Reactions Reactions Hydrolysis of a polysaccharide polysaccharide water disaccharide Example 2C 6 H 10 O 5 n n H 2 O n C 12 H 22 O 11 Hydrolysis of a disaccharide ID: 358681
Download Presentation The PPT/PDF document "Organic Chemistry" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Organic Chemistry
ReactionsSlide2
Reactions
Hydrolysis of a polysaccharide
polysaccharide + water
→ disaccharideExample: 2(C6H10O5)n + nH2O → nC12H22O11
Hydrolysis of a disaccharide
disaccharide + water
→
monosaccharide
Example:
C
12
H
22
O
11
+ H
2
O
→
2C
6
H
12
O
6Slide3
Reactions
Fermentation of glucose
C
6H12O6 → 2C2H5OH + 2CO2Special conditions for fermentation:
optimum temperature range between 20
°C
and 30
°C
little or no oxygen present
enzymes (catalyst) e.g. in yeastSlide4
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 acidExample: ethanol + acidified dichromate → ethanal + chromium ions
CH
3
CH
2
OH + Cr
2O72- + 12H+ → CH3CHO + 2Cr3+ + 7H2O
(For definitions of primary and secondary alcohols, see notes, Subtopic 5.2)Slide5
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 CH3CH(OH)CH3 + Cr2O72-
+ 12H
+
→
CH
3COCH3 + 2Cr3+ + 7H2O
(For definitions of primary and secondary alcohols, see notes, Subtopic 5.2)Slide6
Reactions
Oxidation of an
aldehyde
under acidic conditionsaldehyde + 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 CH3CHO + Cr2
O
7
2-
+ 12H
+
→ CH3COOH + 2Cr3+ + 6H2OSlide7
Reactions
Oxidation of an
aldehyde
by Tollens’ reagentaldehyde + 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 CH2
O + Ag(NH
3
)
2
+
+ H2O → CHOOH + Ag + 2NH3 + 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.Slide8
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.