Twitchell reagent

Two important widely used sulfonic acids are known as Twitchell s reagents, or as in Russia, the Petrov catalysts. These reagents are based on benzene or naphthalene (n) and (12), [3055-92-3] and [82415-39-2], respectively. The materials are typically made by the coupling of an unsaturated fatty acid with benzene or naphthalene in the presence of concentrated sulfuric acid (128). These sulfonic acids have been used extensively in the hydrolysis of fats and oils, such as beef tallow (129), coconut oil (130,131), fatty methyl esters (132), and various other fats and oils (133—135). Twitchell reagents have also found use as acidic esterification catalysts (136) and dispersing agents (137). 

Acidic Hydrolysis. Hydrolysis of esters by use of water and a mineral acid leads to an equilibrium mixture of ester, alcohol, and free carboxylic acid. Complete reaction can only be achieved by removal of alcohol or acid from the equilibrium. Because esters have poor solubility in water, the reaction rate in dilute acids is fairly low. Therefore, emulsifiers such as sulfonated oleic acid or sulfonated aromatic compounds (Twitchell reagent) are added to facilitate the reaction. 

Twitchell Process. The Twitchell Process (9) is one of the earliest processes developed for fat splitting. It is still used in a small way because of its low initial cost and simplicity of installation and operation. However, it is no longer of great commercial importance, due to its high-energy consumption and poor product quality. The process makes use of the Twitchell reagent and sulfuric acid to catalyze the hydrolysis. The reagent is a sulfonated mixmre of oleic or other fatty acid and naphthalene. 

Twitchell process. Commercial process for splitting fats to glycerol and fatty acids by heating the sulfuric acid-washed fat 20-48 hours in an open tank with steam in a mixture of 25-50% water, 0.5% sulfuric acid, and 0.75-1.25% Twitchell reagent. The original Twitchell catalyst was prepared by sulfonation of a mixture of fatty acid and benzene, but toway sulfonated petroleum products are used. 

Twitchell reagent. Catalyst for the Twitchell process (acid hydrolysis of fats). It is a sulfonated addition product of naphthalene and oleic acid, a naphthalenestearosulfonic acid. 

Industry uses acid cleavage of esters on a large scale for saponification of fats, favoring certain catalysts such as the rapid-acting Twitchell reagent. Schlutius76 carried out penetrating experiments on the nature and mode of action of these catalysts. 

Catalysts such as zinc oxide or Twitchell reagent (alkylaryl sulfonic acids) may be used which increase the rate of reaction but not the extent of hydrolysis. Operations may be carried out batchwise at atmospheric pressure and 212°F. with the Twitchell catalyst, or in autoclaves at high pressures up to 450°F. with or without catalyst. Complete miscibility with water may occur at temperatures about 550 to 650 F., depending upon the fat. Continuous countercurrent contact of the water and oil at temperatures below complete miscibility increases the percentage splitting possible, to an extent depending merely upon the time of contacting. 

Twitchell reagent n. Reagent employed for the splitting or hydrolysis of oils and fats, and made by the interaction of sulfuric acid, oleic acid and naphthalene. 

The fatty acids remaining in the vat are boiled with a small quantity (0 05 per cent., or xV f the Twitchell reagent requisite) of commercial barium carbonate, previously mixed with a little water the boiling may be prolonged twenty or thirty minutes, and at the end of that period the contents of the vat are allowed to rest the water separated should be neutral to methyl-orange indicator. 

The oldest catalyst for h., the Twitchell reagent , is a mixture of aromatic hydrocarbons and oleic acid reacted with concentrated sulfuric acid. This... 

Twin-fluid atomizer Twisted pair cable Twitchell splitting Twitchell s reagents Two-film theory... 

Methyl iso-Propyl Ketone (13, 68) In 80 per cent yields by hydrolysis of 2,3-dibromo-2-methylbutane with Twitchell s reagent. Colonge, Bull. soc. chim. (5) 3, (1936). 

CAS 105-54-4 EINECS/ELINCS 203-306-4 UN 1180 (DOT) FEMA 2427 Synonyms Butanoic acid, ethyl ester Butyric acid, ethyl ester Butyric ether Ethyl butanoate Ethyl n-butyrate Ciassification Butanoic acid ester Dehnition Obtained by esterification of n-butyric acid with ethyl alcohol in presence of Twitchell s reagent or MgCb Empirical C6H12O2 Formula CH3CH2CH2COOC2H5 Properties Colorless liq., banana-pineapple odor sol. in water, fixed oils, propylene glycol misc. with alcohol, ether insol. in glycerin 121 C m.w. 116.18 dens. 0.874 m.p. -100.8 C b.p. 

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. 

Constitution op Oils and Fats, and their Saponification. Researches of Chevreul and Berthelot—Mixed Glycerides—Modem Theories of Saponification—Hydrolysis accelerated by (1) Heat or Electricity, (2) Ferments, Castor-seed Ferment, Steapsin, Emul-sin, and (3) Chemical Reagents, Sulphuric Acid, Twitchell s Reagent, Hydrochloric Acid, Lime, Magnesia, Zinc Oxide, Soda and Potash. 

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