Liquid fructose

Molisch s test A general test for carbohydrates. The carbohydrate is dissolved in water, alcoholic 1-naphthol added, and concentrated sulphuric acid poured down the side of the tube. A deep violet ring is formed at the junction of the liquids. A modification, the rapid furfural test , is used to distinguish between glucose and fructose. A mixture of the sugar, 1-naphthol, and concentrated hydrochloric acid is boiled. With fructose and saccharides containing fructose a violet colour is produced immediately the solution boils. With glucose the appearance of the colour is slower. 

The use of a ternary mixture in the drying of a liquid (ethyl alcohol) has been described in Section 1,5 the following is an example of its application to the drying of a solid. Laevulose (fructose) is dissolved in warm absolute ethyl alcohol, benzene is added, and the mixture is fractionated. A ternary mixture, alcohol-benzene-water, b.p. 64°, distils first, and then the binary mixture, benzene-alcohol, b.p. 68-3°. The residual, dry alcoholic solution is partially distilled and the concentrated solution is allowed to crystallise the anhydrous sugar separates. 

Displacement-purge forms the basis for most simulated continuous countercurrent systems (see hereafter) such as the UOP Sorbex processes. UOP has licensed close to one hundred Sorbex units for its family of processes Parex to separate p-xylene from C3 aromatics, Molex tor /i-paraffin from branched and cyclic hydrocarbons, Olex for olefins from paraffin, Sarex for fruc tose from dextrose plus polysaccharides, Cymex forp- or m-cymene from cymene isomers, and Cresex for p- or m-cresol from cresol isomers. Toray Industries Aromax process is another for the production of p-xylene [Otani, Chem. Eng., 80(9), 106-107, (1973)]. Illinois Water Treatment [Making Wave.s in Liquid Processing, Illinois Water Treatment Company, IWT Adsep System, Rockford, IL, 6(1), (1984)] and Mitsubishi [Ishikawa, Tanabe, and Usui, U.S. Patent 4,182,633 (1980)] have also commercialized displacement-purge processes for the separation of fructose from dextrose. 

Note If the chromatogram developed by method B was exposed to ammonia vapors for 10 min before being immersed in liquid paraffin— -hexane (1 -I- 2) the fluorescence of the chromatogram zones became deep red. Glucose and fructose also appeared red. 

The raw materials from which di-D-fructose dianhydrides can be obtained in appreciable yield are readily available from comparatively inexpensive agricultural feedstocks. Thus, these compounds are attractive as chiral-starting materials for chemical synthesis. Their stability to acid and heat, and their relative rigidity, because of the conformational constraints covered here, are also features that might be exploited during syntheses.119 A series of variously substituted di-D-fructose dianhydrides has been prepared,119 starting from 6,6 -dideoxy-6,6 -di-halosucroses. The properties of these and other derivatives of di-D-fructose dianhydrides are summarized in Tables XIV-XX. Two of these derivatives, 48 and 56, exhibit thermotropic liquid-crystal properties.119... 

Treatment of inulin or D-fructose with liquid HF (neat or diluted with liquid SOj) gave a mixture of six di-D-fructose dianhydrides, including 23, 25, 27, and )3-D-fructofuranosyl ) -D-fructopyranose 2,l 3,2 -dianhydride... 

By application of first-order, kinetic equations, B. Anderson and Degn claimed that an equilibrated (25°) aqueous solution of D-fructose contains 31.56% of jS-D-fructofuranose and 68.44% of -D-fructopyranose. N.m.r. studies, however, showed that, at equilibrium, a solution of D-fructose contains /3-D-fructopyranose, -D-fructofuranose, a-D-fructofuranose, and a trace of a-D-fructopyranose the distribution of these isomers was shown by gas-liquid chromatography to be 76,19.5, and 4%, respectively. Based on Anderson and Degn s result, Shallenberger reasoned that, as 0.68 X 1.8 = 1.22 (which approximates the reported sweetness of mutarotated D-fructose ), the furanose form(s) must possess very little sweetness. 

Defaye, K. and Garcia Fernandez, J.M., Protonic and thermal activation of sucrose an the oligosaccaride composition of caramel. Carbohydrate Res., 256, Cl, 1994. Ratsimba, V. et al.. Qualitative and qnantitative evaluation of mono- and disaccharides in D-fructose, D-glucose and sucrose caramels by gas-liquid chromatography-mass spectrometry di-D-fructose dianhydrides as tracers of caramel authenticity, J. Chro-matogr. A, 844, 283, 1999. 

The dehydration of fructose 40 or glucose into 5-hydroxymethylfurfural 41 is a process which has been exploited to convert biomass into higher value products. The reaction has been achieved using a chromium NHC complex, formed in situ from CrCl and the NHC 42 (Scheme 11.10) [16], The reaction is performed in the ionic liquid BMIM+Cl (l-butyl-3-methylimidazolium chloride). 

Liquid Chromatography. - Diasteriomeric phosphonodipeptides have been separated by ion exchange column chromatography.267 H.p.l.c. has been used for the analysis of a variety of biologically active phosphorus compounds, such as aminoacid phosphate esters,26 phosphinothrycin,269 inositol triphosphate,270 fructose diphosphate,271 pyridoxal phosphate,272 and ATP.273... 

Diheterolevulosan was first prepared by Pictet and Chavan67 by treating D-fructose with concentrated hydrochloric acid. Schlubach and Behre68 prepared the same compound by the action of liquid hydrogen chloride on dry fructose in a sealed tube. Sattler and Zerban6 have found this difructose anhydride in the unfermentable residue obtained from cane molasses. 

Fructose separation adsorbents, 7 587t liquid adsorption, 7 665, 674 with zeolite KX, 7 610 Fructosyloligosaccharides (FOS), 23 480 Fruit(s)... 

C4-C6 Alkanes are highly volatile and, hence, of low value as a transportation fuel or a fuel additive. Since high-quality fuels require the generation of liquid hydrocarbons, the fructose-derived HMF and acetone have been converted into their mono- (C9) and bis-aldols (C15), which on Si02-Al203/Pt-catalyzed dehy-dration/hydrogenation produce C9-C15 alkanes (Scheme 2.8). A major drawback of this approach, however, is the fact that HMF, de facto, is a fructose-derived product, and is not producible in an industrially viable price frame at present vide infra. Section 2.3.2). 

The Sarex process employs the full allotment of Sorbex beds in addition to the four basic Sorbex zones. When a Sarex unit processes corn syrup that has an approximate composition (on a dry basis) of 42% fructose, 53% glucose and 5% other saccharides, it produces a fructose enriched corn syrup with >95% purity at >90% recovery [34, 35]. The Sarex process employs sufficient operating temperature to overcome diffusion limitations with a corresponding operating pressure to maintain liquid-phase operation. 

High fructose corn syrup (MFCS) has emerged In recent years as an alternative nutritional sweetener to sucrose. However, the use of HFCS has been confined to those applications suited to liquid syrups, In particular the beverage and canning sectors of the market. The manufacture of fructose as a crystalline product would open up further market opportunities for the sweetener. One company In the USA Is producing crystalline fructose In commodity quantities (1), but at a higher price than sucrose. 

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