The Handbook of Soap Manufacture | Page 7

| Found in | | Point, | | | °C. | ------------------------------------------------------------------------------- Acetic | CH{3}COOH | 17 | Macassar oil. ------------------------------------------------------------------------------ Butyric | C{3}H{7}COOH | ... | Butter, Macassar oil. ------------------------------------------------------------------------------ Isovaleric | C{4}H{9}COOH | ... | Porpoise and dolphin oils. ------------------------------------------------------------------------------ Caproic | C{5}H{11}COOH | ... | Butter, cocoa-nut oil. ------------------------------------------------------------------------------ Caprylic | C{7}H{15}COOH | 15 | Butter, cocoa-nut oil, | | | Limburg cheese. ------------------------------------------------------------------------------ Capric | C{9}H{19}COOH | 30 | Butter, cocoa-nut oil. ------------------------------------------------------------------------------ Lauric | C{11}H{23}COOH | 44 | Cocoa-nut oil, palm-kernel oil. ------------------------------------------------------------------------------ Ficocerylic | C{12}H{25}COOH | ... | Pisang wax. ------------------------------------------------------------------------------ Myristic | C{13}H{27}COOH | 54 | Nutmeg butter, liver fat, | | | cocoa-nut oil, dika fat, | | | croton oil. ------------------------------------------------------------------------------ Palmitic | C{15}H{31}COOH | 62.5 | Palm oil, most animal fats. ------------------------------------------------------------------------------ Daturic | C{16}H{33}COOH | | Oil of Datura Stramonium. ------------------------------------------------------------------------------ Stearic | C{17}H{35}COOH | 69 | Tallow, lard, most solid | | | animal fats. ------------------------------------------------------------------------------ Arachidic | C{19}H{39}COOH | 75 | Arachis or earth-nut oil, | | | rape and mustard-seed oils. ------------------------------------------------------------------------------ Behenic | C{21}H{43}COOH | ... | Ben oil, black mustard-seed | | | oil, rape oil. ------------------------------------------------------------------------------ Lignoceric | C{23}H{47}COOH | 80.5 | Arachis oil. ------------------------------------------------------------------------------ Carnaubic | C{23}H{47}COOH | ... | Carnauba wax. ------------------------------------------------------------------------------ Pisangcerylic | C{23}H{47}COOH | ... | Pisang wax. ------------------------------------------------------------------------------ Hy?nic | C{24}H{49}COOH | ... | Hy?na fat. ------------------------------------------------------------------------------ Cerotic | C{25}H{51}COOH | 78 | Beeswax, China wax, spermaceti. ------------------------------------------------------------------------------ Melissic | C{29}H{59}COOH | 89 | Beeswax. ------------------------------------------------------------------------------ Psyllostearylic| C{32}H{65}COOH | ... | Psylla wax. ------------------------------------------------------------------------------ Theobromic | C{63}H{127}COOH | ... | Cacao butter ------------------------------------------------------------------------------
Medullic and margaric acids, which were formerly included in this series, have now been shown to consist of mixtures of stearic and palmitic, and stearic palmitic and oleic acids respectively.
The acids of this group are saturated compounds, and will not combine directly with iodine or bromine. The two first are liquid at ordinary temperatures, distil without decomposition, and are miscible with water in all proportions; the next four are more or less soluble in water and distil unchanged in the presence of water, as does also lauric acid, which is almost insoluble in cold water, and only slightly dissolved by boiling water. The higher acids of the series are solid, and are completely insoluble in water. All these acids are soluble in warm alcohol, and on being heated with solid caustic alkali undergo no change.
II. Oleic Series:--
-------------------------------------------------------------------------- Acid. | Formula. | Melting | Found in | | Point, | | | °C. | -------------------------------------------------------------------------- Tiglic | C{4}H{7}COOH | 64.5 | Croton oil. -------------------------------------------------------------------------- Moringic | C{14}H{27}COOH | 0 | Ben oil. -------------------------------------------------------------------------- Physetoleic | C{15}H{29}COOH | 30 | Sperm oil. -------------------------------------------------------------------------- Hypog?ic | C{15}H{29}COOH | 33 | Arachis and maize oils. -------------------------------------------------------------------------- Oleic | C{17}H{33}COOH | 14 | Most oils and fats. -------------------------------------------------------------------------- Rapic | C{17}H{33}COOH | ... | Rape oil. -------------------------------------------------------------------------- Doeglic | C{18}H{35}COOH | ... | Bottle-nose oil. -------------------------------------------------------------------------- Erucic | C{21}H{41}COOH | 34 | Mustard oils, marine animal | | | oils, rape oil. --------------------------------------------------------------------------
The unsaturated nature of these acids renders their behaviour with various reagents entirely different from that of the preceding series. Thus, they readily combine with bromine or iodine to form addition compounds, and the lower members of the series are at once reduced, on treatment with sodium amalgam in alkaline solution, to the corresponding saturated acids of Series I. Unfortunately, this reaction does not apply to the higher acids such as oleic acid, but as the conversion of the latter into solid acids is a matter of some technical importance from the point of view of the candle-maker, a number of attempts have been made to effect this by other methods.
De Wilde and Reychler have shown that by heating oleic acid with 1 per cent. of iodine in autoclaves up to 270°-280° C., about 70 per cent. is converted into stearic acid, and Zürer has devised (German Patent 62,407) a process whereby the oleic acid is first converted by the action of chlorine into the dichloride, which is then reduced with nascent hydrogen. More recently Norman has secured a patent (English Patent 1,515, 1903) for the conversion of unsaturated fatty acids of Series II. into the saturated compounds of Series I., by reduction with hydrogen or water-gas in the presence of finely divided nickel, cobalt or iron. It is claimed that by this method oleic acid is completely transformed into stearic acid, and that the melting point of tallow fatty acids is raised thereby about 12° C.
Another method which has been proposed is to run the liquid olein over a series of electrically charged plates, which effects its reduction to stearin.
Stearic acid is also formed by treating oleic acid with fuming hydriodic acid in the presence of phosphorus, while other solid acids are obtained by the action of sulphuric