Stirring reactions

Place 35 ml. of water in the separatory funnel and run it into the vigoroiisly stirred reaction mixture at such a rate that rapid refluxing occurs. Follow this by a cold solution of 15-5 ml. of concentrated sulphuric acid in 135 ml. of water. Two practically clear layers will now be present in the flask. Decant as much as possible of the ethereal layer A) into a 500 ml. round-bottomed flask. Transfer the remainder, including the aqueous layer, into a separatory funnel wash the residual solid with two 10 ml. portions of ether and combine these washings with the liquid in the separatory funnel. Separate the ethereal portion and combine it with (A). Distil off the ether through an efficient fraction-... 

Batch processes for most phenoHc resins employ the equipment shown in Figure 2. Liquid reactants are metered into the stirred reaction vessel through weigh tanks, whereas soHd reactants such as bisphenol A and Ba(OH)2 present handling problems. FaciHties are provided to carry out the reaction under a vacuum or an inert gas. 

Physicochemical relationships are such that soHd potassium chloride can be converted to soHd potassium nitrate ia a one-stage operation of the simplest kiad. The conversion takes place ia a stirred reaction system (Fig. 10). The overall separation is analogous to a rectification and stripping operation ia a distillation process. 

Precipitation and Purification. During the hydrolysis, control tests are made by turbidimetric titration of samples taken intermittently. When the desired degree of hydrolysis is reached, the ester is precipitated from the reaction solution into water. It is important for the precipitate to have the proper texture for subsequent washing to remove acid and salts for thermal stabilization. Before precipitation, the reaction solution is usually diluted with additional aqueous acetic acid to reduce the viscosity. If a flake texture is desired, the solution is poured into a vigorously stirred, 10—15% aqueous acetic acid. To precipitate the acetate in powder form, dilute acetic acid is added to the stirred reaction solution. In both cases, the precipitated ester is suspended in 25—30% aqueous acid solutions and finally washed with deionized water. The dilution, precipitation temperature, agitation, and strength of the acid media must be controlled to ensure uniform texture. 

A. ot-Chloroelhyl ethyl ether. A mixture of 200 g. (201 ml.) of redistilled paraldehyde, b.p. 121-122.5° (equivalent to 4.54 moles of acetaldehyde), and 200 g. (254 ml., 4.34 moles) of absolute ethanol is placed in a 1-1. three-necked flask fitted with a mechanical stirrer and a gas inlet tube reaching to the bottom of the flask. The mixture is cooled to —5° in a mixture of Dry Ice and acetone, and dry hydrogen chloride (Note 1) is passed into the stirred reaction mixture maintained at about —5° until 200 g. (5.48 moles) has been absorbed. During this operation, which requires about 2 hours, the reaction mixture separates into two layers. The upper layer of crude a-chloroethyl ethyl ether is re-... 

The solution in the left flask is stirred for 30 minutes after all the potassium amide has been added. The nitrogen inlet is briefly removed and 120 g. (1.5 moles) of ammonium nitrate is added this discharges the ehartreuse color. (Caution Vigorous foaming occurs.) Ethyl ether (500 ml.) is added and the dry iee condenser is replaced by a standard water-cooled condenser. I he ammonia is evaporated by allowing the stirred reaction mixture to warm to room temperature this takes several hours iti(l it is convenient to have it occur overnight. 

After an additional 10 min, a 1 % solution of hydrochloric acid (100 ml) is slowly added to the stirred reaction mixture and the resultant mixture is transferred to a separatory funnel. The ether layer is separated and washed sequentially with water, 5 % sodium bicarbonate solution, water and saturated salt solution. The washed ether solution is dried over anhydrous sodium sulfate, filtered, and evaporated to give an oily residue (0.45 g). Chromatography of the crude product on silica gel (50 g) followed by crystallization of the solid thus obtained (0.18 g) from ethanol gives 3 -hydroxy-B-homo-cholest-5-en-7a-one acetate (67 0.14 g) mp 90-91° [a]o 99° (CHCI3). 

The trialkylborane is oxidized by the addition to the stirred reaction mixture of 32 ml of a 3 solution of sodium hydroxide, followed by the dropwise addition of 32 ml of 30 % hydrogen peroxide at a temperature of 30-32° (water bath). The reaction mixture is saturated with sodium chloride and the tetrahydrofuran layer formed is separated and washed with saturated sodium chloride solution. The organic solution is dried over anhydrous magnesium sulfate and the THF is removed. Distillation affords 24.5 g (80%) of 4-methyl-1-pentanol, bp I51-153°/735 mm. 

In a dry, 250 ml, three-necked flask equipped with a dropping funnel and magnetic stirrer are placed 40 ml of dry /-butyl alcohol (distilled from calcium hydride) and 4.0 g (0.036 mole) of potassium /-butoxide. The solution is cooled in ice and 40 g (49 ml, 0.49 mole) of dry cyclohexene is added. Bromoform (10 g, 3.5 ml, 0.039 mole) is added to the cooled, stirred reaction vessel dropwise over about hour, and the vessel is stirred an additional hour with the ice bath removed. The reaction mixture is poured into water (approx. 150 ml), and the layers are separated. The aqueous layer is extracted with 25 mi of pentane, and the extract is combined with the organic layer. The combined layers are dried (sodium sulfate), and the solvent is removed. The product is purified by distillation, bp 10078 mm. 

An alternative process from U.S. Patent 3,635,946 A vigorously stirred reaction mixture consisting of 32.B7 g (0.1 mol) of 5-fluorouracilmercury, 100 ml of dimethylformamide and 50 ml of toluene is dried by azeotropic distillation of toluene. It is then cooled to -40°C in a stream of dry nitrogen, and a solution of 21.3 g (0.2 mol) of 2-chlorofuranidin in 20 ml of dried dimethylformamide is gradually added to the stirred mixture, the temperature being maintained between -40°C and -30°C. After completion of the reaction (which is marked by complete dissolution of the starting 5-fluorouracilmercury) i.e. after about 3 to 4 hours, 60 to 80 ml of the solvent are distilled off in vacuo at a bath temperature not exceeding 35°C ... 

Note 4) is poured into the well-stirred reaction. The product is immediately poured onto a mixture of 55.6 g. (0.20 mole) of FeSCW H2O and 1 g. of defatted copper powder in a wide 2-1. beaker. Nitrogen and excess sulfur dioxide bubble off with much foaming. 

The reflux condenser was connected by an adaptor and Teflon tube to a trap of known weight which was cooled by a mixture of acetone and solid carbon dioxide. The flow of nitrogen was stopped, and an excess of water (about 15 ml.) was added dropwise through the dropping funnel to the stirred reaction product. The resulting mixture was heated at the reflux temperature, and the butane was collected in the trap. The weight of butane, b.p. —1° to 0°, was 4.23 1.35 g. (73-76% yield). 

A. 2,2 Sebacoyldicyclokexanone. A solution of 167 g. (1.00 mole) of 1-morpholino-l-cyclohexene 2 and 101 g. (139 ml., 1.00 mole) of anhydrous triethylamine in 500 ml. of dry chloroform (Note 1) is put in a 5-1., three-necked, round-bottomed flask equipped with a mechanical stirrer, a dropping funnel, and a reflux condenser. Tubes of calcium chloride are inserted in the open ends of the dropping funnel and reflux condenser. The reaction flask is immersed in a water bath at 35°, and a solution of 120 g. (0.50 mole) of sebacoyl chloride (Note 2) in 200 ml. of dry chloroform is added to the well-stirred reaction mixture over a period of about 1.5 hours. The reaction mixture gradually as-... 

A solution of 25.8 g. (0.20 mole) of 4-amino-2,2,4-trimethyl-pentane (ierf-octylamine) (Note 1) in 500 ml. of C.P. acetone is placed in a 1-1. three-necked flask equipped with a Tru-Bore stirrer and a thermometer and is diluted with a solution of 30 g. of magnesium sulfate (Note 2) in 125 ml. of water. Potassium permanganate (190 g., 1.20 moles) is added to the well-stirred reaction mixture in small portions over a period of about 30 minutes (Note 3). During the addition the temperature of the mixture is maintained at 25-30° (Note 4), and the mixture is stirred for an additional 48 hours at this same temperature (Note 5). The reaction mixture is stirred under water-aspirator vacuum at an internal temperature of about 30° until most of the acetone is removed (Note 6). The resulting viscous mixture is steam-distilled approximately 500 ml. of water and a pale-blue organic layer are collected. The distillate is extracted with pentane, the extract is dried over anhydrous sodium sulfate, and the pentane is removed by distillation at atmospheric pressure. The residue is distilled through a column (Note 7) at reduced pressure to give 22-26 g. (69-82%) of colorless 4-nitro-2,2,4-trimethylpentane, b.p. 53-5473 mm., < 1.4314, m.p. 23.5-23.7°. 

The air condenser is replaced by an efficient water condenser set downward for steam distillation. One liter of water is added in one portion to the stirred reaction mixture, and stirring is continued for 30 minutes (Note 3). The dropping funnel is replaced by a steam-inlet tube reaching into the liquid, and steam is passed... 

A slug of dye is placed in the feed stream to a stirred reaction vessel operating at steady state. The dye concentration in the effluent stream was monitored as a function of time to generate the data in the table below. Time is measured relative to that at which the dye was injected. 

The level of the water bath should be maintained at the same height as that of the stirred reaction mixture. 

Equation (3-14) is similar to Equation (3-12) for the well-agitated reactor, where the ATmax is given as RT /Ea in which T is the temperature of the stirred reaction mass. A version of Equation (3-14) which applies to unstirred liquids without convection is ... 

B. Preparation of Cyclopropyldiphenylsulfonium Fluoroborate. A suspension of 118.7 g. (0.339 mole) of 3-chloropropyldiphenylsulfonium fluoroborate (Note 2) in 500 ml. of dry tetrahydrofuran (Note 12) is placed in a 2-1., one-necked flask equipped with a magnetic stirring bar and nitrogen inlet tube under nitrogen. Then 5-g. portions of 55% sodium hydride-mineral oil dispersion (15.2 g., 0.350 mole) are added in 30-minute intervals. The resulting mixture is stirred (Note 13) at room temperature for 24 hours. An aqueous solution of 25 ml. of 48% fluoroboric acid (Note 14), 15 g. of sodium fluoroborate (Notes 7, 15), and 400 ml. of water is added to the well-stirred reaction to destroy residual hydride and swamp out chloride ion (Note 16). After 5 minutes 300 ml. of methylene chloride is added, and the top methylene chloride layer is removed from the lower aqueous layer (Note 17). The methylene chloride solution is then extracted with 100 ml. of water. This water layer is combined with the first aqueous layer, and the combined water layers are extracted with an additional 100 ml. of methylene chloride. The methylene chloride portions are combined, dried over anhydrous sodium sulfate, and evaporated at reduced pressure until precipitation occurs. Addition of 1 1. of ether completes the precipitation of the salt. 

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