Sodium hydrogen carbonate reaction with hydrochloric acid

Recognizing Cause and Effect To make sure that the white powder was all sodium chloride and not mixed with sodium hydrogen carbonate, would you need to add a little less or a little more hydrochloric acid to the reaction Explain your decision. 

Reaction with cyanic esters 732 Carbon disulfide (2.28 g, 30 mmoles) in ether (5 ml) is dropped into a solution of the amine (30 mmoles) and triethylamine (3.03 g, 30 mmoles) in ether (20 ml) which is stirred and cooled in ice-water. The mixture is then left at room temperature for 1 h (or 24 h for aromatic amines), treated with phenyl cyanate (3.57 g, 30 mmoles), and diluted with ether (5 ml). The clear solution that results is extracted with dilute hydrochloric acid, with sodium hydrogen carbonate solution, and with water, concentrated, filtered from the precipitated phenyl thiocarbamate, and fractionated. Yields are about 60%. 

Aqueous solutions of sodium nitrite (4.5) and of acetic acid (4 g) are added successively to one of bicyclo[3.2.2]nonane-6-methylamine hydrochloride (13 g) in water (50 ml) while a rapid stream of steam is passed through the solution. When this reaction ceases, further sodium nitrite (2 g) and acetic acid (1.8 g) are added and distillation is continued. The distillate is extracted with ether, and the extracts are washed with dilute hydrochloric acid until free from amine, neutralized with sodium hydrogen carbonate, and evaporated. The residue is mixed with 10% sodium hydroxide solution (10 ml) and distilled in steam. The bicyclo-[3.3.2]decan-3-ol that solidifies in the distillate is collected (7.5 g, 71 %). 

A solution of freshly distilled benzaldehyde (10.6 g, 100 mmol) and anhydrous DMF (50 mL) is added dropwise within 10 min to a stirred mixture of sodium cyanide (0.49 g, 10 mmol) and DMF (50 mL) at 35 °C. After 5 minutes stirring, a solution of freshly distilled methyl vinyl ketone (5.3 g, 75 mmol) in DMF (100 mL) is added at 35 °C over 20 min. Stirring is continued for 1 h at the same temperature and the reaction mixture then treated with twice the amount of water. After repeated extraction with chloroform the combined extracts are washed with dilute hydrochloric acid (pH 2), then with sodium hydrogen carbonate solution, and finally with... 

A) A mixture of 333 parts of 4-(1 -piperazinyDphenol dihydrobromide, 11.2 parts of acetic acid anhydride, 42 parts of potassium carbonate and 300 parts of 1,4-dioxane is stirred and refluxed for 3 days. The reaction mixture is filtered and the filtrate is evaporated. The solid residue is stirred in water and sodium hydrogen carbonate is added. The whole is stirred for 30 minutes. The precipitated product is filtered off and dissolved in a diluted hydrochloric acid solution. The solution is extracted with trichloromethane. The acid aqueous phase is separated and neutralized with ammonium hydroxide. The product is filtered off and crystallized from ethanol, yielding 5.7 parts of 1 acetyl-4-(4-hydroxyphenyl)piperazine MP 181.3°C. 

Procedures for THP-ether formation. Use of hydrochloric acid. Concentrated hydrochloric acid (0.3 ml) was added to a mixture of 2,3-dihydropyran (0.75 mol) and the alcohol (0.5 mol). Reaction commenced immediately on shaking and was moderated by cooling in an ice-water bath. The mixture was shaken for a further 30 minutes, allowed to stand overnight, diluted with ether (150 ml), and the solution washed twice with aqueous sodium hydrogen carbonate solution. The ethereal solution was dried and evaporated, and the residue distilled under reduced pressure. 

Reduction of nitroketones with titanium(m) chloride at pH 1. The foregoing nitroketone may be converted into the diketone by means of the following general procedure. The nitroketone in solution in tetrahydrofuran (0.2 m) is treated with 4 equivalents of titanium(m) chloride (1) (20% aqueous hydrochloric acid solution) and stirred under nitrogen at room temperature for 24 hours. The reaction mixture is then poured into ether and the phases separated. The aqueous phase is extracted several times with ether the organic extracts are combined, washed with 5 per cent sodium hydrogen carbonate and with brine, and then dried over anhydrous sodium sulphate, concentrated and distilled. The yield of heptane-2,5-dione is 66 per cent p.m.r. spectrum (CC14, TMS) 8 1.00 (t, 3H), 2.10 (s, 3H), 2.60 (s, 4H) and 3.41 (q, 2H). 

In a 250-ml round-bottomed flask, provided with a small reflux condenser and a calcium chloride drying tube at the top, place 2.1 g (0.17 mol) of salicylaldehyde, 2.0 ml of anhydrous triethylamine and 5.0 ml (0.052 mol) of acetic anhydride, and reflux the mixture gently for 12 hours. Steam distil the mixture from the reaction flask and discard the distillate. Render the residue in the flask basic to litmus with solid sodium hydrogen carbonate, cool, filter the precipitated crude coumarin at the pump and wash it with a little cold water. Acidify the filtrate to Congo red with 1 1-hydrochloric acid, collect the precipitated o-acetoxycinnamic acid and recrystallise it from 70 per cent propan-2-ol the yield is 0.40 g (11%), m.p. 153-154 °C. 

The residue was subjected to azeotropic operation with toluene two times, and ether was added to the residue. The precipitate derived from trioxane was removed by filtration and washed with ether, and the combined ethereal solutions were concentrated under reduced pressure. The residue was dissolved in ethyl acetate, and the solution was washed with water and aqueous saturated solution of sodium chloride, was dried, and was concentrated to give 4 g of an oily material. The oily material was dissolved in 20 ml of methanol and to the solution was added 20 ml of aqueous 1 N solution of sodium hydroxide, and the mixture was stirred for 14 hours at room temperature. After removal of methanol under reduced pressure, water was added to the mixture, and this solution was acidified to pH 3 with aqueous 2 N hydrochloric acid. The mixture was extracted five times with ethyl acetate, and the ethyl acetate extract was dried and concentrated to give 3.5 g of crude crystals. After addition of ethanol to the crude crystals, the crude crystals were filtered. The filtrate was concentrated, and to the residue was added ethanol and ethyl acetate, and precipitate was collected by filtration. The combined amount of the crude crystals was 1.6 g. After the combined crude crystals were methylated with diazomethane, the reaction product was dissolved in 20 ml of ethyl acetate. To this solution was added 1.5 g of sodium acetate and 300 mg of 10% palladium-carbon, and the mixture was stirred for 2 hours under hydrogen. Then, the reaction product was filtered, and after addition of aqueous saturated solution of sodium hydrogen carbonate to the filtrate, the mixture was extracted two times with ethyl acetate. The extract was washed with an aqueous saturated solution of sodium chloride, dried, and concentrated to give 1.3 g of crude crystals. The crude crystals were recrystallized from ethyl acetate to yield 765 mg of the title compound (melting point 134-135°C, yield 43%). 

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. 

Carboxyphenyl Phenyl Tellurium2 27.2 g (0.2 mol) of 2-aminobcnzoic acid arc dissolved in a mixture of 25 ml of concentrated hydrochloric acid and 70 ml of water. 13.8 g of sodium nitrite dissolved in 20 ml of water are added dropwisc to the stirred amine solution cooled in an icc/walcr bath. Sodium hydrogen carbonate is added until the solution of the diazonium salt is slightly basic. 23 g (56 mmol) of diphenyl ditellurium are dissolved in a mixture of 30 ml of ethanol and 60 ml of THF. To this solution are added 2.3 g (60 mmol) of sodium borohydride dissolved in 33 ml of 1 M aqueous sodium hydroxide. The diazonium salt solution is quickly added to the warm benzenetellurolate solution. 10 ml of 1 M sodium hydroxide are then added and, after the evolution of nitrogen has ceased, the mixture is heated to complete the reaction. The mixture is poured onto ice and diphenyl ditellurium is extracted with benzene. The aqueous phase is acidified with 1 M hydrochloric acid and the product precipitates in analytically pure form yield 28.2 g (43%) m.p. 185° (from toluene). 

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