Beta “bulk” phase

Yamauchi, R. et al. (1998). Oxidation products of beta-carotene during the peroxidation of methyl linoleate in the bulk phase. Biosci. Biotechnol. Biochem. 62(7) 1301-1306. 

Besides the research use of 249Bk for the characterization of the chemical and physical properties of element 97, its relatively rapid decay to 249Cf (0.2% per day) makes it a valuable source of this important isotope of californium for chemical study. This genetic relationship has been exploited in studies of the chemical consequences of beta (fi) decay in the bulk-phase solid state (12, 13). 

The influence of the zeohte on the redox chemistry of components dispersed in them is another topic studied by photoemission techniques [33,35]. Numerous differences between the redox chemistry of transition elements in the bulk phase and in zeolites have been estabUshed, e.g., the stabilization of low (nonzero) valence states as Rh(I) [122-124], Pd(I) [125-127], Ni(I) [128] a different stabilization of intermediate Cu(I) in Y and ZSM-5 or beta [108,121,129] the stabilization of metal atoms in zeolites (Pd in H-Y [130], Pt, Ir in H-ZSM-5 [131]) the acceleration of the valence-state interchange Cu + Cu+ in overexchanged ZSM-5 and beta [89,108,121]. 

While the hop oils are miscible with liquid CO2, the maximum solubility of the alpha and beta acids occurs at 7-8°C [14], which thus represents the optimum temperature for extraction. In practice, liquid plants are usually operated at between 5 and 10°C. It is advantageous to restrict the temperature to less than 10°C as this is the temperature above which the crystalline hexa-hydrate of carbon dioxide decomposes. Dried hops normally contain between 8 and 12% of moisture which would dissolve in liquid CO2 at temperatures in excess of 10°C. By keeping the temperature of extraction below 10°C, an extract containing 5% or less of water can be obtained. This water is held as an emulsion in the resin extract but will separate as a bulk phase from a molten extract. 

The vapour-phase transport method was also successfully used for the preparation of membranes and bulk material of the following zeolites MCM-22 membrane (used for the alkylation of toluene with MeOH to p-xylene),[68] FER-membrane (for the separation of benzene/p-xylene),[69] EMT crystals using a crown ether as structure-directing agent,[70] and zeolite beta (BEA).[71] In the latter two examples, a conversion of agglomerated nanoparticles to highly crystalline zeolite was observed. 

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