Dicarboxyl starch

DAS + 2 NaC102 —> Dicarboxyl starch + 2 NaOCl H202 NaCl + H20 + 02... 

Dicarboxyl starch can also be made by oxidation with sodium hypochlorite or hypobromite (see reference 116). Reaction with hypochlorite is accelerated by use of catalytic amounts of sodium bromide.123,124... 

There are several examples of one-pot reactions with bifunctional catalysts. Thus, using a bifunctional Ru/HY catalyst, water solutions of corn starch (25 wt.%) have been hydrolyzed on acidic sites of the Y-type zeolite, and glucose formed transiently was hydrogenated on ruthenium to a mixture of sorbitol (96%), mannitol (1%), and xylitol (2%) [68]. Similarly a one-pot process for the hydrolysis and hydrogenation of inulin to sorbitol and mannitol has been achieved with Ru/C catalysts where the carbon support was preoxidized to generate acidic sites [69]. Ribeiro and Schuchardt [70] have succeeded in converting fructose into furan-2,5-dicarboxylic acid with 99% selectivity at 72% conversion in a one-pot reaction... 

A very successful approach to the preparation of starch-based emulsion stabilizers has been the development of polysaccharide derivatives of substituted dicarboxylic acids by Caldwell and Wurzburg (4). The invention involves the treatment of starch with substituted cyclic dicarboxylic acid anhydrides having the following structural formula ... 

Oxidation of secondary hydroxyl groups at C-2 and C-3 leads to acyclic dialde-hydes and dicarboxylic derivatives. Selective oxidation of primary hydroxyl groups is more difficult, but can be achieved by stoichiometric as well as catalytic methods. Nitric acid oxidizes monosaccharides into aldaric acids. Oxidation of cellulose or starch by nitrogen dioxide (N2O4) yields 6-carboxy starch and 6-carboxycellulose respectively. Subsequent hydrolysis under well-controlled conditions (0.5-2 M HCl at 150 °C) of these materials yields o-glucuronic acid (o-GlcAp) [12]. 

A product made from renewable raw materials has also been active in this application. Oxidation of the amy-lopectin fraction of starch with periodic acid cleaves some vicinal diol structures to dialdehydes which can be oxidized further to dicarboxylic acids.273 For good activity... 

The considerable amounts of glyoxylic and n-erythronic acid isolated after hydrolysis of hypochlorite-oxidized starch by Whistler and co-workers " " and by Eisenbraun and Purves indicate the significant introduction of keto groups by the oxidation, those keto-D- glucose residues being intermediates in the formation of 2,3-dicarboxyl units. Finally, it should be mentioned that the information obtained from studies of the oxidation of model compounds and of the chemistry of the carbonyl compounds so produced, previously discussed in the text, should be largely applicable to polysaccharides. ... 

The use of cyclic anhydrides of dicarboxylic acids gave monoesters of the dicar-boxylic acids.1912-1915 Maleic anhydride reacted with slurried starch within 30 min at 45 °C at pH 7.5-8.5.1916 Another procedure involved the blending of an acetone suspension of starch with maleic anhydride, followed by evaporation of the acetone, the addition of sodium hydroxide powder, and heating the blend at 120 °C for 7 h.1917... 

Starch carbonate diesters were formed by reaction of starch with alkylene carbonates under diminished pressure at 100-140 °C 2002 The products were proposed as surgical dusting powders. Another method involved dimethyl sulfoxide as the reaction medium, triethylamine as the catalyst, and trans-carbonates of glycosides as the acylating agents. Thionocarbonates were used similarly. The degree of substitution was O.4.2003 Another method involves 1-acyl I, I -carbodiirnidazole or dicarboxylic acid imidazolides at pH 8.O.2004... 

Trimethylene-2,2 -bipyridine-3,3 -dicarboxylic acid and l,l -tetra-methylene-2,2 -bipyridine-3,3 -dicarboxylic add atropisomers were baseline separated in 10 days on potato starch after tremendous effort to prepare the column. The authors stated that attempts to resolve theses acids were only successful with spedally conditioned columns of starch (95JPC14161). It is highly probable that more convenient chiral HPLC conditions are now available. 

Generally speaking, numerous synthons can be extracted from biomass. One known example is that of ethylene, produced from the dehydration of ethanol which is a very common product of fermentation. Another example is 1,3-propanediol, which is a monomer used as a building block for the production of polymers such as polyesters and polyurethanes. Several industrial processes have studied its production by fermentation with the aim of producing it directly from inexpensive plant raw materials (starch or sucrose). To synthesize polyamides and polyesters, we also aim to produce a,(o-dicarboxylic acids by the biological conversion of esters from vegetable oils. 

C21-dicarboxylic acid. See Cyclocarboxypropyloleic acid C-8 dimethyl acetal. See Octanal dimethyl acetal C13-15 dimethyl tert. amine. See Dimethyl C13-15 alkyl amine CDNA. SeeDicloran CDOL. See Cyclododecanol CDON. See Cyclododecanone CDPS. See 4,4 -Dichlorodiphenyl sulfide CDrySet. See Starch... 

N Clear Sodium Silicate. See Sodium silicate NCMC. See Carboxymethyl chitosan N-Creamer 46. See Food starch, modified NCS. See N-Chlorosuccinimide NC Size C-25. See Styrene/acrylates copolymer ND-201 Syrup. See Malt extract 2,6-NDA. See 2,6-Naphthalene dicarboxylic acid NDBC NDBC. See Nickel dibutyidithiocarbamate NDEA. See N-Nitrosodiethylamine NDGA. See Nordihydroguaiaretic acid NDI. See 1,5-Naphthalene diisocyanate NDMA. See N,N-Dimethyl-p-nitrosoaniline N-Nitrosodimethylamine... 

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