Hydrochloric acid byproduct

Vent gases containing EDC vapour, not only from the storage and transport of EDC, but also from the EDC unit itself, must be controlled because of EDC toxicity and other reasons. Conventionally these vent emissions are controlled using thermal oxidation, where the EDC vapour is converted to carbon dioxide, water, and hydrogen chloride. The latter is then scrubbed from the flue gases, resulting in a byproduct hydrochloric acid stream. Consideration is required as to how this stream can be used or disposed of. 

Haifa Also called IMI. One of the two Wet Processes for producing phosphoric acid by the acidulation of phosphate rock the other is the Dorr process. The Haifa process uses hydrochloric acid for the acidulation and solvent extraction for the purification. It is economic only where byproduct hydrochloric acid is available. The overall reaction is... 

Wet Process A process for making phosphoric acid by treating phosphate rock with an acid. The acid is usually sulfuric acid, but hydrochloric and nitric acids are used commercially in special circumstances in Israel, where byproduct hydrochloric acid is available, and in Norway and... 

A company is considering construction of a phosphoric acid plant employing Haifa process technology, which is to use its own byproduct hydrochloric acid for acidulation. Present-day cost of sulfuric acid is 110/tonne. 

HCI can be used where it is available as a byproduct. This is important for developing countries producing NaOH, where there is no captive market for the chlorine that is produced simultaneously. Byproduct hydrochloric acid is sometimes available from other sources and may even create disposal problems. In such cases the production of phosphoric acid by the acidulation of... 

Production of chlorinated solvents, which include carbon tetrachloride, methylene chloride, 1,1,1-trichloroethane, PCE, and TCE, is expected to decline because of environmental concerns. The demand for methyl chloride will also decrease, as Bayer has developed a new process for producing silicones, where the byproduct hydrochloric acid is fed back to the system, regenerating methyl chloride. 

Most of the byproduct HCl is used captively, primarily in oxyhydrochlorination processes for making vinyl chloride and chlorinated solvents or for Mg processing (p, 110), The scale of the industry is enormous for example, 5,2 million tonnes of HCl per annum in the US alone (1993), HCl gas for industrial use can be transmitted without difficult over moderate distances in mild-steel piping or in tank cars or trailers. It is also available in cylinders of varying size down to laboratory scale lecture bottles containing 225 g. Aqueous hydrochloric acid consumption (1993) was 1,57 Mt (100% basis). Price for anhydrous HCl is 330/tonne and for 31,4% aqueous acid 73/tonne (1993) depending on plant location and amount required. 

In 2000, an efficient three-step procedure for the synthesis of 5-substituted 3-isoxazolols (without formation of undesired 5-isoxazolone byproduct) was published. The method uses an activated carboxylic acid derivative to acylate Meldrum s acid, which is treated with A,0-bis(ten-butoxycarbonyl)hydroxylamine to provide the N,0-di-Boc-protected P-keto hydroxamic acids 14. Cyclization to the corresponding 5-substituted 3-isoxazolols 15 occurs upon treatment with hydrochloric acid in 76-99% yield. 

Acid Mineral A Hydrochloric acid Nitric acid Sulphuric acid Pickling Chemical reagent Byproducts, petrochemicals... 

Substitutions are very common synthetic reactions by their very nature they produce at least two products, one of which is commonly not wanted. As a simple example 2-chloro-2-methylpropane can be prepared in high yield by simply mixing 2-methylpropan-2-ol with concentrated hydrochloric acid (Scheme 1.10). Here the hydroxyl group on the alcohol is substituted by a chloride group in a facile SnI reaction. Whilst the byproduct in this particular reaction is only water it does reduce the atom economy to 83%. 

The waste hydrochloric acid (HC1) injected at the site was a byproduct of a combustion process at 1633°C (2972°F). When not recovered, the acidic stream was dumped into holding ponds where it was cooled to about 24°C (75°F) before injection. The concentration of injected acid typically varied from 0.5 to 5% HC1, but ranged as high as about 30%. (The pH of injected acid that back-flowed during one blowout incident ranged from 0.5 to 1.3.)... 

According to the Illinois Environmental Protection Agency (IEPA), a series of gas blowouts has occurred at two waste injection wells in the state (Brower el al., 1989). In each case, well operators were injecting concentrated hydrochloric acid into a dolomite bed. At its plant near Tuscola, the Cabot Corporation injects acid waste from the production of fumed silica into the Cambrian Eminence and Potosi Formations below 5 000 ft (1 500 m) depth. Allied Chemical Corporation injects acid into the Potosi formation below about 3 600 ft (1 100 m). The acid, which is contaminated with arsenic, is a byproduct of the manufacture of refrigerant gas. Since some of the blowouts have caused damage such as fish kills, there is environmental interest as well as operational concern in preventing such accidents. 

Mannheim (1) A process for making hydrochloric acid by roasting sulfuric acid and sodium chloride together in a closed cast iron furnace equipped with a plough. The byproduct sodium sulfate, known as salt cake, may be reciystallized after neutralization and filtration, and used as a detergent ingredient. A potassium variant is used in those locations where native potassium chloride can be found. 

For products requiring high-quality sulfates, chlorosulfonic acid is an excellent corrosive agent that generates hydrochloric acid as a byproduct. A process flow diagram is shown in Figure 13. The effluent washouts are minimal. 

The hydrolysis of acetals are reported to go smoothly.292 However, some precautions should occasionally be taken since it has been reported that treatment of cAO-2-hydroxymethyl-7,7-dimcthoxybicyclo[3.2.0]heptan-m7o-2-ol with a mixture of 3% hydrochloric acid/acetone/wa-ter (1 9 1) gave a mixture of ertafo-2-hydroxy-< .xo-2-hydroxymethylbicyclo[3.2.0]heptan-7-one (5) and 8-hydroxymethyl-2-oxabicyclo[3.3.0]oct-7-en-3-one (6) in 2 1 ratio.323 The reaction is explained by a rearrangement of an intermediate cyclobutanone hydrate, but since other acetals do hydrolyze without similar byproduct formation it seems likely that the neighboring tertiary alcohol must be involved in the rearrangement. 

Apart from the impurities that influence its colour, mercury fulminate may contains a trace of mercuric oxalate, the presence of which was discovered by Shish-kov [19] as early as 1856. Oxalic acid is always formed during the reaction as a byproduct resulting from the oxidation reaction and according to Solonina the amount of oxalic acid formed is larger if hydrochloric acid is present in the reaction mixture. 

ISO 4621 (1986) also specifies analytical methods. Usually, analysis of chromium and the byproducts is preceded by melting with soda and sodium peroxide. The content of water-soluble or acid-soluble chromium is becoming important from the toxicological and ecological point of view. It is determined according to DIN 53 780 with water, or according to ISO 3856, part 1 with 0.1 mol/L hydrochloric acid. 

POLYVINYL CHLORIDE (PVC). [CAS 9002-86-2], The manufacture of polyvinyl chloride resins commences with the monomer, vinyl chloride, which is a gas, shipped and stored under pressure to keep it in a liquid state bp —14°C, fp —160°C, density (20°C), 0.91. The monomer is produced by the reaction of hydrochloric acid with acetylene. This reaction can be carried out in eidier a liquid or gaseous state. In another technique, ethylene is reacted with chlorine to produce ethylene dichloride. This is then cataiytically dehydrohalogcnatcd to produce vinyl chloride. The byproduct is hydrogen chloride. A later process, oxychlorination, permits the regeneration of chlorine from HC1 for recycle to the process. 

The 1,4-benzodiazepinones, exemplified by diazepam (53), undergo hydrolysis in acid and base to yield the corresponding o-aminobenzophenones (54). However, unusual byproducts were observed when diazepam (53) or 2-((V-methyl)amino-5-chlorobenzophenone (54) was hydrolysed in aqueous methanolic hydrochloric acid, and now a mechanism involving a nitrene has been proposed to account for the... 

Diazotization of 3-phenyl-l,6-naphthyridine-2,7-diamine (24) in an excess of hydrochloric acid gave mainly 7-chloro-3-phenyl-l,6-naphthyridin-2-amine (25) along with three separable byproducts (10M HC1, — 10°C, HC1 gasj, substrate), — 10°C, 5h 20°C, 8h 4°C, 2 days 61%) analog likewise.564... 

The initial synthetic approach to conivaptan HCl (1) employed by the Yamanouchi discovery group26 commenced with commercially available benzazepinone 10. Acylation of 10 with p-nitrobenzoyl chloride provided benzamide 11. Subsequent hydrogenation of 11 over palladium on carbon yielded aniline 12, which was in turn condensed with biphenyl-2-carbonyl chloride to provide bis(amide) 13. Bis(amide) 13 was subsequently heated with copper(II) bromide in boiling chloroform/ethyl acetate to furnish a-bromoketone 14. It is interesting that condensation of a-bromoketone 14 with acetamidine hydrochloride in the presence of potassium carbonate in boiling acetonitrile afforded not only the desired imidazobenzazepine product (1 53% yield, 2 steps) but also the related oxazolobenzazepine 15 (7% yield, 2 steps), which presumably resulted from nucleophilic attack of the benzazepinone oxygen on the amidine moiety followed by loss of ammonia. Separation of oxazolobenzazepine byproduct 15 from imidazobenzazepine 1 by silica gel chromatography followed by treatment of the purified imidazobenzazepine free-base with hydrochloric acid then provided conivaptan HCl (1). 

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