Alkynes are hydrocarbons containing a carbon-carbon triple bond. They can be classified as internal or terminal based on substitution. Alkynes undergo characteristic reactions including addition, hydration, and ozonolysis. They are prepared through dehydrohalogenation or reaction of metal acetylides with alkyl halides. Alkynes react as nucleophiles and undergo addition, often regioselectively based on carbocation stability.
Surfactant is a surface active agent which are used to prevent surface tension and interfacial tension. It is important prevent interfacial fluidity, it is amphiphilic molecule having Hydrophilic head and Lipophilic tail. It is important for poorly water soluble drug and it is important to influencing water solubility of poorly water soluble drug. It is important to prevent the inter and intra subject variability.
It act as solubilizing agent, suspending and emulsifying agent, stabilizing agent, wetting agent, detergent, Foaming agent.
It is important for preparation of Nanoemulsion, Nanosuspension, Microemulsion.
It is important to show antibacterial as well as antimicrobial activity.
It is important for Novel drug delivery system, oral drug delivery system, Targeted drug delivery system.
It is important to influencing oral bioavailability of poorly water soluble drug.
An acid is any substance that in water solution tastes sour, changes blue litmus paper to red, reacts with some metals to liberate hydrogen, reacts with bases to form salts, and promotes chemical reactions (acid catalysis).
A base is a substance that can neutralize the acid by reacting with hydrogen ions. Most bases are minerals that react with acids to form water and salts.
Salt is a chemical compound consisting of an ionic assembly of cations and anions.
Surfactant is a surface active agent which are used to prevent surface tension and interfacial tension. It is important prevent interfacial fluidity, it is amphiphilic molecule having Hydrophilic head and Lipophilic tail. It is important for poorly water soluble drug and it is important to influencing water solubility of poorly water soluble drug. It is important to prevent the inter and intra subject variability.
It act as solubilizing agent, suspending and emulsifying agent, stabilizing agent, wetting agent, detergent, Foaming agent.
It is important for preparation of Nanoemulsion, Nanosuspension, Microemulsion.
It is important to show antibacterial as well as antimicrobial activity.
It is important for Novel drug delivery system, oral drug delivery system, Targeted drug delivery system.
It is important to influencing oral bioavailability of poorly water soluble drug.
An acid is any substance that in water solution tastes sour, changes blue litmus paper to red, reacts with some metals to liberate hydrogen, reacts with bases to form salts, and promotes chemical reactions (acid catalysis).
A base is a substance that can neutralize the acid by reacting with hydrogen ions. Most bases are minerals that react with acids to form water and salts.
Salt is a chemical compound consisting of an ionic assembly of cations and anions.
Additive, constitutive and colligative properties with examples; Concept of tonicity in pharmacy, methods to adjust isotonicity; Dipole moment, Dielectric constant and significance to pharmacy
Refractive index and molar refraction, Principle and working of Abbe’s refractometer and Application of molar refraction to determine structures
Optical rotation, Specific rotation, measurement of optical rotation and its applications
Primary metabolites:
General introduction, detailed study with respect to chemistry, sources,
preparation, evaluation, preservation, storage, therapeutic used and
commercial utility as Pharmaceutical Aids and/or Medicines for the
following Primary metabolites:
(d) Proteins and Enzymes : casein,
Additive, constitutive and colligative properties with examples; Concept of tonicity in pharmacy, methods to adjust isotonicity; Dipole moment, Dielectric constant and significance to pharmacy
Refractive index and molar refraction, Principle and working of Abbe’s refractometer and Application of molar refraction to determine structures
Optical rotation, Specific rotation, measurement of optical rotation and its applications
Primary metabolites:
General introduction, detailed study with respect to chemistry, sources,
preparation, evaluation, preservation, storage, therapeutic used and
commercial utility as Pharmaceutical Aids and/or Medicines for the
following Primary metabolites:
(d) Proteins and Enzymes : casein,
Basic concepts of chemistry, alkanes, alkenes, alkynes, benzene, their preparation methods, properties and uses are explained. Isomerism in alkanes and alkynes also discussed.
Hydrocarbons, the fundamental compounds of organic chemistry, are composed of hydrogen and carbon atoms. The diverse world of hydrocarbons is neatly categorized based on their structure and the type of bonds they contain. In Class 11, students delve into the classification of hydrocarbons, exploring alkanes, alkenes, alkynes, and aromatic compounds.
In Class 11 Chemistry, hydrocarbons serve as a fundamental topic within organic chemistry. Hydrocarbons are organic compounds composed exclusively of carbon and hydrogen atoms. The class primarily focuses on four major types of hydrocarbons: alkanes, alkenes, alkynes, and aromatic hydrocarbons.
For more information, visit- www.vavaclasses.com
Aldehydes and ketones are the carbonyl compounds with general formula CnH2nO. Aldehydes have at least one hydrogen atom bonded to the carbonyl group and other group is either hydrogen or an alkyl or aryl group (i.e. Aldehyde has one alkyl or aryl group and one of the hydrogen bonded to the carbonyl carbon) with characteristics functional group -CHO.
Alkenes Final chemicals can lead to the opposite product result, but the reactive-intermediate structures and mechanisms are different.Hydrobromic acid in particular is prone to forming radicals in the presence of various impurities or even atmospheric oxygen, leading to the reversal of the Markovnikov result.
Full study material of Alkyl and aryl halides, preparation, properties, polyhalo compounds, their uses with complete explanation with the relevant examples.
Aldehydes and ketones are organic compounds which incorporate a carbonyl functional group, C=O. The carbon atom of this group has two remaining bonds that may be occupied by hydrogen or alkyl or aryl substituents. If at least one of these substituents is hydrogen, the compound is an aldehyde.
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.
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.
Honest Reviews of Tim Han LMA Course Program.pptxtimhan337
Personal development courses are widely available today, with each one promising life-changing outcomes. Tim Han’s Life Mastery Achievers (LMA) Course has drawn a lot of interest. In addition to offering my frank assessment of Success Insider’s LMA Course, this piece examines the course’s effects via a variety of Tim Han LMA course reviews and Success Insider comments.
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.
Safalta Digital marketing institute in Noida, provide complete applications that encompass a huge range of virtual advertising and marketing additives, which includes search engine optimization, virtual communication advertising, pay-per-click on marketing, content material advertising, internet analytics, and greater. These university courses are designed for students who possess a comprehensive understanding of virtual marketing strategies and attributes.Safalta Digital Marketing Institute in Noida is a first choice for young individuals or students who are looking to start their careers in the field of digital advertising. The institute gives specialized courses designed and certification.
for beginners, providing thorough training in areas such as SEO, digital communication marketing, and PPC training in Noida. After finishing the program, students receive the certifications recognised by top different universitie, setting a strong foundation for a successful career in digital marketing.
2. Introduction
Alkynes are hydrocarbons that have at
least one triple bond, C≡C with the
formula CnH2n-2.
Disubstituted alkynes, R-C≡C-R', are
described as "internal" alkynes;
Monosubstituted alkynes, R-C≡C-H,
are described as "terminal" alkynes.
3. Because of its linear configuration, ten-
membered carbon ring is the smallest that
can contain the alkyne function without
excessive strain.
ethyne (or acetylene) propyne 1-butyne
H-C C-H H-C C- CH3 H-C C-CH2-CH3
2-butyne
Terminal
Internal
CH3-C C-CH3
4. Quizz
Classify each of the following as an internal or
a terminal alkyne:
a) 1-hexyne b) 3-octyne
c) cyclooctyne d) propyne
5. Nomenclature
Akynes are named by general rules similar
to those used for alkanes and alkenes.
The suffix -yne is used in the paren
hydrocarbon name to denote an alkyne,
and the position of the triple bond is
indicated by its number in the chain.
6. Numbering begin at the chain end near the
triple bond so that the triple bond as low a
number as possible.
Compounds containing both double and
triple bonds are called enynes.
CH3CH2CHCH2C CCH2CH3
CH3
Begin numbering at
the end nearer the
triple bond
6-Methyl-3-octyne
7. Numbering of the hydrocarbon chain starts
from the end nearer the first multiple
bond, whether double or triple.
If there is a choice in numbering, double
bonds receive lower numbers than triple
bonds. For example,
HC CCH 2CH2CH2CH CH2
CH3
1-Hepten-6-yne
1
6
7
HC CCH 2CHCH2CH2CH CHCH3
4-Methyl-7-nonen-1-yne
1 6 7 9
8. Preparation of Alkynes
Alkynes are generally prepared by
* Dehydrohalogenation of either geminal
(1,1-) or vicinal (1,2-)alkyl dihalides
(usually Br or Cl), using a strong base,
usually NaNH2.
These reactions are typically E2 reactions
and occur via an alkenyl halide.
9. * The reaction of metal acetylides with
primary alkyl halides.
C C Na + R- X C C R
10. Quizz
What is the alkyne product from the reactions
of the following with NaNH2:
a) 2,2-dibromopropane
b) 1,2-dibromohexane
c) 1,1-dibromooctane
d) 2,3-dibromohexane
11. Structure and Reactivity
The alkyne functional group consists of two
sp hybridised C atoms bonded to each other
via one σ and two bonds.
The 2 bonds are produced by the side-to-
side overlap of the two pairs of p-orbitals
not utilised in the hybrids.
The diagram shows the heats of hydrogenation
of 2-butyne (in the slide: blue in units of kcal/mole)
12. It indicates that alkynes are thermodynamically
less stable than alkenes
to a greater degree than
alkenes are less stable
than alkanes.
The "extra" bond in an alkyne is weaker that an
alkene bond:
2 x 28.3 (C=C) – 65 (C≡C)= 8.4 kcal
13. The 2 C of the C≡C and the 2 atoms
attached directly to the C≡C are linear, so
they cannot exist as cis-/trans- isomers.
Two separate perpendicular p molecular orbitals
σ
σ
14. The bonds are a region of high electron
density; so it allows an acetylinic carbon
to have a greater amount of
electronegative character.
As a result, alkynes are typically
nucleophiles.
Terminal alkynes, R-CC-H, are quite
acidic (pKa = 26).
15. Reacting with a strong base such as
sodium, sodium amide, n-butyllithium or a
Grignard reagent, a terminal alkyne gives
the anion of the terminal alkyne (a metal
acetylide):
2 RC ≡ CH + 2 Na → 2 RC ≡ CNa + H2
16. The acetylide ion is a good nucleophile and
can be alkylated to give higher alkynes.
Like alkenes (C=C), the alkyne C≡C
undergoes a variety of addition reactions in
which one or both of the bonds are
converted to new σ bonds.
17. Alkylation of Alkynes
The acetylide carbanion, RC≡C-, is a good
C-nucleophile and can undergo
nucleophilic substitution reactions (usually
SN2) with 1o or 2o alkyl halides (Cl, Br or I)
to produce an internal alkyne.
18. One or both of the terminal H atoms in
ethyne (acetylene) H-C≡C-H can be
susbtituted providing monosubstituted (R-
C≡C-H) and symmetrical (R=R') or
unsymmetrical (R ≠ R') disubstituted
alkynes R-C ≡ C-R'
19. Mechanism for Alkylation of alkynes
Step 1. The amide ion acts as a
base removing the acidic terminal
H to generate the acetylide ion,
a carbon nucleophile.
Step 2. The carbanion reacts
with the electrophilic carbon in the
alkyl halide with loss of the leaving
group, forming a new C-C bond.
20. Practice Problems
What is the product of the reactions of CH3-C≡C- with each of the following:
a) 2-bromopropane (d) ethanol
b) 1-iodooctane e) ethyl tosylate
c) (R)-2-bromohexane f) bromobenzene
21. Addition Reactions of Alkynes
Alkynes undergo addition reactions in an
analogous fashion to those of alkenes.
Two factors influence the relative
reactivity of alkynes compared to alkenes:
increased nucleophilicity of the starting
system (C≡C vs C=C), and
22. stability of any intermediates
(for example, carbocations).
Since alkynes are thermodynamically less
stable than alkenes, we might expect
addition reactions of alkynes to be more
exothermic and relatively faster than
equivalent reactions of the alkenes.
23. 1. Hydrogenation of Alkynes
Alkynes can be partially reduced to cis-
alkenes with H2 in the presence of poisoned
catalysts,
eg. Pd / CaCO3/ quinoline which is also
known as Lindlar's catalyst.
Alkynes can be reduced to alkanes with H2
in the presence of catalysts (Pt, Pd, Ni etc.)
24. The reaction is stereospecific
giving only the syn addition
product since the new C-H σ
bonds is formed simultaneously
from H atoms absorbed onto the
metal surface.
25. 2. Dissolving Metal Reduction of Alkynes
The reaction of Na in NH3(l) with alkynes
occurs stereospecificly giving only the
trans-alkene via an anti-addition.
26. The reaction proceeds via single
electron transfer from the Na with
H coming from the NH3.
These reaction conditions do not
reduce alkenes.
27. 3. Reaction of Alkynes with HX
When treated with HX alkynes form vinyl
halides.
Hydrogen halide reactivity order :
HI > HBr > HCl > HF
(paralleling acidity order).
28. In the presence of excess HX, a second
addition can occur to the product alkene
giving a geminal dihalide.
Regioselectivity predicted by
Markovnikov's rule with the H adding to
the C with the most H already present.
29. Reaction proceeds via protonation to give
the more stable carbocation intermediate.
Not stereoselective since reaction proceeds
via planar carbocation (CH3C+=CH2 &
CH3CBr+CH3).
30. Quizz
What would be the product from the
reaction of 2-butyne with excess HBr ?
31. For HBr, in the presence of radicals
(compounds such as peroxides) the
radical addition occurs with opposite
regiochemistry:
Quizz. Why does this reaction have the
opposite regiochemistry ?
33. 4. Hydration of Alkynes
Alkynes can be hydrated to form enols that
immediately tautomerise to ketones.
Reagents: aq. acid, most commonly
H2SO4, with a mercury salt.
34. Regioselectivity predicted by
Markovnikov's rule.
Reaction proceeds via protonation to give
the more stable carbocation intermediate.
CH3-C≡CH + H+ CH3-C+= CH2
Not stereoselective since reactions proceeds
via planar carbocation.
35. 5 . Halogenation of Alkynes
Overall transformation: C≡ C to X-C=C-X
(and potentially to X2C-CX2).
Reagent: normally the halogen (e.g. Br2) in an
inert solvent like methylene chloride, CH2Cl2.
36. Reaction proceeds via cyclic
halonium ion.
Stereoselectivity : anti since
the two C-X bonds form in
separate steps one from X2,
the other X-.
37. 6. Ozonolysis of Alkynes
Overall transformation : C≡C to 2 x CO2
Ozonolysis implies that ozone causes the
alkyne to break (-lysis)
38. Reagents : ozone followed by aqueous
work-up.
Note that each of the CC bonds in the CºC
becomes a C=O bond.
39. Problems at home
Classify each of the following as an internal or a terminal
alkyne (from the slide 4)
a) 1-hexyne b) 3-octyne
c) cyclooctyne d) propyne
What is the alkyne product from the reactions of the
following with NaNH2: (from the slide 10)
a) 2,2-dibromopropane
b) 1,2-dibromohexane
c) 1,1-dibromooctane
d) 2,3-dibromohexane
40. What is the product of the reactions of CH3-C≡C-
with each of the following: (from the slide 20)
a) 2-bromopropane (d) ethanol
b) 1-iodooctane e) ethyl tosylate
c) (R)-2-bromohexane f) bromobenzene
What would be the products of the ozonolysis reactions of:
(a) ethyne ? (b) 1-butyne ?
(c) 2-butyne ? (d) cyclooctyne ?