Solid phase halogen compounds

Several studies have shown that sorption of various organic compounds on solid phases could be depicted as an accumulation at hydrophobic sites at the OM/water interface in a way similar to surface active agents. In addition Hansch s constants [19,199-201], derived from the partition distribution between 1-octanol and water, expressed this behavior better than other parameters. Excellent linear correlations between Koc and Kow were found for a variety of nonpolar organic compounds, including various pesticides, phenols, PCBs, PAHs, and halogenated alkenes and benzenes, and various soils and sediments that were investigated for sorption [19,76,80,199-201]. 

Ketones can be a-brominated on solid phase by treatment with synthetic equivalents of bromine, such as pyridinium tribromide (Entry 2, Table 6.1) or phenyltri-methylammonium tribromide (DCM, 20 °C, 3 h [10]). Resin-bound organometallic compounds, such as vinylstannanes [11] or organozinc derivatives [12], react cleanly with iodine to yield the corresponding vinyl or alkyl iodides (see also Section 3.13). Additions of halogens or their synthetic equivalents to C=C double bonds on cross-... 

The work on halogen compounds has been summarised by Swallow and by Spinks and Woods . Reference should also be made to the Annual Reviews of Physical Chemistry, and, for a discussion of the basic processes in the gas phase, to the text by Lind . Dainton has recently discussed the important early stages in the radiolysis of solid and liquid systems. 

The redox coupling found by Mukaiyama makes use of the facile oxidation of phosphines and the strength of the P—O bond (Table 5). In each case the reaction proceeds via an acyloxyphosphonium intermediate (equation 8). The oxidation is carried out by disulfides ° ° and related compounds, DEAD," and halogens. Although this method has been applied to the solid phase synthesis of peptides, it has not found broad application. 

Manoli and Samara, 1999) or capillary electrophoresis (Martinez et al., 1999). All these methods require sophisticated and expensive instruments which are difficult to transport and to adapt for on-site operation or for field monitoring. Moreover, these methods normally include an extraction step (liquid-liquid or solid phase extraction) for which a complex calibration process is needed to account for the appreciable loss of analyte (Thurman and Mills, 1998 Simpson, 2000) that occurs during the process. Further, they involve the use of organic solvents including halogenated compounds on whose use there are legal limitations (US EPA, 1998). 

Copper or iron phthalocyanines encapsulated inX or Y zeolites [25g], which catalyze the oxidation of cyclohexane to Ol/One and to AA with oxygen (in the presence of small amounts of t-BuOOH) at near-ambient conditions. The catalyst remains in the solid phase throughout the reaction, and can be easily filtered off. Moreover, the solvent type affects performance best selectivity to AA (41%) is achieved with methanol [25g], at 12.7% cyclohexane conversion, with a halogen-substituted phthalocyanine of Fe encapsulated in an X zeolite. Cyclohexanone and cyclohex-andione are hypothesized to be the intermediate compounds of the reaction. Incorporation of the zeolite-encapsulated Fe phthalocyanine inside a polymer matrix can serve to enhance catalyst stability and limit leaching phenomena [25h[. 

The reaction requires a dehydrating catalyst, which, for reactions in the liquid phase, is an acid substance this is usually a concentrated mineral acid, but may also be an organic sulfonic acid, acid salt, or halogen compound such as boron trifluoride, zinc chloride, or aluminum chloride. For etherification in the gaseous phase the alcohol vapor is passed over a solid catalyst such as A1203, Ti02, or dehydrated alum.656... 

The first definition is that of sulphonic acids and their derivatives , a term that has already appeared several times. For the purpose of this chapter, we take it to mean any compound of the generic type RS02X, where R is some group bound by carbon to the sulphur and X is a group that is bound to the sulphur by some hetero atom (N, O, S, halogen). Secondly, the phrase thermochemical data is customarily taken to mean heat of formation. AH heat capacity, Cp and entropy, S, all considered for both gaseous and condensed (liquid and/or solid) phases. However, we are personally interested almost exclusively in the heats of formation. Thus our only reference to heat capacity and entropy data is the compilation of data of these quantities2. (See Table 1.)... 

The immense number of chemical compounds formed by the halogens provides chemists with an extraordinary database from which numerous chemical and physical phenomena can be correlated with respect to various periodic trends. From databases like Inorganic Crystal Structure Data (ICSD, http //www.fiz-karlsruhe.de ) and International Centre for Diffraction Data (ICDD, http //www.icdd.com) with 67 000 and 25 000 entries, respectively, one can easily make out that halides are one of the dominant classes of compounds besides oxides. Even within the subset of inorganic solids, there is tremendous diversity of composition, structure, and properties and to summarize this would create its own encyclopedia. Therefore, the discussion in this article is limited primarily to binary halides, their structures, and some of their properties, except halides of elements which are nonmetals. Binary actinide halides are discussed elsewhere see Actinides Inorganic Coordination Chewistif. Complex halides (solid phases containing two or more kinds of metal ions), ... 

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