What are esters, lipids?
Properties and applicatios of esters lipids in human life.
Esters make the aroma of flower
Lesson 1: ESTERS
To know the definition, properties, and some applications of esters
I – DEFINITON, NOMENCLATURE
Consider the reactions:
Ethyl acetate, isoamyl acetate belong to esters
Thus, an ester is obtained by replacing the OH group in the carboxylic group of a
carboxylic acid with an OR group.
Monofunctional esters is RCOOR’, where R is a hydrocarbon moiety or H; R’ is a
A saturated acylic monofunctional esters is formed from a saturated acylic,
monofunctional acid and saturated monofunctional alcohol. It has molecular formula
CnH2nO2 ( where n≥2)
The name of an ester includes the name of the alkyl R’ and the name of the acid
For example: CH3COOC2H5: ethyl acetate, CH2=CH-COOCH3: methyl acrylate,…
II – PHYSICAL PROPERTIES
Esters are liquids or solides at normal conditions and they are slighty water-soluble.
Comparming with acids that have the same molecular weight or the same number of
carbon atoms, esters have boiling points and water-solubility that are lower than that
of the corresponding acids.
Boiling at 163,50C, highly soluble in water
Boiling at 770C, slightly soluble in water
If there are differences of solubility and boiling point between esters, acids, and
alcohols, it is because ester don’t form hydrogen bonding among each other and
ability of making hydrogen bonding between esters and water is poor.
Esters have specific aroma: isoamyl acetate has the ripen bananas; ethyl butyrate and
ethyl propionate have the smell of ripen pineapples; geranyl acetate has the smell of
Figure1.1. Benzyl acetate has the
aroma of jasmine
Figure1.2. Isoamyl acetate has the
aroma of ripe bananas
III – CHEMICAL PROPERTIES
Esters are hydrolyzed in acidic or basic solutions
Experiment:Place 2ml of ethyl acetate in each test-tube, then and 1 ml 20% H2SO4
aqueous solution in the second test-tube. The liquids in these two test-tube separate
into layers. Shake the both test-tube gently, equip them with a condenser then heat
gradually in a water bath for 5 min. In the first test-tube, the liquid is still a 2-layer
mixture; in the second test-tube, the liquid is still a 2-layer mixture, in the second
test-tube, the liquid becomes a homogeneous solution.
In the first test-tube, the reaction occurred:
The reaction is reversible, therefore, the ester is still left, and forms two liquid layers.
The second test-tube, the reaction occurred as follows:
The reaction is irreversible, so the ester reacts (hydrolyzes) completely. The ester
hydrolysis in basic solution is also called saponification.
Besides, ester also have reactions occurring in the hydrocarbon part(s).
IV – SYNTHESIS
Esters are normally syntheszed by boiling a mixture of an alcohol(s) and a carboxylic
acid(s) in the presence of sulfuric acid a catalyst (esterfication).
However, some esters cannot be synthesized by this methods, but are prepared by
For exemple:Vinyl acetate (CH3COOCH=CH2) is synthesized by the addition
reaction between acetic acid and acetylence.
V – APPLICATIONS
• Because esters can dissolve plenty of substances, some eaters are uesed as
solvents to separate, extract organic compounds (ethyl axetate), paint-thinner
( butyl acetate),…
• Some polymers of esters are used to make plastics such as poly (vinyl acetate),
poli (metyl methacrylate), …
• Some esters are aromatic and non-toxic that are used as flavoring substances in
food industry (benzyl formate, ethyl fomate,…), cosmetics ( linalyl acetate,
1. Fill T (true) or F(false) in the blanks beside each statement:
a) Esters are products of reactions between acids and alcohols.
b) Esters are organic compounds containing a COO- group.
c) Saturated acyclic monofunctional eaters have the molecular formula CnH2nO2
( where n≥2)
d) Compound CH3COOC2H5 belongs to a kinds of esters.
e) The product of the reaction between an acid and an alcohol is an esters.
2. How many esters isomers are corresponding to the molecular formula C4H8O2?
3. Compound X has the molecular formula C4H8O2. When X reacted with an aqueous
solution, compound Y was formed that had the molecular formula C4H8O2Na. The
structural formula of X is:
B.C2H5COOCH3 C. CH3COOC2H5
4. Hydrolysis of an ester X that has molecular fomular C4H8O2 in the aqueous NaOH
solution yielding a mixture of two organic compounds Y and Z. Z has the vapor
density of 23 in relation to that of hydrogen. The name of X is:
A. ethyl acetate B. methyl acetate C. methyl propionat
D. propyl formate.
5. What are the differences between the hydrolysis of an ester in acidic and basic
6. Burning completely 7,4 grams of a singular function ester gives 6,72 litres of CO2
(under standard conditions) and 5,4 grams of water.
a) Write the molecular formula of X.
b) Warm up 7,4 grams of X in enough of the aqueous NaOH till the reaction is
completed to gain 3,2 grams of an alcohol Y and an amount of salt Z. Draw the
structural formula of X caculate the mass of X.
• To know the definition and classification of lipids
• To know chemical properties and applications of lipids
I – DEFINITION
Lipids are organic compounds in living cells. Lipids do not dissolve
in water but dissolve well in non-polar organic solvents.
In terms of constitution, almost all lipids are complicated esters
including fats (also called triglyceride), waxes, steroids, and
phospholipids,... In this part, only fats are considered.
Fats are triesters of glycerol and aliphatic acids that are called
triglyceride or triacylglycerol*.
The aliphatic acids are monofunctional long un-branched acids.
The common aliphatic acids in fats are: stearic acid
(CH3[CH2]16COOH), palmitic acid (CH3[CH2]14COOH), and oleic
The structural formula of fats is:
(where R1, R2, R3 are alkyl groups that are the same or different)
(CH3[CH2]16COO)3C3H5 : tristearoylglycerol (tristearin);
(CH3[CH2]7CH=CH[CH2]7COO)3C3H5 : trioleoylglycerol
(CH3[CH2]14COO)3C3H5 : tripanmitoylglycerol (tripalmitin).
------------------------* Acyl is the name of the R-CO- group that is formed by omitting the
–OH group of the acid RCOOH
Figure 1.4. The molecular model of the fat
Fats are the main components of pork fats, beef fats, chicken
fats,...peanut oil, sesame oil, palm oil, and olive oil,...
gure 1.5. Some sources of fats from vegetables and animals
2. Physical properties
At ambient temperature, fats are in liquid or solid state. When the
molecules have unsaturated hydrocarbon moieties, for example
(C17H33COO)3C3H5, fats are in liquid state. On th other hand, the
molecules have saturated hydrocarbons, for example
(C17H35COO)3C3H5, the fats are in solid state.
Animal fats, vegetable oils are insoluble in water, but well soluble in
organic solvent , such as benzene, hexane, chloroform, ... When
adding fats or oil in water, they float on top of water, it is proved
that they are lighter than water.
3. Chemical properties
In terms of constitution, fats are tristers, so they have general
properties of esters such as hydrolysis in acidic solutions,
saponification and reactions occurring at the hydrocarbon moieties.
When fats (for example tristearine) are heated in dilute aqueous
sulfuric acid, the hydrolysic occurs as follows:
(CH3[CH2]16COO)3C3H5 + 3H2O
3 CH3[CH2]16COOH +
Add a small amount of a solid fat (for example tristearin) in a
ceramic mortar containing an a queous sodium hydroxide solution.
Boil gently and stir the resulting solution for 30 minutes. Cool down
the solution yielding a homogeneous solution. Pour 10-15 mL of
saturated aqueous sodium chloride in the solution, stir gently and
let it stand. There is a layer of light, white solid floating on the
surface of the solution. That is sodium salts of alphilatic acids.
(CH3[CH2]16COO)3C3H5 + 3NaOH
3 CH3[CH2]16COONa +
Because these salts are used as soap, the reaction is called
c) Hydrogen addition of liquid fats
When heating the liquid fats, for example triolein (C17H33COO)3C3H5
in a sealed pot and bubble hydrogen through (Ni catalyst), then let
the mixture stand for looling down, a solid block of tristearin is
formed as the result of the reaction:
This reaction is used in industry to transfer liquid fats (oil) to solid
fats for easy transportation or artificial butter and to produce soaps.
Oils and fats have bad smell ( nasty, burnt smell) when stored for a
long period. This is called oil/fat rancidity. The double bond(s) C=C
in the hydrocarbon(s) of unsaturated acids is oxidized slowly to form
peroxide(s) that causes the phenomenon. The peroxide(s) is
decomposed, forming aldehyde(s) that has bad smell and harms the
health of consumers. After being used t fty, cooking oils and fats are
also oxidized partially to form aldehydes, so reusing cooking oils
and fats does not ensure food safety.
Fats have lots of applications in human life. Fats are important foods for human
kinds. Due to complicated biochemical reactions, fats are oxidized slowly, forming
CO2, H2O through which they supply energy for the body. The fats that have not been
used are accumulated in adipose tissues. Fats are materials for the synthesis of some
essential compounds for body. They are responsible for ensuring the transportation
and absorption of compounds that are fat-soluble.
In industry, a large amount of the fats is used to manufacture soap
Besides, fats are used in making some other foods such as noodle,
canned food,... Used cooking oil can be recycled to produce fuels.
1. What's a fat? What are the differences in terms of constitution
and physical properties between cooking oil and animal fat? Give
2. Which of the following statements is are NOT true ?
A. Fats are water insoluble
B. Fats are water insoluble, lighter than water, and well- dissolved in
C. Cooking oil and grease have the same atomic components.
D. Fats are esters of glycerol and carboxylic acids with (a) long,
unbranched carbon chain (s).
3. Trimester of the glycerol and linoleic C17H31COOH and linolenic
C17H29COOH are the components of some kinds of paints. Write the
condensed structural formulas of all possible trimester of these two
acids with glycerol.
4. There are always small amounts of free acids in fats. The number
of milligrams of KOH that are used to neutralize the free acids in 1
gram of a fat is called acidic index of the fat. To neutralize 2,8
grams of a fat, 3.0 ml of a 0.1 M aqueous KOH solution were
required. Calculate the acidic index of the fat.
5. The total number of miligrams of KOH is used to neutralize the
free acids and to saponify all the esters in one gram of a fat is
called soap index of the fat. Calculate the soap index of a fat
sample containing tristearoylglicerol contaminated with some
stearic acid that has the acidic index of 7
LIPID METABOLISM IN THE HUMAN BODY
Lipid is one of the basic components in food for human beings.
When oxidized slowly in the human body with catalytic enzymes,
lipids give 2-3 times more energy than proteins and carbohydrates.
Because lipids are water- insoluble, they cannot penetrate through
intestinal walls to feed the body. Thanks to the catalytic enzymes,
lipids are hydrolyzed to form glycerol and alphatic acids. The
glycerol is absorbed directly; on the other hand, the alphatic acids
are converted to water - soluble forms by the bile to be easily
absorbed through the plicas into the gut. On the intestinal walls, the
glycerol and the alphatic acids are combined to form new lipids. The
new lipids go into blood and the adipose tissues where the lipids are
oxidized to form CO2, H2O and energy for the activities of the body.
CONCEPT OF SOAPS AND DETERGENTS
• To know the concepts of the detergents
• To know methods to Manufacture soaps and detergents
Normal soaps are mixtures of sodium or potasssium salts of alphilatic acids and some
additives. The main components of soaps are salts of panmitic acids or stearic acids.
Besides, the are fillers (that are used to increase soaps’ hardness to cast them into
cakes), antibiotic compounds and flavorings.
2. Manufacturing methods
To Manufacture soaps, people heat fats with aqueous alkaline solution in sealed tanks
at high temperatures.
Are mixtures of sodium salts of aliphatic acids is formed as glues. To separate the
salts from the mixture, the table salt is added into the mixture. The floated aliphatic
salts are mixed with excipients and then pressed into cakes. The mother liquid is used
to separate glycerol that is used in many other fields.
Figure 1.6. A corner of the factory manufacturing soaps
Today, soaps are made following this scheme
Sodium salts of carboxylic acids
To limit the exploitation of oil animal oil vegerable oil for manufacturing soaps and
to meet various needs of life, people have been synthesizing many compuonds which
are not salts of sodium of carboxylic acids but they have washing features as soaps
have. These compounds are called synthetic detergents.
2. Manufacturing methods
Synthetic detergents are synthesized from petroleum. For example, the salts of
dodecylbenzensulfonic acids is a main component of Synthetic detergents that are
manufactured following the graph:
Figure 1.7 Synthetic detergents
III. CLEANING EFFECT OF SOAPS AND SYNTHENIC DETERGENTS
Sodium salts in soaps or synthenic detergents can decrease the surface tension of
dirty stains sticking
On cloth, skin, …. So the dirty stains are dispersed into many small parts that are
dispersed in water and washed out (see figure 1.8)
Figure 1.8. Diagram of cleaning process of soaps
Palmitate or stearate salts of the divalent metals are slightly soluble in water, so the
decrease the cleaning effects of soaps. Therefor, we shouldn’t use soaps to wash in
hard water (hard water has lots of Ca2+ and Mg2+ ions). The salts
dodecylbenzensulfonic acids can dissolve in hard water, so the advantage of the
synthetic detergents comparing with the soaps is used in hard water as well.
1. What is a soap?
2. Fill in T (true) or F (false) in each box at the end f each statement:
a) Soaps are products of saponification
b) Sodium or potassium salts of organic acids are main components of soaps
c) Heating fats with aqueous NaOH solution or KOH soluion produces soap.
d) Synthetic detergents are Synthesized from petroleum.
3. A kind of an animal fat contains 20% tristearoylglixerol, 30% tripanmitoylglixerol
and 50% trioleoylglycerol (weight percent).
a) Write the chemical reactions of the saponification process that occurred.
b) A ton f the fat is saponified with an aqueous NaOH solution. Calculate the mass of
the obtained salts. The yield of the process is assumed to be 90%
4. Show advantages and disadvantages of using sopas and synthetic detergents.
5. How many kilos of fat containing 98% tristearin ( 11% innert impurities are
extracted in the saponification process) are needed tot make a ton of the soap
containing 72% (weight percent) of sodium stearate.
COMPONENTS OF DETERGENTS
Besides the sodium salts of alkylbenzensulfonic acids that are the main cmponents of
detergents, these are 20% of surfactants, and the rest are additives:
- Salts of silicate, phosphate that are responsible for the weakly basic environment to
get rid of acidity of the impurities.
- Na2SO4 filler makes the dentergents porous.
- Bleaching compounds are oxidizing reagents that are used to bleach the colors of
impurities but do not affect cloths and dyes, for example sodium perborate
Na3BO3.4H2O or NaClO.
- Enzymes catalyze for the breaking and removing of impurities origlnate from
- Fluorescent substances make clothes brighter
- Flavorings create comfortable feeling.
REVIEW ESTERS AND FATS
I- KNOWLEDGE TO REMEMBER
The hydroxyl group in the carboxyl group is replaced with an OR group to give an
Constitutional properties: There is a COOR group(s) in the ester molecules of
carboxylic acids, where R is a hydrocarbon moiety.
A monofunctional acyclic saturated ester has the molecular formula CnH2nO2, where n
Fats are triesters of long carbon chain alphilatic acids and glycerol.
• Hydrolysis in presence of an acidic catalyst:
• Hydrogenation of the liquid fats:
1. Compare fats and esters about: elemental components, structural characteristics,
and chemical properties.
2. How many esters are formed when heating a mixture of two carboxylic acids and
glycerol (H2SO4 acid as a catalyst)? Write the structural formulas of these esters.
3. Hydrolysis (catalyzed by acids) of an ester gives glycerol and a mixture of stearic
acid (C17H35COOH) and panmitic acid( C15H31COOH) with a molar ratio of 2:1.
Which one of the following structures can be the structural formula of the ester?
4. Evaporating 7.4 grams of a saturated, monofunction ester A gives a vapor volume
that equals to the volume of 3.2 grams oxygen under the same conditions of
temperature and pressure.
a) Write the molecular formula of A.
b) 7.4 grams of the compound A are saponified with an aqueous NaOH solution until
the reaction is completed to give 6.8 grams of the salt(s). Find the structural formula
and the name of compound A.
5. Hydrolysis of a grams of an ester X gives 0.92 grams of glycerol, 3.02 grams
sodium linoleate C17H31COONa and m grams sodium oleate C17H33COONa.
Calculate a and m. Write all possible structural formulas of X.
6. 8.8 grams of a monofunctional acyclic ester were hydrolyzed with 100 ml of an
1M aqueous KOH (just enough) to give 4.6g of an alcohol Y. The name of X is:
A. ethyl formate. B.ethyl propionate . C.ethyl acetate. D propyl acetate.
7. Completely burning 3.7 grams of a monofunction ester X gives 3.36 litres of
CO2(under standard conditions) and 2.7 grams of water. The molecular formula of X
8. 10.4 grams of a mixture including acetic acid and ethyl acetate react equivalently
with 150 grams of a 4% aqueous sodium hydroxide solution. The weight percent of
ethyl acetate in the mixture equals:
Chapter 2: CACBOHIDRAT
PHYSICAL PROPERTIES AND NATURAL OCCURRENCE
Glucose is a solid that exists as colorless crystal. It is well suluble in water with sweet taste, but less
sweet than sugar cane.
Glucose is present in almost all part off trees, such as leaves flowers, roots, … and most common in
ripe fruits. Particularly,there is a lot of glucose in ripe grapes, hence, it is also called grape sugar. In
honey there is a lot of glucose (about 30%).Glucose is also found in the body of humankinds and
animals. In human blood, there is a small amout of glucose with nearly constant concentration of
II. MOLECULAR STRUCTURE
-The molecular frumula of glucose is C 6H12O6. The structural determination of glucose is based on
the following experimental data.
-Glucose undergoes silver mirror reaction and is oxidized by aqueous bromine solution to yield
gluconic acid. These indicate that there is a CH=O group in the molecule of glucose.
-glucose reacts with Cu(OH)2 producing a blue solution. This reaction indicates that glucose has
many vicinal OH groups.
-glucose forms an ester with five CH3COO groups ,indicating that it has five OH groups
-hexane is obtained by complete reduction of glucose,demonstrating that there are six carbon atoms
in the molecule of glucose ,forming an unbranched chain.
So : Glucose is anacyclic multifunctional compound that contains one aldehyde group and five
hydroxyl groups. The stucture of acyclic glucose is as follows
Or simplified as: CH2OH[CHOH]4CHO
In fact, glucose exists mainly in two cyclicfroms: α-glucose and β- glucose( see the material
III, CHEMICAL PROPERTIES
Glucose has the properties of monoaldehydes and of polyols
1, reacting with Cu(OH)2
Experiment: add in turns to a test- tube a few drops of 0,5% CuSO 4 soluton.1 ml 10% NaOH
solution .after the reaction completion ,decant the unreacted solution ,keep the Cu(OH)2 precipitate.
Add to the precipitate 2 ml of 1% glucose solution .gently shake the test-tube
Phenomenon: the precipitate dissolves, producing a blue solution.
Explanation: at ambient temperature, glucose reacts with Cu(OH) 2 , yielding copper – glucose
Cu(C6H11O6)2 complex which is similar to glycerol does.
2C6H12O6 + Cu(OH)2→ (C6H11O6)2Cu + H2O
b , reaction producing ester
glucose can form an ester containing 5 acetate groups in the molecule when reacting with acetic
anhydride ( CH3CO)2O in the presence of pyridine
2. Properties of aldehydes
a, oxidation of glucose by a solution of AgNO3 and ammonia ( sivel mirror reaction)
add in turns to a clean test- tube containing 1 ml of 1% AgNO 3 solution , then drop to the tube
drowpwise a solution of ammonia until the just formed precipitate is dissolvel again. Add to the
reaction mixture 1ml of 1% glucose solution . Heat gently.
Phenomenon: The wall of the tube is as shiny as a mirror
Explanation: the solution of AgNO3 and ammonia axidizes glucose to form ammoniumgluconate
and silver matel deposited on the wall of the test-tube
HOCH2[CHOH]4CHO + 2 AgNO3 + 3NH3 + H2O
HOCH 2[CHOH]4COONa + 2Ag +
b, oxidation of glucose with Cu(OH)2
in the basic condition ,Cu(OH)2 oxidizes glucose to produce solution gluconate ,copper(I) oxide and
HOCH2[CHOH]4CHO + Cu(OH)2 + NaOH
Cu2O(orange red) + 3H2O
Natri gluconat sodium gluconate
c, reduction of glucose with hydrogen
when hydrogen is introduced into a hot glucose solution in the presence of Ni as a catalyst,a polyol,
names sorbitol, is abtained:
HOCH2[CHOH]4CHO + H2 → HOCH2[CHOH]4CH2OH
3, fermentation reaction
In the presence of an enzyme as a catalyst , glucose in solution was fermented to produce ethylic
alcohol and carbon dioxide:
2C2H5OH + CO2
IV, SYNTHESIS AND APPLICATIONS
In industry , glucose is synthesis by hydrolysis of catalyzed by dilute hydrochloric acid or enzyme .
the hydrolysis of cellulose ( in shavings ,sawdust…), catalyzed by concentrated hydrochloric acid,
produces glucose which is used as a starting material for the manufacture of ethylic alcohol( see
Glucose is a nutrient and is used as an energy drink for the elderly, children, and sick people . In
industry, glucose, prepared from sucrose, is used to make silver mirrors, coat the inner wall of
thermos, and is an intermediate in the production of ethylic alcohol from materials containing starch
One of the isomers of glucose is fructose that has many applications
The acyclic structure of fructose is:
Fructose is a colorless crystalline substance that is well soluble in water and sweeter than sugar cane
Fructose is commonly found in sweet fruits such as pineapples, mangos ,… Especially, 40% of
honey is fructose, hence, honey has sharply sweet taste.
Similar to glucose , fructose reacts with Cu(OH) 2 to produce a blue solution of Cu(C 6H11O6)2
complex ( property of polyols) , and adds hydrogen( hydrogenation) to give polyalcohol
C6H14O6(property of carbonyl group).
Similar to glucose, fructose is oxidized by a solution of AgNO 3 and ammonia and by a solution of
Cu(OH)2 in an alkaline environment . This is the reaxtion of the aldehyde group caused by basic
conditions: fructose is converted to glucose:
1.glucose and fructose
A. both can produce blue solutions when reacting with Cu(OH)2
B. both contain a CHO functional group in the molecule
C. are two allotropes of one substance.
D. exist in the acyclic forms.
2. The following solution are given: glucose, glycerol formaldehyde, ethanol. Which one of the
following reagents can be used to differentiate all of the four solution above?
C, A solution of AgNO3 and NH3
D, Aqueous bromine solution
3, What is carbohydrate ? How many kinds of important carbohydrate are there? State their
definitions and give illustrative examples.
4. Which experiments can be used to prove the molecular structure of glucose?
5. Describe chemical methods to identify each compound in the solution ò the following
A, glucose , glycerol, ethanol, and acetic acid
B, fructose , glycerol, and ethanol
C, glucose , formaldehyde, ethanol, and acetic acid
6. to coat a mirror , a solution ò 36 grams of glucose is heated with a stoichiometric amount ofa
solution of silver nitrate and ammonia .Calculate the amount of silver formed that is deposited on
the surface of the mirror and the amount of silver nitrate required , given that all the reactions occur
SUCROSE, STARCH, AND CELLULOSE
I – SUCROSE
Sucrose (C12H22O11) is the most common sugar that is found in many plants, especially in sugar cane
(figure2.3), sugar beets, and flowers of jaggery.
Depending on the plant origins, commerial products from sucrose are called sugar cane, sugar beets,
1. Physical properties
Sucrose is a colorless and odorless crystalline substance that has sweet taste. It melts at 185 OC.
Sucrose is well soluble in water. Its solubility increases quickly with the increase of temperature (at
20OC, 100ml of water dissolve 211.5 grams of sucrose; at 90 OC, 100ml of water dissolve 420 grams
2. Molecular structure
Sucrose doesn’t undergo the silver mirrow reaction and doesn’t decolorize bromine solutions. This
proves that sucrose doesn’t have the CHO functional group. When a solution of sucrose is heated
with dilute H2SO4, the resulting solution undergoes the silver mirror reachtion, because the solution
after hesting contains glucose and fructose. So:
Sucrose is a disaccharide that is composed of one glucose moiety and one fructose moiety binding
together via an oxygen atom.
Figure 2.3 Sugarcane – the source of sucrose
Thus, in the molecule of sacrose, there is on aldehyde (CH=O) group; there are only hydroxyl (OH)
3. Chemiscal properties
Because sucrose doesn’t have any aldehyde functional groups, it doesn’t have oxidizing ability as
glucose does, but has the property of polyols. On the other hand, sucrose is composed of two
monosaccharides, hence, it undergoes the hydrolysis reaction.
a) Reaction with Cu(OH)2
In solution, sucrose reacts with CU(OH)2 to give a solution of blue copper saccharate.
2C12H22O11 + Cu(OH)2 (C12H21O11)2Cu + 2H2O
When asucrose dolution is heated in the presence of a mineral acid as a caralyst, it is hydrolyzed to
give glucose and fructose:
C12H22O11 + H2O
C6H12O6 + C6H12O6
The hydrolysis of sucrose also occurs in the presence of an enzyme as a catalyst.
4. Production and applications
Squeeze (or soak, extract)
Sugarcane juice (12-15% sugar)
+ Limewater, filter to remote
Sugar solution containing calcium
+ CO2, filter to remove CaCO3
Sugar solution (having color)
+ SO2 (color bleaching)
Sugar solution (colorless)
Concentrate to crystallize, filter
Sucrose is exrtrated from sugarcanes, sugar beets, or flowers of jaggery. In Vietnam, the production
procedure of sucrose from sugarcane inclodes the follwing main step:
Sucrose is importannt food of humankinds. In food industry, sucrose is an ingredient for the
production of cakes and candies, beverages, canned food. In pharmaceutical industry, sucrose is
used to dispense drugs. Sucrose is a material to produce glucose and fructose via hydrolysis that are
used in coating mirrors and the inner wall of thermos.
II – STARCH
1. Physical properties
Starch is a white amorphous solid that is onsoluble in cold water. In hot water, starch bits are
hydrated and swollen to form colloidal solutions, called starch solution.
2. Molecular structure
Starch is one of polysaccharides containing a large number of a α-glucose chains binding together.
Its molecular formula is (C6H10O5)n. The α-glucose chains bind together to form two forms: amylose
and amylopectin (figures 2.4a and 2.4b).
Amylose is ahelical polymer made of α-D-glucose units, bound to each other through α(14)
glycosidis bonds. Amylose has high molecular weight of about 200 000. Amylopectin has branched
structures that are made up of α-glucose. Each short part contains from 20 to 30 glucose units that
are bound together through α(14) glycosidic bonds. Different parts are connected through α(16)
glycosidic bonds. Amilopectin has very high molecular weight of about 1 000 000 – 2 000 000.
Therefore, amylopectin is insoluble in water, as well as in other common solvents.
Figure 2.4. a) Molecular model of amylose
b)moleccular model of amylopectin
Starch (in grains, tubers) is a mixtube of amylose and amylopectin, among which the ratio of
amylopectin is higher. The starch chain is not long, twists to form hollow beads.
Starch is formed in green trees by photosynthesis. Form cacbon dioxide and water, under the action
of sun light and chlorophyll, starch is producted following the scheme below:
3. Chemical properties
When starch is heated in dilute solutions acids, glucose is obitained:
(C6H12O6)n + nH2O
In human and animal body, starch is hydrolyzed by enzymes to glucose.
b) Color reaction with iodine
Experiment: Carry out the experiment as shown in the figure 2.5, the test-tube containing starch
solution and I2 (b) as well as the cross section of a sweet potato + I 2 (c) has intense bluish purple
Figure 2.5. a) Test-tube containing 2% starch solution;
b) Add a few drops of dilute I2 solution into a starch solution;
c) Add a few drops of dilute I2 solution onto the cross section of a sweet potato.
Starch is one of the fundamental nutrients of humans and several animals. In industry, starch is used
to make candies, cakes, glucose and glues.
In human body, starch is hydrolyzed to form glucose by enzyme in the intestine. The most part of
glucose is absorbed via the intestinal wall into blood to nourish the body; the excess is converted to
glycogen by enzymes, which is stored for the body.
Figure 2.6. A “chung” cake make from glutinous rice
III – CELLULOSE
Figure 2.7. Cellulose fibers
1. Physical properties, natural occurrence
Cellulose is a white odorless solid sudstance in form of fibers. Cellulose is insoluble in water and in
many other organic solvents, such a ethanol, ether, benzene,… but soluble in Schweizer’s reagent (a
solution obtained when dissolving Cu(OH)2 in ammonia solution).
Cellulose is the main component that makes up the plant cell wall, forming the skeleton of trees.
Nearly ninety eight percent of cotton is cellulose; cellulose contributes from 40 to 50% of wood by
2. Molecular structure
Cellulose is a polysaccharide that contains a great number of β-glucose binding together to form
long chains. Cellulose has very high molecular weights of about 2 000 000. Cellulose chains bind
together to form cellulose fibers.
Different from starch, cellulose has only unbranched structure; each C 6H10O5 moiety contains three
OH groups, so it can be written as:
(C6H10O5)n or [C6H7O2(OH)3]n.
3. Chemical properties
When cellulose is heated in concentrated solutions of mineral acids, for example, H2SO4 70%,
glucose is obtained:
(C6H10O5)n + nH2O
The hydrolysis of cellulose also occurs in animal stomach by cellulase.
b) Reachtion with nitric acid
When cellulose is heated in a solution of concentrated nitric acid and sulfuric acid, trinitrate is
[C6H7O2(OH)3]n + 3nHNO3(concentrated)
[C6H7O2(ONO2)3]n + 3nH2O
Cellulose trinitrate is easily inflammable and strongly explosive without producing smoke;
therefore, it is used to produce smokeless gunpowder.
Materials containing cellulose (cotton, jute, wood,…) are used directly (yarn spinning to fabricate
clothes, in construction, making wooden furniture,…) or producing paper.
Cellulose is a material for the production af artificial fibers (such as visco, acetate), smokeless
gunpowder and film.
1. Which one of the following statements is true?
A. Fructose undergoes silver mirror reaction, proving that it has a CHO functional group.
B. Hydrolysis of cellulose produces glucose.
C. Hydrolysis of starch produces fructose and glucose.
D. Both cellulose and starch undergo silver mirror reaction.
2. Which one of the following statements is true (T)? Which one is false (F)?
a) Sucrose is considered tobe a short part of starch.
b) Both starch and cellulose are polysaccharides; they differ only in the structure of the glucose
c) When sucrose, starch and cellulose are completely hydrolyzed, all of them produce the same
kind of monosaccharide.
d) When starch and cellulose are completely hydrolyzed, both of them produce glucose.
3. a) Compare the physical properties of glucose, sucrose, starch and cellulose.
b) Find the structural relation between glucose, sucrose, starch and cellulose.
4. Mention the similar chemical properties of sucrose, starch and cellulose. Write the chemical
equations (if any).
5. Write the chemical equa of the reactions (if any) in the following case:
a) Hydrolysis of sucrose, starch and cellulose.
b) Hydrolysis of starch (catalyzed by an acid); after that, the resulting product is reacted with a
solution of AgNO3 and NH3.
Heating cellulose with a mixtube of concentrated HNO3/H2SO4.
6. To coat several thermo bottles, 100 grams of sucrose were hydrolyzed, and the resulting product
was used in the silver mirror reaction. Write the chemical equations of the reactions that occurred.
Calculate the amount of AgNO3 required and the amount of Ag formed, given that all the reactions
Lesson 7: Review
Structure and properties of carbohydrates
Knowledge to remember
a) Glucose and fructose ( C6H12O6 )
Glucose in open-chain form is both monoaldehyde and polyols
Fructose in open-chain form is both monoketone and polyols.It can be converted
to glucose in basic environment:
b) Sucrose( C12H22O11 hay C6H11O5-O-C6H11O5)
The molecule of sucrose doesn’t have a CHO functional group, but has many
c) Starch and cellulose (C6H10O5)n
Starch: The α-glucose units bind together to form helical chains. The molecule
doesn’t have any CHO functional groups.
Cellulose: The β-glucose units bind together to form long chains. The molecule
doesn’t have any CHO functional groups, and each unit has three OH groups;
hence, the molecular formula of cellulose can be written as : [C6H7O2(OH)3]n
2) Chemical properties
a) Glucose undergoes reactions typical for the aldehyde functional group.
CH2OH[CHOH]4CHO + 2AgNO3 + 3NH3 + H2O
CH2OH[CHOH]4COONH4 +2Ag +2NH4NO3
Fructose also undergoes silver mirror reaction, because in basic environment,
fructose is converted to glucose.
b) Glucose, fructose, sucrose, and cellulose undergo reactions tyical for polyols
- Glucose, fructose, and sucrose react with Cu(OH)2 to produce blue soluble
- Cellulose reacts with concentrated nitric acid to give cellulose trinitrate.
[CH6H7O2(OH)3]n +3nHNO3 ( conc)
[C6H7O2(ONO2)3]n +3n H2O
c) Sucrose, starch, and cellulose are hydrolyzed by acidic catalysts or suitable
C6H12O5-O-C6H12O5 + H2O
C6H12O6 + C6H12O6
d) Fermentation reaction to produce ethanol
2C2H5OH aq +2CO2 (K)
1. To differentiate the solution of glucose, the solution of sucrose, and the solution of
acetic aldehyde, which one of the following compounds can be used as reagent?
A. Cu(OH)2 and AgNO3/NH3
B. Bromine solution and NaOH
C. HNO3 and AgNO3/NH3
D. AgNO3/NH3 and NaOH
2. When an organic compound was completely burnt, a 1:1 mixture of CO2 and water
vapor was obtained. This compound can be fermented to yield ethanol. Which one is
A. Acetic acid B.Glucose
3. Describe a chemical method to differentiate among the solutions in each following
a) Glucose, glycerol, acetic aldehyde.
b) Glucose, sucrose, glycerol.
c) Sucrose, acetic aldehyde, starch solution.
4. From one ton of starch containing 20% inert impurities, how many kilogramsof
glucose can be produced, if the total yield of the process is 75% ?
5. Calculate the amount of glucose obtained when hydrolyzing;
a) 1 kg of rice powder containing 80% starch , the rest is inert impurities.
b) 1 kg of sawdust containing 50% cellulose, the rest is inert impurities.
c) 1 kg of sucrose.
Given that the reactions are quantitative
6. When 16.2 grams of carbohydrate X were completely burnt, 13,44 liters CO2 ( at
standard conditions) and 9 grams of water were obtained.
a) Calculate X’s empirical formula. Which kind of carbohydrate is X?
b) 16.2 g of X is heated in acidic solutions to give solution Y. When Y is reacted
with an excess of a solution of AgNO3 and NH3, how many grams of Ag can be
obtained? Given that the total yield of the whole process is 80%
Lesson 8 : Practical task
Synthesis,chemical properties of esters and carbohydrates
EXPERIMENT CONTENT AND PROCEDURE
Experiment 1. Synthesis of ethyl acetate
Add 1 ml ethylic alcohol, 1 ml of pure acetic acid. and one drop of concentrated sulfuric acid to
a test tube. Shake the tube well while heating it in a steam bath for 5 - 6 minutes at 65 ~ 70°C (or
heat the reaction mixture gently on the flame of an alcohol burner). Let it cool down and pour 2 ml
of saturated NaCl solution into the test tube. Make observations and write the chemical equations.
Experiment 2. Saponification reaction
Place in a small porcelain bowl about 1 gram of fat (or plant oil) and 2 -2.5 ml of 40% NaOH
solution. Gently boil the reaction mixture and continuously swirl it with a glass rod. Add from time
to time a few dmps of water to keep the volume of the mixture unchanged. After from 8 .. 10
minutes, add to the mixture 4 5 ml of warm saturated NaCl solution and swirl the mixture. Let the
reaction mixture cool down and make observations.
Explain and write the chemical equations.
Experiment 3. Reaction of glucose with Cu(OH)2
Add 5 drops of 5% CuSO4 solution and about 1 ml of 10% NaOH solution to a test-tube Gently
shake the tube, decant the solution and keep the Cu(OH)2 precipitate. Add to the precipitate 2 ml of
1% glucose solution, gently shake the tube. Make the observations.
Heat the test-tube, make the observations. Explain and write the chemical equations.
Experiment 4. Iodine test for starch.
Add a few drops of iodine soluuou to a test-tube containing 1-2 ml of starch solution (or add a few
drops of iodine solution on the cutting surface of a fresh sweet potato or a cassava).
Note the color change and explain .
Heat the solution for a while, and let it cool down. Make observations of experiment phenomenon.
• To know the concept,classification and name of amines
• To understand the typical properties of amines
I. CONCEPT, CLASSIFICATION AND NOMENCLATURE
Replacement of the hydrogen atoms of NH3 with hydrocarbon moieties gives amines.
Amines usually have isomers of the carbon chains, location of the functional groups
and the order of the amines.
For example: corresponding to the molecular formula of the C4H9N, there are the
Amines are classified in two most common ways:
a, Basing on the hydrocarbon moieties, we have:acyclic amines such as CH3-NH2,
C2H5NH2,.., aromatic amines such as C6H5NH2, CH3-C6H4-NH2,..
b, Basing on the order of amines( the order of an amine is caculated by the number
of the alkyl substituents with the nitrogen atom): primary amines such as C2H5NH2,
secondary amines such as CH3-NH-CH3, tertiary amines such as
Amines are normally called based on the name of the functional class name (akyl/aryl
with the amine function) and the substitutive name (table 3.1).
Table 3.1. Names of some amines
Functional class name
Methylamine, dimethylamine, trimethylamine and ethylamine are gaseous
compounds that have uncomfortable smell of urine and water-soluble.
Amine that have higher molecular weight are liquid or solid. Their boiling points
increase gradually and their solubilities in water decrease gradually with the
increasing molecular weight.
Aromatic amines are liquid or solid and easily oxidized. Standing in the air, the
colorless aromatic amines are transformed to black because of oxidation.
-All amines are toxic