Grease types mixing greases

Water-in-oil emulsion — A type of emulsion in which droplets of water are dispersed throughout oil. It is formed when water is mixed with a relatively viscous oil by wave action. This type of emulsion is sometimes stable and may persist for months or years after a spill. Water-in-oil emulsions containing 50 to 80% water are most common, range in consistency from grease-like to solid, and are generally referred to as chocolate mousse . (See also Chocolate mousse, Emulsification, Oil-in-water emulsion.)... 

Many food soils are encountered in hand dishwashing, such as grease, carbohydrate, protein, dairy, and mixed soils. Baked-on soil requires more vigorous treatment, either mechanical or chemical [26], The type of oily soil is almost exclusively triglycerides. The hydrocarbon chains in food triglycerides are predominantly C12 to Cl6, although higher and lower chains are also present. 

Most of the things we commonly think of as dirt (such as grease, oil, and fat stains) are nonpolar and insoluble in water. When soap and this type of dirt are mixed together, as in a washing machine, the nonpolar hydrocarbon inner parts of the soap micelles dissolve the nonpolar dirt molecules. In effect, new soap micelles are formed, this time with nonpolar dirt molecules in the center (Figure 19.4). In this way, nonpolar organic grease, oil, and fat are dissolved and washed away in the polar wash water. 

The use of Nansen bottles has some disadvantages, one being based on their construction. The closing mechanism impairs flushing of the sampler due to dead volumes and turbulent mixing. Modern samplers of the Nansen type are usually made of plastic materials such as polycarbonate (PC) and poly (vinyl chloride) (PVC) instead of brass (Table 1-2). Such samplers are less robust, but lighter, they are non-corrosive, greasing of the valves becomes unnecessary and interference with sample composition is minimized. 

Colloidal solutions are also a type of emulsion, a mixture of two substances that would not normally mix. A substance that causes one substance to disperse in another is called an emulsifying agent or emulsifier. Soap is an emulsifying agent because it causes grease and water to form an emulsion. Some food additives are emulsifiers because they keep foods that would ordinarily separate into layers, such as peanut butter, in just one smooth emulsion. 

You probably know from experience that a particular solvent, such as water, does not dissolve all possible solutes. For example, you cannot clean your greasy hands with just water because the water does not dissolve the grease. However, another solvent, such as paint thinner, can easily dissolve the grease. The grease is insoluble in water but soluble in the paint thinner. The solubility of a snbstance is the amount of the substance that will dissolve in a given amount of solvent. The solubility of sodium chloride in water at 25 °C is 36 g NaCl per 100 g water, while the solubility of grease in water is nearly zero. The solubility of one substance in another depends both on the tendency toward mixing that we discnssed in Section 12.1 and on the types of intermolecular forces that we discussed in Chapter 11. 

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