Vacuum line systems

Adsorption isotherms conventionally have been determined by means of a vacuum line system whereby pressure-volume measurements are made before and after admitting the adsorbate gas to the sample. For some recent experimental papers, see Refs. 24 and 25. 

The systematic principles of boron hydride structures ahd chemistry are the principal subjects of the present review. There are several reasons why these principles became clear such a long time after the discovery of these compounds (a) most of the compounds must be handled in grease-free vacuum line systems (b) some of the boron hydrides are unstable at ordinary temperatures, explosive on contact with air, and toxic (c) the structures are based on principles, still incompletely developed, of electron-deficient compounds and (d) location of the hydrogen atoms is a crucial part of the structure determinations, unlike the situation in hydrocarbons, and had to be done for the most part in X-ray diffraction studies of single crystals grown at low temperatures. 

This review describes modular greaseless vacuum line systems which we have constructed in our laboratory for the synthesis and manipulation of air and moisture sensitive organometallic compounds. The discussion of these systems reviews important features of vacuum... 

Any discussion of high vacuum line systems must begin with the... 

We have described several vacuum line systems which we have successfully used in our laboratory for a wide variety of manipulations and syntheses. Although the initial costs of some of the equipment and materials used may seem prohibitive, in our experience the added versatility and ruggedness of design that these systems provide is well worth the initial investment. 

Figure 1 (a) Schematic diagram of a standard doubie manifoid. (b) Photo of an actuai high vacuum line system. 

Vacuum line systems under low pressure conditions... 

With suitable safety precautions (see Note) into the reservoir of a high-vacuum line system, 200 ml of liquid vinyl chloride (99.9% pure as supplied, for example, by Ethyl Corporation) is trapped by cooling the reservoir with liquid nitrogen. 

Although CNCF3 is extremely unstable in the condensed phase, as it tends to polymerize below its boiling point of -80 C, it can be stored at liquid nitrogen temperature and handled on conventional vacuum line systems. 

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