Presentation on theme: "Organic Chemistry Reactions. Hydrolysis of a polysaccharide polysaccharide + water → disaccharide Example: 2(C 6 H 10 O 5 ) n + nH 2 O → nC 12 H 22 O."— Presentation transcript:
Hydrolysis of a polysaccharide polysaccharide + water → disaccharide Example: 2(C 6 H 10 O 5 ) n + nH 2 O → nC 12 H 22 O 11 Hydrolysis of a disaccharide disaccharide + water → monosaccharide Example: C 12 H 22 O 11 + H 2 O → 2C 6 H 12 O 6
Reactions Fermentation of glucose C 6 H 12 O 6 → 2C 2 H 5 OH + 2CO 2 Special conditions for fermentation: optimum temperature range between 20°C and 30°C little or no oxygen present enzymes (catalyst) e.g. in yeast
Reactions Oxidation of a primary alcohol primary alcohol + oxidising agent → aldehyde (there will be more reactants and products depending on the oxidising agent) Note: if the aldehyde is not immediately removed it will be further oxidised to a carboxylic acid Example: ethanol + acidified dichromate → ethanal + chromium ions CH 3 CH 2 OH + Cr 2 O 7 2- + 12H + → CH 3 CHO + 2Cr 3+ + 7H 2 O (For definitions of primary and secondary alcohols, see notes, Subtopic 5.2)
Reactions Oxidation of a secondary alcohol secondary alcohol + oxidising agent → ketone (there will be more reactants and products depending on the oxidising agent) Example: propan-2-ol + acidified dichromate → propanone + chromium ions CH 3 CH(OH)CH 3 + Cr 2 O 7 2- + 12H + → CH 3 COCH 3 + 2Cr 3+ + 7H 2 O (For definitions of primary and secondary alcohols, see notes, Subtopic 5.2)
Reactions Oxidation of an aldehyde under acidic conditions aldehyde + oxidising agent + H + → carboxylic acid (there will be more reactants or products depending on the oxidising agent) Example: ethanal + acidified dichromate → ethanoic acid + chromium ions CH 3 CHO + Cr 2 O 7 2- + 12H + → CH 3 COOH + 2Cr 3+ + 6H 2 O
Reactions Oxidation of an aldehyde by Tollens’ reagent aldehyde + Tollens’ reagent → carboxylate anion + silver metal + ammonia (there will be more reactants or products depending on half-reactions) Example: methanal + Tollens’ reagent → methanoic acid + silver + ammonia CH 2 O + Ag(NH 3 ) 2 + + H 2 O → CHOOH + Ag + 2NH 3 + 2H + Since an obvious silver ‘mirror’ forms on the flask if a reaction occurs, this is commonly used to test whether a substance is a ketone or an aldehyde. A ketone cannot be oxidised, so no silver mirror would form. Tollens’ reagent is ammoniacal silver nitrate solution, Ag(NH 3 ) 2 NO 3 (aq) Usually we wouldn’t write the nitrate, since it is a spectator.
And many more… See “Organic_reactiontypes” in the Notes folder for a full list. Some are detailed further in other notes files or the textbook.
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