Acidic removal

The washing with concentrated hydrochloric acid removes unchanged alcohol, if present. 

Reflux 1 g. of the sulphonamide with 2-5 ml. of acetyl chloride for 30 minutes if solution is not complete within 5 minutes, add up to 2-5 ml. of glacial acetic acid. Remove the excess of acetyl chloride by distillation on a water bath, and pour the cold reaction mixture into water. Collect the product, wash with water and dissolve it in warm sodium bicarbonate solution. Acidify the Altered solution with glacial acetic acid Alter oflF the precipitated sulphonacetamide and recrystaUise it from aqueous alcohol. 

Stable to acid removed with base more difficult to hydrolyze than esters... 

It was from studies of nitration with solutions of nitric acid in nitromethane, and later in acetic acid, that Ingold and his co-workers first established the fundamental features of these reactions, and also correctly interpreted them. The use in these experiments of a large excess of nitric acid removed the problem caused by the formation of water. 

To illustrate the specific operations involved, the scheme below shows the first steps and the final detachment reaction of a peptide synthesis starting from the carboxyl terminal. N-Boc-glycine is attached to chloromethylated styrene-divinylbenzene copolymer resin. This polymer swells in organic solvents but is completely insoluble. ) Treatment with HCl in acetic acid removes the fert-butoxycarbonyl (Boc) group as isobutene and carbon dioxide. The resulting amine hydrochloride is neutralized with triethylamine in DMF. 

N). This area of the process has received considerable attention in recent years as companies strive to improve efficiency and reduce waste. Patents have appeared describing addition of SO2 to improve ion-exchange recovery of vanadium (111), improved separation of glutaric and succinic acids by dehydration and distillation of anhydrides (112), formation of imides (113), improved nitric acid removal prior to dibasic acid recovery (114), and other claims (115). 

AH of the [Fe(CN)3] salts maybe considered salts of ferrocyanic acid or tetrahydrogen hexakiscyanoferrate [1712647-5], H4[Fe(CN)3], a strongly acidic, air-sensitive compound. It is soluble in water and alcohol but is insoluble in ether. It can be prepared by precipitation of an etherate by adding ether to a solution of [Fe(CN)3] that was acidified with concentrated sulfuric acid. Removal of the ether of solvation affords a white powder which is stable when dry but slowly turns blue in moist air because of Pmssian Blue formation. 

After acid removal, scrap batteries are fed to a hammer mill in which they are ground to <5 cm particles. The ground components are fed to a conveyor and passed by a magnet to remove undesirable contamination. The lead scrap is then classified on a wet screen through which fine particles of lead sulfate and lead oxide pass, and the large oversize soHd particles are passed on to a hydrodynamic separator. The fine particles are settled to a thick slurry and the clarified washwater recirculated to the wet screen. 

Nitric acid is a strong monobasic acid, a powerful oxidising agent, and nitrates many organic compounds. Until the end of the nineteenth century, it was made by heating a metallic nitrate salt with less volatile concentrated sulfuric acid. Removal of the volatile nitric acid permits the reaction to go to completion. This method is still used for laboratory preparation of the acid. 

Finish removers are manufactured in open or closed ketdes. Closed ketdes are preferred because they prevent solvent loss and exposure to personnel. To reduce air emissions from the solvents, condensers are employed on vent stacks. Mild steel or black iron ketdes are used for neutral or basic removers stainless steel (316 or 317) or reinforced polyethylene ketdes are used for acidic removers. The ketdes are heated to increase dispersion of paraffin waxes and aid in the mixing of other ingredients. Electric or air driven motors drive either sweeping blade or propeller mixers that give sufficient lift to rotate and mix the Hquid. Dispenser-type mixers are used to manufacture thick and viscous removers. Ketde, fittings, mixer, and fill equipment must be fabricated with materials resistant to the chemicals in remover formulas. 

Nitric acid dissolves silver at all concentrations. This is the principal chemical reaction for the dissolution of silver into the soluble nitrate, which is the chemical intermediate for the production of electroplated ware, catalysts, battery plates, pharmaceuticals, mirrors, and silver haUdes for photographic materials. Nitric acid removes silver from the residual pellet in the gold fire assay. 

This mixture can be purified by adding methanol to form methyl lactate [547-64-8] which is separated from the ammonium bisulfate. The methyl lactate is distilled, then hydroly2ed back to the aqueous acid. Removal of most of the water yields 90% lactic acid (29). 

Sodium dodecanoate (sodium laurate) [629-25-4] M 222.3, pK 5.3 (-COOH). Neutralised by adding a slight excess of dodecanoic acid, removing it by ether extraction. The salt is recrystd from aq soln by adding pure Me2CO and repeating the process (see sodium decanoate on p. 468). Also recrystd from MeOH. 

In the sulfuric acid process, the sulfuric acid removed must be regenerated in a sulfuric acid plant which is generally not a part of the alkylation unit and may be located off-site. Spent sulfuric acid generation is substantial typically in the range of 13 to 30 pounds per barrel of alkylate. Air emissions from the alkylation process may arise from process vents and fugitive emissions. 

The use of Pd(Ph3P)4 and MA -dimethylbarbituric acid removed the allyl group in 98% yield. 

When 1-hydroxymelatonin (19) is treated with acid, removal of its 1-hydroxy group leaves an indolyl cation (a hybrid of resonance structures 254,168, and so on) as shown in Scheme 37. If there is a subsequent intramolecular nucleophilic attack by the Ab-nitrogen atom on the side chain or if an intermolecular attack by suitable nucleophiles occurs on this intermediate cation, the birth of a new type of product can be expected. 

In multiresidue analysis, where more analytes with a wide polarity range need to be determined, large transfer volumes are required, and consequently, the selectivity is lower. However, since the major interferences in water analysis are the polar humic and fulvic acids, removing this early eluting interference in coupled-column RPLC will also be feasible in multiresidue methodology. 

The fraction of oil of cade boiling at 260° to 280° is converted into cadinene dihydrochloride by saturating its solution in dry ether with dry hydrochloric acid gas. The hydrochloride is separated, dried, and leorystallised, and the hydrochloric acid removed by heating it with aniline or with sodium acetate in glacial acetic acid. The liberated cadinene is rectified in a current of steam. Cadinene from oil of cade is highly laevo-rotatory, the dextro-rotatory variety being obtained from Atlas cedar oil and West Indian sandalwood oil. 

Hydrobromic acid 50% w/w (325 g) diluted with water (2 liters) was added slowly at the boil and the precipitated embonic acid removed by filtering hot and washing twice with hot water (1 liter). The filtrate and washings were evaporated to dryness in a steam pan and the residue recrystallized from ethyl alcohol (1,200 ml), to yield the dibromide (320 g). 

The dl-a-methYl-3,4-dihYdroxYphenylalanine may be made as described in U.S. Patent 2,868,818. Five-tenths of a gram of 3-hYdroxY-4-methoxYphenylalanine was dissolved in 20 ml of concentrated hydrochloric acid, the solution saturated with hydrogen chloride and heated in a sealed tube at 150°C for 2 hours. The dark reaction mixture was concentrated to dryness in vacuo, excess acid removed by flushing several times with ethanol. On dissolving the dark residue in a minimum amount of water and adjusting the clarified solution to pH 6.5 with ammonium hydroxide the compound separated in fine crystals which were filtered, washed with alcohoi and ether. The crystalline product had a MP of 299.5° to 300°C with decomposition. 

Note. If 1M hydrochloric acid is required, use 90 mL of the concentrated acid. If 0.01 M acid is required, dilute two 50 mL portions of the approximately 0.1 M acid, removed with a 50 mL pipette, to 1 litre in a graduated flask. 

Cupferron Nitroso-R-salt 688 Nitrous acid removal of. 514 Nonaqueous titrations 307 indicators for, 284 solvents for. 283... 

Preparation. It is prepd by dissolving pure Sr nitrate in an excess of perchloric ac, the excess ac neutralized with Sr carbonate, all solids centrifuged off, and the soln chilled until crysts appear (Ref 2). The anhyd salt can also be prepd by drying the hydrate at 250°, yield 50% (Ref 3) or the addn of anhyd perchloric ac to a soln of Sr ion in anhyd trifluoroacetic ac, the pptd solid filtered, and the excess acid removed in a vacuum (Ref 7)... 

Nitric acid, removal of nitrogen oxides from, 43, 84... 

To dissolve more of the solid, we can add acid. The H30+ ions from the acid remove the OH ions by converting them into water, and the Fe(OH), dissolves. 

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