Propionic acid anhydrous

Anhydrous Acetic Acid. In the manufacture of acetic acid by direct oxidation of a petroleum-based feedstock, solvent extraction has been used to separate acetic acid [64-19-7] from the aqueous reaction Hquor containing significant quantities of formic and propionic acids. Isoamyl acetate [123-92-2] is used as solvent to extract nearly all the acetic acid, and some water, from the aqueous feed (236). The extract is then dehydrated by azeotropic distillation using isoamyl acetate as water entrainer (see DISTILLATION, AZEOTROPIC AND EXTRACTIVE). It is claimed that the extraction step in this process affords substantial savings in plant capital investment and operating cost (see Acetic acid and derivatives). A detailed description of various extraction processes is available (237). 

A colourless, odourless, neutral liquid at room temperature with a high dielectric constant. The amount of water present can be determined directly by Karl Fischer titration GLC and NMR have been used to detect unreacted propionic acid. Commercial material of high quality is available, probably from the condensation of anhydrous methylamine with 50% excess of propionic acid. Rapid heating to 120-140° with stirring favours the reaction by removing water either directly or as the ternary xylene azeotrope. The quality of the distillate improves during the distn. 

Heavily fluonnated aminobenzenes, pyridines, and pyrimidines are diazotized in strong-acid media Solid sodium nitrite added directly to the fluonnated amine dissolved in 80% hydrofluonc acid, anhydrous hydrogen fluoride, or (1 1 wt/wt) 98% sulfuric acid in (86 14 wt/wt) acetic and propionic acids affords the electrophilic fluoroarenediazonium ion Addition of an electron rich aromatic to the resultant diazonium solution gives the fluoroareneazo compound [10 II] (equa tions 9 and 10)... 

A mixture of B g (0.0356 mol) of p-(2.2-dichlorocyclopropyl)phenol, 11.2 g (0.2B mol) of sodium hydroxide pellets, 11 g of chloroform and 350 ml of acetone was prepared at 0°C. The cooling bath was removed, the mixture stirred for a minute and then heated on a steam bath to reflux temperature. The reaction mixture was stirred at reflux for three hours and then concentrated in vacuo. The residual gum was partitioned between dilute hydrochloric acid and ether, and the ether layer was separated, dried and concentrated in vacuo. The residual oil (14 g) was partitioned between dilute aqueous sodium bicarbonate and ether. The sodium bicarbonate solution was acidified with concentrated hydrochloric acid and extracted with ether. The ether solution was dried over anhydrous sodium sulfate and concentrated. The residue (9.5 g of yellow oil) was crystallized twice from hexane to give 6.0 g of 2-[p-(2,2-dlchlorocyclopropyDphenoxyl -2-methyl propionic acid in theformof apalecream[Pg.347]

Phenoxyphenyl)Propionic Acid A mixture of 223 grams of 2-(3-phenoxyphenyl)-propionitrile and 400 grams of sodium hydroxide in 1,600 ml of 50% ethanol was refluxed with stirring for 72 hours. After cooling to room temperature, the reaction mixture was poured into ice water. The resulting solution was washed with ether, acidifed with concentrated HCI, and extracted with ether. The ether extract was washed with water, dried over anhydrous sodium sulfate, and evaporated to dryness in vacuo. The residual oil was distilled to yield 203.5 grams (84%) of 2-(3-phenoxyphenyl)propionic acid as a viscous oil BP 168° to 171°C (0.11 mm), no = 1,5742. 

It is appropriate to add here some comments on diazotization in anhydrous carboxylic acids. They may be relevant for the diazotization of heteroaromatic amines carried out in acetic acid/propionic acid mixtures (Sec. 2.2). Extensive studies by Casado et al. (1983, 1984) showed that in nitrosation of secondary amines the nitrosyl ion, nitrosyl acetate, and dinitrogen trioxide are formed, and all three may act as nitrosating agents. The results do not, however, account for the considerable improvement that is claimed in the patent literature (Weaver and Shuttleworth, 1982) to result from the addition of carboxylic acids in the diazotization of heteroaromatic amines. 

Since the metabolite of clomeprop, 2-(2,4-dichloro-3-methylphenoxy)propionic acid, and inabenfide could not be directly determined by GC, they are derivatized to a more stable compound with diazomethane for the metabolite of clomeprop or with anhydrous chloroacetic acid for inabenfide. 

In a 1-1. round-bottomed flask are placed 36.0 g. (0.132 mole) of 2-(/>-tolylsulfonyl)dihydroisoindole,1 2 36.0 g. (0.38 mole) of phenol, 270 ml. of 48% hydrobromic acid (Note 1), and 45 ml. of propionic acid. A few boiling chips are added, and the flask is fitted with a reflux condenser in the top of which is placed a T-tube connected to a source of low-pressure nitrogen and to a mercury bubbler. The mixture is heated under reflux for 2 hours in an atmosphere of nitrogen. The deeply colored reaction mixture is cooled to room temperature, transferred to a 1-1. separatory funnel, and washed with two 200-ml. portions of ether (Note 2). The aqueous phase is then added dropwise over a 1-hour period to a vigorously stirred (Note 3) solution of 200 g. of sodium hydroxide in 600 ml. of water in a 2-1. Erlenmeyer flask immersed in an ice bath. The solution is transferred to a 3-1. separatory funnel and extracted with five 300-ml. portions of ether. The ethereal extracts are combined, dried over anhydrous potassium carbonate (Note 4), and filtered. The solvent is distilled, and the dark residual oil is transferred to a distillation... 

B. d,l-a- Isopropylideneaminooxy)propionic acid. In a 1-1. three-necked flask fitted with a stirrer and a thermometer that can be immersed in the contents of the flask is placed 300 ml. of 5% aqueous sodium hydroxide (0.37 mole). The flask is heated on a water bath until the temperature of the solution reaches 70°, and 52 g. (0.30 mole) of ethyl a-(isopropylideneaminooxy)pro-pionate is added. The mixture is stirred rapidly while the temperature is held at 70° the stirring is continued for 20 minutes beyond the time necessary for the contents of the flask to become homogeneous (Note 4). The solution is cooled and acidified to Congo red paper with 5N hydrochloric acid, and 175 g. of ammonium sulfate is added. The mixture is extracted three times with a total of 300 ml. of a 1 1 mixture of ether and benzene. The combined extracts are dried rapidly over 5 g. of anhydrous magnesium sulfate and filtered (Note 5). The solvent is removed by distillation, and 160 ml. of petroleum ether (b.p. 30-60°) is... 

Dissolve 2.75 g anhydrous sodium carbonate in a mixture of 50 ml acetic acid and 25 ml propionic acid. Add 11.7 g (0.1M) indole... 

Carboxy-2-pyridylthio)propionic acids, prepared by the reaction of 2-mercatopyridin-3-carboxylic acid with 3-bromopropionic acid in aqueous KOH, undergo cyclization upon treatment with anhydrous sodium acetate and acetic anhydride to afford 2,3-dihydrothiopyrano[2,3-3]pyridin-4(4//)-ones. These products undergo further reaction with phenylhydrazine to give the phenylhydrazone (isolated) and then Fischer indole cyclization to give novel 5/7,1177-pyrido[2, 3 2,3]thiopyrano[4,3-3]indoles <2000JHC379>. 

The aqueous mother liquors are extracted with methylene chloride (900 ml). The organic phases are combined, washed with water (800 ml) and dried over anhydrous sodium sulfate. After filtration, the filtrate is concentrated to dryness under a pressure of 20 mm Hg to give a semicrystalline paste (65.0 g) which is recrystallised from acetonitrile (550 ml). The crystals are filtered off, and the product recovered (32.0 g) is recrystallised from acetonitrile (600 ml). There is thus obtained 2-[4-(2-carboxyphenyl)aminophenyl]propionic acid (18.4 g) melting point 191°-192°C. 

A mixture of dl-2-[4-(2 -carboxymethyl-4 -methylphenoxy)phenyl]propionic acid (15.3 g) and polyphosphoric acid (92 g) was heated with stirring at 110-120°C for 2 hours. To the reaction mixture was added water and the resulting mixture was extracted with chloroform. The organic layer was washed with water, dried over anhydrous sodium sulfate and concentrated. The residue was chromatographed on silica gel (75 g) using chloroform as an eluent to give a crude product, which was recrystallized from toluene to give the dl-2-(8-methyl-10,ll-dihydro-ll-oxodibenz[b,f]oxepin-2-yl)propionic acid (9.4 g, 65.3%), m.p. 128-129°C. 

The diethyl 2-[3-bis(methoxycarbonyl)methyl-4-nitrophenyl]-2-methylmalonate obtained above,(4.13 g, 9.71 mmol) was dissolved in acetic acid (40 ml). To the solution were added water (16 ml) and concentrated sulfuric acid (4 ml), and the resulting mixture was heated for 15 hours under reflux. The acetic acid was distilled off under reduced pressure. The residue was concentrated under reduced pressure after addition of toluene. The precipitated crystals were collected by filtration and washed with water to give 2.06 g of the desired compound as a pale brown crystalline product. The filtrate and washing were combined and subjected to extraction using ethyl acetate. The ethyl acetate portion was washed successively with water and an aqueous saturated sodium chloride solution, and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure to leave 0.32 g of 2-(3-carboxymethyl-4-nitrophenyl)propionic acid as a yellow crystalline product. The total amount was 2.38 g (yield 96.8%). 

In 2 N hydrochloric acid (0.5 ml) was dissolved 2-(4-amino-3-carboxymethylphenyl)propionic acid disodium salt, 53 mg, 0.2 mmol). Sodium nitrite (14 mg, 0.2 mmol) was added to the resulting solution under stirring and chilling with ice. The mixture was stirred for 30 minutes under chilling with ice. The mixture was then neutralized with a chilled aqueous saturated sodium acetate solution. To the neutralized mixture was added a solution of thiophenol (0.02 ml, 0.2 mmol) in 6 N aqueous sodium hydroxide solution (0.1 ml), and the mixture was stirred for 2 hours at room temperature. The reaction mixture was then made acidic by addition of 2 N hydrochloric acid, and extracted with ethyl acetate. The ethyl acetate portion was extracted with an aqueous saturated sodium hydrogen carbonate solution. The aqueous portion was then made acidic by addition of 6 N hydrochloric acid and extracted with ethyl acetate. The ethyl acetate portion was washed successively with water and an aqueous saturated sodium chloride solution, and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure to give 28 mg (yield 45%) of the 2-(3-carboxymethyl-4-phenylthiophenyl)propionic acid. 

Propionic acid, /3,/3 -methylimino-bis-, diethyl ester, 20, 35 Propionic anhydride, 21, 14 Protective screen, 22, 97 Pyridine, 20, 50 21, 89 anhydrous, 22, 56... 

These spirodioxindole lactones are opened by methanol, but not by ethanol, to yield methyl ester derivatives of dioxmdole-3-propionic acid. This reaction proceeds even at room temperature in aqueous methanol. Refluxing anhydrous methanol converts the lactone of 5-bromodioxindole-3-propionic acid (m.p. 200.5°C) to the ester (m.p. 118°C) within 1-2 hr. The use of methanol in the cleavage of water-insoluble peptides, such as... 

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