Magnesium oleate

Problem 27.3 Draw the structure of magnesium oleate, a component of bathtub scum. 

If a solution of magnesium oleate is used instead of sodium oleate (soluble in oil but not in water), the oil becomes the external phase, and the water the internal. 

Prepare a little magnesium oleate by treating a solution of sodium oleate with magnesium sulfate. Carefully wash the precipitate free from soluble impurities and dry at about 110°. Suspend 1 g. of the dry salt in 100 cc. of benzene and provide the flask with a reflux condenser. Boil until solution is obtained. Possibly the product is a colloidal dispersion rather than a very perfect solution. It has been found that a very little sodium oleate mixed with the magnesium oleate rendered the emulsions more permanent. 

In a flask of about 150 cc. capacity, put 5 cc. of concentrated magnesium oleate solution, 5 cc. of benzene, 9 cc. of water, and 1 cc. of 1 per cent sodium oleate. Shake vigorously and at intervals of about 1 min. interrupt the shaking and add 2-cc. portions of water until a total of 20 cc. has been added. It is not practicable to go above 96 per cent of water, and emulsions containing about 75 per cent are more satisfactory. 

Magnesium Oleate. C AS 1555-53-9). MgtCmHuO ) . yellowish mass, soluble in linseed oil. hydrocarbons, alcohol, and ether, insoluble in water, combustihlc. formed by reaction of soluble magnesium salt solution... 

Magnesium oleate is insoluble in water and soluble in organic solvents, hence it can be used for dry cleaning. 

According to the above reactions, removal of carbonate groups from the mineral surface should result in the reduction of the intensity of carbonate peak as shown in Fig. 4.33. On the other hand, adsorption and surface precipitation of oleate can take place on the dolomite surface leading also to similar reductions. A new peak at 1351 cm when the oleate concentration reaches about 10 mol/1 can be clearly seen in Fig. 4.33b and the intensity of this peak increases with the increase in the oleate concentration, where precipitation of calcium and magnesium oleates is likely to occur both on the particle surface and in the bulk. The peak heights of both the carbonate and the oleate (7co and 7oi) in the spectra were measured. Bulk precipitation using a common tangent baseline method (Willis et al., 1987) and the ratio Ico/Ioh is plotted in Fig. 4.34. This plot also... 

It can be seen that magnesium addition to calcium oleate solution or vice versa does shift the transmission curve to lower oleate concentrations, indicating co-precipitation of calcium and magnesium oleates due to synergistic effects. Overlapping of both the curves in Fig. 4.36 is also in line with the behavior of the dolomite and francolite systems in microflotation and dissolution experiments. Simultaneous measurements of dissolved species in the supernatant of the precipitated solutions (Fig. 4.37) showed Ca and Mg levels to remain almost constant until solubility products of their oleate are reached (2 x 10 " mol/1... 

At intermediate concentrations (10 to 2 x 10 mol/1. Region II), the solubility Umit of calcium and magnesium oleates may exceed in the interfacial region but not in the bulk solution. Then, surface precipitation of oleate on the mineral particles occurs leading to an increase in oleate depletion and a decrease in the levels of dissolved calcium and magnesium species. The hydrocarbon tails of the oleate molecules would be oriented towards the bulk making the mineral surface hydrophobic. 

At higher concentrations (>2.0 x 10 mol/1. Region III), the slope of the isotherm is higher and a sharp decrease in concentrations of dissolved species takes place. This suggests that oleate depletion and bulk precipitation of calcium and magnesium oleates predominates in this region. 

Calcium hydroxide phosphate Calcium monocarbonate Calcium phosphate monobasic monohydrate Dicyclopentadiene/linseed oil copolymer Dioctyl sodium sulfosuccinate Diphenyl octyl phosphate Hydrogenated polyisobutene Magnesium caprate Magnesium caprylate Magnesium oleate Menhaden oil PEG-10 PEG-18 PEG-240 PEG-2 castor oil... 

Using Table 15.1 as a guide, write the structural formula for a. sodium laurate b. magnesium oleate c. glyceryl trimyristate... 

Magnesium stearate and zinc stearate cool and cover the skin and in combination with fatty oil, such as arachis oU, they form magnesium oleate and zinc oleate. These oleates act as thickening agents and render the oil into oleogels (see Sect. 23.7.3 and Table 23.20). 

Octadecenolc acid, 12-hydroxy-, zinc salt. See Zinc ricinoleate 9-Octadecenolc acid, isodecyl ester. See Isodecyl oleate 9-Octadecenolc acid (Z)-, magnesium salt. See Magnesium oleate 9-Octadecenolc acid, methyl ester (Z)-9-Octadecenoic acid, methyl ester. See Methyl oleate... 

Lauraminopropionic acid Lauryl/myristyl p-aminoproplonic acid Mackam 151L Unitex710-L 1555-53-9 Magnesium oleate 1555-56-2... 

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