Aluminium columns

Hermanson el al. [71] used an aluminium column (276cmx4mm) packed with 80-100 mesh Chromosorb W supporting 8.9% of amine 220 at 95°C with nitrogen as carrier gas and flame ionisation detection. A rectilinear response was obtained between peak area and amount of propylamine, dipropylamine, and propanol between 0.2 and 2.0gg. 

For pre-heating, the disc specimen rotating at a low angular speed was lowered into the flux bulk, so that the distance between its surface and the top surface of the liquid-aluminium column was around 10 mm. When the temperature had equilibrated (typically after 500 s), the specimen rotating at the required speed was lowered into the bulk of molten aluminium, so that the distance from the surface of the disc to the bottom of the crucible... 

Conversion of this racemic material to a mixture of diastereomeric salts began with anion metathesis. Complex 4.18 in the presence of an excess of [Cinchonidinium] [A-TRISPHAT] was applied to a neutral aluminium column. Subsequent elution by CH2CI2 provided the first yellow band which was collected and identified as fra 5-[(5p,5p))-bis (Cp Ru)carbazolyl] [A-TRISPHAT] (4.18a) and frflMi-[(Rp,Rp)-bis(Cp Ru)carbazolyl] [A-TRISPHAT] (4.18b) (Figure 4.9). These complexes were separated through fractional crystallization from CHCls/ether to give samples 1 and 2. 

The analytical column pack ing was made by coating 80-100 mesh Chromosorb W with 30% by weight of W-98 Silicone Gum (Union Carbide Corporation). This was vibration packed into a 6ft x inch aluminium column. The 6ft x inch precolumn was vibration packed with commercial sodium silicofluoride (Matheson Coleman and Bell). These columns were installed in the chromatograph as shown in Fig.83. 

Svob used a combination of gas chromatography and mass spectrometry to analyse lead alkyls. Mutsaars and Van Steen used a combination of gas chromatography with a flame photometric detector to determine lead alkyls in petroleum. An aluminium column (12 ft X 0.25 in i.d.), packed with 10% of 1,2,3-tris-(2-cyanoethoxy) propane on Chromosorb W HMDS (80 to 100 mesh), was followed by a scrubber (stainless steel, 6 in x 0.125 in) packed with a 1 4 mixture... 

Kawahara [165] described a procedure for the determination of phosphorothioate insecticides including Parathion (0-(4-nitrophenyl phos-phorothiate) and Parathion-methyl (dimethyl-p-nitrophenyl phosphorothioate). It consists of solvent extraction, clean-up by thin layer chromatography on silica gel G (0.25mm layer), and identification by gas chromatography on an aluminium column (1.2m x 0.6cm od) packed with equal portions of acid-washed Chromosorb P supporting 5% of DC 200 silicone oil, and unwashed Chromosorb W supporting 5% of Dow-11... 

Place in the flask 2 g. of benzophenone, 15 ml. of isopropanol and 2 5 g. of aluminium isopropoxide. This mixture has now to be heated gently under reflux so that the temperature registered by the thermometer in the column does not exceed 80°, i.e., so that only acetone distils. For this purpose, the flask should preferably be heated in an oil-bath direct heating, even over an asbestos sheet, may cause local overheating and decomposition the use of a water-bath on the other hand may make the column undesirably damp. 

The ester and catalj st are usually employed in equimoleciilar amounts. With R =CjHs (phenyl propionate), the products are o- and p-propiophenol with R = CH3 (phenyl acetate), o- and p-hydroxyacetophenone are formed. The nature of the product is influenced by the structure of the ester, by the temperature, the solvent and the amount of aluminium chloride used generally, low reaction temperatures favour the formation of p-hydroxy ketones. It is usually possible to separate the two hydroxy ketones by fractional distillation under diminished pressure through an efficient fractionating column or by steam distillation the ortho compounds, being chelated, are more volatile in steam It may be mentioned that Clemmensen reduction (compare Section IV,6) of the hj droxy ketones affords an excellent route to the substituted phenols. 

Distd from excess dry NaCI (to remove ethyl aluminium dichloride) in a 50-cm column containing a heated nichrome spiral. 

Despite these qualifications copper and its alloys are used extensively and successfully in much chemical equipment. Uses include condensers and evaporators, pipelines, pumps, fans, vacuum pans, fractionating columns, etc. Tin-bronzes, aluminium-bronzes and silicon-bronzes are used in some circumstances because they present better corrosion resistance than copper or brasses. 

Aluminium spraying of steel street-lighting columns has been used since the 1950s and it is estimated that one producer alone has supplied up to 200000 such columns repainting is simpler, even on neglected columns, than on columns not metal sprayed. Aluminium spraying has been used on reflector towers used in the television link between Manchester and Edinburgh, and on similar structures. 

Procedure. Extract a series of aqueous aluminium solutions containing 5-25 mg aluminium in 5 mL, using the procedure described above under Sample. Calibrate the apparatus by injecting 0.30 L of each extract into the column and recording the peak area on the chromatogram. Plot a graph of peak area against concentration. 

Determine aluminium (present as its acetylacetonate) in the sample solution by injecting 0.30 L into the column. Record the peak area obtained and read off the aluminium concentration from the calibration graph (see Note). 

Interfering cations, except aluminium and zirconium, can be removed by passage through an ion exchange column. In the presence of interfering anions and also aluminium and zirconium, fluoride may be separated as hydrofluorosilicic acid by distilling with dilute perchloric acid at 135 °C (temperature maintained by the addition of water) in the presence of a few glass beads. 

For electronic micrographs, samples were taken from fresh beads and 72 hour beads from the ICR column. The samples were dipped into liquid nitrogen for 10 minutes, then freeze dried for 7 horns (EMITECH, model IK750, Cambridge, UK). The sample was fixed on an aluminium stub and coated with gold-palladium by a Polaron machine model SD515... 

An open column packed with neutral aluminium oxide (grade III) slurry is generally used for semi-preparative separation of large amounts of carotenoid extract, revealing three broad bands (1) carotenes and epoxy-carotenes constitute the first fraction to elute with petroleum ether, (2) monohydroxy and keto-carotenoids with 50 to 80% diethyl ether in petroleum ether are next, and (3) finally, the polyhydroxy carotenoids elute with 2 to 5% diethyl ether in ethanol or... 

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