Method for the preparation of p-isopropenyl phenol
AssigneeMitsui Toatsu Chemicals, Inc.
InventorsKosuke Mimaki, Tsutomu Takase, Mitsuhiro Iwasa, Tomitaka Yamamori
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Abstract
Chemically stable p-isopropenyl phenol is produced in the form of a solution by contacting p-isopropenyl phenol, in the form of a gas or a liquid obtained immediately after condensation of said gas, with a polar solvent such as an alcohol, an ester, or an acid amide. The resultant solution of p-isopropenyl phenol can be used as the starting material for subsequent reaction to obtain useful compounds such as hydroquinone. Alternatively, p-isopropenyl phenol may be isolated in crystalline form by adding to the solution a poor solvent for the phenol such as water, or by cooling the solution.
Claims8
A method for the recovery of p-isopropenyl phenol in the form of a stable solution which comprises contacting p-isopropenyl phenol, in the form of a gas or of a liquid obtained immediately after condensation of said gas, said p-isopropenyl phenol gas being generated by thermal decomposition at a temperature of from 150.degree. to 260.degree. C. and at a pressure up to normal pressure of:
- a. bisphenol A in the presence of a catalytic amount of a base catalyst;
- or
- b. oligomers of p-isopropenyl phenol in the absence of catalyst or in the presence of a catalytic amount of a basic catalyst, directly with a solvent selected from the group consisting of:
- a monohydric alcohol expressed by the formula
- ROH
- wherein R is alkyl containing from 5 to 14 carbon atoms, cycloalkyl containing from 5 to 6 carbon atoms, or aralkyl containing from 7 to 10 carbon atoms;
- a dihydric alcohol or derivative thereof expressed by the formula ##STR6## wherein R.sub.1 and R.sub.2 are independently hydrogen or alkyl containing from 1 to 4 carbon atoms, R.sub.3 is hydrogen, alkyl containing from 1 to 4 carbon atoms or acetyl and m is an integer of from 1 to 4;
- a dihydric alcohol or derivative thereof expressed by the formula
- HOC.sub.n H.sub.2n OR.sub.4
- wherein R.sub.4 is hydrogen, alkyl containing from 1 to 4 carbon atoms or acetyl, and n is an integer of from 3 to 6;
- and a trihydric alcohol or derivative thereof expressed by the formula
- HOC.sub.3 H.sub.5 (OR.sub.5).sub.2
- wherein R.sub.5 is hydrogen, alkyl containing from 1 to 4 carbon atoms or acetyl;
- an ester expressed by the formula
- R.sub.6 COOR.sub.7
- wherein R.sub.6 and R.sub.7 are independently alkyl or cycloalkyl and the total number of carbon atoms in one molecule of the ester is within the range of from 6 to 20;
- and an acid amide expressed by the formula ##STR7## wherein R.sub.8, R.sub.9 and R.sub.9.sub.' are independently hydrogen or alkyl containing from 1 to 4 carbon atoms, and collecting said p-isopropenyl phenol in the form of a solution in said solvent.
The method according to claim 10 wherein said p-isopropenyl phenol gas is generated by thermal decomposition of bisphenol A at a temperature of from 150.degree. to 260.degree. C. and at a pressure up to normal pressure in the presence of a basic catalyst.
The method according to claim 10 wherein said p-isopropenyl phenol gas is generated by thermal decomposition of oligomers of p-isopropenyl phenol at a temperature of from 150.degree. to 260.degree. C. and at a pressure up to normal pressure, said oligomers having been obtained by condensation of a gas generated by thermal decomposition of bisphenol A at a temperature of from 150.degree. to 260.degree. C. and at a pressure up to normal pressure in the presence of a basic catalyst followed by removing phenol from the resultant condensation product.
The method according to claim 10 wherein said p-isopropenyl phenol gas is generated by thermal decomposition of oligomers of p-isopropenyl phenol at a temperature of from 150.degree. to 260.degree. C. and at a pressure up to normal pressure, said oligomers having been obtained by decomposition of hydroxyhydroperoxide having the formula ##STR8## in the presence of an acid catalyst followed by removing acetone, water and the acid catalyst from the resultant decomposition product.
Dependencies are inferred from the claim text.