Aliphatic acids, purification

The submitter states that a number of aromatic mono-and dinitriles have been prepared by this procedure vvith slight or no modification in the temperature. The reaction mixtures were usually worked up by the acetone-ammonia method described in Note 6. Among the compounds prepared by this method are o-nitrobenzonitrile, o-bromobenzonitrile, w-methoxy-benzonitrile, 4,4 -dicyanodiphenylsulfone, 4,4 -dicyanostilbene, a,7-di-(4-cyanophenoxy)propane. With the last, a temperature of 185 190° for 20 minutes gave the best results. The yields before purification ranged between 75% and 95% and after purification between 63% and 79%. Aliphatic acids give low yields of the corresponding nitriles and, in some cases, chlorinated by-products. 

The silica gel may adsorb the esters of the short-chain fatty acids. For the esterification of those acids, a chloroform solution of the Cj—C aliphatic acids (50/rl) is treated with an equal volume of a freshly prepared 1% solution of 2,2,2-trichloroethanol in chloroform, together with 150 /A of heptafluorobutyric anhydride (HFBA) in a closed tube at room temperature for 30 minutes. Excess trichloroethanol is removed by reaction with 50 1 of a 25% solution of palmitic acid in chloroform, added subsequently and left to react at room temperature for 15 minutes. (The trichloroethyl palmitate p>eak comes off the GC column long after the shorter-chain fatty acid ester peaks). Further purification is achieved by shaking with 100 /il of chloroform and 100 1 of 0.1 M HCl the aqueous layer is discarded, and the organic layer is washed with 100 fi of 0.1 M NaOH and evaporated to dryness. The residue is dissolved in 100 fil of diethyl ether for analysis by GC with electron capture detection [46]. 

Aliphatic and aromatic carboxamides, with the exception of p-nitrobenzamide, are dehydrated in this way in high yield. Acid-labile protective groups such as tetra-hydropyranyl and tert-butyldimethylsilyl ether and base-sensitive compounds are not attacked. A,A -Sulfinyldi-1,2,4-triazole, easily prepared from thionylchloride and triazole [THF, (C2H5)3N, 0 °C, 1 h] in 85-95% yield, was used without further purification. 

Hypochlorous acid is used in bleaching fibers and textiles as an antiseptic and as a disinfectant for purification. It also is used as a chlorinating agent for aliphatic and aromatic hydrocarbons. 

Purification. Small amounts of reaction by-products are produced during the liquid-phase oxidation of toluene. These by-products include acetic and formic acids, benzene, benzaldehyde, benzyl alcohol, aliphatic benzyl esters such as benzyl formate and benzyl acetate, biphenyl, 2-, 3-, and 4-methylbiphenyls, and phthalic acid. Of these only benzaldehyde and benzene [71 -43-2] are currendy separated commercially. 

Lubricating oils - [AMIDES, FATTY ACID] (Vol 2) - [PETROLEUM - REFINERY PROCESSES, SURVEY] (Vol 18) -polyamines in [DIAMINES AND HIGHER AMINES ALIPHATIC] (Vol 8) -polymethacrylates additives [METHACRYLIC POLYMERS] (Vol 16) -purification by centrifuge [SEPARATION - CENTRIFUGAL SEPARATION] (Vol 21) -zinc sulfide as pigment [PIGMENTS - INORGANIC] (Vol 19)... 

Physical Properties. The molecular weight of dalbaheptides ranges from about 1150 to 2200. Pure dalbaheptides are obtained as colorless or whitish amorphous powders that usually retain water and solvents. Dalbaheptides are generally water-soluble. Teicoplanin can be obtained as an internal sail or as a partial monoalkaline (sodium) salt depending on tile pH of the aqueous solution in the final purification step. Other dalbaheptides arc obtained as acidic salts, such as hydrochlorides (vancomycin, actaplanin) or sulfates (ristocetin A, avoparcin, eiemomycin). The presence of amino, carboxyl, benzylic, and phenolic hydroxyl functions, sugars, and aliphatic chains influences both water solubility and total charge. 

Affinity Chromatography, The Purification of Biologically Active Compounds by Aliphatic Ammonium Salts in the Assay of Acidic Polysaccharides from Tissues... 

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