Vacuum dessicator

Transfer the filtrate to a ceramic evaporating dish and heat on a water bath until a crystalline scum forms on the top. Cool the dish quickly then filter the mess on the vacuum Buchner to yield 96g of Methylamine Hydrochloride. Concentrate the filtrate once again to obtain a second crop of crystals, -IQg. Concentrate the filtrate a third time as far as possible using the water bath, then store the dish in a vacuum dessicator loaded with Sodium Hydroxide in the bottom for 24 hours. Add Chloroform to the residue left in the crucible to dissolve out Dimethylamine Hydrochloride (distill off the Chloroform to recover - good stuff) then filter on the venerable old vacuum Buchner funnel to yield an additional 20g of Methylamine Hydrochloride, washing the crystals in the funnel with a small poiiion of Chloroform ( 10mL). 

Yam tubers of Dioscorea alata (Umudike cultivar), D. rotundata (asukwu and obiaturugo cultivars)" and D. cayenensis (water yam and Nkokpu cultivars) were obtained from the National Root Crops Research Institute, Umudike, Nigeria. Some tubers were stored 6 or 12 months at room temperature (25-27 °C), some in vacuum dessicators over a suitable dessicant, and some in paper bags placed in a dark cabinet (absence of circulating air). Fresh tubers were peeled by carefully scraping away the cork layer to minimize loss of outer tissue since much of the protein is concentrated here ( ). They were then cut into 2 cu. cm. pieces, quickly frozen with solid CO2 in 50 9 portions in plastic bags, and stored in a freezer until needed. 

Cleavage and fracture fragments of the mineral and glass phases were reacted separately at 25°, 50°, and 100°C. In order to produce levels measurable by XrS, lxlO 1 molar alkali chloride solutions were required. After reaction, these samples were washed with deionized water and stored in a vacuum dessicator. 

Toxicity Tests. Assays for toxicity were conducted on ICR female mice weighing approximately 20 g each. Animals were maintained on Wayne Laboratory Animal diets (Lab-Blox) and water, ad libitum. A known quantity of toxic extract was dried under a stream of dry nitrogen and placed in a vacuum dessicator overnight. The dried extracts were dissolved in phosphate buffered saline containing 5% Tween 80 and administered intraperitoneally. Control animals received an equal volume of the vehicle. Lethality was assessed at kQ h. 

Vigreux column. When no more methanol distills over (ca. 24 h), the dark brown reaction mixture is reduced in volume by the distillation of 100 mL of toluene. While the flask is still hot, 300 mL of cyclohexane are added with vigorous stirring and a yellow, crystalline solid comes out of solution. At this point, the copious amount of solid makes stirring difficult. The mixture is allowed to stand overnight and the yellow solid is collected by suction filtration. The solid is washed with 2 1 cyclohexane/toluene (ca. 300 mL) and, then cyclohexane and is allowed to air dry. The solid is then dried in a vacuum dessicator (25°C, 24 h) to remove the last traces of N,N-dimethylformamide dimethylacetal (a small amount of sublimation of the product will occur). Failure to completely remove the last traces of N,JV-dimethylformamide dimethylacetal results in the gradual darkening of the product over several months time. Yield 190.3 g (86% based on 2-acetylpyridine), mp 127-128°C. 

D-Glucurono-3,6-lactone (3.0 g, 17.0 mmol) is suspended in concentrated hydrochloric add (3 mL) and shaken with ethanethiol (3 mL) for 30 min at 0°C. The reaction mixture is poured into ice water (6 mL), and the solution is then extracted with ethyl acetate (2 x 30 mL). Evaporation of the extracts yields a thick syrup, which is dissolved in methanol, and again evaporated to a syrup, winch is then dried in a vacuum dessicator. The syrup is again dissolved in methanol (20 mL), and the solution is neutralizai by the slow addition of a concentrated solution of sodium hydroxide in methanol. Scratching the sides of the flask promotes crystallization and the product is collected by filtration and washed with methanol... 

A soln of the above ester (0.15 g, 0.22 mmol) in 90% aq AcOH (19 mL) was treated with Zn dust (0.73 g, 11 mmol). The mixture was stirred at rt for 2h, then filtered through Celite, and dried in a vacuum dessicator over NaOH. The residue was taken up in EtOAc (30 mL) and washed sequentially with 10% aq H3PO4 and H20. The organic layer was dried (MgS04), filtered, and concentrated. The remaining traces of AcOH were eliminated by co-evaporation with CHC13 several times. The desired compound 110 was obtained as a yellow oil yield 0.11 g (94%) [a]D25 +4.5 (c 4.5, CHC13) FAB-MS m/z 543 [M + H]+. 

There was a spontaneous heating and the ether boiled. The mixture refluxed for 2 hours after the completion adding. Then it was poured into mixture of 200 parts of 37% hydrochloric acid and 800 parts (by weight) of ice with stirring. Hydrochloride of a,a-diphenyl-l-piperidinepropanol precipitated. It was filtered off, washed with ether, diluted hydrochloric acid and dried over sodium hydroxide in vacuum dessicator. The colorless crystals were light dissolved in hot water and had MP 216°C. The base is the colorless powder with MP 119-120°C. 

The porous samples used in this study were plugs made up from fine glass powder of a few microns in diameter so as to give a non adsorptive, simply-structured medium. They were formed by compressing the powder with a small amount of moisture in a brass cylinder and leaving for several days at room temperature, after which they were dried under mild conditions. Final drying and desorption is carried out in a vacuum dessicator. The appropriate physical properties of a porous sample are given in Table 1. 

Diphenyl Tellurium Difluoride1 in a plastic beaker 1.39 g (4.7 mmol) of diphenyl tellurium oxide are dissolved in 500 m/ of water kept at 60°. The solution is cooled to 20°, 40% hydrofluoric acid is added dropwise to the stirred solution until a pH of 1 - 2 is reached, and the mixture is stirred for a further 20 min. The precipitate is filtered using a plastic funnel, the filter cake is pressed between thick layers of filter paper, the product is dried in a vacuum dessicator, and than recrystallized from methanol yield 0.9 g (60%) m.p. 153°. 

Diphenyl Tellurium Dinitrate1 In a beaker are placed 5 g (18 mmol) of diphenyl tellurium, 20 ml of halide-free nitric acid (d = 1.2) are added, and the initially exothermic reaction is allowed to subside. The mixture is then heated on a boiling water bath for 10 min, the remaining nitric acid is allowed to evaporate in a vacuum dessicator over potassium hydroxide, and the solid residue is recrystallized from chloroform m.p. 160°. 

Tris[2-thienyl] Telluronium Bromide3 2.2 g (4.8 mmol) of bis[2-thienyl] tellurium dibromide are added to a Grignard solution prepared from 1.7 g (10 mmol) of 2-bromothiophene in 50 ml of diethyl ether. The mixture is heated under reflux for 2 h, cooled, added to 15 ml of water, and filtered. The filter cake is washed with water and dried in a vacuum dessicator. The dry product is extracted with a large volume of methanol and the product precipitated by concentration of the extract m.p. 244° (253° corrected). 

A solution of the antidine (6) (5.0g, 23.2mmol) in 95-97% formic acid (10 ml) is heated in an oil bath at 70 -80°C (20 h). After removal of the solvent in vacuo, benzene is added to the residue, and the mixture is evaporated to dryness (repeat three times). The residue is dissolved in water (9 ml), and solid sodium carbonate is added to raise the pH to 8. The aldehyde precipitates immediately. After cooling the mixture overnight in a refrigerator the product is obtained by filtration and dried in a vacuum dessicator to give (5) (2.21 g, 99%). Sublimation at 80-90°C and 2mmHg pressure gives the pure aldehyde, m.p. 204-205°C. 

Record your yield and store the brown product in a vacuum dessicator. 

Filter the yellow product and wash with two 10 ml portions of absolute ethanol and suction dry. Dry in a vacuum dessicator overnight and store product under N2(g) and in the dark at — 20 °C until needed. 

Matheson Gas Products) was used as the carrier gas. Substrates were prepared by vapor deposition of an opaque layer of aluminum on glass microscope slides. Polymer film thicknesses were determined by measuring the step height between a masked and unmasked portion of the specimen with a Rank, Taylor, and Hobson Talystep 1 traversing stylus. Deposited films were stored in a vacuum dessicator prior to measurement of the infrared spectra in order to minimize the absorption of moisture from the atmosphere. 

Anhydrous sodium sulphate (BDH Analar grade or equivalent) was roasted in a muffle furnace at 650°C, cooled and stored in a vacuum dessicator. Reagent grade Florisrl was activated at 650 °C in a muffle furnace, cooled and stored in a vacuum dessicator. Before use, it was deactivated with deionised water (8. 5% v/v) and mixed for 1 hour in a stoppered glass bottle on a ball-mill roller. 

The product was dried in a vacuum dessicator over silica gel to constant weight. After optimisation of sulfonation conditions, all graft copolymers for ion exchange experiments were sulfonated at 90 for 45 minutes. 

A catalyst was prepared by impregnating a sample of alumina with a solution of sodium tungstate and mixing with the aid of ultrasonic agitation. The sample was dried in a vacuum dessicator ( 4 hour) and in air at 90°C (1 hour). Concentrated nitric acid (10 mL) was added and the beaker warmed on a hot plate for 5 minutes and the solid was then washed with 1M nitric acid by decantation. To remove sodium nitrate, 1M nitric acid (250 mL) was added, the catalyst digested for 1 hour on a hot plate and the nitric acid decanted. This washing was repeated three times and the catalyst dried at 150-160°C. 

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