Crystallization crystal collection

Bis-acrylamide (Af,Af -methylene bisacrylamide) [110-26-9] M 154.2, m >300 . Recrystd from MeOH (lOOg dissolved in 500mL boiling MeOH) and filtered without suction in a warmed funnel. Allowed to stand at room temperature and then at -15°C overnight. Crystals collected with suction in a cooled funnel and washed with cold MeOH). Crystals air-dried in a warm oven. TOXIC. 

Hostomsky, J., 1987. Particle size distribution of agglomerated crystal product from a continuous crystallizer. Collection of Czechoslovakian Chemical Communications, 52, 1186-1197. 

The most widely employed thermal reduction process for preparing Mg metal uses PeSi as reducing agent. Mixtures of the substrate, usually calcined dolomite (i.e., MgO, CaO) and PeSi are fabricated into briquettes with a hydrocarbon binder and loaded into Ni-Cr steel (15/28) retorts. After evacuation the retort is subjected to a temperature gradient Mg distills from the hot mixture (at 1150°C) and high-purity Mg crystals collect at the water-cooled end of the retort ... 

The solubility of uric acid depends on concentration and temperature. At high serum concentrations, lower body temperature causes the precipitation of monosodium urate crystals. Collections of these crystals (called micro tophi) can form in joint spaces in the distal extremities. 

This was dissolved with Et20 (82 mL), cooled slowly to —30 °C and kept at that temperature for 6 h. Mother liquor was decanted off under suction and the crystals collected were rinsed twice with cold Et20. The crystals were directly dried in vacuo without any washing to afford (f )-3-benzyloxy-2-methylpropane-l,2-diol (2.1 g, 52 % recovery) as colorless fine needles m.p. 30-31 °°C. 

One deduces the space group from the symmetry in the crystal s diffraction pattern and the systematic absence of specific reflections in that pattern. The crystal s cell dimensions are derived from the diffraction pattern for the crystal collected on X-ray film or measured with a diffractometer. An estimation of Z (the number of molecules per unit cell) can be carried out using a method called Vm proposed by Matthews. For most protein crystals the ratio of the unit cell volume and the molecular weight is a value around 2.15 AVOa. Calculation of Z by this method must yield a number of molecules per unit cell that is in agreement with the decided-upon space group. 

Wikoff, W. R., Schildkamp, W. and Johnson, J. E. (1997). Increased resolution data from a large unit ceU crystal collected at a third-generation synchrotron X-ray source. Acta Crystallogr. D 56, 890-893. 

G. G. Lemmlein, Morphology and Genesis of Crystals, Collected Papers ofC. G. Lemmleim, Moscow, Nauk, 1973 (in Russian)... 

Filter off the precipitated crystals, collect them (carefully, hydro-xylamine is poisonous ), weigh them, and calculate the yield in per cent. Examine the shape of the crystals under a microscope. Write the equations of the reactions. 

N-[2-Hydroxyethyl]ethylenediaminetriacetic acid [150-39-0] M 278.3, m 212-214 (dec). Crystd from warm H2O, after filtering, by addition of 95% EtOH and allowing to cool. The crystals, collected on a sintered-glass funnel, were washed three times with cold absolute EtOH, then again crystd from H2O. After leaching with cold H2O, the crystals were dried at 100° under vacuum. [Spedding, Powell and Wheelwright JACS 78 34 1956]. 

A copious white crystalline precipitate soon settles from the anode to the bottom of the tube T. After an hour or so, interrupt the process, decant the electrolyte from the crystals, collect them on a small filter in a Gooch crucible, wash them with alcohol using a pump, and dry them in air. The decanted solution may be used for another run. 

C) dl-Isoleucine.—One hundred and fifty grams (0.77 mole) of a-bromo-/3-methyl valeric acid is added to 645 cc. of technical ammonium hydroxide (sp. gr. 0.90) in a 1.5-I. round-bottomed flask. A stopper is wired in and the flask allowed to stand at room temperature for a week (Note 9). The stopper is removed and the mixture heated on a steam cone overnight to remove ammonia. The aqueous solution is concentrated under reduced pressure until bumping becomes violent (about 300 cc.). The mixture is then cooled to 150 and the crystals collected on a filter. The crystals are washed with 40 cc. of alcohol and dried. The filtrate is again concentrated to about 150 cc. and a second crop of crystals obtained. This second crop is washed with 25 cc. of water and then with 25 cc. of 95 per cent alcohol. The yield of crude product is 65 g. 

A soln of Z-Aiyr(Mom)-OH [50, R1 = Mom obtained by hydrolysis of (Z)-49 with 1M LiOH in di-oxane] (0.2 g, 0.56 mmol) and SOC1, (2 mL, 27 mmol) in dry Et,0 (2 mL) was stirred below 0 °C for 1.5 h. The soln was concentrated under reduced pressure and the residue was dissolved in CC14 (6mL) and again concentrated. The procedure was repeated three times. Finally, the crystals collected were washed with warm CHC13 and then recrystallized (dioxane) to give H-ATyr(Mom)-NCA as colorless prisms yield 17% mp 148-149 °C. 

Preparation of Trinitrostilbene. To 10 grams of TNT dissolved in 25 cc. of benzene in a 100-cc. round-bottom flask equipped with a reflux condenser, 6 cc. of benzaldehyde and 0.5 cc. of piperidine are added, and the mixture is refluxed on the water bath for half an hour. The material, while still hot, is poured into a beaker and allowed to cool and crystallize. The crystals, collected on a filter, are rinsed twice with alcohol and recrystallized from a mixture of 2 volumes of alcohol and 1 of benzene. Brilliant yellow glistening needles, m.p. 158°. 

C), chilled on an ice bath and the crystals collected and recrystallised and stored as described above. 

As in Experiments 12 and 13 the solid effervesces in the concentrated sulphuric acid and the gas evolved fogs the breath (even more markedly in this case), turns litmus red, and gives a dense smoke with ammonia. When the tube is warmed, the beautiful purple iodine vapor is seen inside and nearly black crystals collect on the cooler upper walls. Lead acetate paper is colored dark brown. Sometimes a powdery light yellow substance (sulphur) is seen collecting on the walls of the tube. 

The diuretic property of celery has been used to prepare herbal medicine (Houghton, 1995). The ripe seeds, herb and root are diuretic (Lust, 1983 Chiej, 1984 Grieve, 1984). The seeds are used mainly as a diuretic and can help clear toxins from the system, especially in cases of gout where uric acid crystals collect in the joints. Root tinctures have been used to cure urinary disorders, such as urinary stones, and used as a kidney stimulant and cleanser. Fresh juice from the whole plant is also used as a cure for urinary tract inflammations and urethritis (http //www.innvista.com/health/herbs/ celery.htm). The herb is used against kidney complaints (Launert, 1981). 

Tetramethylcyclopropylcarbonylchloride (0.093 mol) was added dropwise to 100 ml 25% ammonium hydroxide at ambient temperature and stirred overnight. The mixture was then treated with 100 ml water and extracted twice with 200 ml CH2C12. The extract was washed with a carbonate buffer solution, dried, and concentrated. The residue was treated with 100 ml CHCl3/fte t.a e and crystals collected by filtration. The crystals were washed with hexane and the product isolated in 76% yield as a white solid, mp = 90°C... 

A mixture of m-cyanoaniline (8.46 mmol) and diethylethoxylene malonate (9.13 mmol) were stirred at 100-110 °C 1 hour. The solution was cooled, pale yellow crystals collected, and the product isolated in 100% yield, mp = 109-111 °C. 

Production, isolation and purification Primary sequence from protein or cDNA Growth of suitable crystals Collection of diffraction intensity data ... 

Recrystallized preparations of acrylamide are available commercially or may be prepared as follows. Dissolve acrylamide (70 g) in 1 liter chloroform at 50°C. Filter the solution hot and cool it to —20°C to bring about crystallization. Collect the crystalline acrylamide in a chilled Buchner funnel, wash with chilled (—20°C) chloroform and/or heptane, and dry. Additional discussion of the purification of reagents used for electrophoresis may be found elsewhere (35,36). 

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