MindMap Gallery Organic Chemistry Halogenated Hydrocarbons
Compounds in which hydrogen atoms in hydrocarbon molecules are replaced by halogen atoms are called haloalkanes, or haloalkanes for short. The general formula of halogenated hydrocarbons is: (Ar)R-X, X is a halogen atom, which can be regarded as the functional group of halogenated hydrocarbons, including fluorine, chlorine, bromine, and iodine. Quickly collect, complete knowledge points of alkyl halides in university organic chemistry
Edited at 2021-04-01 22:23:44One Hundred Years of Solitude is the masterpiece of Gabriel Garcia Marquez. Reading this book begins with making sense of the characters' relationships, which are centered on the Buendía family and tells the story of the family's prosperity and decline, internal relationships and political struggles, self-mixing and rebirth over the course of a hundred years.
One Hundred Years of Solitude is the masterpiece of Gabriel Garcia Marquez. Reading this book begins with making sense of the characters' relationships, which are centered on the Buendía family and tells the story of the family's prosperity and decline, internal relationships and political struggles, self-mixing and rebirth over the course of a hundred years.
Project management is the process of applying specialized knowledge, skills, tools, and methods to project activities so that the project can achieve or exceed the set needs and expectations within the constraints of limited resources. This diagram provides a comprehensive overview of the 8 components of the project management process and can be used as a generic template for direct application.
One Hundred Years of Solitude is the masterpiece of Gabriel Garcia Marquez. Reading this book begins with making sense of the characters' relationships, which are centered on the Buendía family and tells the story of the family's prosperity and decline, internal relationships and political struggles, self-mixing and rebirth over the course of a hundred years.
One Hundred Years of Solitude is the masterpiece of Gabriel Garcia Marquez. Reading this book begins with making sense of the characters' relationships, which are centered on the Buendía family and tells the story of the family's prosperity and decline, internal relationships and political struggles, self-mixing and rebirth over the course of a hundred years.
Project management is the process of applying specialized knowledge, skills, tools, and methods to project activities so that the project can achieve or exceed the set needs and expectations within the constraints of limited resources. This diagram provides a comprehensive overview of the 8 components of the project management process and can be used as a generic template for direct application.
Halogenated hydrocarbons
Classification and naming
Classification
According to the attached hydrocarbon group
Halogenated alkanes
Halogenated olefins
Halogenated aromatics
Benzene
benzyl
Isolated
According to the type of carbon atoms connected
primary haloalkane
Tertiary alkyl halide
Secondary haloalkane
name
Common naming: Generally called "halogenated hydrocarbon" or "halogen" according to the attached group.
Nomenclature of haloalkanes
Number from the closest segment
Prioritize alkyl groups
Nomenclature of halogenated alkenes
Based on olefins
Number from the end closest to the double bond
Nomenclature of halogenated aromatics
When the halogen atom is directly connected to the benzene ring, the benzene ring is the parent
When not directly connected, the side chain is the parent
physical properties
solubility
Easily soluble in organic solvents
density
Except for fluoroalkyl and monohalogenated alkyl, most of the others are heavier than water
Stablize
Alkanes monochloride are relatively stable, but chloroform, alkyl bromide and alkyl iodide are easily decomposed by light.
Important halogenated hydrocarbons
Trichloroalkane
Chloroform
Colorless, sweet, non-flammable
difluorodichloromethane
refrigerant
Halothane
Anesthetic
Tetrafluoroethylene
The king of plastics, Teflon
Triclofen
Highly effective and low-toxic insecticide
chemical properties
The electronegativity of the halogen atom is large, so that the halogen atom has a partial negative charge, the α carbon atom has a positive charge, making it vulnerable to attack by nucleophiles, and the βγ carbon atom has a partial positive charge, and the βγ carbon atom has a partial positive charge. H atoms are loose and can easily be removed with halogen atoms, forming an elimination reaction.
nucleophilic substitution reaction
Replaced by hydroxyl group (alkaline hydrolysis)
Substituted by alkoxy to form ether
Preparation of ether (Williamson method for making ether)
This reaction only works for simple primary alkyl halides (elimination of secondary tertiary halides occurs)
Substituted by cyano group to form nitrile
Preparation of amines, amides, carboxylic acids, and esters with one added carbon atom
This reaction only works for simple primary alkyl halides
Replaced by nitrate to form nitrate ester
Reactivity
RI>RBr>RCl
C3RX>C2RX>CRX
Nucleophilic substitution reactivity of various structural halogenated hydrocarbons
Allyl or benzyl (immediate) > tertiary (oscillation) > primary or secondary (heating) > vinyl or benzene (no reaction)
Substituted by amino group to form amine
Nucleophilic substitution reaction process
Bimolecular process SN2
Features
Completed in one step, intermediate (breaking of old bonds and formation of new bonds at the same time)
Product configuration flips
Influencing factors
steric hindrance
reaction speed
CH3X>1>2>3
Single molecule process SN1
Features
Completed step by step, there is a carbocation intermediate (break first and then form)
The product is a racemate
Influencing factors:
Carbocation stability
reaction speed
Allyl or benzyl>tertiary>secondary>primary>CH3X
elimination response
β-Elimination of Halogenated Hydrocarbons
Conditions: strong base, alcohol solvent
Zaitsev Rule
The elimination products of halogenated hydrocarbons are mainly alkenes with more alkyl groups connected to the double bonds.
exception
When the elimination reaction of halogenated alkenes and halogenated aromatics occurs, the main product generated is conjugated olefins
elimination reaction process
Bimolecular process E2
Features
Completed in one step, intermediate (breaking of old bonds and formation of new bonds at the same time)
reaction speed
3>2>1>CH3X
3>2>1>CH3X
Favorable factors
More β-H
Strongly alkaline reagent
high temperature
Single molecule process E1
Features
Completed step by step, there is a carbocation intermediate (break first and then form)
reaction speed
React with metals
Preparation of format reagents
Degree of difficulty
RI>RBr>RCl>RF (usually prepared with alkyl bromide)
Bo>Second>Uncle
Properties and preservation
High activity, unstable
Stored under anhydrous and oxygen-free conditions
Reaction with Grignard reagent·
rearrangement reaction
Occurs in SN1, E1
summary
Four reactions exist simultaneously
Primary halogenated hydrocarbons are mainly SN2 (the proportion of E2 increases under strong base)
Secondary halogenated hydrocarbons, strong nucleophiles, prone to SN2, strong bases are beneficial to E2
When tertiary halogenated hydrocarbons have no base, SN1 and E1 coexist
The reagent is highly alkaline and has a high concentration, so heating up is beneficial to E2
The reagent is highly nucleophilic and its small size is beneficial to SN2
In single molecule reactions, increasing temperature is beneficial to E1