Beakers: glass polypropylene

Notes. (1) The use of sodium fluoroborate solution supersedes the less convenient fluoroboric acid and permits the preparation to be carried out in ordinary glass vessels. If it is desired to employ fluoroboric acid HBF4, it can be prepared by adding 100 g of AR boric acid in small proportions to 325 g of AR hydrofluoric acid (40% HF) cooled in ice the hydrofluoric acid is contained in a polypropylene beaker, in a beaker coated with wax or in a lead vessel. One-third of the above solution should be employed in the preparation. Handle with great care. 

Use. It is important to wear gloves and safety glasses and to work in a fume hood If you do not have all of these items for safe use of HF, do not use HF as a cleaning material Pour the diluted HF from its plastic storage container into a plastic soaking tank (like a polypropylene beaker). Let the glassware soak in the HF for anywhere from 30 seconds to two minutes. Rinse for at least one minute (or five full flushes) with water. Then rinse with distilled or deionized water. The HF can be reused many times until a decrease in effectiveness is obvious. 

The reaction mixture was prepared as follows 0.31 g of AI(OH)3 (98%, J.T.Baker), 0.3 g of sodium hydroxide (p.a., Janssen) and 1 g of deionized water were put into a 60 ml glass beaker and brought to the boil under stirring until a clear solution resulted. Then 9.26 g of tetraethylammonium hydroxide solution (TEAOH, Merck, 20 wt % solution in water) were added and the solution was cooled. In a separate 400 ml polypropylene beaker 9.26 g of Ludox AS-40 (Du Pont, 40 wt % colloidal silica in water) were stirred with a magnetic stirrer (at ca 600 rpm). 

The polyethylene or polypropylene film, (5.0 g precut into strips approximately 1 in X 1 in) is weighed into the extraction thimble, 130 ml of the extraction solvent and a few glass beads are added to the 250 cm flat bottomed flask, the extraction apparatus is connected and heated to boiling. After 3 h the system is allowed to cool to room temperature and the solvent drained into the 250 cm flat bottom flask. The extraction thimble and extraction apparatus are rinsed down with 25 - 30 cm of the extraction solvent and drained into a 250 cm flask. TTie contents of the 250 cm flask are quantitatively transferred to a 250 cm Pyrex glass beaker and concentrated to a 25 - 30 cm volume by evaporation on a hot plate then quantitatively transferred to a 50 cm beaker, concentrated to 6 - 7 ml, and transferred to a 10 cm volumetric flask and diluted to volume with the extraction solvent. 

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