Cryogenic conditions

Reviews of batch calorimeters for a variety of applications are published in the volume on Solution Calorimetry [8] cryogenic conditions by Zollweg [22], high temperature molten metals and alloys by Colinet andPasturel [19], enthalpies of reaction of inorganic substances by Cordfunke and Ouweltjes [16], electrolyte... 

Zollweg J A 1994 Mixing calorimetry at cryogenic conditions Solution Calorimetry, Experimental Thermodynamics... 

Remove components with high melting points or those that may free2e at cryogenic conditions before processing. 

Nickel atoms have also been allowed to react with C2H4 under cryogenic conditions (101,123). Depending on the metal-concentration conditions and the deposition temperature, either mononuclear species, Ni(C2H4) , n = 1-3(123), or multinuclear species, Ni2(C2H4) ,m = 1-2, and Ni3(CjH4)i, may be isolated. Unlike the copper complexes, these species are all colorless the mononuclear ethylene complexes each dis-... 

Another feature often reported is an increase in reaction temperature from cryogenic conditions below or to ambient temperature, without losing selectivity. Sometimes even selectivity is increased in this way. Most often, such improved performance was found for fast organometallic reactions, probably the most prominent example being the Grignard reaction of Merck which was transferred to industrial production in the final stage. 

One main driver was to increase the processing temperature for this class of metallation reactions more towards ambient. Typically, Li alkylations are conducted under cryogenic conditions (e.g. at -60 °C) [83]. Further motivation came from aiming at increasing the yield reducing investment and operating costs. 

Cryogenic conditions (-78 °C) and an expensive reagent (L-Selectride ) to obtain high selectivity for carbonyl reduction in 5 Additional cost for cryogenic step... 

Based on this information the preparation of enone was examined from the unhalogenated (VIII)(X=H). Deprotonation can be performed with n-butyl lithium in THF at 0-5 °C followed by treatment with 3-ethoxy cyclohexen-l-one, followed by an acid quench provides the same enone (XI). This deprotonation also avoids the cryogenic conditions required to prepare enone (XI) when the bromo analog is used. Pyridinium tribromide used for aromatization of enone (XI) to biaryl phenol (X) is an inexpensive reagents ( 80/kg). 

Storing of hydrogen in liquid form at cryogenic condition is attractive in that it offers low weight and volume per unit energy when compared to compressed hydrogen. 

Most measurements show that under ambient conditions, the amount of hydrogen adsorbed in SWNTs is small (<1 wt%), whereas under cryogenic conditions, hydrogen... 

The grinding of crystallized chips has been well-known for about 50 years but yields problems with respect to handling and processing. Very small particle sizes can be achieved by grinding under cryogenic conditions. Lower-IV prepolymers (<0.40 dl/g) are preferred for this process. The handling of smaller particles becomes more difficult due to the increased content of fines and their separation, particularly in continuous gas flow technology. Fines are defined as extremely... 

Elemental composition Kr 68.80%, F 31.20%. Krypton difluoride may be analyzed by GC/MS under cryogenic conditions following its decomposition into its gaseous elements. 

Further, these materials exhibit a high energy absorption and high sound-dampening properties. These properties are retained under cryogenic conditions. However, in general, adhesion of UHMWPE to substrates is poor, even when the suiface is roughened. 

Alternatively, sample may be analyzed by GC/MS (using a capillary column) under cryogenic conditions. 

As a general rule, they should not be used in steam, air, gas or vapour applications or in the presence of variable backpressure. Nevertheless, there are high-performance small spring-loaded valves which are designed specifically for specific services on gas, with backpressure or under cryogenic conditions. 

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