Glacial effects

Glacial ice may have been responsible for removing some of the rock that overlies the Leadville Limestone, exposing the limestone to karstification. As discussed previously, glacial ice also transported igneous and metamorphic material from exposed Precambrian bedrock westward, onto the limestone. Glacial effects on cave sedimentation and karst development vary throughout Lime Creek. 

Hydrolysis may be effected with 10-20 per cent, sodium hydroxide solution (see p-Tolunitrile and Benzonitrile in Section IV,66) or with 10 per cent, methyl alcoholic sodium hydroxide. For diflScult cases, e.g., a.-Naphthoniirile (Section IV,163), a mixture of 50 per cent, sulphuric acid and glacial acetic acid may be used. In alkahne hydrolysis the boiling is continued until no more ammonia is evolved. In acid hydro-lysis 2-3 hours boiling is usually sufficient the reaction product is poured into water, and the organic acid is separated from any unchanged nitrile or from amide by means of sodium carbonate solution. The resulting acid is identified as detailed in Section IV,175. 

Acetylation of the amine may also be effected by boiling with 20 ml. of glacial acetic acid and 14 ml. of acetic anhydride for 15-20 minutes, followed by decomposition of the excess of anhydride with water and, after boiling for 5 minutes, poirring with stirring into about 75 ml. of water the product is appreciably coloured. 

All other things being equal, the strength of a weak acid increases if it is placed in a solvent that is more basic than water, whereas the strength of a weak base increases if it is placed in a solvent that is more acidic than water. In some cases, however, the opposite effect is observed. For example, the pKb for ammonia is 4.76 in water and 6.40 in the more acidic glacial acetic acid. In contradiction to our expectations, ammonia is a weaker base in the more acidic solvent. A full description of the solvent s effect on a weak acid s piQ or on the pKb of a weak base is beyond the scope of this text. You should be aware, however, that titrations that are not feasible in water may be feasible in a different solvent. 

Acetic acid has a sharp odor and the glacial acid has a fiery taste and will penetrate unbroken skin to make bUsters. Prolonged exposure to air containing 5—10 mg/m does not seem to be seriously harmful, but there are pronounced, undesirable effects from constant exposure to as high as 26 mg/m over a 10-day period (8). 

In the case of ethylene, it is necessary to use high temperatures and pressures as well as active catalyst to effect esterification (82). Yields of 40—50% based on ethylene were obtained with boron trifluoride—hydrogen fluoride mixtures as catalysts at 150°C. 2-Butene under pressure at 115—120°C with an excess of glacial acetic acid containing 10% H2SO4 gave as much as a 60% yield of I -butyl acetate (83). 

Nylons 46, 6, 66, 610, 11 and 12 are polar crystalline materials with exceptionally good resistance to hydrocarbons. Esters, alkyl halides, and glycols have little effect. Alcohols generally have some swelling action and may in fact dissolve some copolymers (e.g. nylon 66/610/6). There are few solvents for the nylons, of which the most common are formic acid, glacial acetic acid, phenols and cresols. 

The most reliable method of preparing benzofuroxans is by decomposition of o-nitrophenyl azides. Decomposition can be achieved by irradiation, or more usually by pyrolysis temperatures between 100° and 1.50° are commonly used. Refluxing in glacial acetic acid is the recommended procedure for 4- or 5-sub-stituted 2-nitrophenyl azides, but with 3- or 6-substituted compounds higher boiling solvents are usually necessary. Quantitative studies on the reaction rate have been made, and a cyclic transition state invoked, an argument which has been used to account for the greater difficulty of decomposition of the 6-substituted 2-nitrophenyl azides. Substituent effects on the reaction rate have also been correlated with Hammett a constants, ... 

The identification of camphene is best carried out by its conversion into isobomeol under the influence of acetic acid in the presence of sulphuric acid. In order to effect this conversion, 100 grams of the fraction containing the terpene in substantial quantity are mixed with 250 grains of glacial acetic acid and 10 grams of 50 per cent, sulphuric acid. Tne mixture is heated for two to three hours on a water-bath to a temperature of 50° to 60°. At first the liquid separates into two layers, bat soon becomes homogeneous and takes on a pale red colour. Excess of water is added, and the oil which is precipitated, and which contains the isobomeol in the form of its acetate, is well washed with water repeatedly. It is then saponified by heating with alcoholic potash solution on a water-bath. The liquid is then evaporated and extracted with water, and the residue recrystallised from petroleum ether. 

A synthesis of coumarin has been effected by Meyer, Beer, and Lasch." Ortho-chlorbenzal chloride is heated with glacial acetic acid and potassium acetate—... 

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