1) Various chemical reactions and analyses showed that glucose has the molecular formula C6H12O6 and consists of a six-carbon chain with one aldehyde group, one primary alcohol group, and four other hydroxyl groups.
2) Determining the configurations of D-glucose involved studying its relationship to D-arabinose and other sugars. This indicated that D-glucose has the D configuration shown by structure VII.
3) Further evidence that structure VII represents D-glucose came from comparing it to L-gulose, which upon oxidation produces the same diacid product as D-glucose.
The combination of a carbonyl group and a hydroxyl on the same carbon atom is called a carboxyl group. Compounds containing the carboxyl group are called carboxylic acids. The carboxyl group is one of the most widely occurring functional groups in organic chemistry.
Aromatic Carboxylic acids: Carboxylic acids have an aryl group bound to the carboxyl group is known as aromatic carboxylic acids. The general formula of an aliphatic aromatic carboxylic acid is Ar-COOH.
Acidity of carboxylic acid:
A carboxylic acid may dissociate in water to give a proton and a carboxylate ion. Dissociation of a carboxylic acid involves breaking an O-H bond gives a carboxylate ion with the negative charge spread out equally over two oxygen atoms, compared with just one oxygen atom in an alkoxide ion. The delocalized charge makes the carboxylate ion more stable therefore; dissociation of a carboxylic acid to a carboxylate ion is less endothermic.
Preparation Methods:
1. Oxidation:
The oxidation of aldehyde with oxidizing agents such as CrO3 to forms carboxylic acids containing the same numbers of carbon atoms with a oxidizing agents like chromic acid, chromium trioxide. The silver oxide (Ag2O) in aqueous ammonia solution (Tollen’s reagent) is mild reagent give good yield at room temperature. E.g. Acetaldehyde reacts with CrO3 in aqueous acid to give acetic acid.
2. Grignard reagents (from CO2):
Carboxylic acid can be prepared by the reaction of Grignard reagent (alkyl magnesium halide) with carbon dioxide (CO2) in presence of dry ether. Grignard reagents react with carbon dioxide to forms a magnesium carboxylates which on hydrolysis by dilute HCl produces carboxylic acids.
3. Hydrolysis of nitrile:
The hydrolysis of nitrile or cyanide in presence of dilute acid to forms a carboxylic acid. In this reaction –CN group is converted to a –COOH group.
4. Hydrolysis Reactions:
All the carboxylic acid derivatives can be hydrolyzed into the carboxylic acid in the acidic or basic media; the hydrolysis reaction is fast and occurs in presence of water with no acid or base catalyst.
1. From Ester (Hydrolysis of ester): Ester can be hydrolyzed in either acidic or basic medium to yield carboxylic acid. The ester is heated with an excess of water contains strong acid or base catalyst.
Properties of Carboxylic Acids:
1. Low molecular weights carboxylic acids are colourless liquid at room temperature i.e. lower member ate liquid up to C9 and have characteristic odors whereas higher members are solid.
2. Carboxylic acids are polar organic compound. Low molecular weight carboxylic acids (first four members) are soluble in water whereas solubility in water decrease as molecular weight and chain lengthing increases.
3. Aromatic acids are insoluble in water.
4. Carboxylic acids have higher melting and boiling point due to their capacity to readily form stable hydrogen-bonded dimers.
actinide complexes and uses, Inorganic chemistryRabia Aziz
more chemistry contents are available
1. pdf file on Termmate: https://www.termmate.com/rabia.aziz
2. YouTube: https://www.youtube.com/channel/UCKxWnNdskGHnZFS0h1QRTEA
3. Facebook: https://web.facebook.com/Chemist.Rabia.Aziz/
4. Blogger: https://chemistry-academy.blogspot.com/
actinide complexes and uses
The combination of a carbonyl group and a hydroxyl on the same carbon atom is called a carboxyl group. Compounds containing the carboxyl group are called carboxylic acids. The carboxyl group is one of the most widely occurring functional groups in organic chemistry.
Aromatic Carboxylic acids: Carboxylic acids have an aryl group bound to the carboxyl group is known as aromatic carboxylic acids. The general formula of an aliphatic aromatic carboxylic acid is Ar-COOH.
Acidity of carboxylic acid:
A carboxylic acid may dissociate in water to give a proton and a carboxylate ion. Dissociation of a carboxylic acid involves breaking an O-H bond gives a carboxylate ion with the negative charge spread out equally over two oxygen atoms, compared with just one oxygen atom in an alkoxide ion. The delocalized charge makes the carboxylate ion more stable therefore; dissociation of a carboxylic acid to a carboxylate ion is less endothermic.
Preparation Methods:
1. Oxidation:
The oxidation of aldehyde with oxidizing agents such as CrO3 to forms carboxylic acids containing the same numbers of carbon atoms with a oxidizing agents like chromic acid, chromium trioxide. The silver oxide (Ag2O) in aqueous ammonia solution (Tollen’s reagent) is mild reagent give good yield at room temperature. E.g. Acetaldehyde reacts with CrO3 in aqueous acid to give acetic acid.
2. Grignard reagents (from CO2):
Carboxylic acid can be prepared by the reaction of Grignard reagent (alkyl magnesium halide) with carbon dioxide (CO2) in presence of dry ether. Grignard reagents react with carbon dioxide to forms a magnesium carboxylates which on hydrolysis by dilute HCl produces carboxylic acids.
3. Hydrolysis of nitrile:
The hydrolysis of nitrile or cyanide in presence of dilute acid to forms a carboxylic acid. In this reaction –CN group is converted to a –COOH group.
4. Hydrolysis Reactions:
All the carboxylic acid derivatives can be hydrolyzed into the carboxylic acid in the acidic or basic media; the hydrolysis reaction is fast and occurs in presence of water with no acid or base catalyst.
1. From Ester (Hydrolysis of ester): Ester can be hydrolyzed in either acidic or basic medium to yield carboxylic acid. The ester is heated with an excess of water contains strong acid or base catalyst.
Properties of Carboxylic Acids:
1. Low molecular weights carboxylic acids are colourless liquid at room temperature i.e. lower member ate liquid up to C9 and have characteristic odors whereas higher members are solid.
2. Carboxylic acids are polar organic compound. Low molecular weight carboxylic acids (first four members) are soluble in water whereas solubility in water decrease as molecular weight and chain lengthing increases.
3. Aromatic acids are insoluble in water.
4. Carboxylic acids have higher melting and boiling point due to their capacity to readily form stable hydrogen-bonded dimers.
actinide complexes and uses, Inorganic chemistryRabia Aziz
more chemistry contents are available
1. pdf file on Termmate: https://www.termmate.com/rabia.aziz
2. YouTube: https://www.youtube.com/channel/UCKxWnNdskGHnZFS0h1QRTEA
3. Facebook: https://web.facebook.com/Chemist.Rabia.Aziz/
4. Blogger: https://chemistry-academy.blogspot.com/
actinide complexes and uses
In 1891,Emil fischer devised a method of representing the 3D structures of
molecules in 2D Structures on a plane (Paper) by convention, horizontal line
represent bonds projecting from the plane of paper towards the observer and
vertical line represent away from the observer
In 1891,Emil fischer devised a method of representing the 3D structures of
molecules in 2D Structures on a plane (Paper) by convention, horizontal line
represent bonds projecting from the plane of paper towards the observer and
vertical line represent away from the observer
This presentation is based on the main topics dealing with chapter no 14.of chemistry.this chapter deals with the introduction ,classification,properties and functions of carbohydrates,proteins, Enzymes,vitamins,nucleic acids,lipid etc. this presentation will help students as well as teachers in the teaching learning process
Isomerism - Structural Isomerisms in Organic compoundsDr Venkatesh P
Structural Isomerism in Organic compounds - Chain Isomerism, Positional Isomerism, Functional Isomerism, Metamerism and Tautomerism explained with suitable examples. In Introduction, Definition of Isomerism and Stereoisomerism given simply to understand the difference between Structural and Stereo isomerism.
https://youtu.be/a0snq_oz50A
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
How to Create Map Views in the Odoo 17 ERPCeline George
The map views are useful for providing a geographical representation of data. They allow users to visualize and analyze the data in a more intuitive manner.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
2. Structure of D-Glucose
Elemental Analysis
and
Molecular weight determination
show that the molecular formula of Glucose is
C6H12O6
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3. Reduction of Glucose
Complete reduction with concentrated hydriodic acid in the presence of red
Phosphorous produces n-hexane as the major product.
Glucose n-hexane
Indicates that the 6 carbon atom in the glucose molecule form a consecutive,
unbranched chain.
C-C-C-C-C-C
HI
Red P
C6H12O6 CH3CH2CH2CH2CH2CH3
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4. Glucose readily dissolves in water to give a neutral solution
Indicates that the glucose molecule does not contain a
carboxyl group
NO
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O
O
5. Reaction with hydroxylamine & Hydrogen Cyanide
Glucose on reaction with hydroxylamine produces monoxime or adds one mole
of hydrogen cyanide to give a cyanohydrin.
Glucose Oxime Gluconitrile
Indicates the presence of either an aldehyde or a ketone group, but not both.
C6H12O6
(CHOH) 4
H NOH
CH2OH
NH2OH HCN
(CHOH) 5
CH2OH
CN
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O
O
H
6. Oxidation
Mild oxidation of Glucose with bromine water gives Gluconic acid, a monocarboxylic acid
with molecular formula C6H12O7.
Indicates the presence of an aldehyde group – since only the aldehyde group can be
oxidised to an acid by gaining one oxygen atom without losing any hydrogen atoms.
Glucose Gluconic acid
Six carbon atoms in glucose forms a consecutive unbranched chain, so the aldehyde
group must occupy one end of this chain
C6H12O6
Br2/H2O
Mild Oxidation
(CHOH) 4
CH2OH
COOH
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7. Oxidation
Further oxidation of Gluconic acid with nitric acid gives Glucaric acid, a dicarboxylic acid with a
molecular formula C6H10O8.
Indicates the presence of a primary alcohol group, since oxidation occurs with the loss of two
hydrogens and gain of one oxygen atom. i.e.,
Gluconic acid Glucaric acid
Hence, - CHO & CH2OH occupies the two ends of the six carbon chain
CH2OH COOH
(CHOH) 4
CH2OH
COOH
HNO3
Strong Oxidation
(CHOH) 4
COOH
COOH
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8. Terminal aldehyde group
Glucose reduces ammoniacal solution of silver oxide [Tollen’s reagent] to metallic
silver or a basic solution of cupric ion [Fehling’s solution] to red cuprous oxide.
Silver mirror
Red Precipitate
Confirms the presence of terminal aldehyde group.
C6H12O6
Ag(NH3)OH
Tollen's reagent
Ag ↓
C6H12O6
Cu(OH)2/NaOH
Fehling's Solution
Cu2O ↓
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9. Hydroxyl groups
Glucose on reaction with acetic anhydride in the presence of pyridine to form a pentaacetate.
Glucose Glucose pentaacetate
Confirms five –OH groups in glucose molecule
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C6H12O6
(CH3CO)2O
C5H5N
(CHOCOCH 3)4
CHO
CH2OCOCH 3
10. Hydroxyl groups in a different carbon atom
Organic compounds with two hydroxyl groups attached to a single carbon atom usuallylose water to
produce a carbonyl group.
This suggeststhat in Glucose molecule, each one of the five hydroxyl group is attached to a different
carbon atom.
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OH
OH
O
-H2O
11. Structure of Glucose
These evidence concludes that Glucose is pentahydroxyhexanal
It can be represented by the following gross structure
*C = asymmetric carbon
Glucose [2,3,4,5,6 – pentahydroxy hexanal]
Chem Eazy
CHO
CH2OH
*CHOH
*CHOH
*CHOH
*CHOH
13. Relative configuration
Glucose structure has 4 unlike asymmetric carbon atoms.
This representation is incomplete – because it doesn’t give any idea about the spatial arrangement of
the hydroxyl groups and hydrogen atoms around these four asymmetric centres.
Yet to determine the relative configuration of the asymmetric centres and absolute configuration of the
molecule.
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14. A key compound is D-arabinose, an aldopentose, which must have one of the
following structures
I II III IV
Chem Eazy
H OH
H OH
H OH
CHO
CH2OH
O
H H
H OH
H OH
CHO
CH2OH
H OH
O
H H
H OH
CHO
CH2OH
O
H H
O
H H
H OH
CHO
CH2OH
15. Oxidation of D-arabinose with nitric acid gives an optically active dicarboxylic acid. Under
these conditions structure I & III would have given optically inactive meso diacids.
----plane of ----planeof
symmetry symmetry
I Optically Inactive III Optically Inactive
[meso compound] [meso compound]
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H OH
H OH
H OH
CHO
CH2OH
HNO3
H OH
H OH
H OH
COOH
COOH
H OH
O
H H
H OH
CHO
CH2OH
HNO3 H OH
O
H H
H OH
COOH
COOH
16. II Optically active
IV Optically active
D-arabinose is therefore either II (or) IV and can be represented with configuration in doubt at C-3.
Chem Eazy
O
H H
H OH
H OH
O
H H
H OH
H OH
HNO3
CH2OH COOH
COOH
CHO
3
O
H H
O
H H
H OH
O
H H
O
H H
H OH
HNO3
CHO
CH2OH
COOH
COOH
3
17. When D-arabinose subjected to Kiliani – Fischer synthesis, it gives Glucose & Mannose
D-arabinose V VI
[new asymmetric centre at C-2]
These sugars differ only in configuration at C-2, which is the new asymmetric centre created in the chain
extension. Structure V & VI represent Glucose and Mannose.
Chem Eazy
CHOH (?)
O
H H
H OH
CHO
CH2OH
i) HCN, ii) H2O/H+
iii) NaBH4
CHOH (?)
H OH
O
H H
H OH
CHOH (?)
O
H H
O
H H
H OH
+
CHO CHO
CH2OH CH2OH
3
4 4
2 2
18. Next step is to determine the configurationat C-4 and then to identify which is Glucose & Mannose
Both Glucose & Mannose on oxidation with nitric acid give diacids which are optically active.
This means that the hydroxyl group is on the right, as in structure VII and VIII.
If it were on the left, VII would have yielded an optically inactive meso diacid, IX
VII VIII IX
Chem Eazy
H OH
O
H H
H OH
H OH
CHO
CH2OH
O
H H
O
H H
H OH
H OH
CHO
CH2OH
H OH
O
H H
O
H H
H OH
COOH
COOH
---------------------- Plane of symmetry
19. Structures VII & VIII represent D-Glucose & D-Mannose.
Decide whether VII is Glucose & VIII is Mannose, or the other way around.
To decide this, another aldohexose, L-Gulose (X) is used. When L-Gulose oxidised with nitric acid yields the same
dicarboxylic acid (XI) as that obtained from D-Glucose.
Chem Eazy
O
H H
O
H H
H OH
HO H
CHO
CH2OH
__
__
__
H OH
O
H H
H OH
H OH
CH2OH
CHO
H
N
O
3
H OH
O
H H
H OH
H OH
COOH
COOH
H OH
O
H H
H OH
H OH
CHO
CH2OH
HNO3
1
6
6
1
X (L-Gulose)
Rotated 180°
XI
VII [D-Glucose]
20. L-Gulose when turned upside down (180°) has the same configuration at the asymmetric centres as does
D-Glucose, except that the aldehyde& the primary alcohol groups are interchanged.
Oxidation converts this groups to the carboxyl groups and thus the same diacid (XI) is obtained.
Such a result is not possible with structure VIII, since the structure obtained by interchanging the ends
doesn’t represent a different sugar.
Hence D-Glucose is represented by structure VII and D-Mannose is structure VIII.
D-Glucose
Chem Eazy
H OH
O
H H
H OH
H OH
CHO
CH2OH
