Autoclaving method

The first two groups are distinguished by the fact that autoclave syntheses are used mainly by the Soviet (or Russian) cluster school [1,2,11,16-22], while the American and other schools do not use autoclave techniques [1,23-35]. This distinction is historical and applies not only to technetium compounds, but also to other cluster compounds of d-transition elements [36-41]. Cotton et al. [28] did use an autoclave method once, but it was not further developed [1]. 

It was found [9,49] that all the postulates enumerated above are satisfied by the autoclave method for the reduction of technetious acid in concentrated hydrogen halide solutions by molecular hydrogen under a pressure of 3-5 MPa at 140-220 °C. A series of experiments showed that the final product of the reduction of H [TcOJ under these conditions is a mixture of outwardly similar crystalline substances with similar physico-chemical properties. The composition of the mixture can be described by the general overall formula [TcXi,s o.3 m(H20, OH , H30+)] , where X = I or Br and n > 2.8... 

Thus partial evaporation of HC1 during the synthesis of [Tc2C18]3 by the method of Eakins et al. [24] and by the autoclave method [22,42,43] creates favorable conditions (from the standpoint of the acidity of the solution and the concentration of technetium ions in it) for the formation of the octachloro-ditechnetates (+2.5), since, on the one hand, the rate of reduction of the technetium(IV) ions increases owing to their hydrolysis [42] and, on the other hand, the stability of the hydrolyzed cluster ions formed increases in relation to the reactions involving disproportionation and oxidation by atmospheric oxygen [9,52,80,87]. We may note that under the conditions of more pronounced hydrolysis, the rate of reduction of technetium(IV) increases so much that the formation of metallic technetium becomes possible. 

Other methods are available for the preparation of M.F.A. without the use of an autoclave, but it is doubtful whether they possess advantages over the autoclave method having regard to quality of product and yield. 

Wet (hydrated) autoclave treatment represents the most uniform heating method and is claimed to be preferable over MWO irradiation by some authors (10,15). The main disadvantages of the autoclave method are that one must have access to an autoclave, and it can be time-consuming. 

The autoclave methods use sulfur dichloride, sulfur monochloride or elemental sulfur, the latter two are chlorinated in situ to sulfur dichloride. 

A series of Chromia-Alumina aerogel catalysts containing different contents of chromium was prepared by autoclave method. The specific areas of the catalysis were measured with Ng at 77°K according to the BET method. Their structural properties were determined from the X ray diffraction patterns recorded on a philips diffractometer PW 1050/70. EPR measurements were performed with a 8ruker ZOO TT spectrometer at 77°K operating in X band. DPPH was used as the g value standard. Kinetic data were obtained in dynamic pyrex microreactor operating at atmospheric pressure as described elsewhere (ref. 3). 

The following hydrated autoclave method can be employed for immunohistochemical detection of molecules in both cultured cell and tissue specimens. The method was used, for example, to localize androgen receptor in cultured LNCaP cells (derived from prostatic carcinoma metastasized to lymph node) and biopsy specimens from patients with prostatic carcinoma (Ehara et al 1996). After being removed from the culture medium, the cells on plastic cover slips are fixed with 10% formalin for 10 min at 20°C. Tissue specimens are fixed for 1-2 days and embedded in paraffin. Sections (5 pan) are cut, mounted on glass slides, and heated in an oven for 1 hr at 42°C to promote adherence to the slide. After deparaffmizing and rehydration, the sections are subjected to epitope retrieval treatment as follows. 

Extractions of three of the coals were also carried out in a rocking autoclave (method B) mainly to allow analysis of the gases to be carried out. The results of these extractions are shown in Table II. The high carbon dioxide yields obtained were indicative... 

TABLE VIII. Conversions for Extraction of Morwell Coal (15 g dry) in a Rocking Autoclave (Method B) with Aqueous Solvents (150 g) at... 

Simmon KE, Steadman DD, Durkin S, Baldwin A, Jeffrey WH, Sheridan P, Horton R, Shields MS (2004) Autoclave method for rapid preparation of bacterial PCR-template DNA. J Microbiol Method 56 143-149... 

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