Acid treatment

Therefore, further acid treatment is necessary on both original activated carbons and these after high temperature graphitized and oxidation treatment can introduce the surface oxygenous functional groups. 24 

The oxidation of activated carbons can be divided into two types Gas-phase oxidation and liquid phase oxidation. The gas-phase oxidation is to heat activated carbons at the oxygen-contained inert gas and the most common oxidant is HNO3 in the liquid phase oxidation,the other oxidants include HCl, HCIO, H202, and O3 and so on. The liquid phase oxidation can introduce oxygen-containing functional groups and can remove the ash in activated carbons. The effect of the different oxidation treatment on the activated carbons performances are listed in Table 6.14.  

He-TPD-MS of activated carbons treated by different methods are shown in Fig. 6.30. The types and contents of the surface groups have large changes after 

The relationship between surface structures of the activated carbons and the dispersion of active metal is shown in Table 6.15. It can be seen from Table 6.15 that after oxidation treatment, especially the gas phase oxidation, the pore structures of activated carbons are improved, and the dispersions of Ru are enhanced. 

Some surface groups can be eliminated and the surface alkaline can be enhanced when activated carbon is treated at high temperatures in the H2 or inert atmosphere.Aika et al have studied the effect of H2 treatment on the character of activated carbons. They 

Remove the black residue formed on the metal with a clean, stiff brush while holding the metal under cold, running distilled or deionized water 

Dry the metal by heating at 120°C for 1 h. If the steel part cannot be stored immediately in an area of low humidity (less than 30% RH) apply the adhesive immediately after cleaning  

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The generic term azulene was first applied to the blue oils obtained by distillation, oxidation, or acid-treatment of many essential oils. These blue colours are usually due to the presence of either guaiazulene or velivazulene. The parent hydrocarbon is synthesized by dehydrogenation of a cyclopentanocycloheptanol or the condensation of cyclopentadiene with glutacondialdehyde anil. 

Sulfonic acids can come from the sulfonation of oil cuts from white oil production by sulfuric acid treatment. Sodium salts of alkylaromatic sulfonic acids are compounds whose aliphatic chains contain around 20 carbon atoms. The aromatic ring compounds are mixtures of benzene and naphthalene rings. 

All silicon compounds on oxidation yield silica or silicates these are difficult to detect but silica (given by silicates after acid treatment) is insoluble in all acids except hydrofluoric acid. 

The sulphuric acid treatment removes high-boiling impurities which are not easily separated by distillation. 

Perbenzoic acid. Treatment of a cold sodium methoxide solution with a solution of pure benzoyl peroxide in chloroform affords methyl benzoate and a solution of the sodium salt of perbenzoic acid ... 

The early Escherunoser-Stork results indicated, that stereoselective cyclizations may be achieved, if monocyclic olefins with 1,5-polyene side chains are used as substrates in acid treatment. This assumption has now been justified by many syntheses of polycyclic systems. A typical example synthesis is given with the last reaction. The cyclization of a trideca-3,7-dien-11-ynyl cyclopentenol leads in 70% yield to a 17-acetyl A-norsteroid with correct stereochemistry at all ring junctions. Ozonolysis of ring A and aldol condensation gave dl-progesterone (M.B. Gravestock, 1978 see p. 279f.). 

The acid treatment in each detritylation step may remove purines from deoxyriboses. Purine residues near the 3 -end will suffer the longest cumulative times of exposure to acid and therefore have the greatest chance for depurination . Thus each acid treatment should be as brief as possible. 

Acids carboxylic Acid soaps Acid suppressor Acid treatment Acidulants... 

These are highly purified petroleum products which have been fully refined by either acid treatment or hydrogenation to remove all unsaturates, aromatics, and coloring materials to meet JnitedSfates Pharmacopoeia (USP) requirements. 

The newly formed y-Mn02 actually coats the surfaces of the particles of the soHd phase the MnSO dissolves in the Hquid phase, along with the majority of the ore impurities. The effective surface area is expanded by the etching action of the sulfuric acid. Following the acid treatment step, the slurry is filtered and the cake is carefiiUy washed and dried at a controlled temperature. 

Boron related to boric acid treatment of 5-10 ppm B in feedwater. 

AlkoxyaLkyl hydroperoxides are more commonly called ether hydroperoxides. They form readily by the autoxidation of most ethers containing a-hydrogens, eg, dioxane, tetrahydrofuran, diethyl ether, diisopropyl ether, di- -butyl ether, and diisoamyl ether (10,44). From certain ethers, eg, diethyl ether (in the following, R = H R = 35 — CH2CH2), the initially formed ether hydroperoxide can yield alcohol on standing, or with acid treatment... 

Acid Treatment. The treatment of petroleum products with acids has been in use for a considerable time in the petroleum industry. Various acids such as hydrofluoric acid, hydrochloric acid, nitric acid, and phosphoric acid have been used in addition to the most commonly used sulfuric acid, but in most instances there is Httie advantage in using any acid other than sulfuric. 

Metal Treatment. After rolling, the oxide scale on sheet steel is removed by acid treatment (pickling) (see Metal surface treatments). Phosphoric acid, a good pickling agent, leaves the steel coated with a thin film of iron phosphates. This process improves mst resistance but presents a problem if the steel is to be electroplated. 

Unsaturated ketones react with phenyUiydrazines to form hydrazones, which under acidic conditions cyclize to pyrazolines (35). Oxidation, instead of acid treatment, of the hydrazone with thianthrene radical cation (TH " ) perchlorate yields pyrazoles this oxidative cyclization does not proceed via the pyrazoline (eq. 4). 

An especially interesting case of oxygen addition to quinonoid systems involves acidic treatment with acetic anhydride, which produces both addition and esterification (eq. 3). This Thiele-Winter acetoxylation has been used extensively for synthesis, stmcture proof, isolation, and purification (54). The kinetics and mechanism of acetoxylation have been described (55). Although the acetyhum ion is an electrophile, extensive studies of electronic effects show a definite relationship to nucleophilic addition chemistry (56). 

Rosin is polymerized by acid treatment at elevated temperatures, whereby double bonds are eliminated by dimerization. Dimerized rosin (10) has a higher molecular weight and a correspondingly higher softening point. It is more stable because fewer double bonds remain and conjugation is reduced. 

Reclaim Rubber. The process of reclaiming mbber by chemical digestion has been in use since the late 1800s. Early processes involved the treatment of the mbber cord mix with acid. Acids attack cotton, rayon, and nylon. The acid treatment was used to remove the reinforcing components. 

Silver Chloride. Silver chloride, AgCl, is a white precipitate that forms when chloride ion is added to a silver nitrate solution. The order of solubility of the three silver halides is Cl" > Br" > I. Because of the formation of complexes, silver chloride is soluble in solutions containing excess chloride and in solutions of cyanide, thiosulfate, and ammonia. Silver chloride is insoluble in nitric and dilute sulfuric acid. Treatment with concentrated sulfuric acid gives silver sulfate. 

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