Calcium, detergency

The antioxidant performance of ZnDTP is influenced not only by the base stock composition but also by the dispersants and detergents, demonstrated by Fig. 4.7. The deleterious effect of the dispersant on the oxidation stability of the ZnDTP-containing lubricant is clearly enhanced by calcium detergents [100] and, to a larger extent, magnesium detergents [39], In summary, the additive interaction pattern is influenced by the type of dispersant and detergent, by the base stock composition and by the concentration ratio of the additives used in a formulation [101],... 

A new type of calcium detergent chemistry has been described which has inbuilt friction modification [1]. Using an oscillating Cameron-Plint tribometer, this new class of additive lowers the friction coefficient of finished lubricating... 

Overbased calcium detergents, with base numbers ranging from 250 to 400, form the backbone of the majority of marine lubricants. Although their principal function... 

There is some correlation between the work presented here and other work carried out to investigate the effect of calcium detergents on the anti-wear mechanism of ZDDP [9, 19, and 20]. The study by Wan et al. [20] has shown that there is an antagonistic effect between the detergent and the anti-wear additives which can reduce the effectiveness of the anti-wear properties of ZDDP. This effect occurs by the breakdown of calcium carbonate containing colloids and the deposition of Ca-soap molecules on the surface. 

In the case of lubricant detergents, the hydrophilic or polar part is a metallic salt (calcium, magnesium) and at the center of the micelle it is possible to store a reserve of a metal base (lime or magnesia) the detergent will be able therefore to neutralize the acids produced by oxidation of the oil as soon as they are created. 

In using the alkylphenols, it is possible to obtain three types of detergents the alkylphenols themselves transformed as salts of calcium, the alkylphenol-sulfides conferring antioxidant properties and finally the alkylphenol-sulfides transformed by action of CO2 into alkylsalicylate-sulfides (Figure 9.9). 

Detergents are made by, for example, treating petroleum hydrocarbons with sulphuric acid, yielding sulphonated products which are water soluble. These can also solubilise fats and oils since, like the stearate ion, they have an oil-miscible hydrocarbon chain and a water-soluble ionic end. The calcium salts of these substances, however, are soiu u-ic in water and, therefore, remove hardness without scum formation. 

Detergents are designed to be effective in hard water meaning water containing calcium salts that form insoluble calcium carboxylates with soaps These precipitates rob the soap of Its cleansing power and form an unpleasant scum The calcium salts of synthetic deter gents such as sodium lauryl sulfate however are soluble and retain their micelle forming ability even m hard water... 

Detergents are metal salts of organic acids used primarily in crankcase lubricants. Alkylbenzenesulfonic acids, alkylphenols, sulfur- and methjiene-coupled alkyl phenols, carboxyUc acids, and alkylphosphonic acids are commonly used as their calcium, sodium, and magnesium salts. Calcium sulfonates, overbased with excess calcium hydroxide or calcium carbonate to neutralize acidic combustion and oxidation products, constitute 65% of the total detergent market. These are followed by calcium phenates at 31% (22). 

Sequestration forms the basis for detergent and water-treatment appHcations of polyphosphates. Sequestration of hardness ions by sodium tripolyphosphate used in detergent formulations prevents the precipitation of surfactants by the hardness ions. Sodium polyphosphate glass (SHMP) may be added to water system to prevent the formation of calcium or magnesium scales by reducing the activity of the hardness ions. However, if the ratio of cation to polyphosphate is too high at a given pH, insoluble precipitates such as may result instead of the soluble polyphosphate complexes. The... 

About 264,000 metric tons of elemental capacity is available in North America, plus another 79,000 t (P equivalent) of purified wet phosphoric acid (14). About 85% of the elemental P is burned to P2 5 hydrated to phosphoric acid. Part of the acid (ca 21%) is used direcdy, but the biggest part is converted to phosphate compounds. Sodium phosphates account for 47% calcium, potassium, and ammonium phosphates account for 17%. Pinal apphcations include home laundry and automatic dishwasher detergents, industrial and institutional cleaners, food and beverages, metal cleaning and treatment, potable water and wastewater treatment, antifree2e, and electronics. The purified wet acid serves the same markets. 

Sodium fatty acid ester sulfonates are known to be highly attractive as surfactants. These have good wetting abiHty and exceUent calcium ion stabiHty as weU as high detergency without phosphates, and are used in powders or Hquids. They can also be used in the textile industry, emulsion polymerization, cosmetics, and metal surface fields. Moreover, they are attractive because they are produced from renewable natural resources and their biodegradabiHty is almost as good as alkyl sulfates (134—137). 

The largest use of calcium hypochlorite is for water treatment. It is also used for I I and household disinfectants, cleaners, and mildewcides. Most of the household uses have been limited to in-tank toilet bowl cleaners. In areas where chlorine cannot be shipped or is otherwise unavailable, calcium hypochlorite is used to bleach textiles in commercial laundries and textile mills. It is usually first converted to sodium hypochlorite by mixing it with an aqueous solution of sodium carbonate and removing the precipitated calcium carbonate. Or, it can be dissolved in the presence of sufficient sodium tripolyphosphate to prevent the precipitation of calcium salts. However, calcium hypochlorite is not usually used to bleach laundry and textiles because of problems with insoluble inorganic calcium salts and precipitation of soaps and anionic detergents as their calcium salts. 

Industrial uses make up most of the market for cyanamide. Calcium cyanamide is used directly for steel nitridation (34) and to some extent for desulfurization (36) (see Steel). Cyanamide is used to produce cationic starch (36) and calcium cyanide. Cyanamide is, of course, the raw material for dicyandiamide and melamine. New uses include intermediates for pesticides, detergents (37), medicines such as antihistamines, hypertension, sedatives, contraceptives, etc (38), the photography industry (39), as an additive for fuels and lubricants, as a paper preservative, and as a cement additive. 

Phospha.tes, Pentasodium triphosphate [7758-29-4] sodium tripolyphosphate, STPP, Na P O Q, is the most widely used and most effective builder in heavy-duty fabric washing compositions (see also Phosphoric acid and phosphates). It is a strong sequestrant for calcium and magnesium, with a p c of ca 6, and provides exceUent suspending action for soils. Because of its high sequestration power, it also finds extensive appHcation in automatic-dishwashing detergents. Sodium tripolyphosphate forms stable hydrates and thus aids in the manufacture of crisp spray-dried laundry powders. 

Sodium C rbon te. Sodium carbonate softens water by forming insoluble calcium carbonate with calcium ions in hard water. Carbonate can also reduce calcium levels by ion pairing, although the benefit to detergency is questionable. Buildup of calcium carbonate on machine and fabrics, which can occur with time, is undesirable. Sodium carbonate [497-19-8] does not provide any suspending action. It does, however, provide alkalinity to the wash hquor and is an effective alkah. 

Much of the work that led to elucidating the role of budders as calcium sequestering agents in detergency was done in connection with redeposition studies (34). 

The efforts of the detergent industry toward solution of its part of the eutrophication problem are, at this point, less complete than its response to the biodegradabihty problem. Soda ash, Na2C02, sodium siUcate, and, to a lesser extent, sodium citrate formed the basis of the early formulations marketed in the areas where phosphates were harmed. Technically, these substances are considerably less effective than sodium tripolyphosphate. As a precipitant builder, soda ash can lead to undesirable deposits of calcium carbonate on textiles and on washing machines. 

---