Residual chloride

Titanium tetrafluoride may be prepared by the action of elemental fluorine on titanium metal at 250°C (5) or on Ti02 at 350°C. The most economical and convenient method is the action of Hquid anhydrous HF on commercially available titanium tetrachloride in Teflon or Kynar containers. Polyethylene reacts with TiCl and turns dark upon prolonged exposure. The excess of HF used is boiled off to remove residual chloride present in the intermediates. 

Of course, a primary concern for any physical property measurement, including gas solubility, is the purity of the sample. Since impurities in ILs have been shown to affect pure component properties such as viscosity [10], one would anticipate that impurities might affect gas solubilities as well, at least to some extent. Since ILs are hygroscopic, a common impurity is water. There might also be residual impurities, such as chloride, present from the synthesis procedure. Surprisingly though, we found that even as much as 1400 ppm residual chloride in l-n-octyl-3-methylimi-dazolium hexafluorophosphate and tetrafluoroborate ([OMIM][PFg] and [OMIM] [BF4]) did not appear to have any detectable effect on water vapor solubility [1]. 

Beryllium is extracted from the main source mineral, the alumino-silicate beryl, by conversion to the hydroxide and then through either the fluoride or the chloride to the final metal. If the fluoride is used, it is reduced to beryllium by magnesium by a Kroll-type reaction. The raw metal takes the form of pebble and contains much residual halides and magnesium. With the chloride on the other hand, the pure metal is extracted by electrolysis of a mixture of fused beryllium chloride and sodium chloride. The raw beryllium is now dendritic in character, but still contains residual chloride. 

Reports by the National Canners Association showed negative results on both taste tests and analytical tests for residual chlorides. Asparagus treated and canned in a manner comparable to the celery also gave completely negative results. 

During removal of solvent under vacuum, the residual chloride must not be overheated, as it may explode. 

Rinse the precipitate with several portions of hot distilled water (Figure 3.8). To test for sufficient rinsing (elimination of all residual chloride from the excess barium chloride, HC1, and possibly the sample), collect some of the most recent washings in a test tube and add two drops of silver nitrate solution. If a white precipitate (cloudy appearance) forms, more rinsing is required before proceeding to step 13. Continue to rinse and test until the rinsings are clean. 

D.8.2. F Impurity. It has been observed that [MIMjSbFg produced a small amount of fiuoride ion over time because of its sensitivity to air. Furthermore, residual chloride impurities have been found to exert a large influence on the physical properties of ionic liquids 115). 

In the preparation of MgO from chloride salt precursors, it was observed that the presence of any residual chloride had a detrimental effect on the surface area of the resultant MgO 29). This effect has been related to the ability of chloride to aid sintering and grain growth in the oxide 30). 

Dimethoxycopper(II) is a moisture-sensitive blue compound that is insoluble in common organic solvents. It can be recrystallized from MeOH/NH3 to give a microcrystalline solid. Analysis of copper by iodometric titration provides a quick routine purity determination for dimethoxycopper(II).8 The complete removal of residual chloride from dimethoxycopper(II) is not easily achieved the most likely impurity is CuCl(OMe), which is a green compound.5 Dimethoxycopper(II) must be washed thoroughly as described above to minimize contamination by CuCl(OMe), and is obtained in >98% purity by this procedure (on the basis of the C, H, Cl, Cu, and Li analyses). IR (KBr, cm 1) 2917(vs), 2885(vs), 2806(vs), 1436(w), 1150(w), 1052(vs), 528(vs), 438(s). 

In the past ten years the number of chemistry-related research problems in the nuclear industry has increased dramatically. Many of these are related to surface or interfacial chemistry. Some applications are reviewed in the areas of waste management, activity transport in coolants, fuel fabrication, component development, reactor safety studies, and fuel reprocessing. Three recent studies in surface analysis are discussed in further detail in this paper. The first concerns the initial corrosion mechanisms of borosilicate glass used in high level waste encapsulation. The second deals with the effects of residual chloride contamination on nuclear reactor contaminants. Finally, some surface studies of the high temperature oxidation of Alloys 600 and 800 are outlined such characterizations are part of the effort to develop more protective surface films for nuclear reactor applications. ... 

After the feed solutions were passed onto the resin, the column was washed with four column volumes of 0.35N HN03 to remove residual chloride ions. The column was then washed with four column volumes of one of the following acid solutions ... 

Action of heat oxygen is evolved from a solid perchlorate, and in the residue chloride ions can be tested (see Section IV.14) ... 

The Cr(OH>3 suspension is poured into two 230-ml centrifuge bottles and centrifuged for 5 min at 1900 rpm. The supernate is decanted and replaced with distilled water then the Cr(OH)s is stirred and recentrifuged for 5 min at 1900 rpm. This process is repeated 10 times to remove all traces of residual chloride ion, which is tested for by the addition of silver nitrate solution to the decanted supernate. Preparation of the Cr(OH)s requires 2-3 hr. 

The infra-red studies provide also some insight into the effect of impurities on the hydroxylation of the Ti02 surface. The importance of these effects is easily appreciated if one takes into account that both the main routes (the oxidation or hydrolysis of titanium tetrachloride and the hydrolysis of titanium sulphate) used for the preparation of 1102 samples are likely to leave anionic impurities at the surface. The residual chloride present on the surface of rutile has been shown by Jackson and Parfitt to affect significantly the... 

Pt/Al203 and P1-S11/AI2O3 catalysts were prepared by impregnating y-alumina wiih different solutions of H2PtCl6 and H2PCCI4 + Sd02 respectively. After impregnation, the catalysts were dried consecutively at 60 C and 120°C, and the residual chloride was then removed by steam treatment at for 4 hours. The surface area, pore volume and... 

Residual chloride can act as a catalyst poison (see Sect. 6.2 above), and supported Au catalysts are generally prepared from chloride-containing Au... 

The fact that residual chloride can affect the catalytic properties of supported Au catalysts in more than one way is a possible reason for the reported performances of Au catalysts being very different amongst the various research groups [125], and why apparently inconsequential changes in synthesis variables sometimes have deleterious effects [42]. Understanding the chloride effect will enable a better control of the variables, which are critical to active catalyst preparation. 

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