogen (H) atom attaches to the carbon with more hydrogen atoms
  • the halide (X-) attaches to the carbon with fewer hydrogen atoms
• Hydration occurs as a chemical reaction in which water (H2O) is added to an alkene to form an alcohol.
• Halogenation represents a chemical reaction where one or more halogen atoms F2, Cl2, Br2, I2 are added to a molecule:.

Organic Reactions for Alkynes

• Hydration stands for the addition of H20 to alkynes.
• The end chemical result is a double bond (alkene) in hydroxyl, formally the enol group.
• MARKOVNIKOV'S RULE:
  • Η ATTACHES to the carbon with fewer alkyl substituents
  • X ATTACHES to the carbon with more alkyl substituent
• Hydrogenation entails the addition of H2 which can be controlled by Lindar catalyst.
• Reduction proceeds the addition of 2 equivalents of H2 over a palladium catalyst to yield alkane with Lindar catalyst..
• The result of halogenation is an addition of X2 yielding haloalkanes, the anti-stereochemistry.
• Bromine and Chlorine added to alkynes gives addition products, with the presence of anti-stereochemistry.
• Hydrohalogenation entails the addition of HX to alkenes.
• Follow the rules pertaining to isomers: same number of molecular formulas with different structures/arrangements.
• If there is a HX excess, the product is dihalide.
• Isomers result from MARKOVNIKOV'S rule, meaning terminal end or internal position. -Η= addition to terminal carbon of the triple bond -X= addition to the internal position which would be mores highly substituted