General Chemistry

 

 

Basic Chemical Properties 

Types of Soils 

Types of Surfaces 

Types of Cleaners

 

 

 

 

 

Basic Chemical Properties

Detergents – wetting, penetrating, dispersing, and emulsifying agents Alkalinity 

pH – pH scale, pH buffers, pH versus Alkalinity 

Chlorination 

Acidity 

Solvents 

Chelating Agents

 

 

Water

Water on a surface forms drops. Each drop has a surface tension which is a force around the outside of the drop to keep it attached to itself, like and elastic skin that will not let it mix with other drops.

 

 

Detergents Function As Wetting Agents (Surfactants)

Surface Active Agents: 

Surfactants break the water surface tension and make the drops disperse to cover the entire surface. Chemically you have now made the water wetter.

 

 

Detergents Function As Penetrating Agents

Now that the water drops are evenly spread, penetrating properties of detergents enable the solution to get under the soil and release it from the surface.

 

 

 

Detergents Function As Emulsifying Agents

Now that the soil is released it must be broken into smaller particles, this is done by emulsifying properties of detergents.

 

Detergents Function As Dispersing Agents

Once the soil is emulsified into smaller particles it must be dispersed in the solution until it is rinsed otherwise the particles would settle out and have a dirty residue on the surface.

 

 

Alkalinity

Most soils consist of natural fatty acids which are immiscible with water. Alkalinity reacts with fatty acid to form a fatty acid soap. This is known as saponification. This fatty acid soap can then be rinsed away with water.

 

 

pH Scale

 

 

pH Buffers

Designed to keep pH constant during the cleaning cycle so that detergents can work properly. Detergents function best in an alkaline environment.

 

 

Alkalinity vs. pH

 

 

Chlorination

Chlorine attacks protein, sugar and blood. Proteinous substances are found in all food processing establishments but are dominant in such places as peanut & bean processors, kill plants and sugar refineries. Chlorine also serves as a sanitizing agent. Alkalinity works through saponification. Chlorine works through oxidation forming oxides which can be rinsed away with water.

 

Acidity

Neutralizes alkaline residues 

Dissolves mineral deposits 

Water Hardness 

Milkstone 

Limestone 

Beerstone 

Brightens stainless steel and aluminum

 

Solvents 

A solvent is anything that dissolves another substance, therefore water is a solvent. Synthetic solvent solutions such as glycol ethers (of which butyl is one), petroleum distillates, and d’limonene provide the ingredients necessary to dissolve synthetic greases and oils. 

Emulsification does not occur since the solvents have completely dissolved the oil.

 

Chelating Agents

While detergents keep organic soils dispersed chelating agents keep inorganic soils as dirt, clay and mud dispersed. 

They also provide some wetting and water softening.

 

Types of Soils: Organic

Petroleum derived grease 

Examples – Motor oil, lubricants, waxes, cosmetics, shoe polish 

Natually occurring grease 

Examples – Animal fats, vegetable oils 

Proteinous substances 

Examples – Blood, beans, eggs, nuts, grass stains, fruit stains 

Carbonized soils 

Examples – Smoke, soot

 

Types of Soils: Inorganic

Mineral deposits 

Examples – Milkstone, beerstone, limestone (calcium) from water hardness 

Oxide film 

Examples – Rust, coffee stains, tea stains 

Dirt 

Examples – Soil, clay, mud 

 

Types of Surfaces

Glass 

Plastic 

Ferrous metals 

(containing iron) 

Steel, stainless steel, black iron

Non-ferrous metals 

            (non-iron containing) 

            Aluminum, copper, brass

Masonry 

            Concrete/brick 

Painted Surfaces 

            Wood, plaster, sheet rock 

Porcelain 

            Urinals, toilets

 

Types of Cleaners

Alkaline Detergent (heavy duty, medium duty) 

Chlorinated alkaline detergent 

Acid cleaner 

Water based alkaline solvents 

Neutral detergent

 

Which Cleaner for Which Soil?

 

 

 

Which Cleaner for Which Soil? 

 

 

 

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References/Resources: Rekhelman, Michael. General Chemistry Course-ABC Compounding. "General Chemistry of Industrial Chemicals." The ABC's of General Chemistry Volume I (Feb 1993): Course 1