Carbohydrates Part V: Reactions of Monosaccharides
Summary
TLDRThis educational video delves into the chemical reactions of monosaccharides, focusing on oxidation processes. It explains the conversion of glucose's aldehyde group to a carboxylic acid using Benedict's solution, which contains copper sulfate. The video also covers the enzymatic oxidation of the alcohol group on carbon six to form glucuronic acid and the reduction of glucose to sorbitol, a sugar alcohol used as a sweetener. The discussion includes the role of copper ions as oxidizing agents and the nature of redox reactions.
Takeaways
- đŹ Monosaccharides can undergo different oxidation processes, transforming their chemical structures.
- đŹ Glucose, a common monosaccharide, can exist in both open chain and cyclic forms, affecting how it reacts.
- đ§Ș Benedict's solution, containing copper sulfate, facilitates the oxidation of glucose's aldehyde group to a carboxylic acid.
- đĄ Copper ions act as oxidizing agents in the oxidation process, getting reduced from Cu2+ to Cu+.
- đ Redox reactions involve both reduction and oxidation; in the case of glucose, the aldehyde group is oxidized.
- đ The oxidation of glucose results in the formation of gluconic acid, an aldonic acid, when only the aldehyde group is affected.
- â Strong oxidizing agents like nitric acid can oxidize both the aldehyde and alcohol groups of a monosaccharide, forming aldoric acids.
- đ Glucaric acid is produced when glucose is oxidized by strong agents, affecting both functional groups.
- 𧏠Enzymatic oxidation selectively oxidizes the alcohol group on carbon six of glucose, forming glucuronic acid.
- đ The reduction of glucose involves the conversion of its aldehyde group to a primary alcohol, resulting in a sugar alcohol like sorbitol.
Q & A
What is the primary focus of the video presentation?
-The video presentation primarily focuses on the reactions of monosaccharides, specifically discussing the different oxidation processes that monosaccharides like glucose can undergo.
What are the two forms of monosaccharides mentioned in the script?
-The two forms of monosaccharides mentioned are the open chain projection form and the cyclic form, also known as the Haworth form.
What is the role of Benedict's solution in the oxidation of monosaccharides?
-Benedict's solution facilitates the oxidation of monosaccharides to produce acidic sugar. It contains copper sulfate, which participates in the reaction by providing copper ions that act as oxidizing agents.
How does the oxidation of the aldehyde group in glucose result in the formation of carboxylic acid?
-The aldehyde group of glucose is oxidized to a carboxylic acid, resulting in the formation of gluconic acid. This process is known as oxidation, where the aldehyde end is transformed.
What is the term for a monosaccharide that has undergone oxidation at its aldehyde component?
-A monosaccharide that has undergone oxidation at its aldehyde component is called an aldonic acid.
What happens when a strong oxidizing agent like nitric acid is used on a monosaccharide?
-When a strong oxidizing agent like nitric acid is used, both the aldehyde group and the alcohol group on carbon number six of the monosaccharide are oxidized, resulting in the formation of an aldoric acid, such as glucaric acid.
What is enzymatic oxidation, and how does it differ from other types of oxidation mentioned in the script?
-Enzymatic oxidation is a selective oxidation process facilitated by enzymes or biological catalysts. It differs from other oxidation processes in that it specifically targets the alcohol group on carbon number six, leaving the aldehyde group unaffected.
What is the product of the enzymatic oxidation of glucose, and what type of acid is it classified as?
-The product of the enzymatic oxidation of glucose is glucuronic acid, which is classified as an aldonic acid.
How does the reduction of a monosaccharide differ from its oxidation?
-Reduction of a monosaccharide involves the gain of electrons and hydrogen, which is the opposite of oxidation. In the context of the script, the aldehyde group of glucose is reduced to a primary alcohol, resulting in the formation of a sugar alcohol like sorbitol.
What is the role of hydrogen gas in the reduction of monosaccharides?
-Hydrogen gas serves as a reducing agent in the reduction of monosaccharides, facilitating the conversion of the aldehyde group to a primary alcohol.
What is sorbitol, and what is its common use?
-Sorbitol, also known as glucitol, is a sugar alcohol produced by the reduction of glucose. It is commonly used as a sweetening agent in products like chewing gum.
Outlines
đŹ Oxidation of Monosaccharides
This paragraph introduces the oxidation reactions of monosaccharides, specifically focusing on glucose. It explains the transformation between the open chain (aldose) and cyclic (furanose or pyranose) forms of monosaccharides. The oxidation process involves the conversion of the aldehyde group to a carboxylic acid, facilitated by Tollens' or Benedict's solution, which contains copper sulfate. The role of copper ions as oxidizing agents is highlighted, where they are reduced from Cu2+ to Cu+ during the reaction. The paragraph also mentions that the alcohol group on carbon six remains unaffected during this oxidation, resulting in the formation of aldonic acids, such as gluconic acid from glucose.
đ§Ș Formation of Aldaric Acids and Enzymatic Oxidation
The second paragraph delves into the oxidation of both the aldehyde and alcohol functional groups in monosaccharides, using strong oxidizing agents like nitric acid. This leads to the formation of aldaric acids, exemplified by the conversion of glucose to glucaric acid. The paragraph then contrasts this with enzymatic oxidation, where only the alcohol group on carbon six is oxidized, resulting in the formation of uronic acids like glucuronic acid. The aldehyde group remains unaffected in this selective oxidation process.
đŹ Reduction to Produce Sugar Alcohols
The final paragraph discusses the reduction of monosaccharides, which is the reverse of oxidation. It details the transformation of the aldehyde group in glucose to a primary alcohol, resulting in the formation of a sugar alcohol like glucitol (also known as sorbitol). This process is facilitated by hydrogen gas acting as a reducing agent. The paragraph emphasizes that this reduction reaction is the opposite of oxidation, where electrons and hydrogen are gained. Sorbitol, the product of this reduction, is highlighted as a sweetening agent commonly used in chewing gum.
Mindmap
Keywords
đĄMonosaccharide
đĄOxidation
đĄCyclic form
đĄAldehyde group
đĄCarboxylic acid
đĄBenedict solution
đĄRedox reactions
đĄAldonic acid
đĄAldoric acid
đĄEnzymatic oxidation
đĄSugar alcohol
Highlights
Introduction to reactions of monosaccharides
Different oxidation processes of monosaccharides
Glucose molecule's cyclic and acyclic forms
Oxidation to produce acidic sugar using Benedict solution
Role of copper sulfate in Benedict solution
Transformation of aldehyde group to carboxylic acid
Copper ion's role as an oxidizing agent
Redox reactions involving copper ions and glucose
Formation of gluconic acid from glucose oxidation
Oxidation of both aldehyde and alcohol groups by strong oxidizing agents
Production of glucaric acid through aldoric acid formation
Enzymatic oxidation of the alcohol group on carbon six
Conversion of glucose to glucuronic acid
Reduction of monosaccharides to produce sugar alcohols
Use of hydrogen as a reducing agent in reduction reactions
Transformation of aldehyde to primary alcohol in reduction
Production of sorbitol from glucose through reduction
Sorbitol's use as a sweetening agent in chewing gum
Transcripts
hello everyone welcome to this video
which i will be talking about the
reactions of monosaccharide
in today's presentation we will see the
different
oxidation process that this sugar or
particularly a monosaccharide could
undergo so for example we have here
a molecule of glucose so we
have a howard or a
cyclic form of monosaccharide and we
have a feature form
of monosaccharides so we could
easily uh see the transformation in
in feature form so a feature form is the
open open chain projection
while howard form is a
closed chain or a cyclic cyclic form
so it says here oxidation to produce
acidic sugar can be facilitated by
either tolerance or benedict solution
this benedict solution particularly
contains
copper sulfate that's why in this
reaction you can see the participation
of copper ion
what happens here is the aldehyde end
of a glucose this is your glucose
the aldehyde end or the aldehyde group
of
the glucose will be
transformed into what we call carboxylic
acid so the aldehyde is oxidized so the
process
is called oxydation
okay so remember that uh when
aldehyde is oxidized the product is
carboxylic acids okay so
what is the participation of the copper
ion
copper ion this copper ion
serves as oxidizing
[Music]
oxidizing agent let's put that
here ox a oxidizing agent now in the
process
what you can see is the copper 2 plus
which serves as oxidizing oxidizing
agent
has been reduced
copper oneplus so
these uh reactions are actually
redox in nature when you say redox
that is reduction and oxidation
reduction with respect to the copper two
plus
that is converted to copper
one okay that is reduction so
copper has been reduced to
copper 1 plus
with respect to oxidation it's the
aldehyde that has been oxidized
to carboxylic acid
notice that the six carbon or the oh the
alcohol in carbon number six
remains unaffected
okay so generally when when a
monosaccharide
undergoes oxidation in
in its aldehyde component
generally the the the acid is called
all aldonic
aldonic acid okay so
for example we have a glucose here that
underwent oxidation the
acid the glucose acid is called
gluconic acid okay
so from glucose it becomes gluconic
acid this
reaction here what we can see is
the oxidation of
two functional groups it says here
strong oxidizing agents such as nitric
acid can
oxidize both ends of the monosaccharide
at the same time
so what are those ends this is the
aldehyde group
and this is the alcohol group on carbon
number six remember this is our carbon
number one
and this is our carbon number six so a
strong oxidizing agent such as
strong acid can both oxidize the two
functional group
so notice the transformation of the
aldehyde
it is converted to carboxylic acid
likewise the alcohol on carbon number
six
is also converted to a carboxylic acid
so this is actually a dye
carboxylic dicarboxylic acid
so such reaction
such a reaction is known as formation of
aldoric acid so
specifically when we have glucose that
underwent
oxidation to produce the alderic acid
the product is called glucaric
acid you just have to add aric
acid all right
in this reaction we can see that uh
it's the sixth carbon
or the hydroxyl group in the sixth
carbon
undergoes oxidation remember in the
first
reaction we have seen that
the only the aldehyde that underwent
oxidation in the second reaction we have
seen that
both ends the aldehyde in the the
aldehyde
and the alcohol group on carbon number
six both of them
went um oxidation
however in this um in this process
what we can see here is the oxidation
of the alcohol on carbon number six
so this is called enzymatic oxidation
which is
um facilitated by enzymes or biological
enzyme
notice that in or the aldehyde
remains unaffected still aldehyde but
it's only the carbon number six or the
oh
the hydroxyl group or the alcohol in
carbon number six
underwent oxidation
to form glucoronic acid so
an alcohol is oxidized to
carboxylic acid so generally
a sugar that undergoes oxidation on its
alcohol group
on carbon number six called aldo
ronic acid so you just have to add
uronic acid from glucose
to uronic acid
so this process is a selective selective
process
the second type of reaction is called
reduction to produce
sugar alcohol remember reduction is
somewhat uh
opposite of oxidation so reduction
is by definition is gain
gaining of electron and
hydrogen so in this transformation
we can see that it's the opposite of
oxidation that will take place
all right it says here the
carbonyl group present in a
monosaccharide
either an aldos or ketos can be reduced
to carboxylic group using hydrogen
as a reducing agent so here
let me uh let's write the
the process so a primary alcohol
primary alcohol remember in your organic
chemistry
gets oxidized to aldehyde
so let's write here oxidation o that
represents oxidation
okay and then the aldehyde
is also oxidized to
carboxylic carboxylic acid
okay carboxylic
acid let's just put right there all
right and then uh
the reverse arrow can still be possible
can
is also possible so if the forward
reaction is called oxidation the reverse
reaction is called
reduction so we will reduce the
carboxylic acid back to
aldehyde and that what exactly happens
here okay
and uh what happens in this reaction is
from aldehyde from aldehyde
to a primary alcohol
so we have here if we are going to
reverse this reaction we said earlier
that primary alcohol
let's write primary al
cohol okay a primary alcohol
is oxidized to aldehyde that's the
forward
however the reverse reaction is
aldehyde is reduced
to a primary alcohol so take note of the
process called reduction that's why the
title is reduction
to produce sugar alcohol okay so we have
here
um a transformation of glucose
so what what is the transformation that
happens here
the aldehyde is converted
or transformed into a primary
alcohol okay however the
as you notice the alcohol in carbon
number six
remains the same so what is the role of
hydrogen gas here
it says it serves as reducing
reducing agent so glucitol
is a dye alcohol dye alcoholic
molecule it's commonly known as orbital
which
serves as or used as sweetening agent in
chewing gum
5.0 / 5 (0 votes)