Concerted processes for forming 1,2,4-trihydroxybenzene from hydroquinone
First Claim
1. A method of producing 1,2,4-trihydroxybenzene comprising the steps of:
- (a) mixing p-benzoquinone in the presence of;
(i) at least two equivalents of acetic anhydride per equivalent of the p-benzoquinone, and(ii) a catalytic amount of an acid selected from the group consisting of sulfuric acid, boron trifluoride diethyl etherate, perchloric acid, and trifluoromethanesulfonic acid,under conditions sufficient to form a crude 1,2,4-triacetoxybenzene mixture comprising 1,2,4-triacetoxybenzene, acetic anhydride, acetic acid, and less than 0.5 mol % of 1,4-diacetoxybenzene relative to the initial p-benzoquinone;
(b) combining the crude 1,2,4-triacetoxybenzene mixture with an excess alcohol sufficient to neutralize excess acetic anhydride in the absence of added water and the presence of an acid catalyst, and heating the resulting reaction mixture under conditions sufficient to form 1,2,4-trihydroxybenzene; and
(c) isolating the 1,2,4-trihydroxybenzene.
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Accused Products
Abstract
Flow batteries incorporating an active material with one or more catecholate ligands can have a number of desirable operating features. Commercial syntheses of catechol produce significant quantities of hydroquinone as a byproduct, which presently has limited value in the battery industry and can represent a significant waste disposal issue at industrial production scales. Using a concerted, high-yield process, low-value hydroquinone can be transformed into high-value 1,2,4-trihydroxybenzene, which can be a desirable ligand for active materials of relevance in the flow battery industry. Methods for forming 1,2,4-trihydroxybenzene can include: oxidizing hydroquinone in a first reaction to form p-benzoquinone, converting the p-benzoquinone in a second reaction to form 1,2,4-triacetoxybenzene, deacetylating the 1,2,4-triacetoxybenzene in a third reaction to form 1,2,4-trihydroxybenzene, and isolating the 1,2,4-trihydroxybenzene after performing the first reaction, the second reaction and the third reaction consecutively.
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Citations
19 Claims
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1. A method of producing 1,2,4-trihydroxybenzene comprising the steps of:
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(a) mixing p-benzoquinone in the presence of; (i) at least two equivalents of acetic anhydride per equivalent of the p-benzoquinone, and (ii) a catalytic amount of an acid selected from the group consisting of sulfuric acid, boron trifluoride diethyl etherate, perchloric acid, and trifluoromethanesulfonic acid, under conditions sufficient to form a crude 1,2,4-triacetoxybenzene mixture comprising 1,2,4-triacetoxybenzene, acetic anhydride, acetic acid, and less than 0.5 mol % of 1,4-diacetoxybenzene relative to the initial p-benzoquinone; (b) combining the crude 1,2,4-triacetoxybenzene mixture with an excess alcohol sufficient to neutralize excess acetic anhydride in the absence of added water and the presence of an acid catalyst, and heating the resulting reaction mixture under conditions sufficient to form 1,2,4-trihydroxybenzene; and (c) isolating the 1,2,4-trihydroxybenzene. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification