Hydrochloric acid, removal with water

A. Dispiro[5.1.5.1]telradecane-7,14-dione. Cyclohexanecarbon-yl chloride (Note 1) (30.0 g., 0.205 mole) and 250 ml. of dry benzene are placed in a three-necked, round-bottomed flask equipped with a stirrer, condenser, and dropping funnel. A nitrogen atmosphere is maintained in the system. Dry triethylamine (35.0 g., 0.35 mole) is slowly added, and the mixture is heated under reflux overnight. The amine hydrochloride is then filtered, and the filtrate is washed with dilute hydrochloric acid and with water. Solvent is removed on a steam bath, and the residue is recrystallized from ligroin-ethanol yield 11-13 g. (49-58%), m.p. 161-162°. 

B. 1,2-Bis n-butylthio)benzem. In a 1-1., round-bottomed, three-necked flask fitted with a reflux condenser, a mechanical stirrer, and a thermometer which reaches into the reaction mixture is placed a solution of 59.0 g. (0.25 mole) of o-dibromobenzene in a mixture of 250 ml. of quinoline and 80 ml. of pyridine. To this solution is added 84.0 g. (0.55 mole) of cuprous -butylmer-captide, and the mixture is stirred and heated under reflux (Note 5) for 3.5 hours (Note 6). Heating is stopped and the reaction mixture is allowed to cool to about 100°. It is then poured into a stirred mixture of 1500 g. of ice and 400 ml. of concentrated hydrochloric acid occasional stirring is continued for about 2 hours. The aqueous part is then decanted from the dark brown, gummy residue and is extracted twice with 400 ml. portions of ether. The ether extract is added to the residue, and the resulting mixture is stirred for about 5 minutes. The ether solution is then decanted from the residue and is filtered. The residue is extracted twice more with 400-ml. portions of ether (Note 7). The combined ether extract is washed twice with 100-ml. portions of 10% hydrochloric acid, once with water, and twice with 100-ml. portions of concentrated ammonia (Note 8). After a final wash with water, the ether solution is dried over anhydrous potassium carbonate. The potassium carbonate is collected on a filter, and the ether is removed from the filtrate by distillation. The remaining brown oil is distilled in vacuum, giving a pale orange oil, b.p. 123-124°/0.3 mm., d 1.5684. The yield is 46.5-56.0 g. (73-87%) (Note 9). 

Chloroheptinenearsenoxide, C5Hn.CCl=CH.AsO.—A -Heptinene (240 parts) is heated under reflux for sixteen hours with 900 parts of arsenic trichloride. The excess of trichloride is removed in a vacuum and the residual oil dissolved in 3000 parts of moist ether. Aniline is added until no further precipitation of aniline hydrochloride occurs, the latter being removed and the filtrate washed with dilute hydrochloric acid, then with water, until neutral to Congo red. The oxide remains... 

Naturally occurring talc is mined and pulverized before being subjected to flotation processes to remove various impurities such as asbestos (tremolite) carbon dolomite iron oxide and various other magnesium and carbonate minerals. Following this process, the talc is finely powdered, treated with dilute hydrochloric acid, washed with water, and then dried. The processing variables of agglomerated talc strongly influence its physical characteristics. " ... 

To a mixture of 1.0 g 2,4,6-trihydroxy-3-methyldeoxybenzoin and 20 mL pyridine was added 1.4 mL freshly distilled acetyl chloride at 0°C with stirring. After remaining for 24 h at 0°C, crushed ice was added and the solution was extracted several times with ether. The combined extracts were washed with ice cold hydrochloric acid, then with water, and then dried. Upon removal of ether via distillation, 1.4 g of a reddish brown semisolid mass was obtained. 

To a 2-liter flask are added 51.9 gm (0.7 mole) of glycidol and 400 ml of benzene. The flask is cooled to O C, and a solution of 81.2 ml (0.7 mole) of benzoyl chloride in 60 ml of benzene is placed in one dropping funnel while in another is placed a solution of 97.0 ml (0.7 mole) of triethylamine in 40 ml of benzene. The solutions are added dropwise simultaneously over a 2-hr period and then stirred for an additional 2 hr. The solids are filtered and rinsed with two 50-ml portions of benzene. The filtrate is shaken twice with dilute hydrochloric acid, washed with water until neutral, and dried over sodium sulfate. The benzene is then removed using a water aspirator, and the residue is vacuum-distilled to yield 90 gm (71%) of product, b.p. 97.5°-98.5°C (0.8-0.9mm Hg). The reported [59] boiling point is 103°C (1 mm Hg). 

Where the acetone content is high e.g, wood spirit), or where volatile oils are present, the alcoholic liquid must first be treated by the Thorpe and Holmes method (process B) described in the Appendix. Paraformaldehyde of the usual medicinal grade contains small amounts of nitrogenous bases which are carried over into the distillate. Unless their absence is assured, the reagent must be purified before use by washing, first with dilute hydrochloric acid, then with water until the removal of acid is complete, and finally by air drying. 

Talc is a naturally occurring hydrous magnesium silicate which is pulverized and subjected to flotation processes to remove mineral impiuities. The talc is then finely powdered and treated with dilute hydrochloric acid, washed with water and dried. It is very fine, white to grayish white, impalpable, and odorless. Talc is a crystalline powder, unctuous, and adheres readily to the skin. It is soft to the touch and free from grittiness. To be classified as Talc USP, the following specifications must be met ... 

Prepare two solutions, one containing i g. of diphenylamine in 8 ml. of warm ethanol, and the other containing 0-5 g. of sodium nitrite in i ml. of water, and cool each solution in ice-water until the temperature falls to 5°. Now add o 8 ml. of concentrated hydrochloric acid steadily with stirring to the diphenylamine solution, and then without delay (otherwise diphenylamine hydrochloride may crystallise out) pour the sodium nitrite solution rapidly into the weil-stirred mixture. The temperature rises at once and the diphenylnitrosoamine rapidly crystallises out. Allow the mixture to stand in the ice-water tor 15 minutes, and then filter off the crystals at the pump, drain thoroughly, wash with water to remove sodium chloride, and then drain again. Recrystallise from methylated spirit. Diphenylnitrosoamine is thus obtained as very pale yellow crystals, m.p. 67 68° yield, 0 9-1 o g. 

Hydrolysis of benzonitrile to benzoic acid. BoU 5 -1 g. (5 ml.) of benzo-nitrUe and 80 ml. of 10 per cent, sodium hydroxide solution in a 250 ml. round-bottomed flask fitted with a reflux water condenser until the condensed liquid contains no oUy drops (about 45 minutes). Remove the condenser, and boU the solution in an open flask for a few minutes to remove free ammonia. Cool the liquid, and add concentrated hydrochloric acid, cautiously with shaking, until precipitation of benzoic acid is complete. Cool, filter the benzoic acid with suction, and wash with cold water dry upon filter paper in the air. The benzoic acid (5-8 g.) thus obtained should be pure (m.p. 121°). Recrystal-lise a small quantity from hot water and redetermine the m.p. 

Soil Leaching. Soil leaching or acid extraction uses acid to solubilize metals for removal from soils, a technique akin to that ia the mining industry. After extraction with an acid such as hydrochloric, sulfuric, or nitric, the soil is separated from the acid, rinsed with water to remove excess acid and metals, dewatered, and neutralized. The acid is regenerated and recycled back to the process. The extracted metals can be precipitated and recovered. 

The pH is adjusted to 5.5 and the water phase separated and extracted with additional ether in order to remove the surplus dimethyl anilin. After addition of an excess of ammonia to the solution, the reaction product, N-methylpipecolic acid 2,6-dimethyl anilide, is recovered by extraction with isoamyl alcohol. The isoamyl alcohol solution is evaporated to dryness, the product dissolved in dilute hydrochloric acid, treated with charcoal and reprecipitated with NaOH. N-methylpipecolic acid 2,6-dimethyl anilide is obtained in crystalline form. 

A. 2-Methyl-2-nitropro]f)ane. To a well-stirred suspension of 650 g. (4.11 moles) of potassium permanganate in 3 1. of water, contained in a 5-1. three-necked flask fitted with a reflux condenser, a mechanical stirrer, a thermometer, and a 250-ml. dropping funnel, is added dropwise and with stirring over a 10-minute period, 100 g. (1.37 moles) of i-butylamine (Note 1). When the addition is complete, the reaction mixture is heated to 55° over a period of approximately 2 hours, and then the reaction mixture is maintained at 55° with continuous stirring for 3 hours. The dropping funnel and reflux condenser are replaced by a stopper and a still head fitted for steam distillation and the product is steam distilled from the reaction mixture (Note 2). The liquid product is separated from the denser water layer and then diluted with 250 ml. of ether and washed successively with two 50-ml. portions of aqueous 2M hydrochloric acid and with 50 ml. of water. After the ethereal solution has been dried over anhydrous magnesium sulfate, the solution is fractionally distilled at atmospheric pressure to remove the ether. The residual crude product (Note 3) amounts to 106-128 g. and is sufficiently pure for use in the next step. In a typical run, distillation of 124 g. of the crude product afforded 110 g. (78%) of the pure 2-methyl-2-nitrobutane as a colorless liquid, b.p. 127-128°, d 1.3992. The material slowly solidifies on standing to a waxy solid, m.p. 25-26° (Note 4). 

C. Regeneration of 0-tetralone. Fifty grams (0.20 mole) of /3-tetralone bisulfite addition product is suspended in 250 ml. of water, and 75 g. (0.6 mole) of sodium carbonate monohydrate is added. At this point the pH of the solution is approximately 10. The mixture is extracted with five 100-ml. portions of ether (Note 8). The combined extract is washed with 100 ml. of 10% hydrochloric acid, then with 100-ml. portions of water until the washings are neutral to litmus, and is dried over anhydrous magnesium sulfate. The ether is removed by distillation, and the residue is distilled from a Claisen flask under reduced pressure, preferably in a nitrogen atmosphere. The pure /3-tetralone is obtained as a colorless distillate b.p. 70-71°/0.25 mm. (92-940/1.8 mm., 114-11674.5 mm.) n 1.5594. The yield is 17-21 g. (40-50% based on /3-naphthyl ethyl ether). 

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