Hydrochloric acid regeneration

Effluent-Free Pickling Process with Fluid Bed Hydrochloric Acid Regeneration... 

National Emission Standards for Hazardous Air Pollutants for Source Categories Generic Maximum Achievable Control Technology Standards National Emission Standards for Hazardous Air Pollutants for Steel Pickling—HCI Process Facilities and Hydrochloric Acid Regeneration Plants National Emission Standards for Hazardous Air Pollutants for Mineral Wool Production National Emission Standards for Hazardous Air Pollutants From Hazardous Waste Combustors National Emission Standards for Pharmaceuticals Production... 

Pollutants for Steel Pickling—HCI Process Facilities and Hydrochloric Acid Regeneration Plants Subpart DDD National Emission Standards for Hazardous Air... 

The behavior of oxazoles towards mercuric acetate, which results in formation of electrophilically substituted products, has been studied by Shvaika and Klimisha.312-313 Mercuration of phenyloxazoles in acetic acid results in products mercurated only at the unsubstituted C atoms in the heterocyclic ring. Like halogenation, the order of reactivity of the various positions in the ring is C-5 > C-4 > C-2. The hydrolysis of the mercurated oxazoles with dioxane-concentrated hydrochloric acid regenerates the parent oxazoles,313 whereas treatment with halogens (bromine or iodine) gives the corresponding halooxazole in 55-90% yields.18-312 The reaction thus offers an indirect but efficient method of introduction of... 

The hydrochloric acid regenerated by the second reaction serves to convert more acid into chloride and the process is, therefore,... 

HYDROCHLORIC ACID REGENERATION VIA CALCIUM SULFATE CRYSTALLIZATION FOR NON-FERROUS CHLORIDE LEACHING... 

Figure 7. Flowchart of hydrochloric acid regeneration circuit and calcium sulfate production...

A. Al-Othman and G. Demopoulos, Gypsum Crystallization and Hydrochloric Acid Regeneration by Reaction of Calcium Chloride Solution with Sulfuric Acid, Hydrometallurgy, 96 (2009), 95-102. 

Hydrochloric Acid Regeneration via Calcium Sulfate Crystallization for Non-Ferrous Chloride Leaching Processes.379... 

The characteristic property of aliphatic nitrocompounds of the type RCHiKOj and RjCHNO, is that they are pseiido cids, I. e., whereas they are neutral in the normal form (A), they are able by tautomeric change under the influence of alkali to give the acidic hydroxy form (B) which thus in turn gives the sodium salt (C). When this sodium salt is treated with one equivalent of hydrochloric acid, the acid form (B) is at once regenerated, and then more slowly reverts to the more stable normal form (A). 

If one is absolutely serious about ultra pure safrole then it can be separated from the eugenol-free sassafras oil by treatment with mercuric acetate [1,2,3,4] which likes that terminal double bond that only safrole has. The Hg(AcO)2 latches on to safrole at that double bond bringing it into solution as a solid sort of like the way that eugenol was. The safrole can then be separated from its still oily buddies by vacuum filtration. Safrole is then regenerated to its normal oily form by treatment with hydrochloric acid (HCI) which flicks the Hg(AcO)2 off the safrole and the safrole double bond reforms. As it so happens, the mercuric acetate also reforms intact so that it can be reused again such as in one of those... 

Miscellaneous. Hydrochloric acid is used for the recovery of semiprecious metals from used catalysts, as a catalyst in synthesis, for catalyst regeneration (see Catalysts, regeneration), and for pH control (see Hydrogen-ION activity), regeneration of ion-exchange (qv) resins used in wastewater treatment, electric utiUties, and for neutralization of alkaline products or waste materials. In addition, hydrochloric acid is also utilized in many production processes for organic and inorganic chemicals. 

Cation exchangers are regenerated with mineral acids when used in the form. Sulfuric acid [8014-95-7] is preferred over hydrochloric acid [7647-01-0], HCl, in many countries because it is less expensive and less corrosive. However, the use of hydrochloric acid is the best method of overcoming precipitation problems in installations which deionize water with high concentrations of barium or calcium compared to other cations. A 4% acid concentration is common, although sulfuric acid regenerations may start as low as 0.8—1% to minimize calcium sulfate [7718-18-9] precipitation. 

Today the sulphonation route is somewhat uneconomic and largely replaced by newer routes. Processes involving chlorination, such as the Raschig process, are used on a large scale commercially. A vapour phase reaction between benzene and hydrocholoric acid is carried out in the presence of catalysts such as an aluminium hydroxide-copper salt complex. Monochlorobenzene is formed and this is hydrolysed to phenol with water in the presence of catalysts at about 450°C, at the same time regenerating the hydrochloric acid. The phenol formed is extracted with benzene, separated from the latter by fractional distillation and purified by vacuum distillation. In recent years developments in this process have reduced the amount of by-product dichlorobenzene formed and also considerably increased the output rates. 

Semicarbazones are prepared in high yields from A " -3-ketones. However, regeneration of the parent dienone is usually difficult and inefficient and very low yields are usually obtained on hydrolysis by nitrous acid, hydrochloric acid or acetic anhydride-pyridine. " In some examples higher yields have been obtained with aqueous acetic acid. ... 

Sylvestrene nitrosochloride, CjoHj,. NOCl, is prepared from pure sylvestrene, regenerated from the dihydrochloride in the following manner Four volumes of the terpene are dissolved in six of amyl nitrite and five volumes of strong hydrochloric acid are added, with constant shaking. The heavy oil which separates is shaken with a little ethyl alcohol, when it solidifies, and can be purified by dissolving it in chloroform and precipitating it with petroleum ether. It is finally recrystallised from methyl alcohol, when it melts at 106° to 107°. 

It yields a liquid dihydrochloride, from which, hy the action of aniline, hydrochloric acid is split off. The regenerated sesquitei-pene,. however, differs in character from atractylene. 

When rectified gurjun balsam oil, that is, a mixture of a- and /3-gurjunene, is saturated in ethereal solution with hydrochloric acid gas, and the mixture is left standing for two days at room temperature, and the hydrochloric acid abstracted by heating with sodium acetate, the regenerated sesquiterpene appears to be a bicyclic compound having the following characters —... 

A solution of 5.0 g of a-ethyl-(3-(aminophenyl)propionic acid in 100 ml of water containing 5 ml of concentrated hydrochloric acid was added over a period of h hour to a stirred solution of 3.2 ml of Iodine monochioride in 25 ml of water and 25 ml of concentrated hydrochloric acid heated to 60°C. After addition was complete, the heating was continued for h hour longer at 60° to 70°C. A black oil separated which gradually solidified. The mixture was then cooled and sodium bisulfite was added to decolorize. Recrystallization of the product from methanol gave about 8 g of a-ethyl-(3-(2,4,6-triiodo-3-aminophenyl-pro-pionic acid, MP 147° to 150°C. The product could be further purified by precipitation of its morpholine salt from ether solution and regeneration of the free amino acid by treatment of a methanol solution of the morpholine salt with sulfur dioxide. The pure amino acid had the MP 155° to 156.5°C (corr). 

De-alkalization resins are regenerated with sulfuric or hydrochloric acid. Sulfuric acid is cheaper and easier to... 

The importance of magnesium chloride has probably been exaggerated. There is little doubt that it can act as a catalyst in corrosion reactions by hydrolysing to form hydrochloric acid, being then regenerated by reaction between ferrous chloride and magnesium hydroxide. There is, however, little evidence that this reaction takes place in cold- or hot-water systems, and it is probably confined to steam boilers where it might be a cause of corrosive attack underneath scale deposits it does not constitute a problem in a properly conditioned boiler water. 

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