* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Organic Reactions 1
Survey
Document related concepts
Cracking (chemistry) wikipedia , lookup
George S. Hammond wikipedia , lookup
Enantioselective synthesis wikipedia , lookup
Ring-closing metathesis wikipedia , lookup
Aromatization wikipedia , lookup
Petasis reaction wikipedia , lookup
Organosulfur compounds wikipedia , lookup
Ene reaction wikipedia , lookup
Nucleophilic acyl substitution wikipedia , lookup
Strychnine total synthesis wikipedia , lookup
Transcript
Types of Organic Reactions Most organic compounds that are commercially available are derived from plants. Plants are the ultimate chemists. In order for scientists to recreate compounds we must be able to take a starting compound and manipulate it until we have created the compound we are interested in. There are certain types of reactions in organic chemistry. These will provide us with the different pathways that we can later use to move from one organic family to another. 1. Combustion The reaction of a substance with oxygen, producing oxides and energy. Example: Alkane + oxygen carbon dioxide + water CH4[g] + 2 O2[g] -> CO2[g] + 2 H2O[g] + energy 2. Substitution Reactions This is a chemical reaction that breaks apart a carbon-hydrogen bond and replaces the hydrogen atom with another atom or atom group. Example: Alkane + halogen alkyl halide H H H | | | H-C-C-C-H + Br-Br | | | H H H H H H | | | => H-C-C-C-H | | | Br H H + H-Br propane + bromine => 1-bromopropane + hydrogen bromide Addition Reactions Hydrogen or a halogen is added to an alkene or alkyne at the double or triple bond. a) Hydrogenation Hydrogenation is an addition reaction involving the combination of hydrogen with unsaturated hydrocarbons. Example: H H H H H H H H | | | | | | | | H-C=C-C-C-H + H-H => H-C-C-C-C-H | | | | | | H H H H H H butene + 2H => butane C3H4 + 2H-H => C3H8 propyne + 2H-H => propane b) Halogenation (with Br2 or Cl2) Halides also have the ability to add halogens to the carbons of double or triple bonds creating organic halides. Example: H H H H | | | | H-C=C-H + Cl-Cl => H-C-C-H | | Cl Cl ethene + chlorine => 1,2-dichlororethane C2H2 + Cl-Cl => C2H2B2 ethyne + bromine => 1,2-dibromoethene c) Hydrohalogenation (with hydrogen halides) d) Hydration (with water) Elimination Elimination is a chemical reaction in which an atom or group of atoms is removed from the larger molecule. Example: H H H | | | H-C-C-C-H + OH | | | H Br H => H H H | | | H-C=C-C-H | H 2-bromopropane + hydroxide ion => + propene H-O | H + + Br water + bromide ion Alcohols could also undergo elimination reactions by reacting with an acid to remove a hydrogen atom and a hydroxyl group thus producing alkenes. Example: H H | | H-C-C-H | | H OH + acid => H H | | H-C=C-H | H ethanol + acid => ethene + + H-O | H water Condensation Condensation is an organic reaction when two molecules combine, usually in the presence of a catalyst, with the elimination of water or some other simple molecule. Catalysts commonly used in condensation reactions include acids and bases. The combination of two identical molecules is known as self-condensation. This process forms larger molecules, many of which are useful in organic synthesis. Aldehydes, ketones, esters, alkynes, and alcohols are among several organic compounds that combine with each other to form larger molecules. Example: CH3OH methanol + + CH3OH methanol => => CH3OCH3 + HOH methoxymethane + water For a carboxylic acid undergoing condensation reaction, it combines with another reactant, forming two products - an organic compound and the byproduct of water. In an event when a carboxylic acid reacts with an alochol to produce an ester and water, this process is called esterification. Example: CH3COOH ethanoic acid water + HOCH3 + methanol => => CH3COOCH3 + methyl ethanoate HOH +