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 process for preparing cyclic dehydration products from sugar alcohols is described. The process involve using a mixed-acid catalyst reaction mixture containing a reducing acid, having a pKa of about 1.0-1.5, and at least a strong Brønsted acid or a Lewis acid, having a pKa ≤ 0, or both acids in a solution to dehydrate and ring close said sugar alcohol. Synergistically, the mixed-acid catalysis can produce greater amounts of the desired product at similar levels of compositional accountability than either of the component acid catalysts acting alone.
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:
Reduced color epoxidized fatty acid esters are provided which may be used as primary plasticizers for PVC, in replacement of phthalate plasticizers. The reduced color epoxidized fatty acid esters are prepared from natural fats or oils by transesterification and interesterification processes, whereby through the use of borohydride, materials having Pt-Co colors according to ASTM D1209 on the order of 50 and lower are possible.
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:
Presently disclosed are high purity unsaturated fatty acid esters with an ester moiety characterized by having from five to seven members in a ring structure, which esters when epoxidized find particular utility as primary plasticizers in flexible polyvinyl halide applications. Also disclosed are processes for making the high purity esters.
Abstract:
Described herein are improved methods for the preparation of 5- and 6-membered cyclic mono and diesters of sugar alcohols and anhydrosugar alcohols by reaction with an organic acid RCOOH over a solid acidic substrate. The process is adaptable to a continuous process for simultaneously making and separating the cyclic esters from the sugar alcohols and anhydrosugar alcohols under mild conditions using the solid acid substrate as both the catalyst and a chromatographic bed for separation. The reactions are performed at mild temperatures of 700C to 10O0C and the formation of the cyclic esters is nearly quantitative. Also described is a method for making 5- and 6-membered cyclic mono and diesters of sugar alcohols and anhydrosugar alcohols using microwave irradiation in the presence of the organic acid.
Abstract:
Disclosed herein are methods of synthesizing shorter chain polyols. Methods of hydrolyzing polysaccharides are further disclosed. The present invention is also directed towards methods of selectively synthesizing sorbitol.
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.