Vacuum techniques safety

Safety factor. Even if the above techniques are followed, some uncertainty still remains. To allow for this uncertainty, it has been recommended (98,120) to add 6 to 12 in to the HETP measured in small-scale columns, and possibly more in vacuum columns operating at low liquid rates. This recommendation has been criticized (168) for being too conservative. An alternative recommendation (167) is to add a 10 to 15 percent safely factor. 

Besides phthalocyanine pigments developed for office copiers, new polymorph materials for laser printer utilization have been prepared. These materials, whose absorption characteristics were extended to the near-infrared region, were prepared by vacuum sublimation techniques. Recently, for safety reasons and to reduce the cost of production, solvent-pigment interactions have received great attention [41]. 

Techniques of tritium removal from co-deposited layers in next-generation tokamaks, such as ITER, have an important impact on machine operation. Attempts are being made to develop in-situ co-deposit removal techniques that would not overly constrain machine operation, both in terms of T removal and plasma performance recovery after cleanup. In addition to machine operation considerations, the tritium in the co-deposited layers will also have safety implications. During a severe accident, the vacuum vessel of an operating tokamak can be breached. If a significant inventory of tritium in the form of a saturated layer is present, much of this tritium can be released as tritium oxide as the film reacts with oxygen. 

A Carius tube was charged with 2-(ethylsulfanyl)acrylonitrile (6 1.13 g, 0.01 mol) and a few crystals of hydroquinone. The tube was then cooled to - 78 C and chlorotrifluoroethene (1.7 g, 0.015 mol) was introduced using standard vacuum-line techniques. The tube was sealed and then heated in an oil bath at 120 C for 8 h (the Carius tube was in a metal sleeve and the oil bath was behind a safety shield). The tube was allowed to cool to rt and then placed in liquid Nj and opened. After allowing to warm to rt, the residue was distilled to give 7 yield 1.79 g (83%) bp 94-96 C/0.05 Torr. 

Note about safety—There are many hazards associated with the use of a vacuum and positive pressures of inert gases with the glassware described throughout this chapter, and anyone attempting the following techniques should thoroughly prepare for all of the hazards that are involved. 

Coyne, G.S. (1997) The Laboratory Companion A Practical Guide to Materials, Equipment, and Technique, Wiley, New York. Useful guide to the proper use of laboratory equipment such as vacuum pumps and compressed gases. Also gives relevant safety information. 

The main feature of this unique technique is the operation of a fluidized bed plant at low vacuum conditions. Inertization is not required due to the operation below the minimum ignition pressure. Compared to closed-loop fluidized bed plants, there are many advantages in terms of economic efficiency, ecology and safety aspects ... 

Caution Due to potential toxicity of chromium carbonyl complexes, all procedures should be carried out in a well-ventilated hood. Disposable vinyl or latex gloves and safety glasses should be worn. All procedures are performed anaerobically by using standard vacuum/nitrogen manifold and Schlenk tube techniques. As chromium complexes are unstable in solution when exposed to air and light, the oxidation reaction and subsequent work-up are always carried out under nitrogen in glassware protected with foil. 

Safety notice Unconventional sample supply techniques on commercial MALDI instruments require great care. Possible pitfalls include i) blocking of the vacuum lock due to unacceptable thickness of the target, ii) loss of the sample inside the ion source or inside the vacuum lock. Hi) damage to the instrument from electric discharges. 

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