Soft soaps

The raw materials for the manufacture of soap, the alkali salts of saturated and unsaturated C10-C20 carboxylic acids, are natural fats and fatty oils, especially tallow oil and other animal fats (lard), coconut oil, palm kernel oil, peanut oil, and even olive oil. In addition, the tall oil fatty acids, which are obtained in the kraft pulping process, are used for soap production. A typical formulation of fats for the manufacture of soap contains 80-90% tallow oil and 10-20% coconut oil [2]. For the manufacture of soft soaps, the potassium salts of fatty acids are used, as are linseed oil, soybean oil, and cottonseed oil acids. High-quality soap can only be produced by high-quality fats, independent of the soap being produced by saponification of the natural fat with caustic soda solution or by neutralization of distilled fatty acids, obtained by hydrolysis of fats, with soda or caustic soda solutions. Fatty acids produced by paraffin wax oxidation are of inferior quality due to a high content of unwanted byproducts. Therefore in industrially developed countries these fatty acids are not used for the manufacture of soap. This now seems to be true as well for the developing countries. 

Further important auxiliary agents for the manufacture of soap are caustic soda solution, calcined soda, sodium chloride, and (for the manufacture of soft soap) caustic pottash solution, potassium carbonate, and potassium chloride. 

Odor Fruity odor in high concentrations smells like soft soap with a fishy smell in low concentrations. 

The choice of alkali was more difficult. In Leblanc s time, the alkali was generally a carbonate (C03) or hydroxide (OH) of potassium or sodium extracted from the ashes of salt-rich plants. For example, northerners made an odoriferous soft soap by burning wood and boiling its ashes with animal fat or fish oil. In Spain, Marseilles, Genoa, and Venice, hard Castile soap was made by boiling olive oil with the ashes of seaweed and shore plants. 

It is used to manufacture both hard and soft soaps, as a bleaching agent, and where a highly caustic chemical is required. 

A wide range of substances is permitted for alternative crop production. For example, LOJ, Denmark is the only certifying body reviewed so far that provides maximum concentrations of solutions of sulphur, soft soap and mineral oils. Furthermore, several substances permitted by IFOAM and EU standards are not allowed, such as pyrethrum, copper salts, chloride of lime and soda, or microbial pest controllers. Spain (CRAE 1994) stands on the other end of the spectrum with their exclusive focus on the EC Reg. 2092/91. 

Potassium hydroxide is used to make soft soap, in scrubbing and cleaning operations, as a mordant for woods, in dyes and colorants, and for absorbing carbon dioxide. Other principle uses of caustic potash are in the preparation of several potassium salts, acid-base titrations, and in orgainic sytheses. Also, KOH is an electrolyte in certain alkaline storage batteries and fuel cells. 

The analogy comes from someone who was impressed by the soft acid—soft base work. As a matter of fact, he felt that acids and bases react to give salts, and soap is a salt, and so we have soft soap. 

Potassium carbonate is used in the chemical industry as a source of inorganic potassium salts (potassium silicates, potassium bicarbonate), which are used in fertilizers, soaps, adhesives, dehydrating agents, dyes, and pharmaceuticals. Potassium carbonate used to make potassium lye produces soft soaps, which are liquids or semisolids rather than solids. Other uses of potassium carbonate includes use as a fire suppressant in extinguishers, as a C02 absorbent for chemical processes and pollution control, an antioxidant in rubber additives, and in pharmaceutical formulations. 

The vinasse of sugar beet.—Sugar beet contains about 0 5 per cent, of potash, K20, largely in combination with organic acids. The potash accumulates in the molasses of the best sugar factories. The molasses are fermented and distilled for alcohol. The residue which remains in the retort—called vinasse—may be used as a manure, or it may be mixed with lime and ignited to form what was once called vinasse cinder, and used in the manufacture of soft-soap. It is, however, more profitably refined for potash by fractional crystallization.6 The product has approximately the composition ... 

Uses of the alkali hydroxides.—A soln. of potassium hydroxide is used in the laboratory as an absorbent for carbon dioxide, the sodium compound is not so often used because of the formation of less soluble sodium carbonate which is liable to choke the delivery tubes with crystals. Potassium hydroxide is used in making soft soaps the corresponding sodium compound gives the ordinary hard soaps. The hydroxide fused with a little lime is used as a cautery—pierre a cautere. The alkali lye is also used as a cleansing fluid, since it forms soluble soaps with many greases and fats. The lye also dissolves animal tissues. 

Soft Soaps.—Those differ from ihe hard s oapB in having potassa in place of soda as their alkaline baae. They arc all more or less pasty or gelatinous and they may be made either by the boiling or cold process. Of the soft soaps used in perfumery, that known as fig soap is, however, the only one that is boiled. 

Materials,—The materials used in the manufacture of soap, are the various kinds of oil or fat, resin, and the alkalies, potassa and soda. All oils and fats of whatever kind, vegetal or animal, yield soaps, when treated with alkali, as will he subsequently described. Only a very limited number, however, is used in thiB manufacture and these such as may be obtained at a very low price compared with that of the others. In Great Britain palm-oil is probably consumed in greater quantity than any other, and principally in the production of hard soap for soft soaps, the various kiuds of fish-oils, the drying oils from seeds, and tallow are mostly employed. 

In France, and on the Continent, olive oil is extensively used in soap-making and for soft soaps, hemp-seed oil is highly valued. 

Nevertheless, much room remains for future investigators in this wide field and many improvements may still be expected from further research. Tallow, olive, palm, and cocoa-nut oils, oleic acid, and resin are used for the production of hard soaps fish and seed oils, on the contrary, for soft soaps. The mixture of oleic acid with amall quantities of stearic and margaric acids, which is obtained in the separation of steario acid by pressure, as desoiibod under the artlola Candle, affords an excellent soap, the production of which is a secondary... 

Soft Soap.—This variety of soap differs in many essential particulars from those already described. The alkali need in its production is potassa exclusively, and the oil, either in whole or in part, a drying oil, as that of hemp seed, popples, et cetera, or fish oil, as whale or seal oil. The theory of the reaction of potassa upon fateand oils is precisely the same as in the case of soda. Soaps with potassa base are, however, manufactured on an entirely different system to those of soda or hard soaps. In tbe latter, the soap is withdrawn from the lio when only a portion of the ojl lias been sapomfiod, and fresh lies are added nntil saponification is complete. 

Ordinary soft soap, 1st sample, 44-0 n o 9-5 it 2(1-5 465 ii Vbuviruh. ClIEVItECL. 

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