Soaps direct saponification

The basic process is that of reacting fat stocks with alkali to form soap (direct saponification) and glycerin, followed by washing to remove the glycerin. Two methods of direct saponification are in common use kettle method and continuous saponification). An alternative method is splitting fat stocks with water (hydrolysis) to form fatty acids and glycerine, followed by neutralization of the fatty acids with alkali,... 

Commercially, soap is most commonly produced through either the direct saponification of fats and oils with caustic or the hydrolysis of fats and oils to fatty acids followed by stoichiometric (equal molar) neutralization with caustic. Both of these approaches yield workable soap in the form of concentrated soap solutions (- 70% soap). This concentration of soap is the target on account of the aqueous-phase properties of soap as well as practical limitations resulting from these properties. Hence, before discussing the commercial manufacturing of soap, it is imperative to understand the phase properties of soap. 

Direct Saponification. Direct saponification of fats and oils is the traditional process utilized for the manufacturing of soap. Commercially this is done through either a kettle boiling batch process or a continuous process. 

Comparison of Base Soap Manufacturing Routes. Direct saponification of fats and oils is well known, characteri2ed, and straightforward requires Httle equipment and is relatively energy-efficient. However, it is not very effective with regard to changes in the fats and oils ratio desired for finished soap bar formulations. Furthermore, direct saponification has the drawbacks of lower glycerol yields, limited flexibiUty toward... 

Fatty adds are predominantly used as intermediates. Main applieations are water soluble soaps for household eleaning, personal care, industrial and institutional (I I) cleaning and synthetic rubber manufacturing by emulsion polymerization. Soaps are made by reaction of fatty acids with caustic alkalis, alkali carbonate or ammonia or (>90%) by direct saponification of the triglyceride oil. Another important group of fatty add soaps are dry, water-insoluble metal soaps used as lubricants or stabilizers for PVC and other plastics and aqueous calcium stearate dispersions applied as paper coating... 

For direct saponification routes to soap, once a fat blend has been selected then particularly for toilet soap formulations, some method of raw material pretreatment is often applied. Commonly used methods involve bleaching, either with diatomaceous earth or activated carbon and, less commonly, deodorization... 

Besides olive-oil, the earth-nut, sesame, linseed, coleseed, and black garden poppy-oils, greases, tallows, eio. are also used in the fabrication of marbled soaps but the soap resulting from these different combinations of oily and fatty makers, while being of good quality, cannot be compart to those obtained by the direct saponification of olive-oiL The latter are always denser, firmer, and finer. 

Classification of Soaps—Direct combination of Patty Acids with Alkali— Cold Process Soaps—Saponification under Increased or Diminished Pressure—Soft Soap—Marine. Soap—Hydrated Soaps, Smooth and Marbled — Pasting or Saponification — Graining Out — Boiling on... 

F it is intended to make glycerine soaps by direct saponification—crutching—then the fillingsubstances, glycerine and sugar, should be added to the soap mass immediately after saponification. 

Carboxylate soaps are most commonly formed through either direct or indirect reaction of aqueous caustic soda, ie, alkaH earth metal hydroxides such as NaOH, with fats and oils from natural sources, ie, triglycerides. Fats and oils are typically composed of both saturated and unsaturated fatty acid molecules containing between 8 and 20 carbons randomly linked through ester bonds to a glycerol [56-81-5] backbone. Overall, the reaction of caustic with triglyceride yields glycerol (qv) and soap in a reaction known as saponification. The reaction is shown in equation 1. 

Tho formation of yellow soap from rosin depends on the direct combination of the resin acids with soda. No glycerin is eliminated, there being np proper saponification. The compounds formed, however, by the union of soda with rosin are not separable from their... 

Saponification can proceed directly as a one-step reaction as shown above, or it can be achieved indirectly by a two-step reaction where the intermediate step generates fatty acids through simple hydrolysis of the fats and oils and the finishing step forms soap through the neutralization of the fatty acid with caustic soda. There are practical considerations which must be addressed when performing this reaction on a commercial scale. 

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