Transcript Document
Diazonium salts synthesis HNO3 NO2 H2SO4 H2, Ni HONO N N benzenediazonium ion NH2 Diazonium salts, reactions 1. Coupling to form azo dyes 2. Replacements a) -Br, -Cl, -CN b) -I c) -F d) -OH e) -H f) etc. coupling to form azo dyes N2 G G + an azo dye G = OH, NH2, NHR, NR2, etc. CH3 H3C N N N + N,N-dimethylaniline N2 SO3H CH3 H3C N N N methyl orange SO3H Sandmeyer Ar-N2+ + CuCl Ar-Cl + N2 Ar-N2+ + CuBr Ar-Br + N2 Ar-N2+ + CuCN Ar-CN + N2 Ar-N2+ + KI Ar-I + N2 Ar-N2+ + HBF4 Ar-F + N2 Ar-N2+ + H2O, H+ Ar-OH + N2 Ar-N2+ + H3PO2 Ar-H + N2 Cl Br CN I F H3PO2 NH2 H2O,H+ HBF4 KI CuCN CuBr CuCl NO2 N2 OH Br NaCN NR NO2 HNO3 NH2 H2/Ni H2SO4 NaNO2 HCl C N benzonitrile N2 CuCN I2, Fe NR NO2 NH2 H2/Ni HNO3 H2SO4 NaNO2 HCl I iodobenzene N2 KI Br NaOH NR NO2 NH2 H2/Ni HNO3 H2SO4 NaNO2 HCl OH phenol N2 H2O,H+ p-bromotoluene CH3 CH3 CH3 Br Br2,Fe + Br bp 185oC bp 182oC You cannot separate a mixture of ortho and parabromotoluene in a reasonable purity. Their bp's are too close together! CH3 CH3 CH3 HNO3 H2SO4 + ortho- H2/Ni bp 222oC NH2 NO2 bp 238oC A mixture of ortho & paranitrotoluenes is separable in a reasonable yield and purity NaNO2 HCl CH3 CH3 CuBr Br N2 In syntheses, you may no longer assume that you can separate a pure para isomer from an ortho/para mixture. Either look up the physical properties of the compounds or rely on experience gained in the homework as to which mixtures are separable and which ones are not! m-bromotoluene CH3 CH3 CH3 HNO3 H2SO4 + ortho- H2/Ni bp 222oC NH2 NO2 bp 238oC (CH3CO)2O CH3 CH3 CH3 H2O,OH- Br NH2 Br2,Fe Br NHCOCH3 NHCOCH3 CH3 CH3 H3PO2 HONO Br N2 Br m-bromophenol NO2 NO2 HNO3 H2SO4 Br2,Fe Br H2/Pt OH NH2 N2 Br H2O NaNO2 H+ H+ Br Br p-toluic acid CH3 CH3 CH3 HNO3 H2SO4 + ortho- H2/Ni bp 222oC NH2 NO2 bp 238oC CH3 NaNO2 HCl CH3 H2O, H+ CH3 CuCN heat COOH CN N2 1,2,3-tribromobenzene NO2 (CH3CO)2O H2/Ni HNO3 NHCOCH3 NH2 H2SO4 HNO3 H2SO4 TAR! NH2 Br NH2 Br NHCOCH3 Br2 (aq) H2O, OH- + ortho- heat NO2 NO2 NO2 HONO H3PO2 Br N2 Br Br CuBr Br Br Br H2 Br Br Ni NO2 NO2 Br Br HONO H3PO2 NH2 Br 1,3,5-tribromobenzene NH2 NO2 H2/Ni HNO3 H2SO4 Br2 (aq) polybromination N2 Br Br Br H3PO2 Br Br Br NH2 HONO Br Br Br Spectroscopy of amines Infrared: N—H stretch 3200 – 3500 cm-1 1o often two bands 2o one band 3o no bands N—H bend 1o strong bands 650-900 cm-1(broad) and 1560-1650 cm-1 nmr: N—H 1-5 ppm (often broad and low) p-toluidine N—H stretch N—H bend NH2 c p-ethylaniline d CH2CH3 b a d c b a