Process for the preparation of [2,2]-paracyclophane

Claim 2

A process for preparing [2,2]-paracyclophane, comprising the step of contacting aqueous p-methylbenzyltrimethylammonium hydroxide with sodium hydroxide or potassium hydroxide, in the presence of dimethyl sulfoxide.

Claim 3

The process of claim 1, wherein the p-methylbenzyltrimethylammonium hydroxide is generated in situ by contacting aqueous p-methylbenzyltrimethylammonium chloride or bromide with a base.

Claim 4

The process of claim 1, wherein said contacting is effected in the further presence of an inert water-immiscible hydrocarbon solvent.

Claim 5

The process of claim 3, wherein said inert solvent is benzene, toluene, xylene or tetralin.

Claim 6

The process of claim 1, wherein said contacting is effected at a temperature of 50°-130° C.

Claim 7

The process of claim 5, wherein said temperature is 75°-95° C.

Claim 8

The process of claim 1, wherein a concentrated aqueous solution of p-methylbenzyltrimethylammonium chloride is added portionwise, with stirring, to a mixture of 1 volume part 45-50% aqueous sodium hydroxide or potassium hydroxide, 5-50 volume parts toluene and 1-5 volume parts dimethyl sulfoxide, said mixture containing at least a stoichiometric amount of base, at a temperature of 75°-95° C.; stirring and heating at 75°-95° C. is continued for about 10-100 hours; and resultant [2,2]-paracyclophane is recovered from the organic phase.

Claim 9

In a process for preparing [2,2]-paracyclophane by Hofmann elimination, wherein p-methylbenzyltrimethylammonium hydroxide is heated and resultant [2,2]-paracyclophane is recovered, the improvement wherein the reaction is effected by heating aqueous p-methylbenzyltrimethylammonium hydroxide, in contact with an inert water-immiscible organic solvent, and in the presence of dimethyl sulfoxide.

Claim 10

In a process for preparing [2,2]-paracyclophane by Hofmann elimination, wherein p-methylbenzyltrimethylammonium hydroxide is heated and resultant [2,2]-paracyclophane is recovered, the improvement wherein the reaction is effected by heating aqueous p-methylbenzyltrimethylammonium hydroxide, in contact with an inert water-immiscible organic solvent, and in the presence of dimethyl sulfoxide.

Claim 11

The process of claim 8, wherein the p-methylbenzyltrimethylammonium hydroxide is generated in situ by contacting aqueous p-methylbenzyltrimethylammonium chloride or bromide with sodium or potassium hydroxide.