Cooling Lateral

Expandable PS beads are a material devised to accommodate the transportation drawbacks of foams. Foams take up a lot of room, but not much weight, so a truck or boxcar cannot be used very efficiently. Expandable PS beads can be readily turned into foam at their destination. The beads are impregnated with a volatile liquid like pentane as they are extruded, chopped, and cooled. Later, on site, the beads are heated in small batches with steam. The vaporization temperature of the pentane is just below the melting point of the PS beads. As the beads soften, the pentane flashes (volatilizes) and causes the PS to foam. The polymer is then ready for molding. Coffee cups, ice chests, life preservers, buoys, and floats are often fabricated this way. 

Differential Thermal Analysis (DTA) earlier DTA data showed an unusually large heat of transformation endothermic in heating and exothermic in cooling. Later, through precision calorimetric methods [13], it was determined that the AH to be as high as 4,150 (J/mole), and also established the nature of the transition to be second order which is in agreement with our earlier single crystal X-ray diffraction study [6],... 

In the past the liquefaction of natural gas used a classic cascade cycle. The process required 120,000 hp for liquefaction of over 150 million standard cubic feet (mmscf) per day. Provisions are made for some of these cycles to use seawater for cooling. Later, baseload LNG plants utilized mixed refrigerant cycles, such as Air Products and Chemicals, Inc. s propane precooled mixed refrigerant system. Baseload plant capacities range from about 70 mmscf/day to about 350 mmscf/day of LNG. Baseload plants move LNG from remote sites by ship to populated areas. For... 

This process resembles the open molding process except it is closed like a two-part compression mold (Chapter 14). A measured amount of plastisol is poured or pumped into the closed mold cavity, similar to close molding except that a slight pressure of about 5 psi (34.5 kPa) is applied. The mold is heated to fuse the plastisol then cooled. Later the mold is opened and the product stripped out. This process can provide for accurate thickness control, filling very complex shaped parts, and so on. 

The atmospheric-pressure hydrate formation temperature of 9.6°C quoted above is one of the constraints on operating temperatures in chlorine cooling. Later, we shall also consider the effects of chlorine hydrate in liquefaction systems (Section 9.1.7.2C). The same problem of equipment plugging may occur there, and the melting or decomposition of hydrate when equipment is taken out of service and allowed to warm can result in severe corrosion. International Critical Tables data for the decomposition pressure of chlorine hydrate, which extend to 16°C, fit the equation... 

Topsoe (1940s) First converters tube cooled. Later quench cooling and radial flow. 

Fit a three necked 250 ml. flask with a central rubber-sleeved or mercury-sealed stirrer, c/. Fig. 23(c), p. 45, where only two necks are shown, and with a thermometer the bulb of which reaches as near the bottom of the flask as the stirrer allows the third neck will carry at first a dropping-funnel and later a reflux condenser. Place 20 g. (19-5 ml.) of ethyl acetoacetate and 45 ml. of glacial acetic acid in the flask and by ice-water cooling adjust the temperature of the stirred mixture to 5 -7° maintain this temperature whilst adding a solution of 5 4 g. of sodium nitrite in 8 ml. of water slowly from the dropping-funnel during 15 minutes. Continue the stirring for 20-30 minutes, and then... 

If the crude substance contains an insoluble impurity, difficulty may be experienced at a later stage in estimating how much solute has crystallised from the cold solution. The hot solution should therefore be filtered into another tube through a very small fiuted filter paper contained in a small short-stemmed funnel. The solution must always be clear before cooling is attempted. 

Prepare a paste out of 65g Sodium Azide (lm NaN ) and 65mL of water in a beaker. Add 400mL of either Chloroform or Benzene to this paste (depending on what you have available, but be consistent later on) and stir well. Dump this mixture into a round bottom flask situated in an ice/salt bath, drop in a stirrer magnet, attach a Claisen adapter, addition funnel, and thermometer. Let this mixture cool to OC. 

To a solution of 0.30 mol of ethyllithium (note 1) in about 270 ml of diethyl ether (see Chapter II, Exp. 1) v/as added 0.30 mol of methoxyallene at -20°C (see Chapter IV, Exp. 4) at a rate such that the temperature could be kept between -15 and -2Q°C. Fifteen minutes later a mixture of 0.27 mol of >z-butyl bromide and 100 ml of pure, dry HMPT ivas added in 5 min with efficient cooling, so that the temperature of the reaction mixture remained below 0°C. The cooling bath was then removed and the temperature was allowed to rise. After 4 h the brown reaction mixture was poured into 200 ml of ice-water. The aqueous layer was extracted twice with diethyl ether. The combined solutions were washed with concentrated ammonium chloride solution (which had been made slightly alkaline by addition of a few millilitres of aqueous ammonia, note 2) and dried over potassium carbonate. After addition of a small amount (2-5 ml) of... 

Exp. 4) with cooling to about -20°C. The addition was carried out in about 10 min. Ten minutes later the solution was cooled to -60°C and a mixture of 0.20 mol of dimethyl disulfide and 50 ml of diethyl ether was added in 15 min with efficient cooling, so that the temperature could be kept below -40°C. Five minutes after the addition the mixture was poured into ice-water and three extractions with diethyl ether were carried out. The combined solutions were dried over magnesium sulfate and concentrated in a water-pump vacuum. Distillation of... 

To a mixture of 50 ml of dry THF and 0.050 mol of l-tert.-butoxy-2-pentyne (prepared by ethylation of HC-CCH O-tert.-Ci,H9 in liquid ammonia was added 0.055 mol of butyilithium in about 35 ml of hexane in 10 min at -30°C. After stirring for 20 min at -25°C the solution was cooled to -50°C and 0.06 mol of methyl iodide was added in one portion, followed 10 min later by 50 ml of water. The aqueous layer was separated and extracted twice with diethyl ether. The solutions were dried over magnesium sulfate and concentrated in a water-pump vacuum. 

A mixture of 0.10 mol of freshly distilled 3-methyl-3-chloro-l-butyne (see Chapter VIII-3, Exp. 5) and 170 ml of dry diethyl ether was cooled to -100°C and 0.10 mol of butyllithium in about 70 ml of hexane was added at this temperature in 10 min. Five minutes later 0.10 mol of dimethyl disulfide was introduced within 1 min with cooling betv/een -100 and -90°C. The cooling bath vjas subsequently removed and the temperature was allowed to rise. Above -25°C the clear light--brown solution became turbid and later a white precipitate was formed. When the temperature had reached lO C, the reaction mixture was hydrolyzed by addition of 200 ml of water. The organic layer and one ethereal extract were dried over potassium carbonate and subsequently concentrated in a water-pump vacuum (bath... 

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