Abstract:
A process is described for the acid-catalyzed dehydration of a sugar alcohol, wherein the catalyst comprises a water-tolerant Lewis acid. In particular embodiments, the catalyst comprises a homogeneous water-tolerant Lewis acid, especially a homogeneous Lewis acid selected from the group consisting of bismuth (III) triflate, gallium (III) triflate, scandium (III) triflate, aluminum triflate, tin (II) triflate and indium (III) triflate. Such catalysts are effective for dehydrating both of sorbitol and the 1,4-sorbitan dehydration precursor of isosorbide, and bismuth (III) triflate particularly is beneficial for dehydrating mannitol to isomannide.
Abstract:
A method for acid-catalyzed acylation of an isohexide is described. The method can enable direct alcohol acylation with carboxylic acids. In particular, the method involves reacting an isohexide and an excess of carboxylic acid, in the presence of a water-tolerant Lewis acid catalyst. Water-tolerant Lewis aid catalysts can furnish relatively high diester yields (e.g., ≥ 55%-60%) at lower catalyst loads. This feature, among others, is highly desirable for cost savings, and can improve process economics.
Abstract:
A method for acid-catalyzed acylation of an isohexide is described. The method involves a reaction of an isohexide and an excess of carboxylic acid in the presence of a Lewis acid or a Brnsted acid catalyst. One or more Lewis acid or Brnsted acid can faciliate conversion of isohexides to their corresponding mono and diesters with a pronounced greater regio-selectivity of exo- OH over endo -OH of the isohexide in the product. Particular catalytic acid species include zirconium chloride (ZrCl 4 ) and phosphonic acid (H 3 PO 3 ), which manifest a ratio of exo:endo regioselectivity of about 5.0≠.3:1and about 4.00.3:1, respectively.
Abstract translation:描述了用于酸性催化酰化异己烯酯的方法。 该方法包括在路易斯酸或布朗斯台德酸催化剂存在下异丙醚和过量的羧酸的反应。 一种或多种路易斯酸或布朗斯台德酸可以将异己烯酯转化成其相应的单酯和二酯,其中外OH的显着更大的区域选择性超过产物中异己烯的内-OH。 特别的催化酸性物质包括氯化锆(ZrCl 4)和膦酸(H 3 PO 3),其分别表现出约5.0≠.3:1和约4.00.3:1的外向内区域选择性比。
Abstract:
A process is described for the acid-catalyzed dehydration of a sugar alcohol, wherein the catalyst comprises a water-tolerant Lewis acid. In particular embodiments, the catalyst comprises a homogeneous water-tolerant Lewis acid, especially a homogeneous Lewis acid selected from the group consisting of bismuth (III) triflate, gallium (III) triflate, scandium (III) triflate, aluminum triflate, tin (II) triflate and indium (III) triflate. Such catalysts are effective for dehydrating both of sorbitol and the 1,4-sorbitan dehydration precursor of isosorbide, and bismuth (III) triflate particularly is beneficial for dehydrating mannitol to isomannide.
Abstract:
A method for acid-catalyzed acylation of an isohexide is described. The method can enable direct alcohol acylation with carboxylic acids. In particular, the method involves reacting an isohexide and an excess of carboxylic acid, in the presence of a water-tolerant Lewis acid catalyst. Water-tolerant Lewis aid catalysts can furnish relatively high diester yields (e.g., ≥ 55%-60%) at lower catalyst loads. This feature, among others, is highly desirable for cost savings, and can improve process economics.
Abstract:
Disclosed is a process for making HMF′ or a derivative of HMF by dehydrating one or more hexose sugars in a reduced oxygen environment, in another, related aspect, a method for improving the stability and resistance to degradation of an HMF product Involves adding one or more antioxidants to the HMF product.
Abstract:
A process is described for the acid-catalyzed dehydration of a sugar alcohol, wherein the catalyst comprises a water-tolerant Lewis acid. In particular embodiments, the catalyst comprises a homogeneous water-tolerant Lewis acid, especially a homogeneous Lewis acid selected from the group consisting of bismuth (III) triflate, gallium (III) triflate, scandium (III) triflate, aluminum triflate, tin (II) triflate and indium (III) triflate. Such catalysts are effective for dehydrating both of sorbitol and the 1,4-sorbitan dehydration precursor of isosorbide, and bismuth (III) triflate particularly is beneficial for dehydrating mannitol to isomannide.
Abstract:
Disclosed is a process for making HMF′ or a derivative of HMF by dehydrating one or more hexose sugars in a reduced oxygen environment, in another, related aspect, a method for improving the stability and resistance to degradation of an HMF product Involves adding one or more antioxidants to the HMF product.
Abstract:
A method for acid-catalyzed acylation of an isohexide is described. The method involves a reaction of an isohexide and an excess of carboxylic acid in the presence of a Lewis acid or a Brnsted acid catalyst. One or more Lewis acid or Brnsted acid can facilitate conversion of isohexides to their corresponding mono and diesters with a pronounced greater regio-selectivity of exo-OH over endo-OH of the isohexide in the product. Particular catalytic acid species include zirconium chloride (ZrCl4) and phosphonic acid (H3PO3), which manifest a ratio of exo:endo regioselectivity of about 5.0≠3:1 and about 4.00.3:1, respectively.
Abstract:
A method for acid-catalyzed acylation of an isohexide is described. The method involves a reaction of an isohexide and an excess of carboxylic acid in the presence of a Lewis acid or a Brønsted acid catalyst. One or more Lewis acid or Brønsted acid can facilitate conversion of isohexides to their corresponding mono and diesters with a pronounced greater regio-selectivity of exo-OH over endo-OH of the isohexide in the product. Particular catalytic acid species include zirconium chloride (ZrCl4) and phosphonic acid (H3PO3), which manifest a ratio of exo:endo regioselectivity of about 5.0≠3:1 and about 4.00.3:1, respectively.