The biggest problem with converting para dichloro benzene to hydroquinone is the unreactivity of the two
chlorine atoms. Only very small yeilds if any have been reported by bee's who have attempted it.
the ways I have hear about is fusion in caustic and by useing alkoxides.
well being on a DMSO frenzy I went back to gaylord and checked out some of the reactions that dont use
the dimsyl ion.
DMSO will increase the reactivity of a base in a Sn2 and a SnAr reaction.
this is just what wee (please excuse the pun) need for turning toilet lollies into film developer.
This is an undocumented idea and one well and truly worth experement.
It should be as simple as mixing 2 moles of KOH with 1 mole of p-Cl benzene in dmso then heating.
this should afford hydroquinone.
If your interested in the dimethoxy benzene instead then sodium or potassium methoxide would be what you want.
both of these extracts are from gaylord.
The displacement of aromatic halides by secondary amines in DMSO has been studied rather extensively. The fluoro-compounds undergo substitution by various nucleophiles, such as secondary aliphatic and alicyclic amines, at rates 100 to 1000 times faster than their chloro- analogs. The rate of displacement of fluorine is further enhanced by the order of 103 to 105 in dipolar aprotic solvents, such as DMSO, as compared with reactions in aprotic solvents [Miller, J.; Parker, A. J., J. Am. Chem. Soc. 83, 117-123 (1961)]. Thus, 4-fluoroacetophenone undergoes a very rapid displacement of the halogen by amines, such as morpholine, in DMSO and affords in high yields the corresponding 4-amino derivatives, which are otherwise difficult to prepare [Bader, H.; Hansen, A. R.; McCarty, F. J., J. Org. Chem. 31, 2319-2321 (1966)].
X = F, Cl, Br
The yields of products obtained in DMSO are higher than those obtained with DMF under comparable conditions.
and
When the alkaline hydrolysis of methyl iodide is studied in the presence of hydroxyl ion in DMSO-water, the rate of hydrolysis increases with increasing DMSO content [Murto, J., Suomen Kemistilehti B34, 92-98 (1961)].
Similar results are obtained with other primary alkyl halides (iodides, bromides, chlorides)[Bockmann, T.; Haanaes, E.; Ugelstad, J. , Tidsskr. Kjemi. Bergv. Met. 24, No. 11, 209-215 (1964)]. The rate constants for the reaction of hydroxide ion with ring substituted benzyl chlorides in acetone-water and DMSO-water mixtures are reported as a function of both solvent composition and temperature. The reaction rate increases with increasing DMSO concentration but decreases with increasing acetone concentration [Tommila, E.; Pitkanen, I. P., Acta Chem. Scand. 20, 937-945 (1966)].
In another example, 1-chlorobutane (1 mole) was added over 15 minutes to a stirred suspension of NaCN (1.08 mol) in DMSO (250 ml) at 80°C. The mixture was cooled to maintain temp <140°C. After the addition was complete, the mixture was cooled and diluted with water to 1L. The aqueous mixture was extracted with ether (3 x 150 ml). The ether extracts were washed with 6N HCl, then water, dried over CaCl2, and evaporated yielding a residue which was distilled to provide the product in 93% yield. Adapted from J. Org. Chem., 25 1388 (1960).
chlorine atoms. Only very small yeilds if any have been reported by bee's who have attempted it.
the ways I have hear about is fusion in caustic and by useing alkoxides.
well being on a DMSO frenzy I went back to gaylord and checked out some of the reactions that dont use
the dimsyl ion.
DMSO will increase the reactivity of a base in a Sn2 and a SnAr reaction.
this is just what wee (please excuse the pun) need for turning toilet lollies into film developer.
This is an undocumented idea and one well and truly worth experement.
It should be as simple as mixing 2 moles of KOH with 1 mole of p-Cl benzene in dmso then heating.
this should afford hydroquinone.
If your interested in the dimethoxy benzene instead then sodium or potassium methoxide would be what you want.
both of these extracts are from gaylord.
The displacement of aromatic halides by secondary amines in DMSO has been studied rather extensively. The fluoro-compounds undergo substitution by various nucleophiles, such as secondary aliphatic and alicyclic amines, at rates 100 to 1000 times faster than their chloro- analogs. The rate of displacement of fluorine is further enhanced by the order of 103 to 105 in dipolar aprotic solvents, such as DMSO, as compared with reactions in aprotic solvents [Miller, J.; Parker, A. J., J. Am. Chem. Soc. 83, 117-123 (1961)]. Thus, 4-fluoroacetophenone undergoes a very rapid displacement of the halogen by amines, such as morpholine, in DMSO and affords in high yields the corresponding 4-amino derivatives, which are otherwise difficult to prepare [Bader, H.; Hansen, A. R.; McCarty, F. J., J. Org. Chem. 31, 2319-2321 (1966)].
X = F, Cl, Br
The yields of products obtained in DMSO are higher than those obtained with DMF under comparable conditions.
and
When the alkaline hydrolysis of methyl iodide is studied in the presence of hydroxyl ion in DMSO-water, the rate of hydrolysis increases with increasing DMSO content [Murto, J., Suomen Kemistilehti B34, 92-98 (1961)].
Similar results are obtained with other primary alkyl halides (iodides, bromides, chlorides)[Bockmann, T.; Haanaes, E.; Ugelstad, J. , Tidsskr. Kjemi. Bergv. Met. 24, No. 11, 209-215 (1964)]. The rate constants for the reaction of hydroxide ion with ring substituted benzyl chlorides in acetone-water and DMSO-water mixtures are reported as a function of both solvent composition and temperature. The reaction rate increases with increasing DMSO concentration but decreases with increasing acetone concentration [Tommila, E.; Pitkanen, I. P., Acta Chem. Scand. 20, 937-945 (1966)].
In another example, 1-chlorobutane (1 mole) was added over 15 minutes to a stirred suspension of NaCN (1.08 mol) in DMSO (250 ml) at 80°C. The mixture was cooled to maintain temp <140°C. After the addition was complete, the mixture was cooled and diluted with water to 1L. The aqueous mixture was extracted with ether (3 x 150 ml). The ether extracts were washed with 6N HCl, then water, dried over CaCl2, and evaporated yielding a residue which was distilled to provide the product in 93% yield. Adapted from J. Org. Chem., 25 1388 (1960).
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