7643-75-6Relevant articles and documents
Action patterns and mapping of the substrate-binding regions of endo-(1 → 5)-α-L-arabinanases from Aspergillus niger and Aspergillus aculeatus
Pitson, Stuart M.,Voragen, Alphons G.J.,Vincken, Jean-Paul,Beldman, Gerrit
, p. 207 - 218 (1997)
The substrate binding sites of endo-(1 → 5)-α-L-arabinanases (EC 3.2.1.99) from Aspergillus niger and Aspergillus aculeatus were investigated using reduced and regular (1 → 5)-α-L-arabino-oligosaccharides and high performance anion exchange chromatographic analysis. Calculation of bond cleavage frequencies and k(cat)/K(m), parameters for these substrates enabled the determination of the number of arabinofuranosyl binding subsites and the estimation of the binding affinities of each subsite. The A. aculeatus endo-arabinanase has six subsites arranged symmetrically around the catalytic site, while the A. niger endo-arabinanase has five subsites; two from the catalytic site towards the non-reducing end of the bound substrate and three toward the reducing end. The two subsites directly adjacent to the catalytic sites in both the A. niger and A. aculeatus endo-arabinanase have near-zero net free energy of binding. These results are unlike most glycopyranosyl endo-hydrolases studied which have net negative (unfavourable) energies of interaction at these two subsites, and may be related to the greater conformational flexibility of arabinofuranosyl residues than glycopyranosyl residues. The complete subsite maps are also rationalized with regard to the observed action patterns of these enzymes on linear (1 → 5)-α-L-arabinan.
Hydrogenolysis of sorbitol into valuable C3-C2 alcohols at low H2 pressure promoted by the heterogeneous Pd/Fe3O4 catalyst
Gumina, Bianca,Mauriello, Francesco,Pietropaolo, Rosario,Galvagno, Signorino,Espro, Claudia
, p. 152 - 160 (2018/02/17)
The hydrogenolysis of sorbitol and various C5-C3 polyols (xylitol; erythritol; 1,2- 1,4- and 2,3-butandiol; 1,2-propandiol; glycerol) have been investigated at low molecular hydrogen pressure (5 bar) by using Pd/Fe3O4, as heterogeneous catalyst and water as the reaction medium. Catalytic experiments show that the carbon chain of polyols is initially shortened through dehydrogenation/decarbonylation and dehydrogenation/retro-aldol mechanisms followed by a series of cascade reactions that include dehydrogenation/decarbonylation and dehydration/hydrogenation processes. At 240 °C, sorbitol is fully converted into lower alcohols with ethanol being the main reaction product in liquid phase.
Preparation method of gamma-acetyl n-propanol
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Paragraph 0036; 0037, (2017/12/09)
The invention discloses a preparation method of gamma-acetyl n-propanol. The method includes the steps of (1) adding the hydrolysate of plant fiber or xylose and other raw materials into a reaction still, adding a two-phase reactive solvent and a catalyst, inletting hydrogen, and heating the reaction still to react for several hours; (2) carrying out standing, liquid separation and then solid-liquid separation on reaction materials in the reaction still, obtaining water phase, oil phase and the catalyst, and recycling the catalyst for reutilization; (3) concentrating water phase products, extracting 1, 4-pentanediol in the oil phase, mixing with the concentrated solution, and carrying out further separation to obtain a crude product of 1, 4-pentanediol; (4) pumping the crude product of 1, 4-pentanediol obtained from the water phase and the oil phase in step (3) to a fixed bed reactor, carrying out dehydrogenation to produce gamma-acetyl n-propanol under the action of a catalytic dehydrogenation catalyst or an oxydehydrogenation catalyst. According to the preparation method, raw materials have extensive sources, the production cost is low, no inorganic acid system is used, and the reaction process is environment-friendly.
