Benzoylation water analysis

Materials. GMC and PCLS were synthesized by free radical solution polymerization initiated by benzoyl peroxide as described previously (5,6). Nearly mono and polydisperse polystyrenes were obtained from Pressure Chemical Co. and the National Bureau of Standards respectively. Molecular weight and polydispersity were determined by gel permeation chromatography (GPC) using a Water Model 244 GPC, equipped with a set (102-106 A) of —Styragel columns using THF as the elution solvent. The molecular parameters of the above three polymers are listed in Table I. The copolymer, poly(GMA-co-3-CLS), contained 53.5 mole % 3-CLS and 46.5 mole % GMA, as determined by chlorine elemental analysis. The structure of the copolymer is shown in Figure 1. 

Parameters such as solvent, basic medium and reaction time, affecting the derivatization of alcohols and phenols with benzoyl chloride, were investigated. End analysis was by GC with UVD . a sensitive method proposed for trace determination of phenols in water consists of preconcentration by SPE with a commercial styrene-divinylbenzene copolymer, acylation with pentafluorobenzoyl chloride in the presence of tetrabutylammonium bromide and end analysis by GC with either ECD or ITD-MS. LOD was 3 to 20 ngL for ECD and 10 to 60 ngL for ITD-MS, with 500 mL samples . Acylation with the fluorinated glutaric acid derivative 43 was proposed for determination of urinary phenols, as indicative of exposure to benzene and other aromatic hydrocarbons. End analysis by GC-MS shows strong molecular ions of the derivatives by electron ionization. The proto-nated ions are the base peaks obtained by chemical ionization. LOD was 0.5 mgL and the linearity range 0-100 mg L for phenol . 

In deacylation, as the enzyme cleaved the phenylacyl group, phenylacetic acid was formed, which lowered the pH of the reaction medium. Base was added to maintain the starting pH. (Note Use of ammonium hydroxide led to the formation of desilylated byproducts desilylation was eliminated when bicarbonates were used.) This approach was not required in the acylation reaction. At pH above 7.5 the (R)-and (S)-amines are practically insoluble in water. Organic solvents were used to extract the free amines from the aqueous reaction medium at pH 8.0. p-Fluoro-benzoyl, 1-naphthoyl, and phenylacetyl derivatives of the racemic amine were prepared and their behavior on the chiral HPLC column was studied. Based on ease of preparation and HPLC analysis, the 1-naphthoyl derivatives (Fig. 7) were preferred. Reversed phase HPLC analysis on a Vydac-C18 analytical column used a gradient of acetonitrile (0.1% triethylamine) in water (0.05% phosphoric acid) to quantify the total amide in the reaction mixture. Chiral HPLC analysis on (S,S) Whelk-O Chiral column used isopropanol hexane (30 70) as a solvent system to separate and quantify the (R)- and (S)-enantiomers. 

In the case of peraksine [RP-5 (27)] it was shown to have the formula C19H22N2O2, a fact not readily derived from combustion analysis since the free base crystallized from alcohol in a hydrated form (27). It has also been observed that this water of solvation could be displaced by chloroform (20). Peraksine has UV-absorption typical of a 2,3-disub-stituted indole and reacted with benzoyl chloride to form an 0-benzoyl derivative. The second oxygen was apparently present as a cyclic ether when it was found that although peraksine did not react with hydrazine derivatives, it was reducible with sodium borohydride to furnish a diol (mp 290°-291° [a]j) - -41° in Py diacetate, mp 103°-105°). This diol readily lost the elements of water upon acid treatment to afford a new ether, deoxyperaksine, 230° change in crystalline form (mp 255°-257°). Because of these properties peraksine was considered to possess a cyclic hemiacetal moiety. 

A mixture of 356 mg ClC4F8S02CH2C0Ph (0.84 mmol), 43 mg benzaldehyde (0.4 mmol), and 78 /xL piperidine in 16 mL toluene was refluxed for 1 h with azeotropic removal of water using a Dean-Stark trap. TLC analysis indicated the reaction was completed. The mixture was cooled to room temperature, the solvent was removed under reduced pres sure, and the residue was column chromatographed (hexane/ethyl ether, 10 1) to give 213 mg (2/ ,35 )-2-benzoyl-3-phenyl-4-(4 -chloro-perfluorobutylsulfonyl)-4-phenyl-2,3-dihydrofuran, in a yield of 84%. 

Pyridine has also been used as the basic catalyst and chloride acceptor for benzoylation reactions. In one procedure, amines, volatile alcohols or thiols isolated by benzene extraction, are benzoylated with pyridine (1 ml) and benzoyl chloride (0.5 ml) by shaking intermittently at room temperature for several hours. The pyridine phase is extracted with 2 M HCl and the excess benzoyl chloride is hydrolysed with water for 12 hours. After shaking with 2 M sodium carbonate to remove benzoic acid, the benzene solution is dried and concentrated for analysis [144]. Aminoglycoside antibiotics are derivatized to the benzoyl derivatives in a similar reaction using 90 fi of pyridine and 10 /il of benzoyl chloride at 80 °C for 30 minutes. The pyridine is evaporated in a stream of nitrogen and excess benzoyl chloride is converted to methyl benzoate with methanol, again at 80°C, for 10 minutes. The product is cleaned up for analysis by a rather involved solvent extraction procedure [145]. 

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