Acid fractions separation

FIGURE 5. Effect of humic acid fractions separated on G-75 Sephadex on invertase synthesis in beetroot discs (from Vaughanl )... 

The iso-nitrile may be removed by the following procedure. Shake the crude (undistilled) n-butyl cyanide twice with about half its volume of concentrated hydrochloric acid and separate carefully after each washing then wash successively with water, saturated sodium bicarbonate solution and water. Dry with anhydrous calcium chloride or anhydrous calcium sulphate, and distil. Collect the pure n-butyl cyanide at 139-141°. If a fraction of low boiling point is obtained (because of incomplete drying), dry it again with anhydrous calcium sulphate and redistil. The yield is 95 g. 

Vinylacetic acid. Place 134 g. (161 ml.) of allyl cyanide (3) and 200 ml. of concentrated hydrochloric acid in a 1-htre round-bottomed flask attached to a reflux condenser. Warm the mixture cautiously with a small flame and shake from time to time. After 7-10 minutes, a vigorous reaction sets in and the mixture refluxes remove the flame and cool the flask, if necessary, in cold water. Ammonium chloride crystallises out. When the reaction subsides, reflux the mixture for 15 minutes. Then add 200 ml. of water, cool and separate the upper layer of acid. Extract the aqueous layer with three 100 ml. portions of ether. Combine the acid and the ether extracts, and remove the ether under atmospheric pressure in a 250 ml. Claisen flask with fractionating side arm (compare Fig. II, 13, 4) continue the heating on a water bath until the temperature of the vapour reaches 70°. Allow the apparatus to cool and distil under diminished pressure (compare Fig. II, 20, 1) , collect the fraction (a) distilling up to 71°/14 mm. and (6) at 72-74°/14 mm. (chiefly at 72 5°/ 14 mm.). A dark residue (about 10 ml.) and some white sohd ( crotonio acid) remains in the flask. Fraction (6) weighs 100 g. and is analytically pure vinylacetic acid. Fraction (a) weighs about 50 g. and separates into two layers remove the water layer, dry with anhydrous sodium sulphate and distil from a 50 ml. Claisen flask with fractionating side arm a further 15 g. of reasonably pure acid, b.p. 69-70°/12 mm., is obtained. 

In the initial black Hquor concentration, saponified fatty and resin acid salts separate as tall oil soaps (see Tall oil). These soaps can be skimmed from the aqueous spent Hquor, acidified, and refined to give a cmde tall oil composed of resin acids, chiefly abietic and neoabietic fatty acids, chiefly oleic and Hnoleic and an unsaponifiable fraction made of phytosterols, alcohols, and hydrocarbons. Tall oil is fractionated primarily into fatty acids (see... 

Process Sequence. The process sequence consists of recovery of tall oil soap from the pulping blackhquor, acidulation, ie, conversion of the soap into CTO with sulfuric acid, fractional distillation to separate rosin, and fatty acids and purification of the fatty acid fraction. 

First, the tar acids were removed from the naphtha fractions of light oils and, in the case of CVR tars, carboHc oil. The oils were then mixed with 25—35% sulfuric acid. After separation of the sulfates, the aqueous solution was diluted with water and the resinous material skimmed off. The diluted sulfate solution was boiled to expel any neutral oils, dried by the addition of soHd caustic soda or a2eotropically with ben2ene, and fractionated to yield pyridine, 2-methylpyridine (a-picoline), and a fraction referred to as 90/140 bases, which consisted mainly of 3- and 4-methylpyridines and 2,6-dimethylpyridine (2,6-lutidine). Higher boiling fractions were termed 90/160 and 90/180 bases because 90% of the product distilled at 160 and 180°C, respectively. 

However, for the past 30 years fractional separation has been the basis for most asphalt composition analysis (Fig. 10). The separation methods that have been used divide asphalt into operationally defined fractions. Four types of asphalt separation procedures are now in use ( /) chemical precipitation in which / -pentane separation of asphaltenes is foUowed by chemical precipitation of other fractions with sulfuric acid of increasing concentration (ASTM D2006) (2) solvent fractionation separation of an "asphaltene" fraction by the use of 1-butanol foUowed by dissolution of the 1-butanol solubles in... 

Distillation. Most fatty acids are distilled to produce high quaHty products having exceUent color and a low level of impurities. Distillation removes odor bodies and low boiling unsaponifiable material in a light ends or heads fraction, and higher boiling material such as polymerized material, triglycerides, color bodies, and heavy decomposition products are removed as a bottoms or pitch fraction. The middle fractions sometimes can be used as is, or they can be fractionated (separated) into relatively pure materials such as lauric, myristic, palmitic, and stearic acids. 

Ricinoleic acid (dl 12-hydroxyoleic acid) [14I-22-0J M 298.5, m 7-8° (a-form), 5.0° (7-form), n 1.4717, pKe, -4.5. Purified as methyl acetylricinoleate [Rider J Am Chem Soc 53 4130 1931], fractionally distilling at 180-185°/0.3mm, then 87g of this ester was refluxed with KOH (56g), water (25mL), and MeOH (250mL) for lOmin. The free acid was separated, crystd from acetone at -50°, and distd in small batches, b 180°/0.005mm. [Bailey et al. J Chem Soc 3027 1957.]... 

In a falling film evaporator (4) a water-paraffin mixture is distilled off and completely pumped back to the reactor. The resulting product is separated into a 60% sulfuric acid fraction and paraffin-containing alkanesulfonic acid (5), which is bleached by hydrogen peroxide (6). In a stirred vessel (7) the alkanesulfonic acid is neutralized by 50% sodium hydroxide solution until the pH is exactly 7. The composition of the neutralized product is also given in Table 2. 

FIGURE 13.4 Total ion chromatograms from the ID LC/MS analysis of a yeast ribosomal protein fraction separated using 0.1% TFA (Panel a) and 0.1% formic acid (Panel b) as mobile phase modifiers. TFA produced narrower, more concentrated, peaks for mass analysis that did not overcome the significant electrospray ionization suppression associated with using this modifier for LC/MS studies, resulting in an overall reduction in component intensities. 

GC/MS has also been used to investigate acidic and neutral fractions (after alkaline hydrolysis, separation and trimethylsilylation) of a resinous sample collected from a flint flake dated back to the lower Palaeolithic (roughly 200 000 BC) and recovered near Arezzo in Italy [11]. The results show that the organic material recovered on the flint flake was a pitch obtained from birch bark by a pyrolysis type process. In fact, the main components of the acidic fraction are a series of linear a,oo-dicarboxylic acids ranging from 16 to 22 carbon atoms and a series of oo-hydroxycarboxylic acids ranging from 16 to 22 carbon... 

Two of the methods (ASTM D2007, D4124) use adsorbents to fractionate the deasphaltened oil, but the third method (ASTM D2006) advocates the use of various grades of sulfuric acid to separate the material into compound types. Caution is advised in the application of this method since the method does not work well with all feedstocks. For example, when the sulfuric acid method (ASTM D2006) is applied to the separation of heavy feedstocks, complex emulsions can be produced. 

Distinctions between water-soluble fractions of mixed hydrocarbons may be made by using solvent extraction of the water-soluble base/neutral and acid fractions with methylene chloride (EPA 1991c Thomas and Delfino 1991a). This separation of base/neutral and acid fractions will permit the GC resolution of the type of water soluble hydrocarbons present in the aqueous phase. Hexane has also been used as a solvent (DellAcqua and Bush 1973), as has pentane (Coleman et al. 1984). 

The second example described here is dormant seeds from Rosa canina. Extracts of these seeds also inhibit germination of seeds of several plants (10). In Figure 5 a scheme is given for extraction and separation oF"three different inhibitor compounds. All these are present in the acid fraction. The first essential step is chromatography on Sephadex LH-20, which separates inhibitor I from inhibitor II and III. Inhibitor I was identified as abscisic acid. The other two inhibitors were separated by methylation with diazomethane, fractional distillation, and column chromatography. The second inhibitor is the a-pyrone 1 . Reaction with diazomethane transforms it into the bi-cyclic compound 19. This bicyclic compound is even more active than the parent a-pyrone 1 . Since we sought structural requirements for bioactivity here also,we tested several synthetic a-pyrones ( 0 - 22) for bioactivity. These compounds had no inhibitory activity. We alio tested the cyclopropane derivatives 23 and 24 In Table II, the bioactivity of the bicyclic compound T9 and two such derivatives is compared. The presence of several carboxylic acid groups seems to be essential (or at least helpful) for bioactivity in this case also. 

Fig. 5.1. Scheme of separating the soil fulvic and humic acid fractions. 

The fermentation broth of various Streptomyces species can be separated into an acidic fraction shown to contain pentalenic acid 776) The somewhat less oxidized pentalenolactone precursor has been independently prepared from humulene from which is is probably derived biogenetically Thus, treatment of humulene with mercuric nitrate followed by aqueous potassium bromide solution gave two bromo-mercury derivatives which were oxygenated in the presence of sodium borohydride. The resulting pair of diols (770 and 771) were separately converted to exo methylene... 

The aqueous layer separated from the main carbon tetrachloride solution is shaken out with 100 cc. of carbon tetrachloride, and thus yields about 10 g. of pure acid when the dilute and the concentrated hydrobromic acid fractions are extracted in the same way, about 5 g. and 15 g. respectively of... 

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