Write the chemical equations to illustrate the following reactions : [5×1=5] a) 2,4 DNP test b) Reimer Tiemann reaction c) Williamson's reaction d) Perkin's condensation reaction e) Wurtz Fittig's reaction

Chemical equations for the listed reactions a) 2,4‑DNP test – formation of a 2,4‑dinitrophenylhydrazone from a carbonyl compound. R CO CH3 + H2NNHC6H3(NO2)2 [EtOH, HCl] R CO CH=N NHC6H3(NO2)2 + H2O b) Reimer‑Tiemann reaction – ortho‑formylation of phenol. C6H5OH + CHCl3 + 3 NaOH [reflux] o‑HC6H4CHO + 3 NaCl + 2 H2O c) Williamson’s ether synthesis – SN2 displacement of an alkyl halide by an alkoxide. CH3Br + NaOCH2CH3 [acetone] CH3OCH2CH3 + NaBr d) Perkin condensation – condensation of an aromatic aldehyde with acetic anhydride (or acetic acid) in the presence of sodium acetate to give an α,β‑unsaturated acid. C6H5CHO + CH3COCH3 + NaOAc [reflux] C6H5CH=CHCOOH + CH3COONa + H2O e) Wurtz‑Fittig reaction – coupling of an aryl halide with an alkyl halide using metallic sodium. C6H5Br + CH3Br + 2 Na [dry ether] C6H5CH3 + 2 NaBr

Write the chemical equations to illustrate the following reactions : [5×1=5] a) 2,4 DNP… – Chemistry NEB 2082 Solution

Chemical equations for the listed reactions

a) 2,4‑DNP test – formation of a 2,4‑dinitrophenylhydrazone from a carbonyl compound.

$R - CO - CH X_{3} + H X_{2} NNHC X_{6} H X_{3} (NO X_{2}) X_{2} EtOH, HCl R - CO - CH = N - NHC X_{6} H X_{3} (NO X_{2}) X_{2} + H X_{2} O$

acetophenoneacetophenoneEtOH, HClH₂O

2,4-DNP test: Formation of orange/red hydrazone precipitate (real structure shown)

b) Reimer‑Tiemann reaction – ortho‑formylation of phenol.

$C X_{6} H X_{5} OH + CHCl X_{3} + 3 NaOH reflux o ‑ HC X_{6} H X_{4} CHO + 3 NaCl + 2 H X_{2} O$

phenolphenol+CHCl₃+3NaOHreflux, aqueous NaOH3NaCl+2H₂O

Reimer-Tiemann reaction: Ortho-formylation of phenol (dichlorocarbene intermediate not shown)

c) Williamson’s ether synthesis – SN2 displacement of an alkyl halide by an alkoxide.

$CH X_{3} Br + NaOCH X_{2} CH X_{3} acetone CH X_{3} OCH X_{2} CH X_{3} + NaBr$

CH₃Br+NaOCH₂CH₃acetone, refluxCH₃OCH₂CH₃+NaBr

Williamson ether synthesis (methyl ethyl ether)

d) Perkin condensation – condensation of an aromatic aldehyde with acetic anhydride (or acetic acid) in the presence of sodium acetate to give an α,β‑unsaturated acid.

$C X_{6} H X_{5} CHO + CH X_{3} COCH X_{3} + NaOAc reflux C X_{6} H X_{5} CH = CHCOOH + CH X_{3} COONa + H X_{2} O$

benzaldehydebenzaldehyde+acetic anhydrideacetic anhydride+NaOAcreflux, sodium acetateCH₃COONa+H₂O

Perkin condensation: α,β-unsaturated acid formation (mechanism: aldol-like condensation)

e) Wurtz‑Fittig reaction – coupling of an aryl halide with an alkyl halide using metallic sodium.

$C X_{6} H X_{5} Br + CH X_{3} Br + 2 Na dry ether C X_{6} H X_{5} CH X_{3} + 2 NaBr$

2Nadry ether, refluxtoluenetoluene+2NaBr

Wurtz-Fittig reaction: Aryl-alkyl coupling (radical intermediate)

Write the chemical equations to illustrate the following reactions : [5×1=5] a) 2,4 DNP test b) Reimer Tiemann reaction c) Williamson's reaction d) Perkin's condensation reaction e) Wurtz Fittig's…

Chemical equations for the listed reactions

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