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GRIGINARD’S
REAGENT
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the preparation of a griginard’s reagent great care must be taken that the
reactants are absolutely dry and pure. The other
experimental details are given below: Magnesium: magnesium ribbon is washed with ether and dried in desicater. Ether: it is distilled over sodium metal and P2O5. Ethyl bromide: it is purified and then distilled over P2O5. Take dry ether in a round bottom flask and add pieces of Mg ribbon in it. Fit it with water condenser and add ethyl bromide gradually through the condenser. Heat a little so that magnesium dissolves. Cool if necessary.A clear solution of griginard’s reagent – ethyl magnesium bromide, in ether appears. This ethereal solution is used as griginard’s reagent. |
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C2H5--Br
+ Mg à
C2H5--Mg--Br
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BIMOLECULAR
REACTION
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A chemical reaction in which two molecules react
together in rate determining step is called bimolecular
reaction. A bimolecular reaction may be SN2 or E2.
Rate of reaction of A bimolecular reaction is expressed as: |
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Rate = K[R--X][Nu]
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UNIMOLECULAR
REACTION
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A chemical reaction in which only one molecule takes
part in rate determining step.is called a unimolecular
reaction. A unimolecular reaction may be SN1 or E1.
Rate of reaction of a unimolecular reaction is expressed as: |
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Rate = K[R--X]
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