Saponification under pressure

Magnesia,— It has been proposed to substitute magnesia foi lime in the process of saponification under pressure, but comparative experiments with lime and magnesia, using 3 per cent, of lime and 2 7 per cent, of magnesia Soc, Ghem. Ind., xii., 163), show that... 

Early Synthesis. Reported by Kolbe in 1859, the synthetic route for preparing the acid was by treating phenol with carbon dioxide in the presence of metallic sodium (6). During this early period, the only practical route for large quantities of sahcyhc acid was the saponification of methyl sahcylate obtained from the leaves of wintergreen or the bark of sweet bitch. The first suitable commercial synthetic process was introduced by Kolbe 15 years later in 1874 and is the route most commonly used in the 1990s. In this process, dry sodium phenate reacts with carbon dioxide under pressure at elevated (180—200°C) temperature (7). There were limitations, however not only was the reaction reversible, but the best possible yield of sahcyhc acid was 50%. An improvement by Schmitt was the control of temperature, and the separation of the reaction into two parts. At lower (120—140°C) temperatures and under pressures of 500—700 kPa (5—7 atm), the absorption of carbon dioxide forms the intermediate phenyl carbonate almost quantitatively (8,9). The sodium phenyl carbonate rearranges predominately to the ortho-isomer. sodium sahcylate (eq. 8). 

For the purpose of the identification and quantification of additives (broadly defined) in polymeric materials extraction and dissolution methods are favoured (Sections 3.3-3.7). However, additives are also made accessible analytically by digestion of the sample matrix (cf. Section 8.2). Such wet chemical techniques, that remove the sample matrix first, are often limited to mg amounts because of pressure build-up in destruction vessels. Another reactive extraction approach to facilitate additive analysis is depolymerisation by acid hydrolysis or saponification, sometimes under pressure. This is then frequently followed by chemical methods such as titrimetry or photometry for final identification and quantification. 

Continuous Saponification. Fat stocks, plus caustic and salt solutions, are fed continuously into an autoclave operating under pressure at typically about 250°F (120°C). A recycle stream provides sufficient soap concentration to solubilize the fat stream for good contacting with the caustic. The soap-lye-glycerin mix moves to a mixer/cooler to complete saponification. The cooler temperature reduces the solubility of soap in the lye and aids separation. See also Saponification. 

Toluene, formaldehyde, HC.1, calcium hydroxide, and UNO , comprise the chargestock. In step 1 of this process, the toluene is reacted with concentrated HC1 at about 70°C along with paraformaldehyde. This accomplishes chloromethylation of approximately 98% of the toluene. In step 2, saponification of the chloromethyltoluene is effected with lime and H20 under pressure and at about 125°C. The product is methylbenzyl alcohol. In step 3. the methylbenzyl alcohol is oxidized with HNO3 (dilute) under a pressure of about 20 atmospheres and at a temperature of about 170°C. The main products are o-phthalic acid in HNO3 solution and insoluble terephthalic acid. 

Another possibility is the saponification with steam to obtain monomers from PET, similar to the hydrolysis in liquid water under pressure. In this way TPA can be obtained, on... 

Waxes are considerably more resistant to saponification than fats, and can only be hydrolysed with aqueous solutions of alkalis under pressure, or at atmospheric pressure after prolonged boiling with alcoholic potash. 

Mr. 6. W. Sogers s Process.—Sy another process, namely, that of Mr. GF, W. Rogers of Lancaster, N, T., soap is made under pressure at a lhigh temperature adopted in the above and similar systems, by which the inventor states there is a saving of tune, inasmuch as the soap can be made in from fifteen to twenty-five minutes, with complete saponification. By this plan, moreover, the materials become bleached thus enablin g inferior goods to be employed in the manufacture. The materials are mixed in a tank heated by steam, and the mass thus prepared is run into an iron cylinder capable of holding one or more tons, and subjected to a pressure of about 400 Iba. to the square inch by means of a force-pump driven by steam. The mass is kept in this cylinder until saponification is complete, when it is run into frames. By this system any of the usual combinations of fatty matters may be employed, and the product is said to be both firm and translucent. It should be observed that in both processes given carbonate of soda is used instead of caustic soda, which also renders the employment of common salt unnecessary. 

In this instance, since the molecular weight of stearin is 890 and that of milk of lime is 74, it is at once apparent that for every 1,780 parts of stearin, 222 parts of milk of lime or 168 parts of quicklime, CaO, would be required. It is found in practice, however, that an excess of 3-5 per cent, above the theoretical quantity of lime is necessary to complete the hydrolysis of a fat when carried on in an open vessel at 100°-105 0., but that if the saponification be conducted under pressure in autoclaves the amount of lime necessary to secure almost perfect hydrolysis is reduced to 2-3 per cent, on the fat, the treatment of fats with 3 per cent, of hme under a pressure of 10 atmospheres producing a yield of 95 per cent, of fatty acids in seven hours. The lower the pressure in the autoclave, the lighter will be the colour of the resultant fatty acids. 

Zi9ic Oxide.—The use of zinc oxide as accelerating agent has been suggested by two or three observers. Poullain and Michaud, in 1882, were granted a patent for this process, the quantity of zinc oxide recommended to be added to the oil or fat being 0 2 to 0 5 per cent. Host, in 1903, obtained a Prench patent for the saponification of oils and fats by steam under pressure in the presence of finely divided metals or metallic oxides, and specially mentions zinc oxide for the purpose. 

Saponification under Increased or Diminished Pressure,—Soaps made by boiling fats and oils, under pressure and in vacm, with the exact quantity of caustic soda necessary for complete combination, belong also to this class. Amongst the many attempts which have at various times been made to shorten the process of soap-making may be mentioned Haywood s Patent No. 759, 1901, and Jourdan s French Patent No. 339,154, 1903. 

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... 

Some difference of opinion exists on the saponification of wool fat. Abraham and Cockton were of the opinion that heating in a stoppered flask with N ethanolic potash on a water-bath [ue. under pressure) for two and a half hours gave the most accurate and concordant results. These findings are not in accordance with the results obtained by Richardson and Bracewell, who tried various methods of saponification, including the ethoxide method, and found no advantage over the use of N ethanolic potash. Garratt " also showed that N ethanolic potassium hydroxide saponified wool fat as completely as ethoxide and the values obtained were of the same order as with 0-5N ethanolic potassium hydroxide used in the B,P. method. Two hours boiling is undoubtedly necessary. 

Fatty acids, respectively the alkali salts of fatty acids, have long been produced by saponification of fats or fatty oils by alkali lye. At present the free acids are produced either by hydrolysis of the triglycerides with water in an uncatalyzed reaction at 210-260°C under a pressure of 20-60 bar or in a cata-... 

Typically, the saponification is run with 10% sodium hydroxide solution in a reactor cascade at 95-98°C under stringent pH control. The saponification mixture is separated in a settler. The upper phase consists of alkanes with a small proportion of chloroalkanes, which is removed by oleum refining or dehydrochlorination and high-pressure hydrogenation. The refined alkanes can be recycled to the reactor. In the aqueous lower phase are alkanesulfonates, sodium chloride, and between 4 and 8 wt % hydrotropically dissolved alkanes. An optimal separation can be approached at 95 °C, and residence times of less than 60 min if Fe(III) ions are added and pH values of 3-5 are maintained. 

The presence of water results in very rapid saponification of ethyl benzoate. Dimethyl sulfoxide (Crown Zellerbach Corp.) may be dried by stirring with calcium hydride for 4-8 hours, followed by distillation under reduced pressure at 80-90° without filtration. Commercial 2-butyl alcohol and ethyl benzoate are conveniently dried by stirring for 2-4 hours with calcium hydride followed by filtration. 

C) dl-Serine.—One-half (350-375 g.) of the crude bromo-methoxypropionic acid prepared from the saponification of 800 g. of methyl a-bromo-/3-methoxypropionate is heated with 3.5 1. of concentrated ammonium hydroxide in a glass-lined autoclave (Note T4) for ten to fifteen hours at 90-100°, and the solution from the bomb is concentrated to a thick syrup under reduced pressure (Note 15). Two liters of water is added, and the solution is concentrated to dryness. The cake is dissolved in 1.5 1. of 48 per cent hydrobromic acid and refluxed for two and one-half hours. The resulting dark solution is concentrated to a volume of about 500 cc. and then cooled under the tap. The... 

CANDLE.—Read, in connection with the processes described at pages 430,431 —The operations of saponification of the fat, and decomposition of the lime-soap by sulphuric acid, have been hitherto effected in open vessels, under the ordinary pressure of the atmosphere. An improvement on this plan has been recently proposed by M, Delapchiek, of Besangoo, who substitutes dose vessels in Order to saponify the fat. Wash and decompose the lime-soap under a pressure of about twenty-two pounds to the square inch, by which the operations are considerably facilitated, and their duration shortened. The products by this process are said to be superior to those obtained in open vessels, and a considerable economy of flaid is effected. The apparatus consists essentially of a horizontal boiler, with a man-hole and two safety valves at the top, The heat is furnished by a large steam-pipe, running in a depression along the bottom of the boiler. The... 

In general, two types of chemical reactions are utilized in the manufacture of soap the saponification of triglycerides (fats and oils) and the neutralization of fatty acids (which themselves are produced from the triglycerides by a variety of methods, most notably splitting or hydrolysis of fats and oils with steam under high pressure). Sodium hydroxide (the predominant alkali employed in the manufacture of soaps), potassium hydroxide, sodium carbonate, and triethanolamine are... 

Direct transformation of double-tailed mannuronates into single-tailed sodium uronates was simply achieved through saponification (Scheme 7). Aqueous 0.1 N NaOH (1.1 equiv.) was slowly added to a solution of -alkyl (n-alkyl a-D-manno-pyranosiduronate) 6a-c (1 equiv.) in CH2CI2. After stirring for 1 h at room temperature, the reaction medium was concentrated imder reduced pressure at 30°C and the residue was diluted with hot CH3OH. Silica gel was added and the mixture was concentrated under reduced pressure and dried under vacuum. The residue was suspended in hot CH2CI2, filtered, and rinsed several times with... 

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