Soaps caustic alkali

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. 

Dobbin s reagent analychem A mercuric chloride-potassium iodide reagent used to test for caustic alkalies in soap. dab-anz re a- ant ... 

Wakbukton s method of effecting the purification of rape oil is by treatment with caustic alkali, ia which, the albuminous and other impurities are soluble, and are. separated, associated with soapy matters. In a suitable vessel, containing fifty-two parts of. caustic soda solution, of specific gravity 1-010, are to be put one hundred pounds of the refined oil those are to be stirred with a wooden ladle till well mixed. The mixture is then allowed to stand twenty-four hours undisturbed, in a cold place, after which it is then slowly warmed, and again well stirred. After twenty-four hours subsidence all the oil will have separated if such should not bo entirely the case, the complete separation may be effected by the addition of a small quantity of spirit of wine. The oil drawn off from the liquor is afterwards well washed with hot water, till the pure oil is obtained without taste or color, and if desired, may be passed through a filter. The soap which deposits may be used as an ordinary detergent... 

Olive oil is largely glyceryl oleate, and palm oil, glyceryl palmitate. When warmed with solutions of caustic alkalies, these fats are decomposed, yieldmg soaps, hence the term saponification. Thus, for example, with sodium hydroxide, glyceryl stearate yields free glycerine and sodium stearate, which latter is a sodium soap. Thus... 

Both animal and vegetable oils are used in the manufacture of soap and candles. When fats and oils —such as tallow, palm oil, olive oil—-.are boiled in large east iron pans with caustic alkali, they become decomposed and yield an alkaline salt of the fatty acid—soap and glycerine. The excess of alkali and the glycerine are separated by the addition of a solution of common salt the soap, being insoluble in the brine, rises to the top, and is ladled out as a granular curdy mass, run off into frames—boxes—to cool and solidify. Hard soaps, shell as curd and yellow soap, are compounds... 

White, odorless, tasteless, heavy powder slowly dec by sunlight into mercuric chloride and metallic mercury sublimes at 400-500 without melting, d 7.15. Practically insol in water (0-00020g/]00 ml H20 at 25 ) HCI or alkali and alkaline earth chlorides increase soly in water. Insol in alcohol. ether. Dec by solns of alkali iodides, bromides or cya -nides into the mercuric salt and metallic mecury solns of alkali chlorides act similarly but slowly. It is blackened by ammonia, caustic alkali and alkaline earth solns. Protect from light. Incompat Bromides, iodides, alkali chlorides, sulfates, sulfites, carbonates, hydroxides, lime water, acacia, ammonia, golden antimony sulfide, cocaine, cyanides, copper salts, hydrogen peroxide, iodine, iodoform, lead salts, silver salts, soap, sulfides. 

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... 

The Jjey Tanks, containing caustic alkali of various ascertained strengths, are sometimes placed at one end of the series of soap-pans, and at a suitable height above them, so that the leys may be conveniently run olF by iron shoots into each pan, by turning the tap connected to either tank. Those tanks are commonly made of wrought iron plates riveted together,... 

It had long been the desire of soap-makers to possess some process of saponification less tedious and costly than the ordinary systems of soap-boiling. It was well own that caustic alkalies would convert into saponaceous matter fats and oils, without the application of heat, and it was also well known that during the process of saponification by the ordinary system of boiling over caustic leys, a considerable amount of glycerine was set free, and which, being a substance soluble in water, passed away with the spent or waste leys, causing a direct and positive loss in the manufacture. 

These fatty matters do not reqnire caustic alkali for their conversion into soap, since they have already been converted into fat acids, by the various processes employed in the manufacture of stearine for candle-making. It is usual, therefore, to treat these oils with carbonated alkali, as before shown. There are, however, several methods of neutralising these fat acids with carbonate of soda, from which the manufacturer may select that which has his preference. It is necessary that the soap-pan should he capacious, or that only a moderate charge of oil should be... 

Gluten in Soap.—This process, patented hy Lorherg, consists in making a solution of gluten in caustic alkali, which is afterwards to he mixed with soap to the extent of... 

Soaps made from imimal Itefase.— Although it is well known that caustic alkalies will saponify animal tissues, membraneous matters, and indeed all parts of animals except the bone, this source of soap-making material has not been much explored in this country. On the Continent, however, some attention has been devoted to this subject, and many processes devised for utilizing slaughterers offal and batchers waste as soap materioL Some of these processes are given in Dussauce s Treatise, from which we make a few extracts —... 

Hydrolysis or Saponijication of Oils cuid Fats.—The decomposition of a triglyceride, brought about by caustic alkalies in the formation of soap, though generally represented by the equation already given (pp. 6 and 7)—... 

During the last few years, however, there has been a growing attempt to first separate the glycerol from the fatty acids, and then convert the latter into soap by treatment with the carbonates of soda or potash, which are of course considerably cheaper than the caustic alkalies, but cannot be used in the actual saponification of a neutral fat. The two processes chiefly used for this purpose are those in which the reaction is brought about by enzymes or by Twitchell s reagent. 

It is essential that the boiling by steam should be well maintained throughout the process until all carbonic acid gas has been thoroughly expelled when that point is reached, the steam may be lessened and the contents of the vat or pan gently boiled on strengthwith a little caustic lye until it ceases to absorb caustic alkali, the soap being finished in the manner described under (D). 

NeMimlhimj, (hhiirmj mid Perfimim/,—The free caustic alkali in soap, intendcKl for toilet or laundry purposes, is usually neutralised... 

Tailed Soaps,—By the term toilet Boap is inferred a soap specially adapted for toilet use by reason not only of its good detergent and lathering quaiitum, but also on account of its freedom from caustic alkali and any other ingredient likely to cause irritation or... 

Soap, to be suitable for the purpose, must be free from uncombined caustic alkali, unsaponified fat, silicates, and rosin. 

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