- PROCESS FOR THE CONVERSION OF SUGARS TO LACTIC ACID AND 2-HYDROXY-3-BUTENOIC ACID OR ESTERS THEREOF COMPRISING A METALLO-SILICATE MATERIAL AND A METAL ION
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The present invention regards metallo-silicate materials comprising a metal ion selected from one or more of the group consisting of potassium ions, sodium ions, lithium ions, rubidium ions and caesium ions. The materials are useful preparing lactic acid and 2-hydroxy-3-butenoic acid or esters thereof from a sugar.
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Paragraph 0054; 0055; 0056; 0057; 0058
(2017/03/21)
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- Confinement Effects in Lewis Acid-Catalyzed Sugar Conversion: Steering Toward Functional Polyester Building Blocks
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We report the use of solid Lewis acid catalysts for the conversion of tetrose sugars to four-carbon α-hydroxy acid esters (C4-AHA), which are useful as functional polyester building blocks. Sn-β was by far the most active and selective catalyst, yielding up to 80% methyl vinyl glycolate (MVG), methyl-4-methoxy-2-hydroxybutanoate (MMHB), and α-hydroxy-γ-butyrolactone (HBL) combined at 95% conversion. A very high turnover frequency (TOF) of 330 molC4-AHA molSn h-1 was attained using Sn-β, a more than 6-fold increase compared with homogeneous SnCl4·5H2O. It is shown that, using different Sn-based catalysts with various pore sizes, the product distribution is strongly dependent on the size of the catalyst pores. Catalysts containing mainly mesopores, such as Sn-MCM-41 or Sn-SBA-15, prefer the production of the more bulky MMHB, whereas microporous catalysts such as Sn-β or Sn-MFI favor the production of MVG. This effect can be further enhanced by increasing the reaction temperature. At 363 K, only 20% MVG is attained using Sn-β, but at 433 K, this increases to 50%. Using a kinetic analysis, it was found that, in microporous catalysts, steric hindrance near the Sn active site in the catalyst pores plays a dominant role in favoring the reaction pathway toward MVG. Moreover, the selectivity toward both products is kinetically controlled.
- De Clercq, Rik,Dusselier, Michiel,Dijkmans, Jan,Iacobescu, Remus Ion,Pontikes, Yiannis,Sels, Bert F.
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p. 5803 - 5811
(2015/10/12)
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- Sn-Beta catalysed conversion of hemicellulosic sugars
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Conversions of various pentoses and hexoses into methyl lactate has been demonstrated for the Sn-Beta catalyst. It is found that pentoses are converted to methyl lactate in slightly lower yields (～40%) than what is obtained for hexoses (～50%), but higher yields of glycolaldehyde dimethyl acetal are observed for the pentoses. This finding is in accordance to a reaction pathway that involves the retro aldol condensation of the sugars to form a triose and glycolaldehyde for the pentoses, and two trioses for hexoses. When reacting glycolaldehyde (formally a C2-sugar) in the presence of Sn-Beta, aldol condensation occurs, leading to the formation of methyl lactate, methyl vinylglycolate and methyl 2-hydroxy-4-methoxybutanoate. In contrast, when converting the sugars in water at low temperatures (100 °C), Sn-Beta catalyses the isomerisation of sugars (ketose-aldose epimers), rather than the formation of lactates. The Royal Society of Chemistry 2012.
- Holm, Martin S.,Pagan-Torres, Yomaira J.,Saravanamurugan, Shunmugavel,Riisager, Anders,Dumesic, James A.,Taarning, Esben
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experimental part
p. 702 - 706
(2012/04/23)
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- ZEOLITE-CATALYZED PREPARATION OF ALPHA-HYDROXY CARBOXYLIC ACIDS AND ESTERS THEREOF
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A process for the production of lactic acid and 2-hydroxy-3-butenoic acid or esters thereof by conversion of glucose, fructose, sucrose, xylose and glycolaldehyde dissolved in a solvent in presence of a solid Lewis acidic catalyst.
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Page/Page column 3-4
(2010/06/11)
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- Zeolite-catalyzed preparation of alpha-hydroxy carboxylic acid compounds and esters thereof
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A process for the production of lactic acid and 2-hydroxy-3-butenoic acid or esters thereof by conversion of glucose, fructose, sucrose, xylose and glycolaldehyde dissolved in a solvent in presence of a solid Lewis acidic catalyst.
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Page/Page column 5
(2010/06/11)
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