01.09.2019
 School Dissertation

1

Haloalkanes and Haloarenes

IIT-JEE Chemistry Siddhivinayaka Educational Schools Rajendra Nagar Chowk Hyperlink Road Bilaspur Ph-07752- 237799/238799 Website: www.bajpaigroup.com. e-mail -- [email protected] com CHAPTER

twenty three

LEARNINg Goals

(i) Term haloalkanes and haloarenes in line with the IUPAC approach to nomenclature from other given constructions. (ii) Illustrate the reactions involved in the prep of haloalkanes and haloarenes and figure out various reactions that they undergo.

(iii) Assimialte the structures of haloalkanes and haloarenes with various types of reactions. (iv) Make use of stereochemistry like a tool pertaining to understanding the reaction mechanism. (v) Describe prevalent polyhalogen ingredients.

INTRODUCTION

The replacement of hydrogen atom(s) in a hydrocarbon, aliphatic or aromatic, by tungsten-halogen atom(s) results in the formation of alkyl halide (haloalkane) and aryl halide (haloarene), correspondingly. Many tungsten-halogen containing organic and natural compounds take place in nature and some of these will be clinically beneficial. These classes of ingredients find large applications in industry along with day-to-day life. They are utilized as solvents for comparatively non-polar ingredients and as beginning materials pertaining to the activity of broad variety of organic compounds. Chlorine that contains antibiotic, chloramphenicol, produced by garden soil microorganisms is beneficial for treating typhoid fever.

The substances containing multiple halogen atoms are commonly named as polyhaloalkanes, or polyhaloarenes depending upon the hydrocarbon remains in the molecule. Haloalkanes and haloarenes are very important intermediates in synthetic organic chemistry due to, (i) the greater ease with which these derivatives can be well prepared. (ii) their particular high reactivity. CLASSIfICATION

The compounds produced by replacement of one or more Hydrogen atoms via hydrocarbon molecule by corrersponding number of tungsten halogen atoms are called halogen derivatives or halides.

Hydrocarbon Tungsten halogen Derivative

On the basis of hydrocarbon part halides are categorized as follows:

Halides Example

(a) Alkyl halides (Halogen derivatives of alkanes) CH3

CH2

Craigslist (Ethylchloride)

(b) Alkenyl halide (Halogen offshoot of alkenes) CH2

=CH–Cl (Vinylchloride), CH2

= CH–CH2

–Cl (Allylchloride)

(c) Alkynyl halide (Halogen derivative of alkynes) CH≡C–CH2 –Cl (Propargylchloride)

(d) Aryl halide (Halogen atom is definitely directly attached Chlorobenzene to carbon atom of fragrant nucleus)

Alkyl halides can be categorized as methyl halide, major alkyl halide, secondary alkyl halide (2В°) and tertiary alkyl halide (3В°), according to the number of additional carbon atoms attached to the carbon bearing the tungsten halogen atom.

Methyl halide

X

H

H

H X

L

H

Ur X

R'

H

L X

R'

R"

3rd there’s r

Primary alkyl

halide (1В°)

Secondary alkyl

halide (2В°)

Tertiary alkyl

halide (3В°)

L, R′ and R′′ may be same or different.

To be sure that the alkyl halides consists of halogen atom which is the functional group, which is accountable for the characteristic reactions viz. nucleophilic alternative and eradication reactions, of alkyl halides. So , it is functional group (X) which will decide the size of the reaction (i. e. replacement and elimination) and not the alkyl group. The nature of alkyl group (i. e. 1В°, 2В°, 3В°) will determine the function (whether SN

2 or perhaps SN

you and Electronic

2

or E

one particular

).

HALOALkANES AND HALOARENES2

Haloalkanes and Haloarenes

IIT-JEE Chemistry Siddhivinayaka Educational Senior high Rajendra Nagar Chowk Link Road Bilaspur Ph-07752- 237799/238799 Website: www.bajpaigroup.com. e-mail -- [email protected] com NOmENCLATURE:

The general formula of condensed mono replaced alkyl halide is Cn H2n+1

X, where Back button is a tungsten halogen atom. Alkyl halides usually are represented by simply R – X where R is definitely an alkyl group. For example:

H3C

Br

H3C

CH3

Cl

H3C

H3C

CH3

I

1-bromopropane

1-chloro-2-methylpropane 1-iodo-2, 2-dimethylpropane

Some examples of substituted alkyl and aryl...