Form filter

Prepare the neutral ferric chloride solution (i.e., free from hydrochloric acid) by adding dilute sodium hydroxide solution dropwise to the bench reagent until a slight precipitate of ferric hydroxide is formed. Filter off the precipitate and use the clear filtrate for the test. 

Strongly acidify the residual sodium bicarbonate solution to Congo red with dilute sulphuric acid. If a sohd acid forms, filter. Extract the filtrate or the acidified solution with two 20 ml. portions of ether keep the aqueous solution A). Distil off the ether, and add the residual acid (if a sohd) to the solid separated by filtration. Identify the acid. 

Since 1980, a number of new filters have appeared on the market, utilising some form of mechanical compression of the filter cake, either after a conventional pressure filtration process or as a substitute for it. In most designs the compression is achieved by inflating a diaphragm which presses the slurry or the freshly formed filter cake toward the medium, thus squee2ing an additional amount of Hquid out of the cake. 

Benzenedimethanol (1,2-bishydroxymethylbenzene) [612-14-6] M 138.2, m 61-64 , 63-64 , 64-65 , 65-66.5 , b 145 /3mm. Recrystd from C6H6, H2O, pet ether or pentane. It has been extracted in a Soxhlet with Et20, evaporated and recrystd from hot pet ether. Also dissolve in Et20, allow to evaporate till crystals are formed, filter off and wash the colourless crystals with warm pet ether or pentane. The diacetate has m 35 , 35-36 . [J Am Chem Soc 69 1197 1947, IR and UV J Am Chem Soc 74 441 7952.]... 

C for 6 hours, and allow the solution to stand for 24 hours. If a precipitate forms, filter through a Whatman No. 42 filter paper. This reagent has good keeping qualities and no precipitation should occur for at least 3 months. 

Fluid-loss additives Form filter-cake reduce leak-off in formation if thickener is not sufficient... 

The re-filtration technique of La Mer (3) involves filtering the flocculated suspension and then passing the filtrate once more through this pre-formed filter cake. 

Method A. A slurry of 3.15 g d-lysergic acid monohydrate (monohydrate means dry) and 7.3 g of diethylamine (or 0.1 mole of similar amine) in 150 ml of pure chloroform is heated to reflux. After the lysergic acid is dissolved (a few min) cool the mixture down to where reflux has stopped by removing the heat. Before the mixture cools any further 2 ml of phosphorous oxychloride is added at such a rate as to give reflux (about 2 min). After addition, reflux for 4-5 min further until an amber-colored solution results. Cool to room temp and wash the mixture with 200 ml of 1 M ammonium hydroxide. The chloroform solution was dried with MgSC>4 (this would have to be after separation), filtered, and concentrated by evaporation in vacuo under a temp of 38° (at no time let the temp go over 40°). The last traces of solvent are removed at 2-5 mm. Dissolve the residue in a minimum amount of methanol and acidify with freshly prepared solution of 20% maleic acid in methanol (not aqueous) to precipitate the LSD in its maleate form. Filter the fluffy white needles, wash with cold methanol and air dry to get 2.2 g of LSD that requires no further purification. 

Put 6 g of indole-3-acetic acid into 250 ml of ether and add 3 g of piperidine (or any other equimolar amount of suitable primary amine) in 20 ml of ether. Mix gently for a little while and allow to stand to form precipitate. After all the precipitate has formed, filter it off and heat 7... 

Phenyllithium in ether solution can be directly analyzed after addition of excess triph-enyltin chloride. An insoluble precipitate of tetraphenyltin is formed, filtered, washed, dried and weighed . This method affords a large amplification factor for phenyllithium. 

Rechler, in 1883, obtained a compound containing ammonia which was assumed to be the monammine, by adding aqueous ammonia to a solution of silver nitrate until a precipitate is formed, filtering off the... 

C and then treated with hydrogen chloride gas for 25 minutes with moderate stirring during which lime the temperature exothermed to 67°C. The dark brown batch was then cooled to ambient temperature and a beige suspension which formed filtered. The crude product was washed eight times with 1 liter of 2 12 and the product isolated in 97.2% purity in 33.6% yield. 

Rhombic Sulphur. Pour 4-5 ml of chloroform into a dry test tube in a fume cupboard ) and spill in a sulphur powder in small portions, shaking the contents of the tube, until a saturated solution forms. Filter the solution into a porcelain bowl (do not wet the filter with water, why ), cover it with a glass, and let it stand in the fume cupboard for slow evaporation. Put a drop of the solution on a slide, cover it with a cover glass, and observe under a microscope how the crystals grow. Draw the sulphur crystals. 

The precipitate is filtered off, and the clear liquid concentrated, when a fresh deposit of meoonate of time will be formed. Filter again, wash the precipitate on the filter with a little cold water, and add the wasliings to the filtrate. This is now evaporated down to the consistence of sirup, and allowed to stand for some days. There is then obtained a crystalline mass— a double salt of morphin and codoin—and a dark mother-liquor, containing an acid meoonate of lime, a little morphin, and the narcetn, meoorun, narcotin, and paramorphin. 

To rccrystallize the unknown lipid, dissolve the crude residue in a minimum amount (about 20 mL) of warm acetone on a steam bath (Hood ). After slow cooling of the acetone solution to room temperature and then in ice to allow crystals to form, filter by suction, and wash the solid product with icc-cold acetone. A typical yield is about 0.5 g of purified lipid. Save the purified lipid for characterization. 

Oxodecanoic acid. Dissolve 4.0 g of 3-carboxy-3,4-dibromodecanoic acid in 60 ml of 2m sodium hydroxide solution and heat the solution at 80-90 °C for 2 hours. Cool to room temperature and acidify with dilute sulphuric acid carbon dioxide is evolved and a white precipitate is formed. Filter the precipitated keto acid from the cold solution and recrystallise from light petroleum (b.p. 40-60 °C). 4-Oxodecanoic acid, m.p. 68-69 °C, is obtained the yield is 1.6 g (80%). The infrared spectrum shows absorptions at 3400-2400 cm-1 (OH stretch of COzH) and 1700 cm-1 (0=0). 

Small Quantities. Wear eye protection, laboratory coat, and nitrile rubber gloves. In the fume hood, add the solid dichromate to a container of water (about 100 mL/5 g). Acidify with 3 M sulfuric acid (about 40-60 mL). Slowly, and while stirring, add solid sodium thiosulfate (about 15 g) until the solution becomes cloudy and blue colored. Neutralize the solution with sodium carbonate. After a few minutes, a blue-gray flocculent precipitate is formed. Filter immediately through Celite or let it stand for a week, when much of the supernatant can be decanted. The remaining liquid is allowed to evaporate or is filtered off. The liquid can be washed into the drain. The solid residue should be washed with hot water to remove sodium sulfate, and then dried, packaged, labeled, and sent to a secure landfill site.9,10... 

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