Salt freezing

Before finally assembling the apparatus, the various units are charged as follows A is one-third filled with water to serve as a bubble counter. Generator B is about one-quarter filled with dry arsenious oxide, pea size or powdered. Drying towers G and H are filled with anhydrous calcium chloride. (It is well to place a wad of glass wool in front of the entrance and exit tubes.) In each of the two absorption bottles J and K is placed 200 g. of ethyl malonate. Dish L is filled with an ice-salt freezing mixture. 

The combined yield of crude acid (260-270 g.) is dissolved in 11. of water, boiled with about 25 g. of Norite, filtered through a heated filter, and crystallized by placing in an ice-salt freezing mixture and stirring vigorously. A finely crystalline, colorless product is obtained in this way. If it is allowed to crystallize slowly the crystals are somewhat colored. The yield of pure resorcylic acid melting at 216-217° is 160-170 g. (57-60 per cent of the theoretical amount) (Note 3). 

To obtain the free aldehyde 25 g. of the aldehyde ammonia are dissolved in 25 c.c. of water, a cooled mixture of water (40 c.c.) and concentrated sulphuric acid (30 c.c.) is added, and the acetaldehyde liberated is distilled from the water bath through a calcium chloride U-tube (gently warmed if the external temperature is low) and through an efficient coil condenser. In order to prevent autoxida-tion of the acetaldehyde the apparatus is filled with carbon dioxide before distillation, and, since the vapour pressure of the aldehyde is high, a slow current of carbon dioxide is passed again, for a short time only, at the end of the distillation. Since acetaldehyde boils at 21° the receiver, which is attached to the condenser by means of a cork stopper, must be well cooled in an ice-salt freezing mixture. 

Remove the catalyst by filtration at the pump, distil the solvent using a receiver for fractional distillation and collect the adipic aldehyde by distillation in a vacuum from a small flask fitted with a column. Yield 12-14 g. Pure adipic aldehyde boils at 92°-94°/12 mm., solidifies in an ice-salt freezing mixture and then melts at -8° to - 7°. Keep it in a sealed tube under nitrogen or C02 in order to protect it from auto-oxidation. 

To a saturated solution of 5.5 g. (0.028 mole) of finely powdered cupric acetate monohydrate (Note 1) in 20 riil. of a 1 1 by volume pyridine-methanol mixture (Notes 2, 3, 4, and 5) contained in a 50-ml. round-bottomed flask fitted with a reflux condenser is added 2.0 g. (0.0196 mole) of phenylacetylene (Note 6). The deep-blue suspension becomes green when heated under reflux. After 1 hour of heating, the solution is cooled (Note 7) and added dropwise to 60 ml. of 18N sulfuric add, with stirring and external cooling in an ice-salt freezing mixture (Note 8). The resulting white suspension is extracted with three 25-ml. portions of ether, and the combined ethereal extracts are washed with 15 ml. of... 

IN TRAY WITH INDIVIDUAL ICE CUBE CUPS. POUR WATER INTO EACH CUP. IN ONE, DISSOLVE 1 PINCH OF SALT, IN NEXT 2 PINCHES, AND SO ON. LEAVE ONE WITHOUT SALT. PLACE IN FREEZING COMPARTMENT. CUPS LEAST SALTED FREEZE FIRST. 

B. Isobutyramide. In a 3-1. flask, equipped with an efficient stirrer and a 500-ml. dropping funnel, and surrounded by an ice-salt freezing mixture, is placed 1.25 1. of cold concentrated aqueous ammonia (about 28%). To this 318 g. (3 moles) of isobutyryl chloride is added drop wise with rapid stirring at such a rate that the temperature of the reaction mixture does not rise above 15°, and the evolution of white fumes (mostly ammonium chloride) does not become vigorous. Stirring is continued for 1 hour after the addition of the acid chloride is finished. 

A 250-ml. three-necked flask is equipped with a rubber-sealed mechanical stirrer, two gas-inlet tubes, and a mercury-sealed escape valve consisting of an outlet tube dipping into a test tube of mercury. A solution of 25 g. (0.14 mole) of benzophenone in 125 ml. of 95% ethanol is placed in the flask, which is cooled in an ice-salt freezing mixture. Hydrogen sulfide and hydrogen... 

Most inorganic salts, when they melt, are found to flow and conduct electricity according to a simple Arrhenius law at all temperatures down to their melting points. For instance, unless measurements of high precision are used, the alkali halides appear to remain obedient to the Arrhenius equation even down to the deep eutectic temperatures of their mixtures with other salts. LiCl and KCl form a eutectic mixture with a freezing point of 351°C, some 300 K below either pure salt freezing point, yet the viscosity of the melt barely departs from Arrhenius behavior before freezing. 

In the modem age, a highly developed infrastructure is essential for economic growth and prosperity. Many stmctures essential to this infrastmcture, especially those made of reinforced concrete, have suffered severe degradation since their construction due to the combined effects of deicing salts, freeze-thaw cycles, aggressive environments, and drastically increased live loads. One of the major problems facing the civil engineers of today is to preserve, maintain, and retrofit these structures [1],... 

The brown gas given off when nitric acid and arsenious oxide are heated together is an equimolar fnixture of NO2 and NO. It can be condensed in an ice and salt freezing mixture to a... 

Dissolve 0.5 mole (42.5 grams) of potassium nitrite and 0.6 mole (58 grams) of potassium acetate in 200 ml of water in a 2-liter flask, and cool in an ice-salt freezing mixture to about — 5°. Add 750 grams of finely crushed ice, shaking frequently. (A mechanical stirrer is not satisfactory.) Pass sulfur dioxide slowly. A mass of crystals of potassium hydroxylamine disulfonate, H0 N(S03K)2 2H20, crystallizes out. When the odor of sulfur dioxide shows that an excess has been passed, filter off these crystals under suction and wash them with 100 ml of ice water. The yield is about 85 per cent. 

The side-arm of the Buchner flask is protected with a CaCl2-guard-tube. Now, cool the flask in an ice-salt freezing mixture in an efficient fume cupboard, and pass a steady and brisk stream of diy HCl-gas through the solution for a duration of 2 hours with occasional shaking. 

Sun, W. Mu, R. Luo, X. Miao, C. (2002). Effect of Chloride Salt, Freeze-Thaw Cycling and Externally Applied Load on the Performance of the Concrete, Cement and Concrete Research Vol.32, pp. 1859-1864, ISSN 0008-8846. 

Liq. with aromatic odour. B.p. 250°/740 mm., 130°/14-5 mm., 126°/12-5 mm., I217IO mm. Solidifies in ice salt freezing mixture. Strong base. Sol. HgO, EtOH, E O, CHCI3, CjHg. Turns greenish-yellow in light. 

Refueling. In some respects, the AHTR operations will be simpler because (1) the salt is transparent and thus allows camera views of the reactor core and (2) the salt is less chemically reactive than sodium. However, the temperatures will be higher and will require more careful design of systems to avoid undesired salt freezing. 

By passing the gases through an ice/salt freezing mixture ( 23% NaCl) liquid N2O4 can be obtained. Since the gas and the liquid are reactive towards H2O, the apparatus used should be dry and the powdered Pb(N03)2 should be previously dried. 

It is conveniently made (Figure 6.18) by passing chlorine through dry, freshly prepared yellow HgO and condensing the gas in a tube cooled in an ice/salt freezing mixture ... 

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