Ncert complete conversions class12 chemistry|Ncert complete conversions| organic chemistry class12

Name: Ncert complete conversions class12 chemistry|Ncert complete conversions| organic chemistry class12
Uploaded: 2025-12-28T12:31:07.000Z
Duration: 4 h 27 s

Conversion Reactions of Ethanol to But-1-yne and Other Compounds

Introduction to Conversion Reactions

The session begins with an introduction to the conversion reactions, specifically focusing on ethanol and but-1-yne.

The first exercise involves converting ethanol (CH3CH2OH) into but-1-yne, which has a double bond at the first position.

Step 1: Converting Ethanol to a Halogenated Compound

The initial step is to convert the hydroxyl group (OH) in ethanol into a halogen, preferably chlorine.

This can be achieved by reacting ethanol with thionyl chloride (SOCl2), resulting in CH3CH2Cl.

Step 2: Formation of Sodium Acetylide

To extend the carbon chain and introduce a triple bond, sodium acetylide (HC≡CNa) is used.

Sodium acetylide reacts due to its negative charge attracting the positive part of another compound.

Step 3: Reaction with Ammonia

The reaction proceeds with ethyne being treated with ammonia (NH2-) in liquid ammonia (NH3).

This results in the formation of but-1-yne through further reactions involving sodium acetylide.

Converting Ethane to Bromoethene

Step 4: From Ethane to Bromoethene

Next, there’s a discussion on converting ethane into bromoethene.

Bromination occurs under free radical conditions using HNu or UV light, leading to CH3CHBr.

Step 5: Elimination Reaction for Double Bond Formation

An elimination reaction is performed using alcoholic KOH, removing bromine and hydrogen atoms while forming a double bond.

Final Steps for Bromoethene Production

Step 6: Further Bromination and Elimination

A second bromination step is discussed where bromine reacts in the presence of CCl4.

Step 7: Achieving Vinyl Dibromide

The product formed is identified as vicinal dibromide after both brominations are completed.

Converting Propene into Nitropropane

Step 8: From Propene to Nitropropane

Finally, propene needs conversion into one-nitropropane.

Step 9: Addition Reaction Using HBr

An addition reaction with HBr is suggested where bromine attaches preferentially based on hydrogen availability.

Conclusion on Anti-Markovnikov Conditions

It concludes that anti-Markovnikov conditions apply when HBr reacts alongside hydrogen peroxide (H2O2), ensuring proper placement of substituents during synthesis.

Chemical Reactions and Conversions

Bromopropane to Nitro Group Conversion

The process begins with bromopropane, which can be easily converted due to the presence of halogens. This allows for nucleophilic substitution reactions using a nucleophile containing NO2, such as AgNO2.

Toluene to Benzyl Alcohol Transformation

Toluene, characterized by a benzene ring with a CH3 group, is converted into benzyl alcohol (which has a CH2 group and an OH group). This transformation involves halogenation of the side chain followed by nucleophilic substitution.

Nucleophilic Substitution in Benzyl Chloride

To convert benzyl chloride into benzyl alcohol, NaOH is used in a nucleophilic substitution reaction where the Cl atom is replaced by an OH group. This step highlights the ease of this conversion process.

Propene to Propine Conversion

The transition from propene (with a double bond) to propine (with a triple bond) requires removing the double bond using bromine and CCl4, followed by beta elimination with NaNH2 and liquid ammonia to form propine.

Ethanol to Ethyl Fluoride Reaction

Ethanol (CH3CH2OH) can be converted into ethyl fluoride through halogen exchange reactions like Swarts reaction using AgF or PCl5/SOCl2 for substituting OH with F. This showcases effective methods for creating haloalkanes from alcohols.

Bromoethane to Propanone Conversion

Bromoethane undergoes conversion into propanone (acetone) requiring additional carbon atoms via KCN for cyanide addition and Grignard reagents for further carbon extension before hydrolysis replaces nitrogen with oxygen in the final product.

Butyne Isomerization Process

The discussion includes converting butyne into another isomer by changing the position of its double bond through addition reactions involving HBr while considering Markovnikov's rule for regioselectivity during this transformation process.

Understanding Bromination and Elimination Reactions

Mechanism of Bromine Addition

The addition of bromine to carbon involves breaking a double bond, allowing bromine to attach effectively. This is crucial for achieving the desired product.

In Markovnikov's addition, the negative part of bromine attaches to the carbon with fewer hydrogen atoms, which occurs when there is a Markovnikov orientation in the reaction.

Elimination Process

Following bromination, an elimination step is necessary where bromine is removed, leading to the formation of a double bond in the molecule.

The beta elimination process requires that hydrogen be removed from the carbon with fewer hydrogens, ensuring that a stable double bond forms.

Reaction Conditions

The reaction utilizes alcoholic KOH under heating conditions to facilitate beta elimination, resulting in HBr as a byproduct and forming a new double bond.

Conversion Techniques: From One Compound to Another

Converting 1-Chlorobutane to n-Octane

To convert 1-chlorobutane into n-octane, coupling reactions are employed using Wurtz reaction principles involving sodium (Na).

The Wurtz reaction results in octane formation while eliminating NaCl as a byproduct; this occurs in dry ether conditions.

Benzene Derivatives Synthesis

Converting benzene into biphenyl involves chlorination followed by coupling reactions using sodium in dry ether.

This process leads to biphenyl formation while losing NaCl as another byproduct during coupling.

Functional Group Transformations

Propylene Conversion

Propylene can be converted into propan-1-ol through anti-Markovnikov addition using hydrogen peroxide for effective placement of functional groups.

Ethanol Transformation

Ethanol can be transformed into butyne via halogenation followed by nucleophilic substitution with sodium acetylide.

Elimination and Addition Strategies

From 1-Bromopropane to 2-Bromopropane

The conversion from 1-bromopropane to 2-bromopropane involves beta elimination using alcoholic KOH, facilitating double bond formation between carbons.

Introduction of Bromine

When introducing bromine back into the system after elimination, it should follow Markovnikov's rule for optimal positioning on less substituted carbons.

Benzyl Alcohol to Benzyl Chloride and Beyond

Conversion of Toluene to Benzyl Alcohol

The process begins with converting toluene (CH3) into benzyl alcohol (CH2OH).

Benzyl alcohol is defined as having a CH2 group attached to an OH.

Halogenation can occur in the presence of Cl2 and FeCl3, or using HNu for side-chain reactions.

Bromination and Nitration Steps

To convert benzene into 4-bromo-nitrobenzene, bromination is performed first using Br2 with a Lewis acid like Fe.

After bromination, nitration occurs with concentrated H2SO4 and HNO3, introducing NO2 onto the ring.

The order of these reactions is crucial; bromine directs ortho/para while nitro directs meta.

From Benzyl Alcohol to 2-Phenyl Ethanoic Acid

The next transformation involves converting benzyl alcohol into 2-phenyl ethanoic acid (CH2COOH).

This conversion starts by replacing OH with Cl using SOCl2.

Following this, KCN replaces Cl through nucleophilic substitution, leading to cyanide formation.

Hydrolysis of Cyanide

Hydrolysis converts cyanide (CN-) into carboxylic acid (COOH), completing the reaction sequence.

Converting Ethanol to Propanenitrile

Reaction Overview

Ethanol (CH3CH2OH) is converted into propanenitrile by first substituting Cl for OH via SOCl2.

Nucleophilic Substitution Process

KCN acts as a nucleophile that substitutes chlorine in the alkane chain, resulting in the formation of propanenitrile.

Aniline to Chlorobenzene Transformation

Aniline Structure and Conversion Methodology

Aniline contains an NH2 group on a benzene ring which needs conversion to chlorobenzene.

Diazo Coupling Reaction

The diazotization process uses NaNO2 with HCl at low temperatures to form diazonium salt.

Sandmeyer Reaction Application

Chlorine can be introduced via Sandmeyer reaction using CuCl and HCl after forming diazonium salt.

From 2-Chlorobutane to 34-Dimethylhexane

Initial Structure Analysis

Starting from 2-chlorobutane, where chlorine is positioned at the second carbon atom.

Coupling Reaction Mechanism

A coupling reaction involving two moles of chlorinated compound occurs in dry ether presence leading to dimethylhexane formation.

Woodward's Reaction Insight

In this Woodward's reaction, sodium facilitates the release of chlorine allowing carbon atoms from both molecules to couple together.

Conversion of 2-Methylpropene

Final Transformation Steps

Converting 2-methylpropene requires adding chlorine at specific positions while maintaining other groups intact.

Breaking Double Bonds and Substitution Reactions

Mechanism of Breaking Double Bonds

To break a double bond, chlorine is added. The addition can be Markovnikov or anti-Markovnikov.

In the case of HCl addition, the negative part (Cl-) should attach to the carbon with fewer hydrogen atoms, indicating a Markovnikov addition.

Conversion of Ethyl Chloride to Propanoic Acid

Ethyl chloride (CH3CH2Cl) is converted to propanoic acid (CH3CH2COOH) using cyanide (KCN).

A nucleophilic substitution reaction occurs where chlorine is replaced by cyanide, forming CH3CH2CN.

Hydrolysis Process

Cyanide can be easily converted into carboxylic acid through hydrolysis using H3O+.

Reactions Involving Butene and Iodine

Breaking Double Bond in Butene

For butene (C4H8), HBr is used to break the double bond.

The position for bromine must be determined based on whether a Markovnikov or anti-Markovnikov addition is desired.

Anti-Markovnikov Addition with Hydrogen Peroxide

To achieve an anti-Markovnikov product, hydrogen peroxide (H2O2) is utilized during the reaction.

Formation of 1-Bromobutane

After adding bromine and hydrogen, 1-bromobutane forms as a result of this process.

Finkelstein Reaction Overview

Mechanism of Finkelstein Reaction

The Finkelstein reaction involves replacing bromine with iodine using sodium iodide (NaI) in dry acetone.

Conversion from 2-Chloro-2-Propanol to Propene

Elimination Reaction Steps

Starting with 2-chloro-2-propanol, elimination occurs via alcoholic KOH leading to propene formation.

Final Product Formation

After elimination, further reactions are needed to introduce OH at the end product.

Isopropyl Alcohol and Iodoform Reaction

Conversion Process for Iodoform Test

Isopropyl alcohol reacts to form iodoform (CHI3), which requires oxidation into a ketone first.

Requirement for Methyl Ketones in Iodoform Test

(2088)s The iodoform test necessitates methyl groups adjacent to carbonyl compounds; thus acetone formation is crucial before proceeding with NaOI for iodoform production.

Nitration of Chlorobenzene

Nitration Strategy

Chlorobenzene undergoes nitration due to chlorine's ortho/para directing effects.

Nitrogen Reactions and Substitutions

Introduction to Nitrogen Compounds

The use of concentrated H2SO4 and HNO3 is essential for introducing nitrogen groups into compounds, specifically at the para position on a benzene ring.

Challenges in Nucleophilic Substitution

Breaking bonds in aromatic compounds is challenging due to partial double bond character, making nucleophilic substitution reactions slow. Strong conditions such as high temperature and strong nucleophiles are required for successful reactions.

Reaction Conditions

KOH is introduced under vigorous conditions (e.g., 443 Kelvin) to facilitate the reaction with OH as a strong nucleophile. Dilute HCl is also used to ensure that the bond breaks effectively.

Conversion of Bromopropane

From 2-Bromopropane to 1-Bromopropane

The conversion process involves removing bromine through beta elimination using alcoholic KOH, resulting in propene formation by creating a double bond between carbon atoms.

Markovnikov's Rule Application

In subsequent reactions, HBr addition follows Markovnikov's rule where Br attaches to the more substituted carbon atom, facilitated by peroxide (H2O2) leading to anti-Markovnikov addition outcomes.

Wurtz Reaction Overview

Chlorobenzene to Butane Conversion

The Wurtz reaction involves coupling two alkyl halides (chlorobenzene and butane) using sodium in dry ether, resulting in the formation of butane while producing NaCl as a byproduct. This method requires doubling the moles of reactants involved.

Benzene Derivatives: Friedel-Crafts Reaction

Synthesis of Diphenyl from Benzene

A Friedel-Crafts reaction can be performed using Lewis acid catalysts like FeCl3 for chlorination followed by another coupling reaction involving sodium in dry ether, yielding diphenyl or biphenyl products.

Rearrangement Reactions: Tertiary Butyl Bromide

Conversion Process Explained

Tertiary butyl bromide undergoes rearrangement into isobutyl bromide through elimination steps facilitated by alcoholic KOH followed by an addition step with HBr under anti-Markovnikov conditions using peroxide for proper orientation of substituents.

Aniline Transformation

Direct Reaction Mechanism

Aniline can be converted into phenyl isocyanide via a direct carbylamine reaction involving chloroform (CHCl3) and potassium hydroxide (KOH), which upon heating yields phenyl isocyanide efficiently without intermediate steps.

Hydration Processes: Propylene Conversion

Acid-Catalyzed Hydration

Propylene can be converted into propan-2-ol through acid-catalyzed hydration where water adds across the double bond following Markovnikov’s rule, ensuring that OH attaches preferentially to the more substituted carbon atom during this process. This marks an introduction to alcohol chemistry within organic synthesis discussions.

Conversion of Benzyl Chloride to Benzyl Alcohol

Mechanism of Conversion

The conversion involves a nucleophilic substitution reaction where benzyl chloride (CH2Cl) is transformed into benzyl alcohol (CH2OH) using aqueous NaOH.

The process can also be achieved by introducing NaOH directly, leading to the formation of an alkoxide intermediate before protonation to yield the alcohol.

Ethyl Magnesium Chloride and Propan-1-ol Formation

Grignard Reagent Utilization

Ethyl magnesium chloride (C2H5MgCl) is used as a Grignard reagent to convert into propan-1-ol (CH3CH2CH2OH). This requires adding one extra carbon atom during the reaction.

The reaction occurs in dry ether, where the ethyl group attaches to a carbon with a positive delta charge, facilitating the formation of an alcohol upon hydrolysis.

Methyl Magnesium Bromide Reaction

Synthesis of Methyl Propan-2-ol

Methyl magnesium bromide (CH3MgBr) reacts with acetone to form methyl propan-2-ol, requiring three additional carbons for completion.

The negative part from the Grignard reagent interacts with acetone's positive site, leading to further reactions that ultimately produce an alcohol after hydrolysis with water.

Oxidation Reactions: Butanol to Butanoic Acid

Strong Oxidizing Agents

To convert butanol into butanoic acid, strong oxidizing agents like K2Cr2O7 in acidic conditions are employed due to their effectiveness in oxidizing primary alcohols directly into carboxylic acids.

Benzyl Alcohol Conversion to Phenyl Ethanoic Acid

Halogenation and Cyanation Steps

Benzyl alcohol is first converted into a halogenated compound using reagents like SOCl2 before undergoing cyanation with KCN, resulting in benzyl cyanide formation. This step replaces chlorine with cyanide effectively.

Three-Nitro-Bromo-Benzene Transformation

Nucleophilic Substitution Challenges

In converting three-nitro-bromo-benzene into benzoic acid, challenges arise due to the stability of aromatic compounds; thus, magnesium and ether are utilized initially for creating reactive intermediates necessary for substitution reactions involving COH groups.

Magnesium Bromide and Carbon Reactions

Conversion of Magnesium Bromide

The process begins with magnesium bromide (MgBr) being introduced, which is a Grignard reagent. The goal is to replace MgBr with COH.

A reaction involving carbon dioxide (CO2) occurs, where the oxygen has a delta negative charge and carbon has a delta positive charge, facilitating the attachment of carbon atoms.

This results in the formation of a benzene ring where one carbon attaches to another, while oxygen bonds with magnesium bromide.

Hydrolysis and Product Formation

After hydrolysis using H3O+, COH groups are formed along with carboxylic acid (COOH), leading to the same product as before.

The discussion shifts to 4-methylacetophenone, which needs conversion into 1,4-dicarboxylic acid through specific reactions.

Reduction and Oxidation Processes

Reduction Steps

To convert acetophenone into CH2 in the presence of zinc amalgam and HCl, reduction takes place that transforms C double bond O into CH2.

Retaining CH3 while converting C double bond O into CH2 leads to further reactions involving KMnO4 as a strong oxidizing agent.

Oxidation Reactions

KMnO4 reacts under KOH conditions to convert side chains directly into COH groups during oxidation processes.

Cyclohexane Conversion

Ozonolysis Process

Cyclohexane is converted into hexanedioic acid by breaking bonds through ozonolysis using O3 followed by zinc and water treatment.

In ozonolysis, broken bonds receive double bond O attachments on carbons involved in the reaction.

Final Conversions

The transformation from CHO groups to COOH requires KMnO4 for oxidation after ozonolysis.

Butanal and Ethylbenzene Transformations

Butanal Conversion

Butanal undergoes direct oxidation using KMnO4 or K2Cr2O7 to yield butanoic acid (COOH).

Ethylbenzene Reaction

Ethylbenzene can be converted into benzoic acid (COOH). Directly applying KMnO4 facilitates this transformation effectively.

Acetophenone Transformation Techniques

Acetophenone Reduction

Acetophenone's conversion involves removing carbon via reduction with zinc amalgam in HCl presence. This changes its structure significantly.

Final Steps for Benzoic Acid

Further reactions involve heating with KMnO4 and KOH leading to successful transformations resulting in benzoic acid from acetophenone.

This structured approach highlights key chemical transformations discussed throughout the transcript while providing clear timestamps for reference.

Understanding Organic Reactions and Conversions

Carbon Compounds and Hydrolysis

The process of adding a double bond oxygen (C=O) to carbon compounds is discussed, emphasizing the interaction between negative and positive charges.

Phenyl ethylene is defined as having an ethylene group on a phenyl ring (C6H5-CH=CH2), which can be converted into benzoic acid (COOH).

The conversion involves using KMnO4 and KOH, resulting in the formation of potassium benzoate through hydrolysis.

Conversion Processes

The next exercise involves converting propanone (CH3C=O) to propene (CH2=CH-CH3), starting with reduction reactions.

Lithium aluminum hydride can be used for reduction, transforming C=O into alcohol (OH), leading to dehydration where water is lost.

Benzoyl Chloride Formation

Benzoic acid (COOH) is converted into benzoyl chloride by reacting with SOCl2, replacing OH with Cl.

Following this, a reduction reaction using palladium in the presence of H2 leads to the formation of benzaldehyde from benzoyl chloride.

Aldehyde Transformations

Ethanol (CH3CH2OH) is transformed into 3-hydroxybutanal through mild oxidation using PCC.

An aldol condensation occurs in dilute NaOH presence, combining two moles of aldehyde to form an aldol product.

Acetophenone Synthesis

The synthesis of meta-nitroacetophenone from benzene involves Friedel-Crafts acylation using acid anhydride and AlCl3 for acetylation.

Nitration follows with concentrated HNO3 and H2SO4, directing nitro groups to the meta position due to their directing effects.

Benzaldehyde to Benzophenone Conversion

To convert benzaldehyde (CHO) into benzophenone, Grignard reagent (phenyl magnesium bromide - MgBr-) is introduced.

This reaction highlights how magnesium interacts with bromine and carbon atoms during the synthesis process.

Benzene Ring and Grignard Reagents

Understanding the Structure

The discussion begins with the structure of a benzene ring, highlighting the presence of carbon (C) and negatively charged oxygen (O).

A magnesium bromide (MgBr) is introduced, indicating that magnesium will have a positive charge while another part of the molecule carries a negative charge.

Hydrolysis Process

The conversion from bromo-benzene to 1-phenyl ethanol is outlined, emphasizing the need for hydrolysis by adding water to create a double bond.

The formation of Grignard reagents using magnesium in dry ether is discussed, which facilitates further reactions.

Reactions Involving Aldehydes

Conversion Steps

The process involves converting benzaldehyde into 3-phenylpropan-1-ol through specific reactions with aldehydes.

Mechanism Insights

It explains how positive and negative charges interact during these reactions, leading to product formation.

Aldol Condensation Reaction

Key Concepts

The transition from benzaldehyde to an aldol compound via aldol condensation is highlighted.

It mentions that one molecule has alpha hydrogen while another does not, affecting the reaction outcome.

Reaction Dynamics

Details on how hydrogen atoms are transferred between molecules during aldol condensation are provided.

Final Product Formation

Structural Changes

The final compound formed after several reactions includes both hydroxyl (-OH) and carbonyl (CHO) groups linked by double bonds.

Reduction Process

Discusses reducing CHO to OH through catalytic hydrogenation, breaking double bonds in the process.

Alpha-Hydroxy Phenyl Acetic Acid Synthesis

Overview of Reactions

Benzaldehyde remains constant while synthesizing alpha-hydroxy phenyl acetic acid by introducing an extra carbon atom at the alpha position.

Chemical Interactions

Sodium cyanide (NaCN), in presence of HCl, facilitates addition reactions on carbonyl compounds leading to structural changes.

This structured summary captures key insights from the transcript while providing timestamps for easy reference.

Chemical Reactions and Conversions

Understanding Cyanohydrin Formation

The process begins with benzene, where carbon (C) is positively charged and hydrogen (H) is negatively charged, leading to the formation of cyanide (CN).

In acidic conditions, the negative oxygen (O-) transforms into hydroxyl (OH), resulting in the creation of cyanohydrin.

Conversion of Benzoic Acid

The next step involves converting benzoic acid into meta-nitrobenzyl alcohol. Benzoic acid has a carboxylic group (-COOH).

A nitration reaction using concentrated HNO3 and H2SO4 directs the nitro group (NO2) to the meta position due to the directing effects of -COOH.

Reduction Process

Following nitration, reduction occurs using lithium aluminum hydride (LiAlH4), which converts COH into CH2OH.

This completes the transformation from benzoic acid to meta-nitrobenzyl alcohol.

Conversion Example: Chloroethane to Propanamine

The conversion from chloroethane to propanamine requires an additional carbon atom, achieved through nucleophilic substitution with NaCN.

After forming propanenitrile, reduction with LiAlH4 adds hydrogen across carbon and nitrogen bonds.

Benzyl Chloride Transformation

Benzyl chloride is converted into 2-phenylethanamine by introducing an extra carbon via NaCN.

Nucleophilic substitution replaces chlorine with cyanide (CN), followed by catalytic hydrogenation for reduction.

From Benzene to Aniline

To convert benzene into aniline, a nitro group is introduced using concentrated HNO3 and H2SO4 for nitration.

Reduction follows using tin (Sn) and hydrochloric acid (HCl), transforming NO2 into NH2.

Dimethylation of Aniline

The goal shifts towards converting aniline into N,N-dimethylaniline through methyl substitutions on nitrogen.

Methyl iodide (CH3I) facilitates this substitution process by replacing hydrogen atoms on nitrogen with methyl groups.

Final Steps in Hexane Conversion

The final task involves converting a compound containing Cl and CH2 groups into hexane 1,6-diamine through appropriate reactions.

Understanding Hexamine and Its Derivatives

Introduction to Hexamine

Hexamine, also referred to as hexamethylenetetramine, consists of six carbon atoms. The compound has two amino groups (NH2) attached at the first and sixth positions.

Initially, there are four carbons present in the structure, but it is necessary to add two more carbons to achieve the desired configuration.

Reaction with KCN

The method involves a reaction with potassium cyanide (KCN), where K+ is positive and CN- is negative. This leads to nucleophilic substitution involving chlorine.

The product will include CH2 units along with cyanide groups after the reaction.

Reduction Process

A reduction process is required to convert the triple bond between carbon and nitrogen into a single bond using catalytic hydrogenation (H2) with platinum or lithium aluminum hydride.

After reduction, cyanide groups will be converted into CH3 units while maintaining NH2 groups at both ends of the molecule.

Conversion of 4-Nitroaniline

Target Compound: 2-Bromobenzoic Acid

The goal is to convert 4-nitroaniline into 2-bromobenzoic acid. Nitro refers to a nitro group located at the fourth position on the benzene ring.

Bromination Reaction

Bromination can be performed by adding bromine in the presence of iron (Fe).

The methyl group (CH3) acts as an ortho/para-directing group while nitro acts as a meta-directing group during bromination.

Bromination Mechanism

Positioning of Bromine

Bromination occurs primarily at ortho positions due to CH3's directing influence; however, if occupied, it may occur at para positions.

Removal of Nitro Group

Following bromination, efforts must be made to remove the nitro group from its position through reduction using Sn/HCl which converts it into an amine (NH2).

Diazotization Process

Formation of Diazonium Salt

Diazotization involves reacting with NaNO2 and HCl under cold conditions (0° - 5°C), resulting in diazonium salt formation.

Final Steps for Conversion

To eliminate nitrogen gas from diazonium salt, a reaction with H3PO2 is conducted which results in retaining only CH3 and bromine in the final product.

Oxidation Step Towards Carboxylic Acid

Oxidation Using KMnO4

An oxidation step transforms CH3 into carboxylic acid (COOH), utilizing potassium permanganate (KMnO4).

Conversion Examples: From Aniline to Nitro Compounds

Converting 3-Methyl Aniline

The conversion from 3-methyl aniline requires transforming NH2 into NO2 via diazotization followed by reactions that replace Cl with NO2 using HBF4.

Final Reactions for Tri-Bromo Benzene Production

Direct Bromination Approach

For producing tri-bromo benzene from aniline, direct bromination occurs using aqueous Br₂ in water’s presence targeting three specific positions on the benzene ring.

Directing Reactions in Organic Chemistry

Understanding Directing Effects

The NH2 group directs bromine to ortho and para positions during electrophilic substitution reactions.

Bromine is positioned at both ortho and para sites, indicating the influence of the NH2 group on reactivity.

Reaction Mechanism

A diazonium salt is formed through a reaction involving NaNO2 and HCl under cold conditions (0° to 5°C). This results in N2 being positive and Cl negative.

The subsequent reaction with H3PO2 in water leads to the loss of H3PO3 and N2, yielding 1,3,5-tribromobenzene as a product.

Conversion of Ethanoic Acid to Methanamine

Starting Material Identification

Ethanoic acid (CH3COOH) contains two carbons and needs conversion into methanamine (CH3NH2), which has one carbon.

Chlorination Process

Chlorination using SOCl2 replaces hydrogen with chlorine, forming an acid chloride that can be further reacted with excess NH3 to introduce the NH2 group.

Hofmann Degradation Reaction

Amide to Amine Conversion

The Hofmann degradation involves treating an amide with bromine and NaOH, converting it into an amine by removing the carbonyl oxygen atom from the amide structure.

Example: Hexanenitrile to Aminopentane

Hexanenitrile (C6H13N) undergoes hydrolysis followed by chlorination using SOCl2 to form an amide before applying Hofmann degradation for conversion into aminopentane (C5H11NH2).

Hydrolysis of Cyanides

Hydrolysis Steps

Cyanides are converted into carboxylic acids via hydrolysis in the presence of water and H+. This process transforms CN groups into COOH groups effectively.

Final Conversion Steps

Following hydrolysis, further reactions lead from ethylamine (C2H5NH2) back down to methanamine through degradation processes like Hofmann's method again.

Stability of Diazonium Salts

Characteristics of Diazonium Salts

Aliphatic diazonium salts are highly unstable compared to aromatic ones; they decompose rapidly upon exposure to moisture or slight water addition leading to nitrogen gas release.

Formation of Alcohol from Diazonium Salt

Upon decomposition, aliphatic diazonium salts yield alcohol products such as ethanol when reacting under specific conditions involving hydroxylation steps.

Amidation Reactions

Converting Carboxylic Acids

Carboxylic acids react with ammonia or its derivatives under acidic conditions leading towards amidation processes where new functional groups are introduced effectively transforming structures accordingly.

This structured approach provides a comprehensive overview while maintaining clarity on key concepts discussed throughout the transcript.

What is the Process of Converting Ethanoic Acid to Propanoic Acid?

Introduction to Acids

Ethanoic acid (CH3COOH) and propanoic acid (CH3CH2COOH) are introduced as key compounds in the discussion.

The process involves introducing carbon atoms to facilitate the conversion.

Formation of Haloalkanes

Lithium aluminum hydride is used for reduction, leading to an alcohol with the same carbon structure.

A reaction with SOCl2 replaces the hydroxyl group (OH) with chlorine, forming a haloalkane.

Substitution Reactions

Chlorine is substituted by cyanide using NaCN, resulting in propanenitrile through nucleophilic substitution.

Hydrolysis converts cyanide back into an alcohol.

How to Convert Methylamine to Ethylamine?

Conversion Steps

The goal is to convert methylamine (CH3NH2) into ethylamine (CH3CH2NH2).

Initially, methylamine is converted into a diazonium salt using NaNO2 and HCl.

Stability and Reaction Pathways

The diazonium salt formed is unstable; adding water leads directly to alcohol formation.

Further reactions replace OH with chlorine again, preparing for another substitution step.

Reduction Processes Involving Nitro Compounds

From Nitro-Methane to Diethylamine

Nitro-methane undergoes reduction using Sn and HCl, converting NO2 into NH2.

An extra carbon atom needs to be added; this can be achieved through carbylamine reactions involving CHCl3 and KOH.

Final Reduction Steps

The final product requires reducing NC back into NH2 while ensuring proper hydrogenation occurs.

Converting Propanoic Acid Back to Ethanoic Acid

Degradation Techniques

Discusses how propanoic acid can be converted back into ethanoic acid via Hofmann degradation methods.

Amide Derivatives

Amides serve as derivatives of carboxylic acids; excess ammonia facilitates this transformation.

Final Steps: Alcohol Formation from Diazonium Salts

Unstable Diazonium Salts

The instability of aliphatic diazonium salts allows for easy conversion into alcohol upon adding water.

Oxidation Processes

Strong oxidizing agents like KMnO4 are utilized for further oxidation processes leading towards desired products.

Exercises on Conversions: Nitrobenzene to Benzoic Acid

Reduction Sequence

Nitrobenzene must first be reduced using H2 in the presence of palladium, yielding aniline.

Synthesis of Benzene Derivatives and Reactions

Sandmeyer Reaction with Benzene Diazonium Salt

The reaction begins with benzene diazonium salt at 0 to 5°C, where nitrogen gas (N2) is liberated, and chloride (Cl) acts negatively.

The reaction proceeds with cyanide (CN), leading to the formation of benzonitrile. This step is crucial for converting COH into the desired product through hydrolysis.

Nitration and Bromination Steps

To synthesize meta-bromophenol from benzene, nitration is performed using concentrated H2SO4 and HNO3, introducing a nitro group (NO2).

Following nitration, bromination occurs at the meta position due to the directing effect of the nitro group. Lewis acid Fe is used as a catalyst for this halogenation process.

Reduction and Conversion to Diazonium Salt

The nitro group undergoes reduction in presence of Sn and HCl, converting NO2 into an amino group (NH2), while bromine remains intact.

The amino group can then be converted back into a benzene diazonium salt using NaNO2 and HCl at low temperatures. This forms N2 positive and Cl negative species.

Hydrolysis to Form Hydroxyl Group

Hydroxyl groups are introduced by reacting diazonium salts with dilute H2SO4, resulting in phenolic compounds.

Synthesis Involving Benzoic Acid and Aniline

Benzoic acid reacts with aniline (NH2), forming an amide via chlorination using SOCl2. Chlorine replaces NH2 during this transformation.

Hofmann Degradation Process

Amides can be degraded through Hofmann degradation using bromine and NaOH, resulting in amines by losing carbonyl groups.

Tri-Bromo-Fluoro Benzene Synthesis

Starting from aniline, tri-bromofluorobenzene synthesis involves multiple bromo substitutions facilitated by water reactions due to ortho/para directing effects of NH2.

Diazotization Reaction for Fluorination

Diazotization occurs under specific conditions yielding N2 positive species that facilitate further reactions involving BF4 negative ions replacing Cl negative ions.

Final Transformations Leading to Amines

Heating leads to loss of nitrogen gas (N2), allowing fluorine incorporation into the structure while eliminating other components like BF3.

Conversion from Benzyl Chloride to Ethylene Amines

Benzyl chloride transforms into diphenylethylene amine through nucleophilic substitution involving NaCN in ethanol followed by catalytic hydrogenation.

Para-Chloro Aniline Formation

Chloro-benzene converts into para-chloroaniline via introduction of a nitro group followed by reduction processes utilizing palladium catalysts.

Chemical Reactions and Conversions

Overview of Ethanol Reduction

The process begins with the use of ethanol, which is involved in a reduction reaction.

Aniline is converted to para-bromoaniline; aniline contains an NH2 group attached to benzene.

To limit ortho substitution during bromination, the NH2 group must be protected using acid chloride (e.g., CH3C(O)Cl).

Protection and Bromination Steps

After protection, bromination occurs with Br2 in the presence of Fe, yielding only the para product due to the protected NH2 group.

Hydrolysis follows, converting the protected compound back into an amine (NH2), allowing further reactions.

Conversion from Benzamide to Toluene

Benzamide (with C=O and NH2 groups) is transformed into toluene through Hofmann degradation using Br2 and NaOH.

This results in the formation of a diazonium salt (N2^+ Cl^-) at low temperatures (0° to 5°C).

Final Transformations

The diazonium salt undergoes a reaction with H3PO2 and water, leading to loss of N2 and yielding benzene.

Finally, benzene is converted into toluene via Friedel-Crafts alkylation using CHCl3 and anhydrous AlCl3.

Reaction Pathway for Benzyl Alcohol

Benzyl alcohol undergoes conversion into a diazonium salt similarly as before, followed by reactions with CuCN and KCN.

The cyanide formed can then be hydrolyzed using H3O^+, resulting in conversion from COH to alcohol through lithium aluminum hydride reduction.