Acid Hydrochloric Oxalic

Novolacs are usually made under acidic conditions. Oxalic, sulfuric, toluene sulfonic, phenyl sulfonic, methane sulfonic, hydrochloric, and phosphoric acids are the most common catalysts, though nearly any moderately strong acid will probably do. Often selection of the acid has significant effects on the resultant polymer structure or performance. Sometimes acids are selected for their volatility, as it may be necessary to distill the acid off in some processes. 

Diaziridines are weak bases, They can be extracted from organic solvents with aqueous mineral acids. With increasing number and chain length of alkyl substituents the solubility in aqueous mineral acids decreases. l-MethyI-2-n-butyl-3-hexyldiaziridine is soluble only in concentrated hydrochloric acid. Stable oxalates can in some cases be prepared from 1-aIkyI-diaziridines (43). The salts are stable indefinitely and by the action of alkali the diaziridines can be recovered. Diaziridines dialkylated on nitrogen (44) are hardly capable of salt... 

The acidic catalysts used for these reactions include formic acid, HX (X = F, Cl, Br), oxalic acid, phosphoric acid, sulfuric acid, sulfamic acid, and p-toluenesulfonic acid.4 Oxalic acid is preferred since resins with low color can be obtained. Oxalic acid also decomposes at high temperatures (>180°C) to C02, CO, and water, which facilitates the removal of this catalyst thermally. Typically, 1-6 wt % catalyst is used. Hydrochloric acid results in corrosive materials and reportedly releases carcinogenic chloromethyl ether by-products during resin synthesis.2... 

Preparation A mixture of phenol and formaldehyde is taken in the distillation vessel. To this hydrochloric acid or sulphuric acid or oxalic acid is added. Now the reaction mixture is heated under reflex at about 100-120°C for 2-4 hours. Water is a by-products which is distilled off at the atmospheric pressure. The resin to obtained is having the Melting point 65-75°C. 

Table 1 Catalysts used for the dehydration of polysaccharides Organic acids Oxalic acid, levulinic acid, maleic acid, p-toluenesulfonic acid Inorganic acids Phosphoric acid, sulfuric acid, hydrochloric acid, iodine, or hydroiodic acid generated in situ...

Novolac resins are condensation products of phenol and formaldehyde made in the presence of an acid catalyst such as hydrochloric acid, sulfuric acid or oxalic acid. For novolac resins, mole ratios of phenol to formaldehyde vary from 1 0.5... 

Subsequent work by Petersen et al. also used TRU-Resin columns with a HPIC instrument however, the effects of column length were investigated and a 3-cm length was selected.61 Other parameters such as resin size and flow rate were examined, and eluent compositions were studied to minimize the use of oxalic acid. Decreased oxalic acid concentrations reduced the frequency of instrument cleaning. In the final scheme, the Np and Am were eluted in hydrochloric acid, followed by Pu and Th together as tetravalent species in a gradient that added oxalic acid. Last to elute was U. Coelution of Pu and Th was considered satisfactory because isobaric interferences between these elements was not a problem. 

Essentially, all primary skin irritants include acids, alkalis, metals, salts, and solvents. Among organic acids one may include acetic acid, acrylic acid, carbolic acid, chloroacetic acid, formic acid, lactic acid, oxalic acid, and salicylic acid. Among inorganic acids one may list arsenious acid, chromic acid, hydrochloric acid, hydrofluoric acid, nitric acid, phosphoric acid, and sulfuric acid. Alkalis include butylamines, ethylamines, ethanolamines, methylamines, propylamines, and triethanolamine. One also may include ammonium carbonate, ammonium hydroxide, calcium carbonate, calcium cyanamide, calcium hydroxide, calcium oxide, potassium carbonate, potassium hydroxide, sodium carbonate (soda ash), sodium hydroxide (caustic soda), and sodium silicate. 

Panzer obtained a gel-like carbohydrate substance from defatted bacilli (human strain) by successive extraction with water, hydrochloric acid, sodium carbonate, sodium nitrate, hot water and potassium hydroxide. The resulting liquors each yielded a gum-like substance which was sulfur-, nitrogen- and phosphorus-free. Oxidation of this derivative with nitric acid gave oxalic acid but no mucic acid. Panzer concluded that the substance was probably a pectin but not a galactan. It is now known that drastic oxidation of this nature would give oxalic acid from any sugar derivative. It is possible that by using controlled oxidation, mucic acid could be obtained from this carbohydrate. 

The lengths of the elongated particles can be shortened by dissolution in hydrochloric acid or oxalic acid. It is interesting to note that only the length becomes shorter by dissolution. This makes it easy to obtain hematite particles having the desired aspect ratio. This technique may also be applied to other particles having anisotropic shapes. 

The Occupational Safety and Health Administration permissible exposure limits for various corrosives are as follows glacial acetic acid, 10 ppm acetic anhydride, 5 ppm hydrofluoric acid, 3 ppm sulfuric acid, lmgm oxalic acid, lmgm nitric acid, 2 ppm bromine, 0.1 ppm chlorine, Ippm fluorine, 1 ppm hydrochloric acid, 5 ppm. 

Picric Acid is tested for the presence of resinous and tarry matters, sulphuric acid, hydrochloric acid, oxalic acid, and their salts. General impurities and adulterations, e.g., oxalic acid, nitrates, pii rntas, boric acid, alum, sugar, etc., remain insoluble on shaking the sample with ether, and may lx- further examined. The melting point of the pure acid, is 1 2° C. Dinitrophenol may be estimated by Allen s process (Journ. Soc. Dyers, etc., 4,84). Mineral or non-combustible matter must not exceed 0.3 per cent, by weight. 

Morphological studies explain the mechanisms of E-glass corrosion. According to these studies, acid corrosion of E-glass is caused by calcium and aluminum depletion which varies depending on the acid type, fiber type, and acid concentration. Oxalic and sulfuric acids are more corrosive than nitric and hydrochloric acids. This difference is due to the fact that, in oxalic acid, precipitated products are formed which decrease the concentration of leachates in solution. In addition to the loss of mineral content, fibers develop axial and spiral cracks. Crack formation depends on the rate of material depletion. 

All routes used toxic substances such as methanol, acetic acid (D), oxalic acid ethyl ester (A-D), cyclohexane (A), toluene, sulfuric acid and hydrochloric acid. Overall, no major differences were observed with the exception of viologen used in A This substance is toxic to fish, meaning that the sewage of A has to be processed in a water treatment plant, which is not necessary in B. 

Sodium nitrate Sodium chloride Sulphuric acid Nitric acid Hydrochloric acid Potassium hydroxide Sodium hydroxide Acetic acid Oxalic acid Silver nitrate > Ammonium hydroxide Potassium sulphate Potassium nitrate... 

Acids (sulfuric acid, hydrochloric acid, acetic acid, or oxalic acid) X... 

The hydration of olefins to alcohols has been carried out on a large scale by hydrolyzing the sulfuric acid esters formed by the absorption of the olefins in sulfuric acid. In the case of the higher olefins these reactions occur with comparative ease. Thus, isobutylene may be hydrated to tertiary butanol in cold, moderately concentrated sulfuric acid.81 Some of the pentenes and heptenes may be hydrated in dilute (5 to 10 per cent) solutions of formic, acetic, or oxalic acids as well as in weak solutions of the mineral acids.83 With 60 per cent concentrations of hydroiodic acid, isobutylene yields the iodide almost exclusively, but at lower concentrations increasing amounts of the alcohol are fonned84 Similar phenomena attend the absorption of the higher olefins in hydrobromic acid. Hydrochloric acid, on the other hand, does not show such marked activity toward the higher olefins ind is practically devoid of activity toward ethylene. 

The most important acids for polyether purification are orthophosphoric acid [120,121, 129], hydrochloric acid [122], sulfuric acid [121, 131], formic acid [123], tartaric acid [124], oxalic acid [126], adipic acid [126] and carbon dioxide [127, 128, 130]. 

The aramonium salt, (NHi)HjCrOj, is formed by mixing 100 c.c. of water, 5 c.c. of cone, hydrochlorio acid, 10 grms. of ammonium chloride, 10 c.c. of 5 per cent, chromic acid, -and 25 c.c. of 30 per cent, hydrogen dioxide. If in the preparation of the red perchromates, the mixture is treated with hydrochloric, oxalic or acetic acid, before the addition of hydrogen dioxide, the blue perchromates are formed. 

Diphenylacetaldehyde has been prepared by the isomerization of l,2-dihydroxy-l,2-diphenylethane either thermally or in the presence of sulfuric acid oxalic acid, or acetic anhydride. The aldehyde has also been produced by the reaction of 2,2-diphcnyl-2-hydroxyethyl ether with sulfuric acid or oxalic acid, by the reaction of hydrochloric acid with 2-amino-l,l-diphenylethanol," by the reaction of hydrobromic acid with 2-dicthylamiiio-1, l-ethyl ether, by live thermal rearrangement of... 

Sulphuric Acid, Hydrochloric Acid, and Oxalic Acid-, and their salts are detected by adding to the filtered aqueous solution of the sample solutions of the picrates of barium, silver, and calcium. These salts are readily made by boiling picric acid with the carbonates of the respective metals and filtering other soluble salts of these methods may be substituted for the picrates, but they are less satisfactory. 

In an alternative process, the fine-ground xenotime is treated by fusing it with molten caustic soda at 400 °C, or by mixing it with sodium carbonate and roasting at 900 °C for several hours. The hydroxide residue is dissolved in hydrochloric acid and filtered to remove impurities such as siUca, cassiterite etc. The rare earths are precipitated as oxalates by adding oxalic acid. The oxalates are oxidized to rare earth oxides (Gupta and Krishnamurthy 2005). 

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