Viscosity hydrochloric acid

During World War II, polychloroprene was chosen as a replacement for natural rubber because of its availability. Two copolymers of chloroprene and sulphur which contain thiuram disulphide were available (Neoprene GN and CG). One of the first successful applications of these polychloroprene adhesives was for temporary and permanent sole attachment in the shoe industry. However, these polychloroprene cements show a decrease in viscosity on ageing and a black discolouration appears during storage in steel drums. Discolouration was produced by trace amounts of hydrochloric acid produced by oxidation of polychloroprene... 

Other uses of HCI are legion and range from the purification of fine silica for the ceramics industry, and the refining of oils, fats and waxes, to the manufacture of chloroprene mbbers, PVC plastics, industrial solvents and organic intermediates, the production of viscose rayon yam and staple fibre, and the wet processing of textiles (where hydrochloric acid is used as a sour to neutralize residual alkali and remove metallic and other impurities). 

Tetraethoxysilane-water-alcohol-hydrochloric acid solutions of appropriate compositions become viscous and spinnable in the course of hydrolysis and condensation of SiCCX Hs). Fig.l shows the time change of the viscosity of a Si(0C2H5)4 solution with the [H2O]/... 

Hydrolysis rate measurements. Hydrolysis rates were examined by mixing polymer solutions with hydrochloric acid, in apparatus previously described (5). Solutions of polymer and acid are mixed rapidly, and the torque on a rotating PTFE coated fork, attached to a Brookfield LVTD viscometer, recorded as a function of time. Decreases in viscosity were approximated to first-order, and half-lives for viscosity loss calculated. 

One difficulty in Equation 6 lies in the determination of the diffusivity constant for highly concentrated acids over a broad range of temperature. However, available data (13), combined with viscosity values of hydrochloric acid, lead to estimates shown in Tables I and II for the field cases that will be described later on. 

A 31.5% hydrochloric acid solution is pumped from one storage tank to another. The power input to the pump is 2 kW and is 50% efficient. The pipe is plastic PVC pipe with an internal diameter of 50 mm. At a certain time the liquid level in the first tank is 4.1 m above the pipe outlet. Because of an accident, the pipe is severed between the pump and the second tank, at a point 2.1 m below the pipe outlet of the first tank. This point is 27 m in equivalent pipe length from the first tank. Compute the flow rate (in kg/s) from the leak. The viscosity of the solution is 1.8 X 10 3 kg/m s, and the density is 1600 kg/m3. 

B. (3-Bromo-3,3-difluoropropyl)trimethylsilane. A 1-L, four-necked flask is equipped with a mechanical stirrer, thermometer, Claisen adapter, septum inlet, reflux condenser (the top of which is connected to a calcium chloride drying tube), and a solid addition funnel. The flask is charged with (1,3-dibromo-3,3-difluoropropyl)trimethylsilane (78.3 g, 0.25 mol), and anhydrous dimethyl sulfoxide (200 mL), and the solid addition funnel is charged with sodium borohydride (11.5 g, 0.30 mol) (Notes 7 and 8). The stirred solution is warmed to 80°C, and sodium borohydride is added at a rate sufficient to maintain a reaction temperature of 80-90°C (Note 9). Toward the end of the addition, an additional portion of dimethyl sulfoxide (200 mL) is added via syringe to lower the viscosity of the reaction mixture. After the addition is complete, the mixture is cooled in an ice-water bath, diluted with 100 mL of pentane, and cautiously quenched with 12 M hydrochloric acid until no further gas evolution occurs. The mixture is transferred to a separatory funnel and washed with three, 100-mL portions of 5% brine. The pentane extract is dried over calcium chloride and the solvent removed through a 15-cm Vigreux column. Further fractionation yields 41.5 g (72%) of 3-bromo-3,3-difluoropropyltrimethylsilane, bp 139-141 °C (Note 10). 

The fractions coilected are each run dropwise into 100 ml of stirred methanol to which two drops of concentrated hydrochloric acid have been added.Turbidity or precipitation will be observed from about the 6th fraction to about the 20th fraction.The precipitated fractions are filtered off, washed with methanol and dried to constant weight in vacuum at 20 °C. For each fraction the viscosity is measured in water at 25 °C using a capillary viscometer (capillary diameter 0.35 mm) and at as high a concentration as possible (10 g/l) in order to minimize errors.The limiting viscosity number, and hence the molecular weight, is estimated (see Sect. 2.3.3.3.1). Adjacent fractions for which there may be insufficient material for a viscosity measurement,can be combined where necessary. 

The studies of Pauli he. cit.) and his co-workers, however, have revealed the fact that isohydric solutions of different acids do not effect equal combination with the isoelectric protein relatively more acetic acid for example being combined than hydrochloric acid in isohydric solutions. Again, both the actual position of these maxima as well as the magnitudes of the viscosities observed vary much with the nature of the acid employed. Thus the relatively weak oxalic acid appears to be a much stronger acid than sulphuric acid, whilst trichloracetic acid does not differ appreciably from acetic acid in its effect on the viscosity of albumin. It is probable that the degree of solvation of the protein molecules and of the protein salts must not be regarded as constant but that they vary both with the nature of the salt and in the presence of neutral salts which exert like alcohol a desolvating action more or less complete on the solvated isoelectric protein as well as on the undissociated protein salts. 

Viscosity.—The viscosity,12 7], of soln. of hydrochloric acid containing N mol. of HC1 per litre, determined by W. H. Green at 24-9°, referred to water at 0° unity, and also in absolute units ... 

Commercial casein is usually manufactured from skim milk by precipitating the casein through acidification or rennet coagulation. Casein exists in milk as a calcium caseinate-calcium phosphate complex. When acid is added, the complex is dissociated, and at pH 4.6, the isoelectric point of casein, maximum precipitation occurs. Relatively little commercial casein is produced in the United States, but imports amounted to well over 150 million lb in 1981 (USDA 1981C). Casein is widely used in food products as a protein supplement. Industrial uses include paper coatings, glues, plastics and artificial fibers. Casein is typed according to the process used to precipitate it from milk, such as hydrochloric acid casein, sulfuric acid casein, lactic acid casein, coprecipitated casein, rennet casein, and low-viscosity casein. Differences... 

Hertog et al. (119) developed a fast HPLC method for the identification and quantification of five major flavonoid aglycones (quercetin, kaempferol, myricetin, luteolin, and apigenin) in freeze-dried vegetable and fruits. However, due to the inadequate resolution of quercetin and luteolin on RP-HPLC on Nova-Pak C]8, two different eluents of different solvent strength and viscosity were utilized. The conditions for hydrolysis and extraction were tested based on different conditions of hydrochloric acid concentration (1.2-2.0 M), reaction period (0.5-6 h), and meth-... 

Acid-in-oil emulsion can extend the propagation of acid considerable distances into a reservoir because the continuous (oil) phase prevents or minimizes contact between the acid and the rock [4,678,689]. Emulsification also increases viscosity and will improve the distribution of the acid in layered and heterogeneous reservoirs. Acidizing foams are aqueous, in which the continuous phase is usually hydrochloric acid (carbonate reservoirs) or hydrofluoric acid (sandstone reservoirs), or a blend, together with suitable surfactants and other stabilizers [345,659]. Foaming an acidizing fluid increases its effective viscosity, providing mobility control when it is injected [678]. 

Insoluble Matter Transfer about 5 g of sample, accurately weighed, into a 250-mL Erlenmeyer flask, add a 1 1 mixture of 2.7 N hydrochloric acid water, cover the flask with a watch glass, and boil the solution gently until it loses its viscosity. Filter the solution through a tared filtering crucible, wash the residue with water until the washings are free from acid, dry at 105° for 1 h, and weigh. 

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