Ethylbenzene → 2-Ethylbenzene-1-carbothioamide
Reaction equation
[S-:1][C:2]#[N:3].[NH4+].[CH2:5]([C:7]1[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=1)[CH3:6].F>>[CH2:5]([C:7]1[CH:12]=[CH:11][CH:10]=[CH:9][C:8]=1[C:2]([NH2:3])=[S:1])[CH3:6]Participants
Procedure
In a polyethylene vessel having a capacity of 1 liter, at -20° C and with agitation, 46 g of ammonium thiocyanate (0.6 mol) and subsequently 53 g of ethylbenzene (0.5 mol) are added in portions to 0.5 l of 98% hydrofluoric acid. Subsequently, agitation is continued for 20 hours at room temperature, and the reaction mixture is then poured onto ice, thus causing the separation of a precipitate which slowly crystallizes. The precipitate is suction-filtered and washed with water. By steam distillation, about 10 g of ethylbenzene are recovered from the precipitate. After drying, 66 g (0.4 mol) of ethyl-thiobenzamide having a slightly yellow color and a melting point of 115 - 117° C are obtained, which corresponds to a conversion rate of 80% relative to the ethylbenzene used. The yield, relative to converted ethylbenzene, is 95% of the thoeretical yield. The product can be recrystallized from toluene or chlorobenzene. The gas chromatogram shows that substitution by the thioamide group has occured in p-position at a rate of more than 95%. The 4-ethylbenzonitrile may be obtained from the thioamide in known manner using alkali, thereby splitting off H2S.
Workup
- customIn a polyethylene vessel having
- additionthe reaction mixture is then poured onto ice
- customthe separation of a precipitate which
- customslowly crystallizes
- filtrationThe precipitate is suction-filtered
- washwashed with water
- distillationBy steam distillation, about 10 g of ethylbenzene
- customare recovered from the precipitate
- customAfter drying
Sources & evidence
- ORD record
- ord-ca1fd5b426dd4819a3b8109fedb37d69
- Source dataset
- uspto-grants-1977_02
- Patent number
- US04008264
Reaction notes
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