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General Chemistry 2 Assignment - Preparation of amine (Group 13 and 18)

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A presentation by Group 13 & Group 18

A presentation by Group 13 & Group 18

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    General Chemistry 2 Assignment - Preparation of amine (Group 13 and 18) General Chemistry 2 Assignment - Preparation of amine (Group 13 and 18) Presentation Transcript

    • Presenters:Tan Cai YingZainabIqbal
      1
      PREPARATION OF AMINE
      Reduction of Nitro Compound
    • About Nitro Compound
      organic compounds that contain one or more nitro functional groups: -NO2 (O-N=O)
      The O-N=O bond angle is very nearly tetrahedral
      There are 2 type of nitro compound:
      2
      zwitter ionic polar structures
      A positively charged nitrogen and two equivalent negatively charged oxygens
    • Reduction of Nitro Compoundto Amine
      3
      Preparation of amine involves nitration of the ring and subsequent reduction of the nitro group to an amino group –NH2. In aromatic and aliphatic nitro compounds, nitro group undergoes similar reactions. However depending on the attachment of functional groups (aryl or alkyl ), the reactivity may be different.
    • The various reduction stages of the nitro group are given below:
      4
      The reaction involve removal of water
    • Reduction of Nitro Compound
      In general, reduction is easily achieved either by catalytic hydrogenation (H2 + catalyst), with reducing metals in acid(Zinc or tin or iron or metal salt such as SnCl2 in dilute mineral acid can also be used)
      For example:
      5
    • 6
      Catalytic reduction Ni or Pt/3H2
      CH3CH2NH2 + 2H2O
      CH3CH2NH2 + 2H2O
      (Given by both aromatic and aliphatic nitro compound)
      1。Amine
      1。Amine
      Reduction in acidic medium(6H)
      CH3CH2NO2
      Zn/HCl . Fe/HCl.Sn/HCl
      Zn/NH4Cl(neutral medium)
      Reducing agent
      CH3CH2NHOH+H2O
      N-ethyl hydroxylamine
      As amines can classified to be primary , secondary and tertiary. Most primary amines can be obtained by reduction of nitro compound
      The final product depends on the nature of the reducing agent as well as the pH of the medium.
    • Aliphatic nitro compounds can be reduced to aliphatic amines using several different reagents:
      Catalytic hydrogenation using platinum (IV) oxide (PtO2) or Raney nickel
      Iron metal in refluxing acetic acid
      Samarium diiodide
      7
      Aromatic nitro compounds can be reduced to aromatic amines using several different reagents:
      Zinc Dust and AmmoniumCatalytic
      Catalytic ydrogenation using platinum (IV) oxide (PtO2) or Raney nickel
    • Catalytic reduction
      8
      • The nitro group is easily reduced by catalytic hydrogenation using Pd/C catalyst in ethanol.
    • Reduction by metal in acidic solutions
      9
      • Metals (Fe, Sn and Zn) and HCl are sued for reducing a nitro group (-NO2) to an amino group (-NH2).
    • 10
      Methylnitrobenzene
      Methylphenylamine
      Reduction with lithium aluminium hydride ,LiAlH
      • Aliphatic nitro compounds are reduced to p-amines with LiAlH4.
    • If the reduction involve the nitro compound which have di- and polynitro groups ,hydrogen sulfide in aqueous or alcoholic ammonia is use for selective reduction of one nitro group. Treating 2,4-dinitrotoluene with hydrogen sulfide and ammonia result in reduction of the 4-nitro group.
      11
      In the reduction of di- or polynitro aromatic compounds by gaseous H2S over a solid catalyst,additions of CO gas promotes the formation of amino group from all nitro groups in the molecule
    • 12
      • The reduction of nitro compound is highly exothermic reaction. The heat is given out when the nitro group is reduce and amino group being form.
    • Laboratory Example
      13
      In the laboratory, reacting a nitro-aromatic with a mixture of tin and conc. hydrochloric acid by heating under reflux will reduce it to a primary aromatic amine (-NH2 directly attached to benzene ring). In industry , metal like iron powder and acid are used or a direct reduction in the gas phase with hydrogen or transition metal catalyst.
      C6H5NO2 + 6[H] ==> C6H5NH2 + 2H2O
      Redox Reaction:
      2C6H5NO2(aq) + 14H+(aq) + 3Sn(s) ==> 2C6H5NH3+(aq) + 3Sn4+(aq) + 4H2O(l)
    • Reduction ofNitrilecompoundPresenters:Priscilla Pang Jie-YiTyo Ann Kei
      14
      PREPARATION OF AMINE
    • In nitrile reduction, a nitrile is reduced to an amine or with a suitable chemical reagent.
      Reagents for the conversion to amines are lithium aluminium hydride( LiAlH4), Raney nickel( Nickel catalyst),
      hydrogen or diborane (B2H6).
    • This organic reaction is one of several nitrogen-hydrogen bond forming reactions.
      Reactions are sensitive to acidic or alkaline conditions, which can cause hydrolysis of -CN group.
    • The reduction of nitriles using LiAlH4
      Lithium tetrahydridoaluminate, LiAlH4 is more commonly
      employed for the reduction of nitriles on the laboratory scale.
      Similarly, LiAlH4 reduces amides to amines.
    • There are four hydrogens ("tetrahydido") around
      the aluminium in a negative ion.
      The "(III)" shows the oxidation state of the aluminium,
      and is often left out because
      aluminium only ever shows the +3 oxidation
      state in its compounds.
      The structure of LiAlH4 is:
    • In the negative ion,
      one of the bonds is a co-ordinate covalent bond
      using the lone pair on a hydride ion (H-)
      to form a bond with an empty orbital on the aluminium.
      The nitrile reacts with the lithium tetrahydridoaluminate
      in solution in ethoxyethane
      followed by treatment of the product
      of that reaction with a dilute acid.
    • [H] means "hydrogen from a reducing agent".
    • The reduction of nitriles using hydrogen
      and a metal catalyst
      The carbon-nitrogen triple bond in a nitrile can also be reduced by reaction
      with hydrogen gas in the presence of a variety of metal catalysts.
      Commonly quoted catalysts are palladium, platinum or nickel.
      The reaction will take place at a raised temperature and pressure.
    • It is impossible to give exact details because it will vary from catalyst to catalyst.
      For example, ethanenitrile can be reduced to ethylamine by reaction
      with hydrogen in the presence of a palladium catalyst.
      Overall, the carbon-nitrogen triple bond is reduced to give a primary amine.
      Primary amines contain the -NH2 group.
    • Preparation Of Amines
      Reduction Of Primary Amides
      Presenter : See TeckJia
      Wong Wei Leong
    • Amide Reduction
      Amides are a group of organic compounds derived from ammonia(NH3).
      Amide reduction in chemistry is the organic reduction of amides.
      Amides, RCONR'2, can be reduced to the amine, RCH2NR'2 by conversion of the C=O to -CH2-
    • Reagents are lithium aluminium hydride and catalytic hydrogenation.
      Requires high temperature and pressure.
    • The main reaction product is an amine.
      The nature of the amine obtained depends on the substituent present on the original amide.
    • Preparation of amiNe
      Hofmann degradation of amides
      Presenters:
      Mak Yong jing
      vigneshraaj
    • Hofmann degradation of amides
      Definition
      The Hofmann rearrangement is the organic reaction of a primary amide to a primary amine with one fewer carbon atom.
    • Continue..
      Mechanism
      The reaction of bromine with sodium hydroxide forms sodium hypobromite, which transforms the primary amide into an intermediate isocyanate. The intermediate isocyanate is hydrolyzed to a primary amine giving off carbon dioxide
    • 1) Removal of proton from amide N
    • 2) Formation of N-Bromo amide
    • 3) Removal of another proton from amide N
    • 4) Rearrangement through Migration of aryl group
    • 5) Hydrolysis of isocyanate intermediate
    • 6) The formation of amine
      R―NH2
      Amine
    • Applications of Hofmann degradation of amides
      Aliphatic & Aromatic amides are converted into aliphatic & aromatic amines respectively.
      In the preparations of Anthranilic Acid from Pthlamide.
      Nicotinic acid is converted into 3-Amino pyridine.
      The Symmetrical structure of α-phenyl propanamide does not change after hofmann reaction.
    • TheEnd
    • A presentation from Group 13See TeckJia 1001025171Wong Wei Leong 1001025884Mak Yong Jing 1001025654Vigneshraaj 1001025877Group 18Tan Cai Ying 1001025965ZainabIqbal 1000923191Tyo Ann Kei 1001025268Priscilla Pang Jie-Yi 1001025675