Mannitol in water

Sorbitol and mannitol represent a pair of hexytols that differ only in the configuration of one hydroxy group at C2. This slight difference in their configurations gives both compounds differing physicochemical properties. For example, sorbitol is three and one half times more soluble than mannitol in water. Previous MD simulation of these hexytols (2) pointed out some characteristics that warrant further discussion. In particular their conformations depended on the solvent system. 

Table II shows the average end-to-end distance over 20 ps for mannitol and sorbitol in vacuuo and in solution of an argon-like (L-J) solvent and SPC/E water. The average lengths all indicate sickle shapes, except for mannitol in water which is fully extended. This points to a specific solute-solvent interaction between mannitol and water, not just an unspecific solvent effect that is not present in solvent other than water. The model non-aqueous solvent is very artificial, but it should represent the main features of the class of non-polar, spherically symmetric solvents.

Figure 2. Time evolution of the end-to-end distance of ([])sorbitol in water (X)mannitol in water (o) mannitol in a U solvent.

Polyuria is a common side effect of Li treatment. To test whether inositol would mitigate Li -induced polydipsia-polyuria, rats were given either 2.5% mannitol or inositol in water. Half the rats in each group were injected intraperitoneally daily with either LiCl or NaCl. A fifth group was injected with LiCl daily but drank tap water. Li induced marked polydipsia, and Li -treated rats that drank the inositol solution had significantly less polydipsia than Li -treated rats that drank tap water or mannitol in water [Bersudsky et al. 1992). 

Figure 6.18 Plot of tonicity versus concentration for mannitol in water.

A potentiometric study of complexes formed by boric acid or potassium borate with mannitol in water or aqueous KCl solution has been carried out.2 The formation constant -Kcn of the mono-mannitoboric complex was determined (pAcn = 0.20 in HgO as solvent). 

Fig. 5.5. Effect of temperature on the diffusivity of mannitol in water solution.

Figure 2 Cooling curve for 5% mannitol in water with 5 mm liquid thickness.

Figure 5 Temperature curves for freeze-drying of 5% mannitol in water with...

Tartrate reagent. Dissolve, separately, 10 g of sodium hydrogen tartrate (NaHC4H40e,H20), 2 5 g of hydrazine sulphate and 10 g of mannitol, in water, mix the three solutions and dilute to 1 litre with water. 

Removal of bases from mixtures of bases and neutral compounds. The procedure here is essentially the same as in (i) above. The base is retained by the column. Use a solution of 0 05 g. of benzylamine and o-i g. of mannitol in 100 ml. of water. The effluent contains only mannitol. 

Aubertein Rehling (Ref 15) have shown that treatment with water at approx 100° causes PETN to hydrolyze. At 125° and under pressure, hydrolysis proceeds quite quickly, and is considerably enhanced by the presence of 0.1% HNO3. Regardless of whether it occurs in water alone or in water acidified with nitric acid, the hydrolysis produces mainly Penta-erythritol Dinitrate. A dil NaOH soln causes PETN to hydrolyze.more rapidly than acidified water. PETN neither reduces Fehling s reagent nor enters into addition products with any aromatic nitro compd. In this respect it differs from both Erythritol Tetranitrate and Nitro-mannitol... 

Figure 2 The rate of water loss and residual water content during freeze drying. Moxa-lactam disodium formulated with 12% mannitol in aqueous solution at 30% solids 10 mL tubing vials with a solution fill depth of 1 cm. The chamber pressure was 0.05 torr (6.6 Pa). (From Ref. 2.)...

Figure 7 The effect of chamber pressure on the rate of primary drying, (a) 0.18 M methylprednisolone sodium succinate 2 mL in molded vials (2.54 cm2), shelf temperature +45°C. (Smoothed data from Ref. 6.) (b) Dobutamine hydrochloride and mannitol (4% w/w in water), 12 mL in tubing vials (5.7 cm2) and shelf surface temperature +10°C. (MJ Pikal. Unpublished data.) (Modified from Ref. 1.)... 

The mother liquor was then treated with a small amount of ether, whereupon it separated into two layers. The lower layer consisted of a black sirup, which, when treated with absolute alcohol very slowly deposited some crystals, 1 g., consisting largely of D,L-mannitol. The upper layer was treated with a large volume of ether, which caused the precipitation of a considerable quantity of a brown sirup. Crystallization began almost immediately, especially when the sirup was treated with absolute alcohol. The crystals were collected and there was obtained in this way 12 g. of crude allitol. After solution in water and precipitation with alcohol, the crystals melted at 140°, but still contained a small amount of impurity. After several recrystallizations they melted at 149°. 

The unmodified catalyst was prepared by dissolving cobalt nitrate hexahydrate (19.76g, 68 mmol) in water (9 ml) and impregnating the solution into alumina (16.0 g). The catalyst was dried at 105°C in static air for 3 h and calcined at 400°C for 1 h. The mannitol-containing catalyst was prepared as described above, except that mannitol (2 g, 11 mmol) was dissolved in the cobalt nitrate solution prior to impregnation. The Co/mannitol ratio was 6.2. 

Visible spectroscopy (Figure 1.7) shows that mannitol does not form a complex with cobalt nitrate hexahydrate in water, even when heated to reflux. This... 

Another proof of the configuration of D-mannitol and also of D-manno-n-manno-octitol (XVI), which is likewise dependent on the experimental proof of the equivalent symmetry of D-mannitol is the following. D-Mannose has been converted, by successive cyanohydrin syntheses, first to a mannoheptose and then to a mannooctose which on reduction yielded a mannooctitol whose octaacetyl derivative is optically inactive. (It was not possible to examine the octitol itself because of its very low solubility in water.)87 The meso character of the octaacetate shows that the mannooctitol must possess a meso configuration, with a plane of symmetry between carbon atoms 4 and 5. To write its formula, the hydroxyl at carbon atom 7 is placed on the... 

Molecular dynamics (MD) simulations show that the conformations of sorbitol and mannitol depend on the typ e of solvent. The predicted conformations agreed well with experiment, supporting the view that MD has a good predictive value for solutions of carbohydrates. Preliminary dynamics results for methoxy-tetrahydropyran (MTHP) show that the methoxy group moves more in water than in vacuum. 

In this work we discuss further the previous results from simulations of sorbitol and mannitol and compare them with new calculations and recent experimental data. We also present some preliminary data for methoxy-tetrahydropyran (MTHP) in vacuo and in water. 

Table III. NMR Proton Coupling Constants for Mannitol and Sorbitol in Water...

Recent 620.6 MHz nmr results on sorbitol and mannitol (9) confirm that sorbitol rotates more freely in water than mannitol. This suggests that there is less solute-solvent interaction in sorbitol. Calorimetric results (J ) predict that sorbitol and mannitol should have hydration behavior similar to that described above. Those workers, however, referred to structure breaking properties, even though no structural data was obtained. 

There are many reports of hexitol borates, but most of these are probably not true esters but complexes. Only two well-defined crystalline esters, 1-D-mannitol monoborate - and 2-D-mannitol monoborate are known. The borate esters are unstable in water. 

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