Alkaline sucrose

C (decomp.) It is made by the oxidation of toluene-o-sulphonamide with alkaline permanganate. Saccharin has about 550 times the sweetening power of sucrose, and is used extensively as a sweetening agent, usually in the form of the sodium salt. The use of saccharin is restricted in the U.S. 

Alkaline Degradation. At high pH, sucrose is relatively stable however, prolonged exposure to strong alkaU and heat converts sucrose to a mixture of organic acids (mainly lactate), ketones, and cycHc condensation products. The mechanism of alkaline degradation is uncertain however, initial formation of glucose and fructose apparendy does not occur (31). In aqueous solutions, sucrose is most stable at —pH 9.0. 

High alkalinities of limed juice serve several functions. Foremost is to retard sucrose hydrolysis, one of the oldest reactions in the Uterature of chemical kinetics (6). Sucrose hydrolysis proceeds much more slowly at a moderately high pH than at an even slightly acidic pH. 

Methylfurfural may be prepared by a modification of this method, which is more rapid but gives lower yiddsd A solution of 800 g. of sucrose in i 1. of hot water is allowed to flow slowly into a boiling solution of 500 g. of stannous chloride crystals, 2 kg. of sodium chloride, and 4 1. of 12 per cent sulfuric acid in a 12-I. flask. The aldehyde distils ofl as rapidly as it is formed and is steam-distilled from the original distillate after rendering it alkaline witlr sodium carbonate. The product is isolated by benzene extraction of the second distillate and distillation under reduced pressure. The yield is 27-35 g- (10-13 per cent of the theoretical amount). 

Astacin (P,P-carotene-3,3, 4,4 -tetraone) [514-76-1] M 592.8, m 228", 240-243"(evacuated tube), 550,000 at 498mm (pyridine). Probable impurity is astaxanthin. Purified by chromatography on alumina/fibrous clay (1 4) or sucrose, or by partition between pet ether and MeOH (alkaline). Crystd from pyridine/water. Stored in the dark under N2 at -20°. [Davis and Weedon J Chem Soc 182 I 960.]... 

Richards et al.23-24 proposed that the alkaline degradation reaction proceeds via a slow, rate-determining SJCB mechanism, where the substitution at the C-l of the D-glucose moiety by oxyanions derived from l -OH or 3 -OH resulted in 1- or 3-O-P-D-glucopyranosyl-D-fructose (see Fig. 4) the mechanism implies that T - time thyl sucrose is degraded via 3 -displacement and 3 -(3-methylsucrose via the 1 -displacement. The 1- or 3-<3-[3-D-glucopyranosyl-D-fructose intermediates are then... 

Sucrose can, however, degrade to D-glucose and D-fructose in slightly alkaline solution at pH up to 8.3 (sucrose is most stable611 at pH 8.3-8.5, although the reason for this requires some elucidation), but this degradation proceeds by the normal acid-hydrolysis mechanism. In sucrose manufacture, therefore, the main reaction causing sucrose loss, between pH 7 and about 8.3, is the same acid hydrolysis that occurs at lower (acid) pH. 

The reversible reactions are initiated by an equilibrium between neutral and ionized forms of the monosaccharides (see Fig. 6). The oxyanion at the anomeric carbon weakens the ring C-O bond and allows mutarotation and isomerization via an acyclic enediol intermediate. This reaction is responsible for the sometimes reported occurrence of D-mannose in alkaline mixtures of sucrose and invert sugar, the three reducing sugars are in equilibrium via the enediol intermediate. The mechanism of isomerization, known as the Lobry de Bruyn-... 

Because alkali degradation of sucrose does not result in inversion products, in slightly alkaline solution (pH < 8.5), the loss of sucrose to invert sugar (glucose + fructose) is a consequence of the acid hydrolysis mechanism, which provides D-glucose and D-fructose for further alkaline degradation. 

Vukov6 has developed equations based on experimental data that predict the effect of temperature, pH, and ionic strength on rate constants of sucrose decomposition in acid and alkaline medium. Other workers61 report that Vukov s equation generally agrees with their experimental rate data. 

The final chapter, by Clarke, Edye, and Eggleston (New Orleans, Louisiana), deals with the centuries-old technological problem of maximizing yield in the extraction of sucrose from cane or beet juice. Somewhat remarkably, important misconceptions about the fundamental aspects of alkaline degradation of sucrose still persist. The authors of this chapter effectively interpret traditional sugar technology, based largely on empirical art, in clear terms of accepted fundamental principles of chemistry. 

The subcellular location of PG was studied in cells disrupted by osmotic lysis through formation and disruption of sphaeroplasts from self-induced anaerobically-grown cells. A discontinuous sucrose-density gradient produced four bands labelled I, II, III and IV. Band I included many vesicles and a peak of alkaline phosphatase activity (a vacuolar marker in yeasts), NADPH cytochrome c oxidoreductase activity, an endoplasmic reticulum marker, and... 

The transesterification of sucrose has been performed with a fatty acid ester of a volatile alcohol in the presence of an alkaline catalyst in a dipolar, aprotic solvent.142 The reaction of sucrose (293 mmoles) with methyl dodecanoate (293 mmoles) in A/,N-dimethylformamide in the presence of sodium methoxide in a pressure bomb for 8 h at 130° gave, after solvent extraction and crystallization, sucrose mono(dodecanoate) (m.p. 72-80° [a]D+52°) in 50% yield.142 Commercialization of these sucrose esters has so far been limited, in part because of the use of expensive solvents, and, in part, because solvent remaining in the product makes it unsuitable for use as a food emulsifier. In view of this situation, methods have been developed in which the use of toxic and expensive solvents has been avoided. 

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