Ice Condenser

The large amounts of water vapour (1 g ice at the usual process pressure of approximately 0.1 mbar has a vapour volume of approximately 10 m ) which are produced during primary drying (sublimation) can only be pumped off economically by a cold condensation surface. 

The geometry of the mushroom-shaped valve ensures good guidance of the water vapour within the condenser. 

An example of a calculation of the chamber-condenser valve will illustrate this more clearly  

Total water content in the product (G) (kg) Sublimation time (t) (h) 

Note The maximum admissible process pressure in the drying chamber results from the maximum admissible ice temperature as well as a safety margin of approximately 5 K  

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A dry 1-L, three-necked, round-bottomed flask equipped with a large Teflon-covered magnetic stirring bar, a thermometer, and a dry ice condenser (Note 1) is flushed with argon (Note 2), then capped with a serun stopper and subsequently maintained under a positive pressure of argon (Note 3). A 30 dispersion of lithium metal (in mineral oil) containing 1% sodium (13.9 g, 2.00 g-atom of lithium) (Note 4) is rapidly weighed and transferred to the flask. 

The dry ice condenser used with the apparatus should have sufficient condensing capacity to prevent the loss of significant amounts of methyl... 

A slight positive pressure of argon was maintained in the vessel throughout the reaction by using an argon line connected to both a bubbler containing Nujol and the inlet on the dry ice condenser. 

B. 3,3-Dimethoxycyclopropene. A 500-ml., three-necked, round-bottomed flask is equipped with a magnetic stirrer, a gas-inlet tube, a thermometer, and an acetone-dry ice condenser charged with acetone-... 

A 1-1., three-necked, round-bottomed fiask is equipped with an efficient dry-ice condenser (Note 1), a mechanical stirrer, and a gas-inlet tube. The fiask is immersed in an acetone-dry ice bath and 600 ml. of anhydrous ammonia is introduced. After replacing the inlet tube with a... 

A gas bunbling device is attached to the dry-ice condenser. A simple apparatus consists of two 500-ml. filtering flasks equipped with... 

An apparatus resembling that pictured by Schlatter is assembled in a good hood. Two 5-1. three-necked flasks are mounted side by side about 10 cm. apart and about 10 cm. above the bench top or stand base. These arc referred to as the left and right flasks. Kach flask is provided with a dry ice condenser in the outermost neck, and each condenser is [imlected from the... 

Prevent containment overpressure Reactor building spray injection system Reactor building spray recirculation system Reactor building fan coolers Ice condensers Prevent containment overpressure Containment spray injection system, containment spray recirculation system containment fan c ng system, ice conde... 

The final three phenomena, items 11 through 13, are addressed in the containment performance models of MARCH, accounting for mass and energy additions to the containment, the burning of combustible gases, the effects of core sprays, ice condensers, and suppression pools. MARCH calculates only the containment loads it does not model the containment failure. 

PWRs indicate that most of the containments have relatively low conditional probabilities of early failure, although a large variability exists in the contributions of the different failure mod< "or both large dry and ice condenser containments. 

For DCH, the original document (NUREG/CR-6075) was with criticism, but consensus w.i.s aciiieved in the supplimentary report that proposed a basis for extrapolation to all PWRs eiih Zion-like features. Resolution of DCH for ice-condenser plants, and CE and B W plants w i also achieved. 

Deuterioammonia (about 5 ml) is generated by adding deuterium oxide (14 ml) to a stirred suspension of magnesium nitride (20 g) in mineral oil (30 ml). Tlie deuterioammonia is collected directly in the reaction flask (equipped with a dry ice condenser) at —79° after passing through a trap which is kept at 0°. 

To a solution of 14.5 g of 2-bromo-2 -(2-chlorobenzoyl)acetanilide in 100 ml of tetrahy-drofuran, an excess of liquid ammonia (ca 150 ml) was added. The ammonia was kept refluxing with a dry-ice condenser for 3 hours after which time the ammonia was allowed to evaporate and the solution was poured into water. Crystals of 2-amino-2 -(2-chloro-benzoyOacetanilide were collected, which after recrystallization from ethanol melted at 162° to 164 C. 

Acetylene was passed into a stirred solution of 3.05 grams (0.44 mol) of lithium in 300 ml of liquid ammonia until the blue color exhibited by the mixture had disappeared. Ethyl /3-chlorovinyl ketone (47.4 grams 0.40 mol) dissolved in 50 ml dry ether was then added to the resulting solution of lithium acetylide over a period of 20 minutes, during which the color deepened through yellow to reddish-brown. The mixture was stirred under reflux maintained with a Dry Ice condenser for 2 hours. Thereafter, dry ether (200 ml) was added and the ammonia was permitted to evaporate with stirring overnight. 

The checkers used a dry ice condenser during the introduction of ammonia to the reaction flask and replaced it with an air condenser before the addition of sodium. 

To minimize loss of volatile products such as benzene, it is advisable to employ a dry ice condenser on top of the conventional condenser. 

A solution of 5 (20 mmol) in CH2C12 (100 mL) was treated with liquid NH3 (100 mL) and while the NH3 was refluxing the mixture was stirred for 5h in a flask fitted with a dry-ice condenser. The NH, was then allowed to evaporate at rt and the CH2C12 solution was washed with H20, dried and evaporated in vacuo to leave the 2-(aininoacetamido)benzophenone 6. 

Propanone, l-chloro-l,l,3,3,3-pentafluoro-] (b.p. 7.8° available from PCR, Inc. or Allied Chemical Corp.) are combined in a flask fitted with a dry ice condenser and a magnetic stirring bar. The refluxing mixture is stirred for 4-0 hours and then allowed to warm gradually to room temperature. The contents of the flask are extracted three times with anhydrous ether, and the combined extracts are distilled at atmospheric pressure. After the ether has been removed, continued distillation gives 22.8-28.5 g. (55-69%) of l,l,l-trichloro-3,3,3-trifluoroacetone, b.p. 83.5-84.5°, infrared (film) 1790 cm. - This compound is stored at room temperature in a tightly stoppered bottle. In the absence of reliable toxicity data, it should be handled with normal precautions. 

A water pump purchased from Little Giant Pump Company, Oklahoma City, Oklahoma, was used by the submitters to circulate ice-water through the condenser. The checkers used a dry ice condenser. 

The reaction is exothermic. The checkers found that the yield of the final product was raised from 57% in the first run to 71% in the second and third runs when the triethylamine was added at 30-34° with slight cooling. Another procedural change made by the checkers in Part A in these last two runs was that the dry ice condenser was kept in place for more than 8 hours after the... 

A 3-1. three-necked flask, equipped with a Dry Ice condenser (Note 1), a sealed Hershberg-type stirrer, and an inlet tube, is set up in a hood and charged with 108 g. (0.75 mole) of a-naphthol (Note 2). The stirrer is started, and to the rapidly stirred flask contents (Note 3) is added 11. of liquid ammonia as rapidly as possible (about 5 minutes). When the naphthol has gone into solution (about 10 minutes), 20.8 g. (3.0 g. atoms) of lithium metal (Note 4) is added in small pieces and at such a rate as to prevent the ammonia from refluxing too violently (Note 5). After the addition of the lithium has been completed (about 45 minutes), the solution is stirred for an additional 20 minutes and is then treated with 170 ml. (3.0 moles) of absolute ethanol which is added dropwise over a period of 30-45 minutes (Note 6). The condenser is removed, stirring is continued, and the ammonia is evaporated in a stream of air introduced through the inlet tube. The residue is dissolved in 1 1. of water, and, after the solution has been extracted with two 100-ml. portions of ether, it is carefully acidified with concentrated hydrochloric acid. The product formed is taken into ether with three 250-ml. extractions, and then the ether extract is washed with water and dried over anhydrous sodium sulfate. The ether is removed... 

Process documentation 2, drying chamber with shelves 3, operation control 4, ice condenser 5, vacuum pump with exhaust filter 6, refrigeration machine for the ice condenser 7, refrigeration machine for the shelves 8, circulation pump for the brine 9, heat exchanger (Lyovac GT 6, AMSCO Finn-Aqua, D-50354 Hiirth, Germany). 

Figure 2.8.1 shows a typical installation for flasks and other containers in which the product is to be dried. The condenser temperature for this plant is offered either as -55 °C or as -85 °C. For this type of plant, a condenser temperature of -55 °C is sufficient as this temperature corresponds with a water vapor pressure of approx. 2.1 10 2 mbar, allowing a secondary drying down to approx. 3 10-2 mbar. This is acceptable for a laboratory plant, in which the limitations are not the condenser temperature but the variation of heat transfer to the various containers, the rubber tube connections and the end pressure of the vacuum pump (2 stage pump, approx. 2 10 2 mbar). Figure 2.8.2 shows that these units are designed for very different needs. The ice condenser in this plant can take up 7.5 kg of ice at a temperature down to -53 °C. 

A 2-1. three-necked flask is thoroughly dried and fitted with a large dry-ice condenser, a mechanical stirrer, a nitrogen inlet, and a powder funnel in an efficient hood. With nitrogen flowing through the system, 62.5 g. (1.60 moles) of commercial sodium amide (Note 1) is added rapidly. (Caution Sodium amide is corrosive and readily decomposes in the presence of moisture.) The funnel is replaced by a gas-inlet tube, the condenser is filled with a mixture of dry ice and acetone, and ca. 400 ml. of liquid... 

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