Processes for preparing benzoquinones and hydroquinones
View Patent ↗A process for the preparation of hydroquinone compounds comprising, reacting an aromatic hydroxy compound with an oxidizing agent in a biphasic solvent system. The reaction is carried out in the presence of a transition metal hydroxy phosphate catalyst to produce the corresponding hydroquinone compound.
1. A process comprising:
oxidizing an aromatic hydroxy compound with an oxidizing agent in a biphasic solvent system in the presence of a transition metal hydroxy phosphate catalyst to produce a corresponding hydroquinone compound;
wherein the aromatic hydroxy compound has a formula:
wherein each occurrence of R 1 is independently selected from the group consisting of a hydrogen and a hydrocarbyl group.
2. The process of claim 1 , wherein said hydroquinone compound is mixed with a corresponding benzoquinone compound.
3. The process of claim 1 , wherein said aromatic hydroxy compound is selected from the group consisting of phenol, 2,6-dimethyl phenol, 2,6-di-tertiary-butyl phenol, 2-tertiary-butyl phenol, alpha-naphthol, meta-cresol, ortho-cresol, ortho-phenylphenol, ortho-benzylphenol, 2,3 ,6-trimethyl phenol, ortho-vinylphenol, 2-isopropylphenol, 2,6-diisopropylphenol, 2,3 ,5,6-tetramethylphenol, 2,3 ,5-trimethylphenol, and mixtures of two or more of the foregoing aromatic hydroxy compounds.
4. The process of claim 1 , wherein said aromatic hydroxy compound comprises ortho-cresol.
5. The process of claim 1 , wherein said oxidizing agent is selected from the group consisting of hydrogen peroxide, cumene hydroperoxide, tertiary-butyl hydroperoxide and peracetic acid.
6. The process of claim 1 , wherein said oxidizing agent is hydrogen peroxide.
7. The process of claim 1 , wherein said transition metal hydroxy phosphate is selected from the group consisting of copper hydroxy phosphate, manganese hydroxy phosphate, copper-manganese hydroxy phosphate, iron hydroxy phosphate and nickel hydroxy phosphate.
8. The process of claim 1 , wherein the amount of said transition metal hydroxy phosphate catalyst is 0.05 to 10 weight percent based on the weight of the aromatic hydroxy compound.
9. The process of claim 1 , wherein said reaction occurs at a temperature of 25° C. to 80° C.
10. The process of claim 1 , wherein the biphasic solvent system comprises water and a water-immiscible solvent.
11. The process of claim 10 , wherein the water-immiscible solvent is selected from aliphatic straight chain, branched chain or cyclic solvents having 6 to 15 carbon atoms or mixtures of two of more of the foregoing solvents.
12. The process of claim 10 , the water-immiscible solvent is selected from the group consisting of cyclohexane, n-heptane, hexane, octanol, n-decane and decalene.
13. The process of claim 1 , wherein the amount of water-immiscible solvent used is 10 milliliters to 1000 milliliters per mole of the aromatic hydroxy compound.
14. The process of claim 1 , wherein the amount of water used is 100 milliliters to 2000 milliliters per mole of the aromatic hydroxy compound.
15. The process of claim 1 , wherein said process is carried out in a batch mode, semi-continuous mode or in a continuous mode.
16. The process of claim 15 , wherein said batch mode is carried out for 1 to 24 hours.
17. The process of claim 1 , wherein said hydroquinone is substantially free of metal derived from the transition metal hydroxy phosphate catalyst.
18. A method of making a polycarbonate comprising reacting a carboxylate precursor and one or more hydroquinones or a mixture of one or more hydroquinones and a dihydroxy aromatic compound wherein the one or more hydroquinones is prepared according to the process of claim 1 .
19. A process for preparing 2-methylhydroquinone, said process comprising:
reacting ortho-cresol with hydrogen peroxide in a biphasic solvent system in the presence of a transition metal hydroxy phosphate catalyst to form said hydroquinone compound, wherein the biphasic system comprises a mixture of water and water-immiscible solvent and wherein the transition metal hydroxy phosphate catalyst is selected from a group consisting of a copper hydroxy phosphate, manganese hydroxy phosphate and a copper manganese hydroxy phosphate.
20. The process of claim 19 , wherein said 2-methyl hydroquinone compound is substantially free of metal derived the from the transition metal hydroxy phosphate catalyst.
21. The process of claim 19 , wherein said 2-methylhydroquinone compound is mixed with a corresponding benzoquinone compound.
22. The process of claim 19 , the water-immiscible solvent is selected from the group consisting of cyclohexane, n-heptane, hexane, octanol, n-decane and decalene.
23. A method of making a polycarbonate comprising reacting a carboxylate precursor and a one or more hydroquinones or a mixture of one or more hydroquinones and a dihydroxy aromatic compound wherein the one or more hydroquinones is prepared according to claim 19 .