Buchner filters

This method can also be used to analyse soil samples. For instance, fenpropi-morph, which is a non-polar pesticide with good UV sensitivity but poor selectivity, has, after treatment, been determined in soil samples (31). In this example, an amount of soil was extracted overnight with acetonitrile this was then poured into a Buchner filter and rinsed with the same solvent. The acetonitrile solution was concentrated and, prior to LC analysis, the extract was diluted with water and 100 p.1 were then injected into the LC system. 

The resulting suspension is placed in a round flask equipped with a scraper-agitator device, and agitation is effected for 48 hours in an ice water bath. The antibiotic is isolated from the mother liquor by filtration through a Buchner filter. The filter cake is washed with 5 liters of a methyl alcohol and water mixture (1/2.5 by volume) cooled to 4°C. After drying in an oven at reduced pressure, 2.805 kilograms of a greyish-yellow crude product is obtained. 

The solid is collected on a Buchner funnel and washed with three 30-cc. portions of cold water. The alloxantin is dissolved by boiling the wet solid for fifteen minutes with 250 cc. of water, and the hot solution is filtered to remove the sulfur (Note 2). Alloxantin dihydrate crystallizes from "the filtrate in glistening plates which should be pressed as dry as possible on a Buchner filter, washed with about 30 cc. of ether, and dried in a vacuum desiccator (Note 3). The yield is 8-10 g. (55-69 per cent of the theoretical amount) (Note 4). The product melts with decomposition at 234-238° (Note 5), and is pure enough for most purposes. 

Special Buchner funnel cleaning alert. The standard ceramic Buchner funnel is not transparent, and you can t see whether or not the bums who used the funnel the last time to collect a highly colored product, didn t clean the funnel properly. The first time you Buchner filter crystals from an alcohol solution, the colored impurity dissolves, bleeds up into your previously clean crystals, and you may have to redo your entire experiment. I d rinse the Buchner funnel with a bit of hot ethanol before I used it, just for insurance. 

Wash 10 mL of sedimented 6% crosslinked agarose with distilled water on a glass or Buchner filter and remove excess water by suction. 

Filter the avidin-agarose matrix (from Section 3 3.1., step 6) on a glass or Buchner filter (or pack in a column) and wash four times with 2 vol of 6M guanidine HC1 in 0.2MKC1, pH 1 5, to dissociate the tetramenc avidin... 

Caution should be exercised in evaporation of the ether, as the di tert-butoxy compounds are appreciably volatile at reduced pressure. If a rotary evaporator is used for the concentration, the water bath should be kept at or below room temperature, and the residue should not be pumped after it is clear that the bulk of the ether has been evaporated. The submitters report ca. 130 g of oily residue at this stage. Treatment of the oily residue with 105 mL of ether leads to partial crystallization. During washing of the crystals in a Buchner filter with more ether, an almost complete solubilization takes place, but eventually 0.1-0.5 g of cis-2,3,7,10-tetraoxabicyclo[4.4.0]decane remains as an insoluble residue. This compound... 

A first step involves the preparation of 2-cyano-6-methoxynaphthalene (cyanonerolin). 90 g of 2-bromo-6-methoxynaphthalene are heated with 60 g of cuprous cyanide in a metal bath at 240° to 250°C stirring for one hour. At the instant when the cuprous cyanide begins to react and dissolves, the mass turns brown, liquefies and heats up strongly. The molten mass is poured onto a cold surface, is pulverized and sifted. This powder is treated with dilute ammonia (1 liter of water to 300 cc of commercial ammonia solution). The solution is filtered on a Buchner filter and the precipitate that remains on the filter is washed with dilute ammonia and then with water. 

A mixture of 3.2 parts 4-chloro-p-fluoro-butyrophenone, 3.5 parts l-oxo-4-phenyl-2,4,8-triazaspiro(4,5)decane, 2 parts Na2C03 and 0.1 part KI in 200 parts hexone is refluxed with stirring for 50 hours. The mixture is cooled to room temperature, 200 parts water are added and the layers are separated. The organic layer is dried over 10 parts MgS04, filtered and the solvent removed under reduced pressure on the water bath. The residue is treated with 50 parts diisopropylether. The precipitate is filtered on a Buchner filter and recrystallized from 20 parts hexone at room temperature. The solid is filtered off and dried to yield l-oxo-4-phenyl-8-[3-(4-fluorobenzoyl)-propyl] -2,4,8-triazaspiro(4.5)decane, melting point 190° to 193.6°C, as a light brown amorphous powder. 

Filter the resin using a large glass sintered (small pore size) Buchner filter (this can take a fairly long time ). 

Filter crucible and Buchner filter assembly Procedure... 

One drop of concentrated sulfuric acid is added to a mixture of 110 g. (1.0 mole) of hydroquinone and 206 g. (190.3 ml., 2.02 moles) of acetic anhydride (Note 1) in a 1-1. Erlenmeyer flask. The mixture is stirred gently by hand it warms up very rapidly, and the hydroquinone dissolves. After 5 minutes the clear solution is poured onto about 800 ml. of crushed ice. The white crystalline solid which separates is collected on a Buchner filter and washed with 1 1. of water. The filter cake is pressed occa-... 

According to the Industrial Filtration Corporation the rotary filter is indicated when the slurry will permit a cake K in. or more in thickness to build in 2 to 3 minutes when poured into a Buchner filter under 25 in. of suction. 

Other glassware used are several 500 ml Erlenmeyer flasks, about 5 pieces of plain (not Pyrex) glass tubing about three feet long, and a Buchner filtering funnel with the filtering flask it fits into. 

The precipitated polymer (white solid) is filtered using a Buchner filter and dried under vacuum. 

Add the sintered-glass funnel to the Buchner filter system and attach the vacuum source. Fill the funnel to a depth of 2 cm using anhydrous silica. Filter the aqueous polymer solution through the silica. A blue colour will appear, indicating the Cud I) species that is formed in the presence of oxygen. The solution of polymer must be freeze-dried overnight to remove all water and leave a white solid polymer product. Yields >90% are typical. 

To a mixture of amine (2 mmol) and 2,5-heaxanedione (1 mmol), under stirring and at room temperature (or 60 °C), catalyst (12 mol% for a-Zr(KP04)2 or 6 mol% for a-Zr(CH3P03)i.2(03PC6H4S03H)o 8) was added. After an appropriate time the reaction was diluted with dichloromethane, filtered on a Buchner filter and washed with a 5% HC1 solution to remove the excess amine. The organic solution was evaporated under vacuum and afforded the pyrrole derivative with good purity. 

---