Amines, Amino acids and polymers Flashcards by Rosie Pritchard

What is an amine

derivative of ammonia NH3
classified as primary, secondary or tertiary

aliphatic amine consists of N atom attached to at least 1 straight or branched carbon chain

aromatic- N attached to aromatic ring

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Classifying amines

Primary- R–N–H 1 alkyl group attached
H

secondary- R–N–R 2 alkyl group attached
H

tertiary- R–N–R 3 alkyl group attached
R

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naming amines

suffix amine

find longest C chain with N attached and name

use N to show position of branched chains attached to amine group

if 2 of same group attached just use Di- prefix

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How does an amine react as a base

Weak base - only partially dissociates
accept proton from an acid

N atom donates lone pair of electrons
forms dative covalent bond with a proton
amine=proton acceptor

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amine base acid reaction

Amine + base –> ammonium salts

e.g.
C2H5NH2 +HCl —> C2H5NH3+Cl-
or
CH3CH2NH2 + H2SO4 –> (CH3CH2NH3+)2 SO42-

Name- amine first then acid suffix

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preparation of an aliphatic amine A
from Haloalkane

Reagents- ammonia + haloalkane

conditions: excess ammonia dissolved in ethanol (H2O would produce aldehyde)

reaction type: nucleophilic sub

overall: CH3CH2CH2Cl + NH3 –> CH3CH2CH2NH2 + HCl

technically in 2 stages :
CH3CH2CH2Cl + NH3 -> CH3CH2CH2NH3+ Cl- (salt formation)

CH3CH2CH2NH3+ Cl- + NaOH –> CH3CH2CH2NH2 + NaCl + H2O (amine formation)

same mech as other nucleophilic sub - break c-cl bond then arrow from ammonia to C
then draw intermediate, arrow from N-H bond to N and arrow from Cl- to that H

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Further substitution in aliphatic amine

primary amines can undergo further sub

where the H groups on the N are replaced another alkyl chain can happen once or twice ( form di or tri amines)

e.g. CH3CH2CH2Cl + CH3CH2CH2NH2 –> (CH3CH2CH2)2NH + HCl

technically in 2 stages :
CH3CH2CH2Cl + CH3CH2CH2NH2 -> (CH3CH2CH2)2NH2+ Cl- (salt formation)

(CH3CH2CH2)2NH2+ Cl- + NaOH –> (CH3CH2CH2)2NH + NaCl + H2O (amine formation)

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disadvantages of Further substitution in aliphatic amines

low % yield of desired product/amine

sep by fractional distillation of desire amine from mixture is needed and costly

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How doe you avoid Further substitution in aliphatic amines

Use excess ammonia

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Preparation of an aliphatic amine B
from nitrile

Reagents: Nitrile and H2

Conditions: Nickel cat

Reaction type: reduction

overall equ: CH3CH2CN + 2H2 –> CH3CH2CH2NH2

OR reagent of NaCN / KCN dissolved in ethanol - nucleophilic sub

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preparation of an aromatic amine

Reagents: Nitroarene, tin (Sn) and conc HCl

Conditions: Heat under reflux (till all tin dissolves)

Reaction: Reduction

Overall: C6H5NO2 + 6[H] –> C6H5NH2 + 2H2O

C6H5NH2 - phenylamine

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Amide functional group

O
=
R-C-N–
l

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Classifying amides

Primary- CO–N–H 1 carbon groups attached H

secondary- CO–N–C 2 carbon groups attached H

tertiary- CO–N–C 3 carbon groups attached C

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naming amides

use suffix amide

then name longest chain

use N to signify branching off N - still use prefix from branching e.g. methyl

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preparation of amides- acyl chlorides

Reagents: acyl chlorides with ammonia and amines

No conditions

overall reaction:
CH3COCl + 2NH3 –> CH3CONH2 + NH4Cl

this produces a primary amide but you can produce other types as well using e.g. CH3NH2 or (CH3)2NH

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preparation of amides- carboxylic acid

Only seen in production of polyamides

Reagents: carboxylic acid, amine

No conditions

Overall:
CH3COOH + CH3NH2 –> CH3CONHCH3 +H20

Primary amine forms secondary amide

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different types of hydrolysis of amides

Acid-catalysed hydrolysis

Base-catalysed hydrolysis

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Acid-Catalysed hydrolysis of amides

Reagent: HCl (aq) - must be aq (can be any acid)
Conditions: Heat

produces a carboxylic acid and ammonium salt - breaks the C-N bond

overall:
CH3CONHCH3 + HCl (aq) –> CH3COOH + CH3NH3+Cl-

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Base-Catalysed hydrolysis of amides

Reagent: NaOH (aq) - must be aq (can be any alkali)
conditions: heat

produces carboxylic acid and an amine- breaks the C-N bond

Overall:
CH3CONHCH3 + NaOH –> CH3COO-Na+ + CH3NH2

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alpha Amino acid general formular

H H O
N C C
H OH

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Amin acid def

definition:
Basic amine group - NH2
Acidic carboxyl group - COOH
attached to same C

How many naturally occurring amino acids are there

Amino acid reaction- amine group

NH2 is basic and accepts protons - reacts with acid

neutralisation- produces salt

Overall:
NH2C(CH3)HCOOH + HCl –> NH3C(CH3)HCOOH + Cl-

Amino acid reaction - carboxylic acid (neut)

COOH is acidic and donates proton - reacts with alkali

Neutralisation- produces salt

Overall:
NH2C(CH3)HCOOH + NaOH –> NH2C(CH3)HCOO-Na+ + H2O

Amino acid reaction - carboxylic acid (esterification)

Overall: NH2C(CH3)HCOOH + C2H5OH + H+ --> NH2C(CH3)HCOOC2H5 + H2O

Stereoisomer definiton

same structural formular but diff spatial arrangement of their atoms

Optical isomer definition

pair of non superimposable mirror images of 1 another contain chiral centre

Chiral centre

carbon atom with 4 different groups attached

Drawing a pair of optical (Enantiomers)

drawn using tetrahedral shape (109.5) about the Chiral C other isomer is drawn as the mirror image so if the --- line is on the left of 1 it will be on the right of the other with same group attached

equation for the number of optical isomers

2^n n= no of chiral centres

what is a racemic mixture

equal amounts of 2 optical isomers in a mixture

Addition polymerisation of alkenes

alkene monomers can join to form long saturates molecules called addition polymers in addition polymerisation reagent: alkene monomer Conditions: high temp and pressure + catalyst A D ( A D ) general equation: n C=C --->( --C-C-- ) B E ( B E ) n Alkene monomer ---> alkane polymer

processing waste addition polymers, benefits

benifitits for sustaiabiltiy by: combustion for energy for production removal of toxic waste products e.g. HCl use as an organic feedstock for production of plastics and other organic chemicals sorted and recycled

how to minimise environmental damage when managing polymers

develop biodegradable polymers and can be broken down by microorganisms e.g. PLA made from lactic acid develop photodegradable polymers- oil based polyemers which bonds weaken by absorbing light use alkaline scrubber to neutralise toxic gases e,g, HCl produced when burning

Problems with disposal of addition polymers

NON biodegradable- non polar C chain doesnt breakdown by hydrolysis very stable dont breakdown naturally Burning produces toxic gas e.g. Cl2 or HCl

Condensation polymerisation

2 monomers with diff functional groups or 1 with 2 functional groups H2O or HCl (small molecule) is lost forms: polyesters and polyamides- fibres in clothing

Polyesters formation (carboxylic acid)

reagents: dicarboxylic acid + diol condensation polymerisation loose H2O to form ester bond COO lose OH from acid and H from alcohol) same equation as addition

Polyesters formation (Acyl chloride )

reagents: diacyl chloride + diol condensation polymerisation loose HCl to form ester bond COO lose Cl from acyl and H from alcohol) same equation as addition

Polyesters formation (1 monomer)

reagent: monomer with Carboxylic acid and alcohol functional group condensation polymerisation loose H2O to form ester bond COO lose OH from acid and H from alcohol) same equation as addition

Polyamides formation (carboxylic acid)

reagents: dicarboxylic acid + diamine condensation polymerisation loose H2O to form amide bond CONH (lose OH from acid and H from amine) same equation as addition e.g. kevlar

Polyamides formation (acyl chloride)

reagents: diacyl chloride + diamine condensation polymerisation loose HCl to form amide bond CONH lose Cl from acyl and H from amine) same equation as addition

Polyamides formation (1 monomer)

reagent: monomer with Carboxylic acid and amine functional group condensation polymerisation loose H2O to form amide bond CONH lose OH from acid and H from amine) same equation as addition

Hydrolysis of polymers- basics

add- cant be hydrolysed as non polar bonds C=C con- can be hydrolysed due to polar bonds COO or CONH Acid or base

Acid cat hydrolysis of polyester

Reagent- HCl(aq) / any aq acid conditions- heat products- dicarboxylic acid + dialcohol

base cat hydrolysis of polyester

Reagent-NaOH(aq) / any aq base conditions-heat products-salt of dicarboxylic acid and dialcohol

Acid cat hydrolysis of polyamide

Reagent- HCl(aq) / any aq acid conditions- heat products- dicarboxylic acid and ammonium salt of diamine

base cat hydrolysis of polyamide

Reagent-NaOH(aq) / any aq base conditions- heat products- Salt of a dicarboxylic acid and a diamine

degradable polymer def

polymer that breaks down into smaller fragments when exposed to light, heat or moisture undergo hydrolysis

biodegradable polymer def

polymer that breaks down completely into CO2 and H2O undergo hydrolysis e.g. PLA - derived from Corn starch

Photodegradable polymer

Condensation polymers contain C=O bonds are photodegradable C=O absorbs light radiation - breaks