Suspension, evaporative cooling sampling

Sample Solution Fill a 100-mL porcelain crucible halffull of ashless filter paper pulp. Place 2 g of the finished catalyst, in droplet or flake form and accurately weighed, on top of the paper pulp. Transfer the crucible to a muffle furnace set at room temperature, and slowly raise the temperature to 650° so that the stearine melts into the paper, and the organic mass bums and chars slowly. Continue heating at 650° for 2 h or until the carbon is burned off. Cool, add 20 mL of hydrochloric acid, quantitatively transfer the solution or suspension into a 400-mL beaker, and carefully evaporate to dryness on a steam bath. Cool, add 20 mL of hydrochloric acid, warm to aid dissolution (catalysts containing silica will not dissolve completely), transfer into a 500-mL volumetric flask, dilute to volume with water, and mix. Allow any solids to settle, pipet a clear, 50-mL aliquot into a 400-mL beaker, and dilute to 250 mL with water. (If there is suspended matter in the volumetric flask, filter a portion through a dry, medium-speed filter paper into a dry receiver, and pipet from the receiver.)... 

A 1.2-mL sample of Sn(SC5H5)(n-C4H9)3 (1.40 g, 3.5 mmol) is added to a suspension of 0.81 g (1.64 mmol) Mn2( i-Br)2(CO)8 (ref. 4) in 30 mL of freshly distilled THF in a 100-mL flask equipped with N2 inlet, stirrer, and dropping funnel. This mixture is stirred at ambient temperature under nitrogen for 1 hr then the volume of solvent is reduced by evaporation in vacuum to 3 mL. Cooling this solution to -15° causes orange crystals of the product to precipitate. These crystals are collected by filtration, washed twice with cold (0°) hexane, and allowed to dry in air. Yield 0.85 g, 94%. Recrystallization of the material can be carried out using hexane as a solvent. 

A suspension of 28.5 g. (0.098 mole) of 2-(4-bromophenethyl)-benzyl alcohol in 150 mL. of 48% hydrobromic acid is stirred at reflux for 3 hours. The cooled two-phase mixture is extracted with benzene. Evaporation of the washed and dried benzene extract under reduced pressure leaves the product as the residual solid, m.p. 63°-75° C. Recrystallization from hexane affords purified material, m.p. 76°-77.5° C. A sample for analysis melts at 76.5°-78° C. after further recrystallization from hexane. Source Christy 1976... 

Procedure. The reaction is conducted in a quartz crucible. A small portion of the powdered sample is treated with about 5-10 times the quantity of zinc chloride and a drop of water. After evaporation, the crucible is covered and the contents heated for five minutes over a bare flame. The cooled mass is stirred with a drop or two of hot water, the suspension is transferred to a conical tube, and centrifuged. One drop of the clear liquid is treated with a drop of a 1 % aqueous solution of sodium tetraphenyl borate. If potassium is present, a white precipitate or turbidity appears. 

Ethyl Cellulose. Pretreated cellulose (100 g) was charged into a two liter stirrer pipe bomb, combined with NaOH (80 g, 2.0 M), ethyl chloride (250 g, 4.0 M) and 300 mL toluene and the mixture was heated to 130 for two hours. After cooling to 5 , the bomb was opened, excess ethyl chloride was allowed to evaporate and the residue poured into two liters of water. The toluene was steam distilled from the suspension and the ethyl cellulose was recovered by filtration. Approximately 46 g of ethyl cellulose, D.S. = 1.56, was obtained. A sample of ethyl cellulose prepared under identical conditions except omitting the catalyst was obtained in reduced yield (21 g) due to the higher water... 

---