Crystal washing

NHjCONHNHj.HCl) and 1-5 g. of crystallised sodium acetate in 10 ml. of water in a test-tube. Add 1 ml. of acetone, close the tube with a cork and shake vigorously. Allow the mixtme to stand, with occasional vigorous shaking, for 10 minutes it is advantageous to cool in ice. FUter the crystals, wash with a httle cold water, and recrystaUise from water or dilute alcohol. The m.p. of acetone semicarbazone is 187°. 

D. Now the ether will be a deep reddish yellow. Distill off the ether...quack...and take the temp up to 170 C to drive off any other volatiles. Should recover 90%+ of the original weight of oil. Now add 500 ml of saturated bisulfite and stir for 1.5 hours...Quack Vacuum Filter, the duck fat crystals Wash with water and ether, yield dull fine ppt in the filter cake...stable bisulfite addition product...can be stored forever...QuackU Yield -50 to 80% depending on a ducks technique ... 

Scale-up depends on the mechanical complexity of the crystal-transport system and techniques for removing heat. Vertical oscillating spiral columns are likely limited to about 0.2 m in diameter, whereas horizontal columns of several meters are possible. Scale-up is limited by design of melter and/or crystal-washing section. Vertical or horizontal columns of several meters in diameter are possible. 

Lead diethyidithiocarbamate [17549-30-3] M 503.7, pKj 3.36 (for A,A-diethyldithio-carbamate). Wash with H2O and dry at 60-70°, or dissolve in the min vol of CHCI3 and add the same vol of EtOH. Collect the solid that separates and dry as before. Alternatively, recryst by slow evaporation of a CHCI3 soln at 70-80°. Filter the crystals, wash with H2O until all Pb ions are eluted (check by adding chromate) and then dry at 60-70° for at least lOh. [Justus Liebigs Ann Chem 49 1146 1977.]... 

To a suspension of 500 mg of 6a-fluoro-triamcinolone in 75 ml of acetone is added 0.05 milliliters of 72% perchloric acid and the mixture agitated at room temperature for 3 hours. During this period the crystals gradually dissolve and the clear solution is neutralized with dilute bicarbonate and the acetone removed in vacuo. The resulting crystalline suspension is filtered and the crystals washed with water. The dried material is recrystallized from 95% alcohol to give the pure acetonide. 

In dim red light, the weighed hydrazide contained in one of the 500 ml flasks (ca. 67 g 95% of theory) is washed into a 1000 ml beaker with 263 ml IN hydrochloric acid. 239 ml distilled water, 239 ml ethanol (95%), and 37 ml 2,4-pentanedione are added, and the well-mixed solution left to stand in the dark at room temperature until the reaction is complete, i.e., about 30 minutes. The reaction mixture is neutralized with the addition of 263 ml 1 N sodium hydroxide, and the beaker covered with parafilm and refrigerated to ensure complete precipitation. The pyrazole is filtered at the pump, the mother liquor being returned to the beaker and used to wash out the last few crystals, washed with cold water, and sucked dry under a stream of dry nitrogen. The product is dried in vacuo over barium oxide or phosphorus pentoxide for at least twelve hours before proceeding to the next step, wherein anhydrous conditions will increase yield. Hofmann calls for drying the pyrazole in vacuo at 60°, which indicated the product to be fairly stable. So all the hydrazide is converted prior to aminization. 

Write the formulas of the substances called soda crystals (washing soda), calcined soda, baking soda, and caustic soda. 

Copper(I) Bromide. Prepare 10 ml of a 20% aqueous solution of coppep(II) bromide, heat it, and pass into it a stream of sulphur dioxide. What substance precipitates Filter off the crystals, wash them with water, and dry them in a vacuum desiccator over potassium hydroxide. 

Preparation of a Complex Ammonium Salt of Copper(II). Dissolve 0.5 g of finely triturated copper(II) sulphate pentahydrate in 12.5 ml of a 15% ammonia solution. If the solution is turbid, filter it. Slowly add 7.5 ml of ethanol to the filtrate and let it stand for a few hours in the cold. Filter off the formed crystals, wash them first with a mixture of ethanol and a concentrated ammonia solution (1 1), and then with ethanol and ether. Dry them at room temperature. Into what ions does the product dissociate in the solution Consider the structure of the complex ion from the viewpoint of the valence bond theory. 

Alternatively, recryst by slow evaporation of a CHCI3 soln at 70-80°. Filter the crystals, wash with H2O until... 

Dissolve 20 g. of cuprous chloride, CuCl, in the least possible volume of concentrated hydrochloric acid. Cool the solution in ice and slowly add 500 cc. of concentrated ammonia. Keeping the temperature at 0°, add 55 g. of carbon disulfide and shake vigorously at frequent intervals. After standing some 6 days in an ice box at approximately 0°, shining green crystals of the thio-carbonate separate from the solution. Filter off these crystals, wash them with cold water, and quickly dry them on paper. The potassium salt can be made with slight modifications of these directions. 

SODIUM CARBONATE Na,C03 10RO Na,C03-H20 sal soda, crystal washing soda concentrated washing soda Grocery Grocery... 

---