Sorbitol, organic structure

Hydrogenation reactions, particularly for the manufacture of fine chemicals, prevail in the research of three-phase processes. Examples are hydrogenation of citral (selectivity > 80% [86-88]) and 2-butyne-l,4-diol (conversion > 80% and selectivity > 97% [89]). Eor Pt/ACE the yield to n-sorbitol in hydrogenation of D-glucose exceeded 99.5% [90]. Water denitrification via hydrogenation of nitrites and nitrates was extensively studied using fiber-based catalysts [91-95]. An attempt to use fiber-structured catalysts for wet air oxidation of organics (4-nitrophenol as a model compound) in water was successful. TOC removal up to 90% was achieved [96]. 

FIGURE 1.1 Structures of organic compounds referred to in the text (a) sucrose (also known as saccharose), (b) dimethyl sulfoxide (DMSO), (c) dimethylformamide (DMF), (d) sorbitol, (e) mannitol, (f) nitrilotriacetic acid (NTA), (g) citric acid, (h) N,N,N, N -fran,s-1,2-diaminocyclohexane-tetraacetic acid (CyTA), (i) saccharic acid, (j) glutamic acid. 

This chapter is an overview of architectures adopted for the catalytic/biocatalytic composites used in wide applications like the biomass valorization or fine chemical industry. On this perspective, the chapter updates the reader with the most fresh examples of construction designs and concepts considered for the synthesis of such composites. Their catalytic properties result from the introduction of catalytic functionalities and vary from inorganic metal species e.g., Ru, Ir, Pd, or Rh) to well-organized biochemical structures like enzymes e.g., lipase, peroxidase, (3-galactosidase) or whole cells. Catalytic/biocatalytic procedures for the biomass conversion into platform molecules e.g., glucose, GVL, Me-THF, sorbitol, succinic acid, and glycerol) and their further transformation into value-added products are detailed in order to make understandable the utility of these complex architectures and to associate the composite properties to their performances, versatility, and robustness. 

Crude Solid. The simplest way to use enzymes in organic solvents is to suspend a precipitate or a lyophilisate. The enzyme does not need to be of high purity, but some care should be taken during the preparation. In aqueous solution, the enzyme has an optimal pH, dictated by the ionization state under which the amino acids involved in the catalysis must be to allow activity. The solid enzyme must be in the same ionization state when used in organic solvents (15). For this purpose, it is important to precipitate the enzyme or lyophilize it from a solution buffered at this pH. This applies to the other forms of solid enzyme preparations. The other important point is the drying of the preparation. It has been observed that the secondary structure of proteins can be affected by lyophilization (16). This can be avoided by the use of lyoprotectants such as sorbitol (17) or salts such as KCl (18). 

Yamasaki S, Tsutsumi H (1995) The dependence of the polarity of solvents on 1,3 2,4-di-o-benzylidene-D-sorbitol gel. Bull Chem Soc Jpn 68 123-127 Yamasaki S, Ohashi Y, Tsutsumi H, Tsujii K (1995) The aggregated higher-structure of 1,3 2,4-di-o-benzylidene-D-sorbitol in organic gels. Bull Chem Soc Jpn 68 146-151 Zweifel H (2001) Plastics additives handbook. Hanser, Munich, Chapter 18... 

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